Organoclay compositions for drilling fluids useful to provide substantially constant rheology profiles to such fluids over a wide temperature range

FIELD OF THE INVENTION

The present invention relates to a method to provide a drilling fluid additive including an organoclay composition wherein a phyllosilicate clay is exchanged with a quaternary ammonium ion having one or more branched alkyl substituents.

BACKGROUND OF THE INVENTION

Drilling fluids have been used since the very beginning of oil well drilling operations in the United States and drilling fluids and their chemistry are an important area for scientific and chemical investigations. Certain uses and desired properties of drilling fluids are reviewed in U.S. Patent Application 2004/0110642 and 2009/0227478 and U.S. Pat. Nos. 7,345,010, 6,339,048 and 6,462,096, issued to the assignee of this application, the entire disclosures of which are incorporated herein by reference.

Nevertheless, the demands of the oil-well drilling environment require increasing improvements in rheology control over broad temperature ranges. This becomes particularly true, for example, as the search for new sources of oil involves greater need to explore in deep water areas and to employ horizontal drilling techniques.

SUMMARY OF THE INVENTION

In one embodiment, the present disclosure provides a method to provide a substantially constant rheological profile of an oil-based drilling fluid over a temperature range of about 120° F. to about 40° F. by using an organoclay composition as a drilling fluid additive. The organoclay composition may comprise: a phyllosilicate clay; and quaternary ammonium ions having a formula of [N—R¹R²R³R⁴]⁺ wherein one or more of R¹, R²and R³is a mixture of branched alkyl groups, each branched alkyl group having 12 to 22 total carbon atoms, a linear backbone and one or more C₁to C₃branching alkyl groups, wherein the branching alkyl groups are distributed at different carbon positions along the linear backbone of the branched alkyl group; and wherein when one or more of R²and R³are not branched alkyl groups, one or more of R²and R³are a first linear alkyl group having 1 to 22 total carbon atoms. R⁴is selected from the group consisting of: a second linear alkyl group having 1 to 6 carbon atoms, an aryl group, and combinations thereof. In some embodiments, each branched alkyl group has 12 to 18 total carbon atoms. In some embodiments, each branched alkyl group has 14 to 18 total carbon atoms. In some embodiments, one or more of R²and R³are each a first linear alkyl group having 12 to 22 total carbon atoms; 1 to 6 total carbon atoms or 7-11 total carbon atoms. In some embodiments, R⁴is independently a benzyl group, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group or a hexyl group. In some other embodiments, one or more of R²and R³are methyl and R⁴is benzyl. In some other embodiments, R², R³and R⁴are each methyl.

In one embodiment, the present disclosure provides for an organoclay composition comprising a mixture of (i) a phyllosilicate clay and quaternary ammonium ions having a formula of [NR¹R²R³R⁴]⁺ and (ii) a phyllosilicate clay and quaternary ammonium ions having a formula of [NR⁸R⁹R¹⁰R¹¹]⁺. For the organoclay composition comprising a phyllosilicate clay and quaternary ammonium ions having a formula of [NR¹R²R³R⁴]⁺, one or more of R¹, R²and R³is each a mixture of branched alkyl groups each having 12 to 22 total carbon atoms wherein the branched alkyl group has one or more C₁to C₃alkyl groups distributed at different carbon positions along a linear backbone of the branched alkyl group.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present invention provides for a method of providing a substantially constant rheological profile of an oil-based drilling fluid over a temperature range of about 120° F. to about 40° F. The method includes the steps of adding drilling fluid additive to the drilling fluid, wherein the drilling fluid additive organoclay compositions where a phyllosilicate clay is exchanged with quaternary ammonium ions having a formula of [NR¹R²R³R⁴]⁺ wherein at least one of R¹, R²and R³is a mixture of branched alkyl groups. It has been unexpectedly found that such organoclay compositions exhibit different properties compared to prior art organoclay compositions exchanged with quaternary ammonium ions having a formula of [NR^aR^bR^CR^d]⁺ where at least one of R^a, R^b, R^cand R^dis a not a mixture of branched alkyl groups but a single branched alkyl group, such as 12-methyl stearyl, having a branching point located at a single position along the linear backbone of the branched alkyl group.

In each of the embodiments, below “substantially free of quaternary carbon atoms” shall mean that a quaternary carbon atom is not detected by C¹³NMR.

First Embodiment

In some embodiments, the branched alkyl group, of one or more of R¹, R²and R³, has an average number of branches, per branched alkyl group, of at least 0.7. In some other embodiments, the branched alkyl group, of one or more of R¹, R²and R³, has an average number of branches per branched alkyl group ranging from 0.7 to 7. In some other embodiments, the branched alkyl group, of one or more of R¹, R²and R³, has an average number of branches per branched alkyl group ranging from 0.7 to 5. In some other embodiments, the branched alkyl group, of one or more of R¹, R²and R³, has an average number of branches per branched alkyl group ranging from 0.7 to 3. In each such embodiment, a methyl branch is at, least 50% of the branching alkyl groups based on the total number of branches.

In some embodiments, each branched alkyl group, of one or more of R¹, R²and R³, has a distribution of branching points distributed along the linear backbone of the branched alkyl group ranging from a 2 carbon atom position on the linear backbone, counting from a 1 carbon atom position which is bonded to N⁺, to a ω-2 carbon atom position, where ω is a terminal carbon atom position on the linear backbone. In such embodiments, a methyl branch is at least 50% of the branching alkyl groups based on the total number of branches.

In some embodiments, the linear backbone, of the branched alkyl group of one or more of R¹, R²and R³, contains less 0.5 atom % of quaternary carbon atoms. In other embodiments, the linear backbone, of the branched alkyl group one or more of R¹, R²and R³, is substantially free of quaternary carbon atoms.

The organoclay composition may contain sufficient quaternary ammonium ions to satisfy 50 to 150 percent of phyllosilicate cation exchange capacity. In some embodiments, the quaternary ammonium ions are in a concentration of 90 to 140 percent of phyllosilicate cation exchange capacity wherein the positive charge of the quaternary ion, in excess of the exchange capacity, is balanced by an inorganic anion or organic anion or anionic polymer. In some embodiments, the quaternary ammonium ions are in a concentration of 95 to 130 percent of phyllosilicate cation exchange capacity wherein the positive charge of the quaternary ion, in excess of the exchange capacity, is balanced by an inorganic anion or organic anion or anionic polymer. Examples of organic anions are found in U.S. Pat. No. 5,718,841 which is incorporated by reference in its entirety herein.

Second Embodiment

In one embodiment, the present disclosure provides for a method to provide a substantially constant rheological profile of an oil-based drilling fluid over a temperature range of about 120° F. to about 40° F. by using an organoclay composition as a drilling fluid additive, wherein the organoclay composition comprising: a phyllosilicate clay; and quaternary ammonium ions having a formula of [NR¹R²R³R⁴]⁺ wherein R¹is a mixture of branched alkyl groups, each branched alkyl group having 12 to 22 total carbon atoms, a linear backbone and one or more C₁to C₃branching alkyl groups, wherein the branching alkyl groups are distributed at different carbon positions along the linear backbone of the branched alkyl group; and wherein R²and R³are independently selected from the group consisting of: a first linear alkyl group having 1 to 22 total carbon atoms, wherein R⁴is selected from the group consisting of: a second linear alkyl group having 1 to 6 carbon atoms, an aryl group, and combinations thereof. In some embodiments, each branched alkyl group has 12 to 18 total carbon atoms. In some embodiments, each branched alkyl group has 14 to 18 total carbon atoms. In some embodiments, one or more of R²and R³are each the first linear alkyl group having 12 to 22 total carbon atoms; 1 to 6 total carbon atoms or 7-11 total carbon atoms. In some embodiments, R⁴is independently a benzyl group, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group or a hexyl group. In some other embodiments, one or more of R²and R³are methyl and R⁴is benzyl. In some other embodiments, R², R³and R⁴are each methyl.

In some embodiments, the R¹branched alkyl group has an average number of branches, per branched alkyl group, of at least 0.7. In some other embodiments, the R¹branched alkyl group has an average number of branches per branched alkyl group ranging from 0.7 to 7. In some other embodiments, the R¹branched alkyl group has an average number of branches per branched alkyl group ranging from 0.7 to 5. In some other embodiments, the R¹branched alkyl group has an average number of branches per branched alkyl group ranging from 0.7 to 3. In each such embodiment, a methyl branch is at least 50% of the branching alkyl groups based on the total number of branches.

In some embodiments, the R¹branched alkyl group has a distribution of branching points distributed along the linear backbone of the branched alkyl group ranging from a 2 carbon atom position on the linear backbone, counting from a 1 carbon atom position which is bonded to N⁺, to a ω-2 carbon atom position, where ω is a terminal carbon atom position on the linear backbone. In such embodiments, a methyl branch is at least 50% of the branching alkyl groups based on the total number of branches.

In some embodiments, the linear backbone, of the R¹branched alkyl group, contains less 0.5 atom % of quaternary carbon atoms. In other embodiments, the linear backbone, of the R¹branched alkyl group, is substantially free of quaternary carbon atoms.

Third Embodiment

In one embodiment, the present disclosure provides for a method to provide a substantially constant rheological profile of an oil-based drilling fluid over a temperature range of about 120° F. to about 40° F. by using an organoclay composition as a drilling fluid additive, wherein the organoclay composition comprises a phyllosilicate clay; and quaternary ammonium ions having a formula of [NR¹R²R³R⁴]⁺ wherein R¹and R²are a mixture of branched alkyl groups, each branched alkyl group having 12 to 22 total carbon atoms, a linear backbone and one or more C₁to C₃branching alkyl groups, wherein the branching alkyl groups are distributed at different carbon positions along the linear backbone of the branched alkyl group; and wherein R³is a first linear alkyl group having 1 to 22 total carbon atoms, R⁴is selected from the group consisting of: a second linear alkyl group having 1 to 6 total carbon atoms, an aryl group, and combinations thereof. In some embodiments, each branched alkyl group has 12 to 18 total carbon atoms. In some embodiments, each branched alkyl group has 14 to 18 total carbon atoms. In some embodiments, R³is a first linear alkyl group having 12 to 22 total carbon atoms; 1 to 6 total carbon atoms or 7-11 total carbon atoms. In some embodiments, R⁴is independently a benzyl group, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group or a hexyl group. In some other embodiments, R³is methyl and R⁴is benzyl. In some other embodiments, R³and R⁴are each methyl.

In some embodiments, the branched alkyl group, of R¹and R², has an average number of branches, per branched alkyl group, of at least 0.7. In some other embodiments, the branched alkyl group, of R¹and R², has an average number of branches per branched alkyl group ranging from 0.7 to 7. In some other embodiments, the branched alkyl group, of R¹and R², has an average number of branches per branched alkyl group ranging from 0.7 to 5. In some other embodiments, the branched alkyl group, of R¹and R², has an average number of branches per branched alkyl group ranging from 0.7 to 3. In each such embodiment, a methyl branch is at least 50% of the branching alkyl groups based on the total number of branches.

In some embodiments, each R¹and R²branched alkyl group has a distribution of branching points distributed along the linear backbone of the branched alkyl group ranging from a 2 carbon atom position on the linear backbone, counting from a 1 carbon atom position which is bonded to N⁺, to a ω-2 carbon atom position, where ω is a terminal carbon atom position on the linear backbone. In such embodiments, a methyl branch is at least 50% of the branching alkyl groups based on the total number of branches.

In some embodiments, the linear backbone, of each R¹and R²branched alkyl group, contains less 0.5 atom % of quaternary carbon atoms. In other embodiments, the linear backbone, of each R¹and R²branched alkyl group, is substantially free of quaternary carbon atoms.

Fourth Embodiment

In some embodiments, each R¹, R²and R³branched alkyl group has an average number of branches, per branched alkyl group, of at least 0.7. In some other embodiments, each R¹, R²and R³branched alkyl group has an average number of branches per branched alkyl group ranging from 0.7 to 7. In some other embodiments, each R¹, R²and R³branched alkyl group has an average number of branches per branched alkyl group ranging from 0.7 to 5. In some other embodiments, each R¹, R²and R³branched alkyl group has an average number of branches per branched alkyl group ranging from 0.7 to 3. In each such embodiment, a methyl branch is at least 50% of the branching alkyl groups based on the total number of branches.

In some embodiments, each R¹, R²and R³branched alkyl group has a distribution of branching points distributed along the linear backbone of the branched alkyl group ranging from a 2 carbon atom position on the linear backbone, counting from a 1 carbon atom position which is bonded to N⁺, to a ω-2 carbon atom position, where ω is a terminal carbon atom position on the linear backbone. In such embodiments, a methyl branch is at least 50% of the branching alkyl groups based on the total number of branches.

In some embodiments, the linear backbone, of each R¹, R²and R³branched alkyl group, contains less 0.5 atom % of quaternary carbon atoms. In other embodiments, the linear backbone, of each R¹, R²and R³branched alkyl group, is substantially free of quaternary carbon atoms.

Fifth Embodiment

In one embodiment, the present disclosure provides for a method to provide a substantially constant rheological profile of an oil-based drilling fluid over a temperature range of about 120° F. to about 40° F. by using an organoclay composition as a drilling fluid additive, wherein the organoclay composition comprises a mixture of (i) a phyllosilicate clay and quaternary ammonium ions having a formula of [NR¹R²R³R⁴]⁺ and (ii) a phyllosilicate clay and quaternary ammonium ions having a formula of [NR⁸R⁹R¹⁰R¹¹]⁺. For the organoclay composition comprising a phyllosilicate clay and quaternary ammonium ions having a formula of [NR¹R²R³R⁴]⁺, one or more of R¹, R²and R³is each a mixture of branched alkyl groups each having 12 to 22 total carbon atoms wherein the branched alkyl group has one or more C₁to C₃alkyl groups distributed at different carbon positions along a linear backbone of the branched alkyl group. In some embodiments, the branched alkyl group may have 12 to 18 total carbon atoms or 14 to 18 total carbon atoms. In embodiments, when one or more of R²and R³is not a branched alkyl group, R²and R³are each a first linear alkyl group having 1 to 22 total carbon atoms. R⁴is selected from the group consisting of a second linear alkyl group having 1 to 6 carbon atoms, an aryl group and combinations thereof. In some embodiments, one or more of R²and R³are each the second linear alkyl group having 12 to 22 total carbon atoms; 1 to 6 total carbon atoms or 7-11 total carbon atoms; and R⁴is independently a benzyl group, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group or a hexyl group. In some other embodiments, one or more of R²and R³are methyl and R⁴is benzyl. In some other embodiments, R², R³and R⁴are each methyl.

For the organoclay composition comprising a phyllosilicate clay and quaternary ammonium ions having a formula of [NR⁸R⁹R¹⁰R¹¹]⁺, one or more of R⁸, R⁹and R¹⁰is each a third linear alkyl group having 12 to 22 total carbon atoms. In embodiments, when one or more of R⁹and R¹⁰are not the third linear alkyl group then R⁹and R¹⁰are each a fourth linear alkyl group having 1 to 22 total carbon atoms. R¹¹is selected from a fifth linear alkyl group having 1 to 6 total carbon atoms, an aryl group and mixtures thereof. In some embodiments, the third linear alkyl group may have 12 to 18 total carbon atoms or 14 to 18 total carbon atoms. In some embodiments, one or more of R⁹and R¹⁰are each the fourth linear alkyl group having 12 to 22 total carbon atoms; 1 to 6 total carbon atoms or 7-11 total carbon atoms. In some embodiments, R¹¹is independently a benzyl group, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group or a hexyl group. In some other embodiments, one or more of R⁹and R¹⁰are methyl and R¹¹is benzyl. In some other embodiments, R⁹, R¹⁰and R¹¹are each methyl.

In some embodiments, each branched alkyl group, of [NR¹R²R³R⁴]⁺, has an average number of branches, per branched alkyl group, of at least 0.7. In some other embodiments, the branched alkyl group, of [NR¹R²R³R⁴]⁺, has an average number of branches, per branched alkyl group, ranging from 0.7 to 7. In some other embodiments, the branched alkyl group, of [NR¹R²R³R⁴]⁺, has an average number of branches, per branched alkyl group, ranging from 0.7 to 5. In some other embodiments, the branched alkyl group, of [NR¹R²R³R⁴]⁺, has an average number of branches, per branched alkyl group, ranging from 0.7 to 3. In each such embodiment, a methyl branch is at least 50% of the branching alkyl groups based on the total number of branches.

In some embodiments, each branched alkyl group, of [NR¹R²R³R⁴]⁺, has a distribution of branching points distributed along the linear backbone of the branched alkyl group ranging from a 2 carbon atom position on the linear backbone, counting from a 1 carbon atom position which is bonded to N⁺, to a ω-2 carbon atom position, where ω is a terminal carbon atom position on the linear backbone. In such embodiments, a methyl branch is at least 50% of the branching alkyl groups based on the total number of branches.

In some embodiments, the linear backbone, of each branched alkyl group of [NR¹R²R³R⁴]⁺, contains less 0.5 atom % of quaternary carbon atoms. In other embodiments, the linear backbone, of each branched alkyl group of [NR¹R²R³R⁴]⁺, is substantially free of quaternary carbon atoms.

The organoclay composition may contain sufficient quaternary ammonium ions to satisfy 50 to 150 percent of phyllosilicate cation exchange capacity. In some embodiments, the quaternary ammonium ions are in a concentration of 90 to 140 percent of phyllosilicate cation exchange capacity wherein the positive charge of the quaternary ion, in excess of the exchange capacity, is balanced by an inorganic anion or organic anion or an anionic polymer. In some embodiments, the quaternary ammonium ions are in a concentration of 95 to 130 percent of phyllosilicate cation exchange capacity wherein the positive charge of the quaternary ion, in excess of the exchange capacity, is balanced by an inorganic anion or organic anion or anionic polymer. Examples of organic anions are found in U.S. Pat. No. 5,718,841 which is incorporated by reference in its entirety herein.

Sixth Embodiment

In one embodiment, the present disclosure provides for a method to provide a substantially constant rheological profile of an oil-based drilling fluid over a temperature range of about 120° F. to about 40° F. by using an organoclay composition as a drilling fluid additive, wherein the organoclay composition comprises comprising a mixture of (i) a phyllosilicate clay and quaternary ammonium ions having a formula of [NR¹R²R³R⁴]⁺ wherein R¹is a mixture of branched alkyl groups having 12 to 22 total carbon atoms and (ii) a phyllosilicate clay and quaternary ammonium ions having a formula of [NR⁸R⁹R¹⁰R¹¹]⁺ wherein one or more of R⁸, R⁹and R¹⁰is each a third linear alkyl group having 12 to 22 total carbon atoms. In some embodiments of the organoclay composition of an phyllosilicate clay and the quaternary ammonium ions having a formula of [NR¹R²R³R⁴]⁺, branched alkyl group of R¹has one or more C₁to C₃alkyl groups distributed at different carbon positions along a linear backbone of the branched alkyl group. In some embodiments, the branched alkyl group, of [NR¹R²R³R⁴]⁺, may have 12 to 18 total carbon atoms or 14 to 18 total carbon atoms. In some embodiments, one or more of R²and R³are each a first linear alkyl group having 1 to 22 carbon atoms and R⁴is selected from: a second linear alkyl group having 1 to 6 total carbon atoms, an aryl group. In some embodiments, one or more of R²and R³are each the first linear alkyl group having 12 to 22 total carbon atoms, 1 to 6 total carbon atoms or 7-11 total carbon atoms. In some embodiments, R⁴is independently a benzyl group, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group or a hexyl group. In some other embodiments, one or more of R²and R³are methyl and R⁴is benzyl. In some other embodiments, R², R³and R⁴are each methyl.

In some embodiments of the organoclay composition of an phyllosilicate clay and the quaternary ammonium ions having a formula of [NR⁸R⁹R¹⁰R¹¹]⁺, one or more of R⁹and R¹⁰are each a fourth linear alkyl group having 1 to 22 total carbon atoms. R¹¹is selected from a fifth linear alkyl group having 1 to 6 total carbon atoms, an aryl group and mixtures thereof. In some embodiments, the third linear alkyl group, of [NR⁸R⁹R¹⁰R¹¹]⁺, may have 12 to 18 total carbon atoms or 14 to 18 total carbon atoms. In some embodiments, one or more of R⁹and R¹⁰are each the fourth linear alkyl group having 12 to 22 total carbon atoms; 1 to 6 total carbon atoms or 7-11 total carbon atoms. In some embodiments, R¹¹is independently a benzyl group, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group or a hexyl group. In some other embodiments, one or more of R⁹and R¹⁰are methyl and R¹¹is benzyl. In some other embodiments, R⁹, R¹⁰and R¹¹are each methyl.

In some embodiments, the R¹branched alkyl group, of [NR¹R²R³R⁴]⁺, has an average number of branches, per branched alkyl group, of at least 0.7. In some other embodiments, the R¹branched alkyl group, of [NR¹R²R³R⁴]⁺, has an average number of branches, per branched alkyl group, ranging from 0.7 to 7. In some other embodiments, the R¹branched alkyl group, of [NR¹R²R³R⁴]⁺, has an average number of branches, per branched alkyl group, ranging from 0.7 to 5. In some other embodiments, the R¹branched alkyl group, of [NR¹R²R³R⁴]⁺, has an average number of branches, per branched alkyl group, ranging from 0.7 to 3. In each such embodiment, a methyl branch is at least 50% of the branching alkyl groups based on the total number of branches.

In some embodiments, the R¹branched alkyl group, of [NR¹R²R³R⁴]⁺, has a distribution of branching points distributed along the linear backbone of the R¹branched alkyl group ranging from a 2 carbon atom position on the linear backbone, counting from a 1 carbon atom position which is bonded to N⁺, to a ω-2 carbon atom position, where ω is a terminal carbon atom position on the linear backbone. In such embodiments, a methyl branch is at least 50% of the branching alkyl groups based on the total number of branches.

In some embodiments, the linear backbone, of the R¹branched alkyl group of [NR¹R²R³R⁴]⁺, contains less 0.5 atom % of quaternary carbon atoms. In other embodiments, the linear backbone, of the R¹branched alkyl group of [NR¹R²R³R⁴]⁺, is substantially free of quaternary carbon atoms.

Seventh Embodiment

In one embodiment, the present disclosure provides for a method to provide a substantially constant rheological profile of an oil-based drilling fluid over a temperature range of about 120° F. to about 40° F. by using an organoclay composition as a drilling fluid additive, wherein the organoclay composition comprises mixture of (i) a phyllosilicate clay and quaternary ammonium ions having a formula of [NR¹R²R³R⁴]⁺ wherein R¹and R²are each a mixture of branched alkyl groups having 12 to 22 total carbon atoms and (ii) a phyllosilicate clay and quaternary ammonium ions having a formula of [NR⁸R⁹R¹⁰R¹¹]⁺ wherein one or more of R⁸, R⁹and R¹⁰is each a third linear alkyl group having 12 to 22 total carbon atoms. In some embodiments of the organoclay composition comprising mixture of (i) a phyllosilicate clay and quaternary ammonium ions having a formula of [NR¹R²R³R⁴]⁺, the branched alkyl group has one or more C₁to C₃alkyl groups distributed at different carbon positions along a linear backbone of the branched alkyl group. In some embodiments, the branched alkyl group may have 12 to 18 total carbon atoms or 14 to 18 total carbon atoms. R³is a first linear alkyl group having 1 to 22 total carbon atoms, R⁴is selected from a second linear alkyl group having 1 to 6 carbon atoms, an aryl group and mixtures thereof. In some embodiments, R³is the first linear alkyl group having 12 to 22 total carbon atoms, 1 to 6 total carbon atoms or 7-11 total carbon atoms; and R⁴is independently a benzyl group, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group or a hexyl group. In some other embodiments, R³is methyl and R⁴is benzyl. In some other embodiments, R³and R⁴are each methyl.

In some embodiments of the organoclay composition comprising a phyllosilicate clay and quaternary ammonium ions having a formula of [NR⁸R⁹R¹⁰R¹¹]⁺, the third linear alkyl group may have 12 to 18 total carbon atoms or 14 to 18 total carbon atoms. In some embodiments, one or more of R⁹and R¹⁰are each a fourth linear alkyl group having 1 to 22 total carbon atoms. In some embodiments, one or more of R⁹and R¹⁰are each the fourth linear alkyl group having 12 to 22 total carbon atoms; 1 to 6 total carbon atoms or 7-11 total carbon atoms. In some embodiments, R¹¹is selected from a fifth linear alkyl group having 1 to 6 total carbon atoms, an aryl group and combinations thereof. In some embodiments, R¹¹is independently a benzyl group, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group or a hexyl group. In some other embodiments, one or more of R⁹and R¹⁰are methyl and R¹¹is benzyl. In some other embodiments, R⁹, R¹⁰and R¹¹are each methyl.

In some embodiments, the R¹and R²branched alkyl groups, of [NR¹R²R³R⁴]⁺, has an average number of branches, per branched alkyl group, at least 0.7. In some other embodiments, the R¹and R²branched alkyl groups, of [NR¹R²R³R⁴]⁺, has an average number of branches, per branched alkyl group, ranging from 0.7 to 7. In some other embodiments, the R¹and R²branched alkyl groups, of [NR¹R²R³R⁴]⁺, has an average number of branches, per branched alkyl group, ranging from 0.7 to 5. In some other embodiments, the R¹and R²branched alkyl groups, of [NR¹R²R³R⁴]⁺, has an average number of branches, per branched alkyl group, ranging from 0.7 to 3. In each such embodiment, a methyl branch is at least 50% of the branching alkyl groups based on the total number of branches.

In some embodiments, the R¹and R²branched alkyl groups, of [NR¹R²R³R⁴]⁺, has a distribution of branching points distributed along the linear backbone of the R¹and R²branched alkyl groups ranging from a 2 carbon atom position on the linear backbone, counting from a 1 carbon atom position which is bonded to N⁺, to a ω-2 carbon atom position, where ω is a terminal carbon atom position on the linear backbone. In such embodiments, a methyl branch is at least 50% of the branching alkyl groups based on the total number of branches.

In some embodiments, the linear backbone, of the R¹and R²branched alkyl groups of [NR¹R²R³R⁴]⁺, contains less 0.5 atom % of quaternary carbon atoms. In other embodiments, the linear backbone, of the R¹and R²branched alkyl groups of [NR¹R²R³R⁴]⁺, is substantially free of quaternary carbon atoms.

Eighth Embodiment

In some embodiments, the branched alkyl group has one or more C₁to C₃alkyl groups distributed at different carbon positions along a linear backbone of the branched alkyl group. In some embodiments, the branched alkyl group may have 12 to 18 total carbon atoms or 14 to 18 total carbon atoms. In some embodiments, the third linear alkyl group may have 12 to 18 total carbon atoms or 14 to 18 total carbon atoms. In some embodiments, R⁴is independently a benzyl group, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group or a hexyl group. In some other embodiments, R⁴is benzyl. In some other embodiments, R⁴is methyl.

In some embodiments, one or more of R⁹and R¹⁰are each a fourth linear alkyl group having 1 to 22 total carbon atoms. In some embodiments, one or more of R⁹and R¹⁰are each the fourth linear alkyl group having 12 to 22 total carbon atoms; 1 to 6 total carbon atoms or 7-11 total carbon atoms and R¹¹is independently a benzyl group, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group or a hexyl group. In some other embodiments, one or more of R⁹and R¹⁰are methyl and R¹¹is benzyl. In some other embodiments, R⁹, R¹⁰and R¹¹are each methyl.

In some embodiments, the R¹, R²and R³branched alkyl groups, of [NR¹R²R³R⁴]⁺, has an average number of branches, per branched alkyl group, at least 0.7. In some other embodiments, the R¹, R²and R³branched alkyl groups, of [NR¹R²R³R⁴]⁺, has an average number of branches, per branched alkyl group, ranging from 0.7 to 7. In some other embodiments, the R¹, R²and R³branched alkyl groups, of [NR¹R²R³R⁴]⁺, has an average number of branches, per branched alkyl group, ranging from 0.7 to 5. In some other embodiments, the R¹, R²and R³branched alkyl groups, of [NR¹R²R³R⁴]⁺, has an average number of branches, per branched alkyl group, ranging from 0.7 to 3. In each such embodiment, a methyl branch is at least 50% of the branching alkyl groups based on the total number of branches.

In some embodiments, the R¹, R²and R³branched alkyl groups, of [NR¹R²R³R⁴]⁺, has a distribution of branching points distributed along the linear backbone of the R¹, R²and R³branched alkyl groups ranging from a 2 carbon atom position on the linear backbone, counting from a 1 carbon atom position which is bonded to N⁺, to a ω-2 carbon atom position, where ω is a terminal carbon atom position on the linear backbone. In such embodiments, a methyl branch is at least 50% of the branching alkyl groups based on the total number of branches.

In some embodiments, the linear backbone, of the R¹, R²and R³branched alkyl groups of [NR¹R²R³R⁴]⁺, contains less 0.5 atom % of quaternary carbon atoms. In other embodiments, the linear backbone, of the R¹, R²and R³branched alkyl groups of [NR¹R²R³R⁴]⁺, is substantially free of quaternary carbon atoms.

Ninth Embodiment

In some embodiments of quaternary ammonium ion having formula of (i) [NR¹R²R³R⁴]⁺, when one or more of R²and R³are not branched alkyl groups, one or more of R²and R³are each a first linear alkyl group having 1 to 22 carbon total atoms. R⁴is independently selected from a second linear alkyl group having 1 to 22 total carbon atoms, an aryl group and mixtures thereof. In some embodiments, one or more of R²and R³are each the first linear alkyl group having 12 to 22 total carbon atoms; 1 to 6 total carbon atoms or 7-11 total carbon atoms; and R⁴is independently a benzyl group, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group or a hexyl group. In some other embodiments, one or more of R²and R³are methyl and R⁴is benzyl. In some other embodiments, R², R³and R⁴are each methyl.

In some embodiments of the quaternary ammonium ion having formula of [NR⁸R⁹R¹⁰R¹¹]⁺ wherein, R⁸is the third linear alkyl group and R⁹and R¹⁰are each a fourth linear alkyl group having 1 to 22 total carbon atoms, and R¹¹is selected from a fifth linear alkyl group having 1 to 6 total carbon atoms, an aryl group and mixtures thereof. The fourth linear alkyl group may have 12 to 22 total carbon atoms; 1 to 6 total carbon atoms or 7-11 total carbon atoms. R¹¹is independently a benzyl group, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group or a hexyl group. In some other embodiments, one or more of R⁹and R¹⁰are methyl and R¹¹is benzyl. In some other embodiments, R⁹, R¹⁰and R¹¹are each methyl.

In some embodiments of the quaternary ammonium ion having formula of [NR⁸R⁹R¹⁰R¹¹]⁺, R⁸and R⁹are the third linear alkyl group and R¹⁰is a fourth linear alkyl group having 1 to 22 total carbon atoms, and R¹¹is selected from a fifth linear alkyl group having 1 to 6 total carbon atoms, an aryl group and mixtures thereof. The fourth linear alkyl group may have 12 to 22 total carbon atoms; 1 to 6 total carbon atoms or 7-11 total carbon atoms. R¹¹is independently a benzyl group, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group or a hexyl group. In some other embodiments, one or more of R⁹and R¹⁰are methyl and R¹¹is benzyl. In some other embodiments, R⁹, R¹⁰and R¹¹are each methyl.

In some embodiments of the quaternary ammonium ion having formula of [NR⁸R⁹R¹⁰R¹¹]⁺, R⁸, R⁹and R¹⁰are the third linear alkyl group and R¹¹is selected from a fifth linear alkyl group having 1 to 6 total carbon atoms, an aryl group and mixtures thereof. R¹¹is independently a benzyl group, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group or a hexyl group. In some other embodiments, one or more of R⁹and R¹⁰are methyl and R¹¹is benzyl. In some other embodiments, R⁹, R¹⁰and R¹¹are each methyl.

The organoclay composition may contain sufficient quaternary ammonium ions to satisfy 50 to 150 percent of phyllosilicate cation exchange capacity. In some embodiments, the quaternary ammonium ions are in a concentration of 90 to 140 percent of phyllosilicate cation exchange capacity wherein the positive charge of the quaternary ion, in excess of the exchange capacity, is balanced by an inorganic anion or organic anion or an anionic polymer. In some embodiments, the quaternary ammonium ions are in a concentration of 95 to 130 percent of phyllosilicate cation exchange capacity wherein the positive charge of the quaternary ion, in excess of the exchange capacity, is balanced by an inorganic anion or organic anion or anionic polymer. Examples of organic anions are found in U.S. Pat. No. 5,718,841 which is incorporated by reference in its entirety herein.

Preparation of Quaternary Ammonium Ions

Quaternary ammonium ions are obtained when fatty amines are quaternized with alkylating agents such as methyl chloride, benzyl chloride and the like. Note that the fatty amines may contain one or more of alkyl chains per amine group. Various commercial processes have been developed to produce fatty (long alkyl chain) amines. Fatty acids can be readily converted into fatty amines using a nitrile path as outlined in U.S. Pat. No. 5,634,969 for instance. Fatty amines may also be prepared by reacting fatty alcohol with aminating agents as disclosed in, for instance, U.S. Pat. Nos. 4,683,336 or 4,994,620. Alternatively, long alkyl chain internal- and/or terminal-olefins can be converted into fatty amines via hydrobromination and reaction with aminating agents as disclosed in U.S. Pat. Nos. 4,024,189 or 7,342,136. Said olefins can be obtained through oligomerization of shorter olefins or by cracking larger paraffin wax type molecules.

Fatty alkyl chains can be derived from a variety of natural oleo-chemical sources. These sources can be used to supply raw materials for either the nitrile or alcohol routes that yield fatty amines. Palm or tallow fatty acids are popular raw materials for organoclay manufacture because of cost and availability. The majority of fatty acids that are derived from animal or plant sources are linear. Fatty acids can be converted to fatty alcohol which then are used in the fatty alcohol route to make fatty amines.

Saturated branched chain fatty acids can also be obtained from natural fatty acids. Isostearic acid is a byproduct in the dimer acid production but yields are relatively low making such materials expensive. Recently, significant advances have been made to isomerize natural feed stocks so that linear alkyl chains can be converted into branched alkyl chains, U.S. Pat. No. 5,677,473. Technology described in US 2011/0263884 discloses a high yield skeletal isomerization process of unsaturated linear fatty acids such as oleic acid. The process is highly selective and cost effective (Ind. Eng. Chem. Res. 2012, 51, 12041-12045). Isostearic acid typically is an isomeric mixture where the branching occurs at various positions along the chain. Isostearic acids are commercially available under the Century, Emersol, Emery, Oxocol and Prisorine brand names.

Petrochemical processes have been developed that convert natural gas or olefins such as ethylene, propylene and the like, into fatty alkyl chains to prepare products such as, for example, fatty alcohols. Cracking of paraffin can also yield long chain olefins that can be converted into fatty alcohols via a hydroformylation process. The performance of petrochemical based linear primary alcohols and derivatives are in many applications comparable to oleo-based alcohol products because the chemical composition is essentially the same. However, the various petrochemical processes can also yield chains with a certain degree of branching. Ziegler, Fisher-Tropsch, Oxo and Querbet alcohols all contain varying degrees of branched alkyl chains. Typical long chain petrochemical alcohols that are commercially available are NEODOL (Shell), EXXAL (Exxon) and ALFOL, SAFOL, MARLIPAL, ISALCHEM, ALCHEM and LIAL (Sasol) alcohols. U.S. Pat. Nos. 5,849,960, 6,150,322, 7,781,390 and references therein describe processes and compositions of linear as well as branched petrochemical alcohols. The skeletal isomerization of long chain olefins into branched olefins followed by selective hydroformylation yield branched alcohols such as NEODOL 67, which is a highly branched alcohol (Handbook of Detergents, Part F: Production). Hence, alkyl branching can occur at any location around the alkyl chain, and the branching group can be methyl, ethyl or even longer alkyl groups. The average number of branching per alkyl chain can be determined with ¹H and ¹³C NMR analysis, while alkyl chain length distribution can be estimated with GC. An average branching per alkyl chain above unity means that some alkyl chains have more than one branch per alkyl chain.

Phyllosilicate Clays

Phyllosilicate clay includes natural or synthetic phyllosilicate clay, or mixtures thereof, which undergo ion exchange reactions with quaternary ammonium cations forming an organoclay. Representative natural phyllosilicate clays include smectites, palygorskite, sepiolite, vermiculites, and micas. Examples of smectite-type clays include montmorillonite, bentonite, hectorite, saponite, stevensite, and beidellite. In some embodiments, the phyllosilicate clay includes swelling clays such as hectorite and Wyoming-type bentonite. In some embodiments, the phyllosilicate clay is a mixture of hectorite and bentonite. Bentonite and its properties are described at length in the chapter entitled “Bentonite,” in Carr, D., ed. 1994, Industrial Minerals and Rocks, 6th Edition (published by the Society For Mining, Metallurgy and Exploration, Colorado). Smectite-type clays are well known in the art and are commercially available from a variety of sources. Phyllosilicate clays useful in accordance with the present invention are described in detail in “Hydrous Phyllosilicates, Reviews in Mineralogy, Volume 19, S. W. Bailey, editor.” Other useful literature can be found in Elsevier book series entitled “Developments in Clay Science”, in particular Volume 5 entitled “Handbook of Clay Science.”

Smectite clays which are layered, platy, hydrophilic silicate materials. In the dry state, several nano-sized clay layers are normally stacked on top of each other and these stacks, or tactoids, are agglomerated into particles. However, the platelets spontaneously separate from each other when dry clay powder is dispersed in water. This “delamination of layers” is at times also referred to as “exfoliation of layers.” Smectite clay layers carry a net negative charge on the platelets that is neutralized by metal cations that are positioned on the surfaces of the platelets. An organoclay is formed when the metal cations are exchanged with organic cations. This reaction may be partially completed or driven to completion. Organic surface treatment is often necessary to improve the compatibility of the clay with organic systems. Similar to “pristine” inorganic clays in water, organoclays can delaminate in organic systems (solvents, polymers): i.e. the clay layers that are now decorated with organic cations are separated from each other when they are exfoliated in said systems.

In an embodiment, the phyllosilicate clay may include crude clay or beneficiated clay. The crude clay contains gangue or non-clay material whereas the gangue material has been largely removed from the beneficiated clay. In an embodiment using crude clay, substantial cost savings may be realized because the steps for the clay beneficiation process and conversion to the sodium form are eliminated.

In some embodiments, the phyllosilicate clays include synthetic phyllosilicate clays including synthetic vermiculite, synthetic smectite, synthetic hectorite, synthetic fluorohectorite and synthetic mica. The performance of synthetic clay based organoclays may differ, either positively or negatively, from those based on naturally occurring clays. These differences may be due to chemical composition and homogeneity thereof, ion exchange capacity, location of the ion exchange sites, impurities, surface area, platelet size and distribution, and or other reasons. These clays, also, may optionally be purified if desired.

The exchangeable inorganic cations of the phyllosilicate clay may be sodium or another cation. Preferably the exchangeable cations will be sodium. In some embodiments, the exchangeable cations can be a mixture of sodium, magnesium and calcium. In one embodiment, the sodium form of the smectite clay may be used. To prepare the sodium form of one embodiment, bentonite clay may be converted to the sodium form by preparing an aqueous clay slurry and passing the slurry through a bed of cation exchange resin in the sodium form. In another embodiment, the sodium form of the smectite clay may be prepared by mixing the clay with water and a soluble sodium compound, such as sodium carbonate, sodium hydroxide, etc.

In an embodiment, the phyllosilicate clay includes smectite-type clay having a cation exchange capacity of at least 45 mMols per 100 grams of clay, 100% active clay basis, as determined by the well-known ammonium acetate method or equivalent method. In another embodiment, the phyllosilicate clay includes smectite-type clay having a cation exchange capacity of at least 75 mMols per 100 grams of clay, 100% active clay basis.

The clay may be either sheared or non-sheared forms of the above-listed smectite clays. In one embodiment, the sheared form of the smectite clay may provide improved performance as compared to non-sheared clay material. Elementis Specialties, Inc. and its predecessor have issued patents describing the shearing of smectite clay, as described in U.S. Pat. Nos. 4,695,402 and 4,742,098 which are incorporated herein by reference in their entirety.

The organoclays, described herein, may be used in a variety of applications. In some embodiments, the organoclays may be used a rheology modifiers, anti-settling agents, sag control additives, or as adsorbants or as absorbants where the organoclay will host other ion pairs within the gallery. In some embodiments, the organoclays may be used as additives in greases, adhesives, sealants, inks, consumer products such as lipstick, deodorant, nail polish and the like.

In some embodiments, the organoclays, described herein, may be used in coating systems where the organoclay is dispersible in organic or solvent-based i.e. non-aqueous, fluids or aqueous systems to provide a wide variety of rheological and viscosity-modifier properties to such fluids. These non-aqueous fluids include oil-based paints and coatings as well as oil-based inks, drilling fluids, caulks and adhesives.

Coating Composition

In one embodiment, the organoclay compositions described herein may be used as a rheological additive for a non-aqueous fluid system.

In one embodiment, such organoclays may be used as a drilling fluid additive as set forth below.

Preparation of the Drilling Fluids

In some embodiments, compositions according to the present invention may be used as an additive to oil- or synthetic-based drilling fluids. In some embodiments, compositions according to the present invention may be used as an additive for oil- or synthetic-based invert emulsion drilling fluids employed in a variety of drilling applications.

The term oil- or synthetic-based drilling fluid is defined as a drilling fluid in which the continuous phase is hydrocarbon based. Oil- or synthetic-based drilling fluids formulated with over 5% water or brine may be classified as oil- or synthetic-based invert emulsion drilling fluids. In some embodiments, oil- or synthetic-based invert emulsion drilling fluids may contain water or brine as the discontinuous phase in any proportion up to about 5%, 10%, 15%, 20%, 25%, 30% or 50%. Oil muds may include invert emulsion drilling fluids as well as all oil based drilling fluids using synthetic, refined or natural hydrocarbon base as the external phase.

According to some embodiments, a process for preparing invert emulsion drilling fluids (oil muds) involves using a mixing device to incorporate the individual components making up that fluid. In some embodiments, primary and secondary emulsifiers and/or wetting agents (surfactant mix) are added to the base oil (continuous phase) under moderate agitation. The water phase, typically a brine, may be added to the base oil/surfactant mix along with alkalinity control agents and acid gas scavengers. In some embodiments, rheological additives as well as fluid loss control materials, weighting agents and corrosion inhibition chemicals may also be included. The agitation may then be continued to ensure dispersion of each ingredient and homogenize the resulting fluidized mixture.

Base Oil/Continuous Phase

According to some embodiments, diesel oil, mineral oil, synthetic oil, vegetable oil, fish oil, paraffinics, and/or ester-based oils can all be used as single components or as blends.

Brine Content

In some embodiments, water in the form of brine is often used in forming the internal phase of the drilling fluids. According to some embodiments, water can be defined as an aqueous solution which can contain from about 10 to 350,000 parts-per-million of metal salts such as lithium, sodium, potassium, magnesium, cesium, or calcium salts. In some embodiments, brines used to form the internal phase of a drilling fluid according to the present invention can also contain about 5% to about 35% by weight calcium chloride and may contain various amounts of other dissolved salts such as sodium bicarbonate, sodium sulfate, sodium acetate, sodium borate, potassium chloride, sodium chloride or formates (such as sodium, calcium, or cesium). In some embodiments, glycols or glycerin can be used in place of or in addition to brines.

In some embodiments, the ratio of water (brine) to oil in the emulsions according to the present invention may provide as high a brine content as possible while still maintaining a stable emulsion. In some embodiments, suitable oil/brine ratios may be in the range of about 97:3 to about 50:50. In some embodiments, suitable oil/brine ratios may be in the range of about 90:10 to about 60:40, or about 80:20 to about 70:30. In some embodiments, the preferred oil/brine ratio may depend upon the particular oil and mud weight. According to some embodiments, the water content of a drilling fluid prepared according to the teachings of the invention may have an aqueous (water) content of about 0 to 50 volume percent

Emulsifiers

According to some embodiments, an emulsifier can also be added to the drilling fluid in order to form a more stable emulsion. The emulsifier may include organic acids, including but not limited to the monocarboxyl alkanoic, alkenoic, or alkynoic fatty acids containing from 3 to 20 carbon atoms, and mixtures thereof. Examples of this group of acids include stearic, oleic, caproic, capric and butyric acids. In some embodiments, adipic acid, a member of the aliphatic dicarboxylic acids, can also be used. According to some embodiments, suitable surfactants or emulsifiers include fatty acid calcium salts and lecithin. In other embodiments, suitable surfactants or emulsifiers include oxidized tall oil, polyaminated fatty acids, and partial amides of fatty acids.

In some embodiments, heterocyclic additives such as imidazoline compounds may be used as emulsifiers and/or wetting agents in the drilling muds. In other embodiments, alkylpyridines may be used to as emulsifiers and/or wetting agents in the drilling muds.

Industrially obtainable amine compounds for use as emulsifiers may be derived from the epoxidation of olefinically unsaturated hydrocarbon compounds with subsequent introduction of the N function by addition to the epoxide group. The reaction of the epoxidized intermediate components with primary or secondary amines to form the corresponding alkanolamines may be of significance in this regard. In some embodiments, polyamines, particularly lower polyamines of the corresponding alkylenediamine type, are also suitable for opening of the epoxide ring.

Another class of the oleophilic amine compounds that may be suitable as emulsifiers are aminoamides derived from preferably long-chain carboxylic acids and polyfunctional, particularly lower, amines of the above-mentioned type. In some embodiments, at least one of the amino functions is not bound in amide form, but remains intact as a potentially salt-forming basic amino group. The basic amino groups, where they are formed as secondary or tertiary amino groups, may contain hydroxyalkyl substituents and, in particular, lower hydroxyalkyl substituents containing up to five and in some embodiments up to three carbon atoms in addition to the oleophilic part of the molecule.

According to some embodiments, suitable N-basic starting components for the preparation of such adducts containing long-chain oleophilic molecule constituents may include but are not limited to monoethanolamine or diethanolamine.

Weight Agents

In some embodiments, weighting materials are also used to weight the drilling fluid additive to a desired density. In some embodiments, the drilling fluid is weighted to a density of about 8 to about 18 pounds per gallon and greater. Suitable weighting materials may include barite, ilmenite, calcium carbonate, iron oxide and lead sulfide. In some embodiments, commercially available barite is used as a weighting material.

Filtrate Reduces

In some embodiments, fluid loss control materials are added to the drilling fluid to control the seepage of drilling fluid into the formation. In some embodiments, fluid loss control materials are lignite-based or asphalt-based. Suitable filtrate reducers may include amine treated lignite, gilsonite and/or elastomers such as styrene butadiene.

Blending Process

In some embodiments, drilling fluids may contain about 0.1 pounds to about 15 pounds of the drilling fluid additive per barrel of fluids. In other embodiments, drilling fluids may contain about 0.1 pounds to about 10 pounds of the drilling fluid additive per barrel of fluids, and in still other embodiments, drilling fluids may contain about 0.1 pounds to about 5 pounds of the drilling fluid additive per-barrel of fluids.

As shown above, a skilled artisan will readily recognize that additional additives such as weighting agents, emulsifiers, wetting agents, viscosifiers, fluid loss control agents, and other agents can be used with a composition according to the present invention. A number of other additives besides rheological additives regulating viscosity and anti-settling properties can also be used in the drilling fluid so as to obtain desired application properties, such as, for example, anti-settling agents and fluid loss-prevention additives.

Method of Use

In some embodiments, a drilling fluid additive may be added to a drilling fluid. In some embodiments, the drilling fluid additive may be added to a drilling fluid in combination with other additives.

In some embodiments, a drilling fluid additive is added to a drilling fluid in an amount of about 0.1 ppb to about 30 ppb. In other embodiments, a drilling fluid additive is added to a drilling fluid in an amount of about 0.25 ppb to about 15.0 ppb. In other embodiments, a drilling fluid additive is added to a drilling fluid in an amount of about 0.5 ppb to about 10.0 ppb. In some embodiments, a drilling fluid additive is added to a drilling fluid in an amount of about 2.5 ppb. In some embodiments, a drilling fluid additive is added to a drilling fluid in an amount of about 5.0 ppb. In some embodiments, a drilling fluid additive is added to a drilling fluid in an amount of about 10.0 ppb. In some embodiments, a drilling fluid additive is added to a drilling fluid in an amount of about 15.0 ppb. In some embodiments, a drilling fluid additive is added to a drilling fluid in an amount of about 20.0 ppb. In some embodiments, a smaller amount of a drilling fluid additive of the present invention is required to achieve comparable rheological stability results as a known drilling fluid additive.

The drilling fluid additive and drilling fluid may be characterized by several rheological or hydraulic aspects, i.e., ECD, high shear rate viscosity, low shear rate viscosity, plastic viscosity, regulating property viscosity and yield point, of a drilling fluid. The rheological aspects may be determined using a Fann viscometer as per standard procedures found in API RP13B-2 “Standard Procedures for Field Testing Oil-based Drilling Fluids”. Viscosity readings can be measured at 600 rpm, 300 rpm, 200 rpm, 100 rpm, 6 rpm and 3 rpm. ECD can be determined by: standard hydraulics calculations found in API RP13D “Rheology and Hydraulics of Oil-well Drilling Fluids.” For the purposes of this invention high shear rate viscosity (“HSR”) corresponds to the viscosity measured at 600 rpm as per API RP13B-2 procedures. For the purposes of this invention, low shear rate viscosity (“LSR”) corresponds to the viscosity measured at 6 rpm as per API RP 13B-2 procedures. Plastic viscosity (“PV”) corresponds to the 600 rpm reading minus the 300 rpm reading. Yield Point (“YP”) corresponds to the 300 rpm reading minus plastic viscosity.

In some embodiments, the addition of the drilling fluid additive to a drilling fluid results in a substantially constant ECD as temperature is varied over a range of about 120° F. to about 40° F. For the purposes of this invention, a substantially constant ECD may include a decrease or increase in ECD over such temperature variation. In one embodiment, the increase in ECD may include: up to 0.5%; up to 1%; up to 2%, up to 3%, up to 4%; up to 5%; up to 10%; up to 20%; up to 30%; and up to 40%. In one embodiment, the decrease in ECD may include: up to 0.5%; up to 1%; up to 2%, up to 3%, up to 4%; up to 5%; up to 10%; up to 20%; up to 30%; and up to 40%. In one embodiment, the increase in ECD may range from 1% up to 10%. In another embodiment, the increase in ECD may range from 1% up to 5%.

In some embodiments, the addition of the organoclay drilling fluid additive to a drilling fluid results in a substantially constant rheological profile throughout a temperature range. A substantially constant rheological profile of a drilling fluid may be determined by the change in viscosity of the drilling fluid as the temperature of the drilling fluid is reduced from bottom hole temperature typically encountered in deep water drilling, to temperatures typically encountered in the riser in deep water drilling. In some embodiments, the rheological profile of a drilling fluid is measured in terms of the increase in high rate (600 rpm) Fann 35A viscosity of the drilling fluid when the drilling fluid is cooled from about 120° F. to about 40° F. In some embodiments, a substantially constant rheological profile is achieved when the change in high shear rate viscosity of a drilling fluid is less than about 90% over a temperature range of about 120° F. to about 40° F. In other embodiments, a substantially constant rheological profile is achieved when the change in high shear rate viscosity of a drilling fluid is less than about 85% over a temperature range of about 120° F. to about 40° F. In some embodiments, a substantially constant rheological profile is achieved when the change in high shear rate viscosity is less than about 80% over a temperature range of about 120° F. to about 40° F. In some embodiments, a substantially constant rheological profile is achieved when the change in high shear rate viscosity is less than about 75% over a temperature range of about 120° F. to about 40° F. In other embodiments, a substantially constant rheological profile is achieved when the change in high shear rate viscosity of a drilling fluid is less than about 70% over a temperature range of about 120° F. to about 40° F. In other embodiments, a substantially constant rheological profile is achieved when the change in high shear rate viscosity of a drilling fluid is less than about 65% over a temperature range of about 120° F. to about 40° F. In other embodiments, a substantially constant rheological profile is achieved when the change in high shear rate viscosity of a drilling fluid is less than about 60% over a temperature range of about 120° F. to about 40° F. In other embodiments, a substantially constant rheological profile is achieved when the change in high shear rate viscosity of a drilling fluid is less than about 55% over a temperature range of about 120° F. to about 40° F. In other embodiments, a substantially constant rheological profile is achieved when the change in high shear rate viscosity of a drilling fluid is less than about 50% over a temperature range of about 120° F. to about 40° F. The viscosity of the drilling fluid may be measured according to API RP 13B procedures.

In some embodiments, a drilling fluid according to the present invention may have a lower viscosity at 40° F. than conventional muds formulated with sufficient conventional organoclay to provide suspension at bottom hole temperatures. When used in drilling operations, drilling fluids according to the present invention may allow the use of a lower pumping power to pump drilling muds through long distances, thereby reducing down-hole pressures. Consequently, in some embodiments, whole mud loss, fracturing and damage of the formation are all minimized. In some embodiments, drilling fluids according to the present invention may maintain the suspension characteristics typical of higher levels of conventional organoclays at higher temperatures. Such suspension characteristics may reduce the tendency of the mud to sag. Sag may include the migration of weight material, resulting in a higher density mud at a lower fluid fraction and a lower density mud at a higher fluid fraction. A reduction of sag may be valuable in both deep water drilling as well as conventional (non deep water) drilling. The present invention may be particularly useful in deep water drilling when the mud is cooled in the riser. A mud using a drilling fluid additive according to the present invention will maintain a reduced viscosity increase in the riser when compared to drilling fluids containing conventional rheological additives.

Blending Process

Drilling fluids preparations preferably contain between ¼ and 20 pounds of the inventive mixture per barrel of fluids, more preferred concentration is ¼ to 10 pounds-per-barrel and most preferably ¼ to 5 pounds-per-barrel.

As shown above, a skilled artisan will readily recognize that additional additives: weighting agents, emulsifiers, wetting agents, viscosifiers, fluid loss control agents, and other agents can be used with this invention. A number of other additives besides rheological additives regulating viscosity and anti-settling properties, providing other properties, can also be used in the fluid so as to obtain desired application properties, such as, for example, anti-settling agents and fluid loss-prevention additives.

The drilling fluids of the present invention generally have a lower high shear rate viscosity at 40° F. than conventional muds formulated with sufficient conventional organoclay to provide suspension at bottom hole temperatures. When used in drilling operations, the present drilling fluids allow the use of a lower pumping power to pump drilling muds through long distances, thereby reducing down-hole pressures. Consequently, fluid loss, fracturing and damage of the formation are all minimized. The present invention is particularly useful in deep water drilling when the mud is cooled in the riser. A mud using the described invention will maintain a reduced viscosity increase in the riser when compared to drilling fluids containing conventional rheological additives. One advantage is a stable rheological profile which corresponds to a substantially constant equivalent circulating density over a temperature range of about 120° F. to about 40° F.

For the purposes of this application, the term “about” means plus or minus 10%.

EXAMPLES

The following examples further describe and demonstrate illustrative embodiments within the scope of the present invention. The examples are given solely for illustration and are not to be construed as limitations of this invention as many variations are possible without departing from the spirit and scope thereof.

Quaternary ammonium compounds bearing branched alkyl groups may be made with any known process. Non limiting synthesis examples to prepare such branched quaternary ammonium compounds are given below starting with branched alcohols as branched alkyl source or branched fatty acids as the branched alkyl source.

Example 1

A. Synthesis Of Benzyl Dimethyl (Branched Alkyl) Quaternary Ammonium Chloride

Step 1: Synthesis of a (branched alkyl) bromide from a (branched alkyl) alcohol.

In a 1 L, three-necked flask, fitted with a mechanical stirrer, a thermometer, and a dropping funnel, is placed 113 g of Neodol 67 alcohol. The alcohol is cooled to 0° C. by immersing the flask in an ice bath, and 55 g of phosphorus tribromide is slowly added with stirring at such a rate as to keep the temperature at 0° C. (about two hours). The cooling bath is removed, and stirring is continued until the mixture reaches room temperature; it is then allowed to stand overnight.

To the flask was added 200 ml diethyl ether and 200 ml deionized water. The pH of the mixture was adjusted to neutral with 5% potassium hydroxide under ice bath cooling. Subsequently the solution was transferred to a separatory funnel, the bottom layer was drained and the top layer was washed with brine solution three times. The top layer was then collected and filtered to remove white precipitate; about 105 g of branched alkyl bromide was thus collected after diethyl ether was removed by rota-evaporation.

Neodol 67 (Shell) mainly is a mixture of C16 and C17 branched primary alcohols and is produced through selective hydroformylation of branched olefins, which are derived from ethylene. The hydrocarbon backbone of Neodol 67 is linear with one or more methyl branching groups directly bonded to the backbone. These methyl branches are distributed along the backbone.

Step 2: Synthesis of a dimethyl (branched alkyl) tertiary amine

A total of 30.7 g of branched alkyl bromide (from Step 1) was added to 147 ml of dimethylamine ethanolic solution. The mixture is stirred at room temperature for 24 h, then a 10% aqueous solution of sodium hydroxide is added and the mixture is extracted three times with diethyl ether. The organic layers were washed, dried and then concentrated.

Step 3: Synthesis of benzyl dimethyl (branched alkyl) quaternary ammonium chloride

A four-neck, 250 mL round-bottom flask equipped with a reflux condenser, thermocouple and 2 glass stoppers is charged with 20 g of dimethyl (branched alkyl) tertiary amine (from Step 2), 5.8 g of benzyl chloride and roughly 100 mL isopropyl alcohol. Next, 3.5 g of sodium bicarbonate was added to the mixture under stirring and the flask was kept at 75° C. for 48 hours. Then the reaction mixture was filtered hot over a Büchner funnel equipped with filter paper to remove solid sodium bicarbonate. Ethanol was removed by rota-evaporation, and the residue was dissolved in 100 ml of diethyl ether and extracted with three portions of 100 ml deionized water, all aqueous extracts were then combined and water was removed by rota-evaporation.

B. Organoclay Preparation

A sodium bentonite clay ore from Wyoming was dispersed in water at about 5 wt. % clay solids. The crude clay slurry was mixed overnight at ambient temperature and then centrifuged to yield a beneficiated clay slurry. Roughly 30 wt % of the crude bentonite clay was discarded during the beneficiation process, and the resulting purified clay slurry was ion exchanged into the sodium form prior to shearing with a Manton Gaulin homogenizer. The beneficiated and sheared clay had a cation exchange capacity of about 102 milliequivalents (meq.) per 100 grams clay as determined by the methylene blue method. The clay slurry was diluted with water to yield 2% clay solids at reaction and then heated to 65° C. prior to reaction with a certain cation exchange equivalent of benzyl dimethyl (branched alkyl) quaternary ammonium chloride, per 100 grams of clay (dry basis). After reaction, the organoclay was filtered, dried in a forced air oven set at 45° C. and milled to a fine powder. The sample was labeled 3383-11-2.

Example 2

Synthesis Of Dimethyl Di(Branched Alkyl) Quaternary Ammonium Bromide

Using a branched petrochemical alcohol as the starting material, a (branched alkyl) bromide and dimethyl (branched alkyl) tertiary amine were prepared as described in steps 1 and 2 of Example 1A.

A four-neck, 250 mL round-bottom flask equipped with a reflux condenser, thermocouple and 2 glass stoppers is charged with 25 g of dimethyl (branched alkyl) tertiary amine, 15.2 g of (branched alkyl) bromide and about 100 mL isopropyl alcohol. Next, 4.4 g of sodium bicarbonate was added to the mixture under stirring and the flask was kept at 75° C. for 120 hours or longer until the amine value is below one. Then the reaction mixture was filtered hot over a Büchner funnel equipped with filter paper to remove solid sodium bicarbonate. Isopropyl alcohol was removed by rota-evaporation. Purity of the final product was confirmed with ¹H NMR.

Organoclay Preparation

An organoclay was prepared according to the procedure of Example 1B using dimethyl di(branched alkyl) quaternary ammonium bromide as the quaternary ammonium compound. The organoclay sample was labeled 3279-36-1.

Example 3

A. Synthesis Of Dimethyl Di(Branched Alkyl) Quaternary Ammonium Bromide

A dimethyl di(branched alkyl) quaternary ammonium bromide compound was prepared as described in Example 1A where the branched alkyl group was derived from a branched fatty acid compound.

Step 1: Prisorene 3515 (Croda) isostearyl alcohol was used in the synthesis of a branched alkyl bromide in a similar manner as described in Example 1, Step A1. Prisorene 3515 is a fully hydrogenated alcohol and is derived from isostearic acid, which is a branched-chain fatty acid derived from vegetable oils or animal fats. Isosteraric acid is not a single molecule, but a rich isomeric mixture in which the branching occurs at different positions along the alkyl chain. The branching is short, mostly methylenic and multiple branching also occurs in small amounts.

Step 2: Synthesis of a dimethyl (branched alkyl) tertiary amine

The branched alkyl bromide, derived from isostearyl alcohol, was mixed with dimethylamine ethanolic solution. The mixture is stirred at room temperature for 24 h, then a 10% aqueous solution of sodium hydroxide is added and the mixture is extracted three times with diethyl ether. The organic layers were washed, dried and then concentrated.

Step 3: Synthesis of dimethyl di(branched alkyl) quaternary ammonium bromide

The procedure of Example 2 was followed using the branched alkyl bromide and dimethyl (branched alkyl) tertiary amine each derived from isostearyl alcohol.

B. Organoclay Preparation

An organoclay was prepared according to Example 1B, using a cation exchange equivalent of a dimethyl di(branched alkyl) quaternary ammonium bromide compound where the branched alkyl groups were obtained from an isostearyl alcohol. The sample was labeled sample was labeled 3279-22-2.

Comparative Example 1

Following the procedure of Example 1B, a control organoclay was prepared using a commercially available benzyl dimethyl hydrogenated tallow quaternary ammonium chloride and this sample was labeled as 3383-11-1.

Comparative Example 2

Following the procedure of Example 1B, a control organoclay was prepared with commercially available dimethyl dihydrogenated tallow ammonium chloride and this sample was labeled 3279-22-1.

Comparative Example 3

A polyamide was prepared as described in U.S. Pat. Nos. 7,345,010 and 7,799,742 each of which is incorporated by reference in its entirety herein.

Testing of Branched Alkyl Compositions

Mud compositions were prepared for evaluation based on Formulation 1 that contained a synthetic IAO as a base oil and were weighted to 13 ppg with an oil:water ratio of 75:25.

TABLE 1

Formulation 1

Raw Materials
Charge (g)

Base Oil: IAO
172

Primary Emulsifier:
10
MultiMixer Mix 2 min.

25% Calcium Chloride
69
MultiMixer Mix 4 min.

Brine

Lime
10
MultiMixer Mix 4 min.

Tested Additive
(See Tables)
MultiMixer Mix 5 min.

Weighting Agent: Barite
270
MultiMixer Mix 30 min.

The mud compositions were dynamically aged using a roller oven for 16 hours at 150° F., then statically aged for 16 hrs at 40° F., then were dynamically aged for 16 hours at 250° F., 300° F., and 350° F. using a roller oven. After the muds were water cooled for one hour, they were mixed on a Hamilton beach MultiMixer for 10 minutes. Viscosity measurements of the muds were measured using the Fann OFI-900 at 120° F. initially and after each thermal cycle using test procedures API RP 13B. For 40° F. static aging, the test was made at 40° F.

Example 4

Organoclay 3279-36-1 (Example 2), was prepared using Formulation 1 and tested as discussed above. The rheological profile is shown below in Table 2.

TABLE 2

ppb 3279-36-1 Test Conditions

4 ppb
4 ppb
4 ppb
4 ppb
4 ppb
4 ppb

OFI 900 Visc.
Initial
HR 150° F.
SA 40° F.
HR 250° F.
HR 300° F.
HR 350° F.

@ 120° F.
120° F. Test
120° F. Test
40° F. Test
120° F. Test
120° F. Test
120° F. Test

600 RPM
66
58
115
69
66
44

Reading

300 RPM
42
36
68
43
41
23

Reading

200 RPM
33
28
51
34
32
13

Reading

100 RPM
23
19
33
24
22
8

Reading

6 RPM
10
8
11
10
9
2

Reading

3 RPM
9
7
9
9
9
1

Reading

Apparent
33
29
58
35
33
22

Visc., cPs

Plastic Visc.,
24
22
47
26
25
21

cPs

Yield Point,
18
14
21
17
16
2

Lbs/100 ft²

Electrical
883
1067
1067
1059
932
581

Stability

10 Sec Gel
10
10
11
11
11
2

10 Min Gel
—
14
17
17
17
3

Example 5

Organoclay 3279-36-1 (Example 2), was prepared using Formulation 1 and tested as discussed above. The rheological profile is shown below in Table 3.

TABLE 3

ppb 3279-36-1 Test Conditions

7 ppb
7 ppb
7 ppb
7 ppb
7 ppb
7 ppb

OFI 900 Visc.
Initial
HR 150° F.
SA 40° F.
HR 250° F.
HR 300° F.
HR 350° F.

@ 120° F.
120° F. Test
120° F. Test
40° F. Test
120° F. Test
120° F. Test
120° F. Test

600 RPM
100
88
197
109
101
47

Reading

300 RPM
68
55
118
73
66
27

Reading

200 RPM
56
44
88
59
55
18

Reading

100 RPM
43
32
57
44
41
11

Reading

6 RPM
20
15
19
22
21
4

Reading

3 RPM
19
14
17
20
19
3

Reading

Apparent
50
44
99
55
51
24

Visc., cPs

Plastic Visc.,
32
33
79
36
35
20

cPs

Yield Point,
36
22
39
37
31
7

Lbs/100 ft²

Electrical
1128
1126
1126
1103
942
1012

Stability

10 Sec Gel
25
17
20
24
24
5

10 Min Gel
—
23
28
30
34
7

ECD (ppg)
13.6
13.4
13.8
13.7
13.6
13.2

Example 6

Organoclay 3279-36-1 (Example 2), was prepared using Formulation 1 and tested as discussed above. The rheological profile is shown below in Table 4.

TABLE 4

ppb 3279-36-1 Test Conditions

10 ppb
10 ppb
10 ppb
10 ppb
10 ppb
10 ppb

OFI 900 Visc.
Initial
HR 150° F.
SA 40° F.
HR 250° F.
HR 300° F.
HR 350° F.

@ 120° F.
120° F. Test
120° F. Test
40° F. Test
120° F. Test
120° F. Test
120° F. Test

600 RPM
177
155
290
198
175
81

Reading

300 RPM
122
100
179
137
122
47

Reading

200 RPM
101
80
138
113
102
37

Reading

100 RPM
76
57
94
83
76
25

Reading

6 RPM
37
27
35
39
38
10

Reading

3 RPM
35
24
31
36
36
9

Reading

Apparent
89
78
145
99
88
41

Visc., cPs

Plastic Visc.,
55
55
111
31
53
34

cPs

Yield Point,
67
45
68
76
69
13

Lbs/100 ft²

Electrical
1278
1291
1291
1331
860
1067

Stability

10 Sec Gel
45
26
36
41
41
12

10 Min Gel
—
34
51
49
55
17

Example 7

Organoclay 3279-36-1 (Example 2), and polyamide, comparative example 3, was prepared using Formulation 1 and tested as discussed above. The rheological profile is shown below in Table 5.

TABLE 5

ppb Comparative Example 3

2 ppb
2 ppb
2 ppb
2 ppb
2 ppb
2 ppb

ppb 3279-36-1 Test Conditions

4 ppb
4 ppb
4 ppb
4 ppb
4 ppb
4 ppb

OFI 900 Visc.
Initial
HR 150° F.
SA 40° F.
HR 250° F.
HR 300° F.
HR 350° F.

@ 120° F.
120° F. Test
120° F. Test
40° F. Test
120° F. Test
120° F. Test
120° F. Test

600 RPM
89
95
182
85
70
46

Reading

300 RPM
61
62
109
56
43
26

Reading

200 RPM
50
49
81
46
33
20

Reading

100 RPM
37
35
49
34
22
12

Reading

6 RPM
19
17
14
19
12
4

Reading

3 RPM
18
15
12
18
11
4

Reading

Apparent
45
48
91
43
35
23

Visc., cPs

Plastic Visc.,
28
33
73
29
27
20

cPs

Yield Point,
33
29
36
27
16
6

Lbs/100 ft²

Electrical
1634
1322
1322
1159
725
494

Stability

10 Sec Gel
23
19
14
21
13
7

10 Min Gel
—
31
24
37
29
17

ECD (ppg)
13.6
13.5
13.8
13.5
13.3
13.2

Example 8

Organoclay 3279-22-1 (Comparative example 2) was prepared using Formulation 1 and tested as discussed above. The rheological profile is shown below in Table 6.

TABLE 6

ppb 3279-22-1 Test Conditions

7 ppb
7 ppb
7 ppb
7 ppb
7 ppb
7 ppb

OFI 900 Visc.
Initial
HR 150° F.
SA 40° F.
HR 250° F.
HR 300° F.
HR 350° F.

@ 120° F.
120° F. Test
120° F. Test
40° F. Test
120° F. Test
120° F. Test
120° F. Test

600 RPM
98
86
279
115
90
59

Reading

300 RPM
65
56
193
77
62
35

Reading

200 RPM
54
46
156
64
51
26

Reading

100 RPM
41
35
115
48
40
18

Reading

6 RPM
20
17
57
24
21
7

Reading

3 RPM
19
14
55
22
20
7

Reading

Apparent
49
43
140
58
45
30

Visc., cPs

Plastic Visc.,
33
30
86
38
28
24

cPs

Yield Point,
32
26
107
39
34
11

Lbs/100 ft²

Electrical
1066
1339
1339
1193
1134
1166

Stability

10 Sec Gel
24
16
58
25
23
8

10 Min Gel
—
24
64
31
31
12

ECD (ppg)
13.6
13.5
14.8
13.7
13.6
13.3

Example 9

Organoclay 3279-22-1 (Comparative example 2) was prepared using Formulation 1 and tested as discussed above. The rheological profile is shown below in Table 7.

TABLE 7

ppb 3279-22-1 Test Conditions

4 ppb
4 ppb
4 ppb
4 ppb
4 ppb
4 ppb

OFI 900 Visc.
Initial
HR 150° F.
SA 40° F.
HR 250° F.
HR 300° F.
HR 350° F.

@ 120° F.
120° F. Test
120° F. Test
40° F. Test
120° F. Test
120° F. Test
120° F. Test

600 RPM
60
61
110
66
60
40

Reading

300 RPM
38
37
71
42
38
22

Reading

200 RPM
30
29
56
33
30
14

Reading

100 RPM
21
20
38
23
21
8

Reading

6 RPM
9
9
16
11
9
2

Reading

3 RPM
8
8
15
10
8
2

Reading

Apparent
30
31
55
33
30
20

Visc., cPs

Plastic Visc.,
22
24
39
24
22
18

cPs

Yield Point,
16
13
32
18
16
4

Lbs/100 ft²

Electrical
939
1060
1060
1120
959
626

Stability

10 Sec Gel
11
9
16
12
12
2

10 Min Gel
—
14
21
16
15
4

Example 10

Organoclay 3279-22-1 (Comparative example 2) was prepared using Formulation 1 and tested as discussed above. The rheological profile is shown below in Table 8.

TABLE 8

ppb 3279-22-1 Test Conditions

10 ppb
10 ppb
10 ppb
10 ppb
10 ppb
10 ppb

OFI 900 Visc.
Initial
HR 150° F.
SA 40° F.
HR 250° F.
HR 300° F.
HR 350° F.

@ 120° F.
120° F. Test
120° F. Test
40° F. Test
120° F. Test
120° F. Test
120° F. Test

600 RPM
125
128
323
147
130
63

Reading

300 RPM
88
88
225
105
93
42

Reading

200 RPM
74
73
187
89
78
34

Reading

100 RPM
57
55
141
69
62
25

Reading

6 RPM
30
28
73
36
33
12

Reading

3 RPM
29
25
68
34
31
11

Reading

Apparent
63
64
162
74
65
32

Visc., cPs

Plastic Visc.,
37
40
98
42
37
21

cPs

Yield Point,
51
48
127
63
56
21

Lbs/100 ft²

Electrical
1278
1089
1089
1438
762
1176

Stability

10 Sec Gel
33
28
68
37
35
14

10 Min Gel
—
38
84
46
45
19

A summary of rheological properties for various compositions prepared in Formula 1 is shown in Table 9.

TABLE 9

[Tested Sample] Concentrations

Mixture of

Inventive Example

Mixture of
1 and

Comparative
Comparative

Comparative
Inventive
Inventive
Examples 1 and 2
Example 2

Example 1
Example 1
Example 2
4/2 ppb
4/2 ppb

7 ppb

7 ppb

7 ppb

4/2 ppb

4/2 ppb

HR
7 ppb
HR
7 ppb
HR
7 ppb
HR
4/2 ppb
HR
4/2 ppb

150 F.
SA 40 F.
150 F.
SA 40 F.
150 F.
SA 40 F.
150 F.
SA 40 F.
150 F.
SA 40 F.

OFI 900 Visc. @
120 F.
40 F.
120 F.
40 F.
120 F.
40 F.
120 F.
40 F.
120 F.
40 F.

120° F.
Test
Test
Test
Test
Test
Test
Test
Test
Test
Test

600 RPM
86
279
88
197
83
196
87
178
95
182

Reading

300 RPM
56
193
55
118
55
116
56
105
62
109

Reading

200 RPM
46
156
44
88
45
87
44
78
49
81

Reading

100 RPM
35
115
32
57
34
57
31
49
35
49

Reading

6 RPM Reading
17
57
15
19
17
21
17
19
17
14

3 RPM Reading
14
55
14
17
15
19
15
17
15
12

Apparent Visc.,
43
140
44
99
42
98
44
89
48
91

cPs

Plastic Visc., cPs
30
86
33
79
28
80
31
73
33
73

Yield Point,
26
107
22
39
27
36
25
32
29
36

Lbs/100 ft²

Electrical
1339
1339
1126
1126
1314
1314
1541
1541
1322
1322

Stability

10 Sec Gel
18
58
17
20
18
20
18
18
19
14

10 Min Gel
24
62
23
28
25
29
30
29
31
24

ECD (ppg)
13.5
14.8
13.4
13.8
13.5
13.8
13.5
13.7
13.5
13.8

Example 11

A mixture of Comparative Example 2 and Comparative Example 3 was prepared using Formulation 1 and tested as discussed above. The rheological profile is shown below in Table 10.

TABLE 10

Comparative Example 3

1 ppb
1 ppb
2 ppb
2 ppb
3 ppb
3 ppb

Comparative Example 2

3 ppb
3 ppb
3 ppb
3 ppb
3 ppb
3 ppb

OFI 900 Visc.
Initial
HR 150° F.
Initial
HR 150° F.
Initial
HR 150° F.

@ 120° F.
120° F. Test
120° F. Test
120° F. Test
120° F. Test
120° F. Test
120° F. Test

600 RPM
84
71
75
66
63
61

Reading

300 RPM
52
45
46
40
40
38

Reading

200 RPM
40
35
37
31
32
30

Reading

100 RPM
27
25
26
21
22
21

Reading

6 RPM
14
13
12
9
11
11

Reading

3 RPM
13
12
11
8
10
10

Reading

Apparent
42
36
38
33
32
31

Visc., cPs

Plastic Visc.,
32
26
29
26
23
23

cPs

Yield Point,
20
19
17
14
17
15

Lbs/100 ft²

Electrical
668
975
1465
1322
1543
1586

Stability

10 Sec Gel
20
17
15
11
13
12

10 Min Gel
—
26
—
18
—
21

Example 12

A mixture of Comparative Example 2 and Comparative Example 3 was prepared using Formulation 1 and tested as discussed above. The rheological profile is shown below in Table 11.

TABLE 11

Comparative Example 3

1 ppb
1 ppb
1 ppb
1 ppb
1 ppb
1 ppb

Comparative Example 2

4 ppb
4 ppb
4 ppb
4 ppb
4 ppb
4 ppb

OFI 900 Visc.
Initial
HR 150° F.
SA
HR 250° F.
HR 300° F.
HR 350° F.

@ 120° F.
120° F. Test
120° F. Test
40° F. Test
120° F. Test
120° F. Test
120° F. Test

600 RPM
87
74
133
82
69
42

Reading

300 RPM
57
48
82
55
44
24

Reading

200 RPM
45
38
63
44
35
16

Reading

100 RPM
32
28
43
33
25
10

Reading

6 RPM
17
14
19
18
13
3

Reading

3 RPM
16
13
18
17
12
3

Reading

Apparent
44
37
67
41
35
21

Visc., cPs

Plastic Visc.,
30
26
51
27
25
18

cPs

Yield Point,
27
22
31
28
19
6

Lbs/100 ft²

Electrical
822
1044
1044
879
738
476

Stability

10 Sec Gel
16
19
21
20
17
3

10 Min Gel
23
28

34
29
9

ECD (ppg)
13.5
13.4
13.6
13.5
13.4
13.2

Example 13

A mixture of Comparative Example 2 and Comparative Example 3 was prepared using Formulation 1 and tested as discussed above. The rheological profile is shown below in Table 12.

TABLE 12

Comparative Example 3

2 ppb
2 ppb
2 ppb
2 ppb
2 ppb
2 ppb

Comparative Example 2

4 ppb
4 ppb
4 ppb
4 ppb
4 ppb
4 ppb

OFI 900 Visc.
Initial
HR 150° F.
SA
HR 250° F.
HR 300° F.
HR 350° F.

@ 120° F.
120° F. Test
120° F. Test
40° F. Test
120° F. Test
120° F. Test
120° F. Test

600 RPM
105
87
178
83
68
47

Reading

300 RPM
70
56
105
54
43
27

Reading

200 RPM
57
44
78
43
34
21

Reading

100 RPM
42
31
49
31
24
13

Reading

6 RPM
23
17
19
17
14
5

Reading

3 RPM
22
15
17
15
13
5

Reading

Apparent
53
44
89
42
34
24

Visc., cPs

Plastic Visc.,
35
31
73
29
25
20

cPs

Yield Point,
35
25
32
25
18
7

Lbs/100 ft²

Electrical
1395
1541
1541
1044
616
466

Stability

10 Sec Gel
26
18
18
19
17
7

10 Min Gel
—
30
29
35
35
16

ECD (ppg)
13.6
13.5
13.7
13.5
13.4
13.2

Example 14

A mixture of Comparative Example 2 and Comparative Example 3 was prepared using Formulation 1 and tested as discussed above. The rheological profile is shown below in Table 13.

TABLE 13

Comparative Example 3

3 ppb
3 ppb
3 ppb
3 ppb
3 ppb
3 ppb

Comparative Example 2

4 ppb
4 ppb
4 ppb
4 ppb
4 ppb
4 ppb

OFI 900 Visc.
Initial
HR 150° F.
SA
HR 250° F.
HR 300° F.
HR 350° F.

@ 120° F.
120° F. Test
120° F. Test
40° F. Test
120° F. Test
120° F. Test
120° F. Test

600 RPM
74
80
152
81
69
50

Reading

300 RPM
48
51
88
53
44
30

Reading

200 RPM
39
40
64
42
35
22

Reading

100 RPM
28
29
40
33
25
14

Reading

6 RPM
15
16
14
17
15
5

Reading

3 RPM
14
15
12
16
14
5

Reading

Apparent
37
40
76
41
35
25

Visc., cPs

Plastic Visc.,
26
29
64
28
25
20

cPs

Yield Point,
22
22
24
25
19
10

Lbs/100 ft²

Electrical
1670
1733
1733
1137
888
503

Stability

10 Sec Gel
18
18
14
21
22
8

10 Min Gel
—
30

35
38
19

ECD (ppg)
13.4
13.4
13.6
13.5
13.4
13.3

Example 15

The effect of temperature on the viscosity of a 100% solids epoxy coating was examined. The formulation of Table 14 was prepared.

TABLE 14

Description: 800 g batch; 70 mm blade heavy

duty; 1 L stainless steel jacketed mixing pot

Formula & Procedure

1) Set water bath to 150° F./65° C. Add the following
800 g

materials (+/−0.1 g).

Epon 828
238.37

Erysys GE-8
37.35

Organoclay additive
10.36

Methanol/Water (95/5) Polar activator
3.31

2) Add while mixing @ 300-700 rpm.

TI Pure R-900
76.15

Nicron 503
34.47

Minex 4
34.47

Heucophos ZPA (Heubach)
5.60

Wolastocoat 10 ES
121.65

Cimbar UF (Barytes)
139.47

3) Add the following Let Down ingredients to mix pot (+/−0.1 g)

Epon 828
96.94

Tint -Ayd HS 20317
1.87

4) Mix 10 min at 1000 rpm at 120° F. while covered.

Total
800.00

Part B: Lite 2001 LV Amine (AHEW 132) 100 Part A: 28.25 Part B

The viscosity of the Part A system was measured at 72° F. and at 40 OF. The sag of the Part A+Part B expoxy coating was then measured. The results are shown in Table 15.

TABLE 15

Part “A”
Part “A”

Brookfield
Brookfield
PART “A” +

viscosity, cp
viscosity, cp
PART “B”

measured at 72° F.
measured at 40 F.
SAG, mils

Blank
26800
164000
10

Comparative
48400
362000
18

example 1

Example 1
49600
238000
19

The data in Table 15 demonstrates that for the Part A system, addition of the inventive organoclay of example 1 and the organoclay of comparative example 1 results in an increased viscosity and a thicker coating for the Part A+B system compared to Part A and Part A+B in the absence of organoclay. Comparison of the Part A system at 72° F. versus 40° F. shows that the inventive organoclay, example 1, increases the viscosity but advantageously not to the degree as the organoclay of comparative example 1.

The present disclosure may be embodied in other specific forms without departing from the spirit or essential attributes of the invention. Accordingly, reference should be made to the appended claims, rather than the foregoing specification, as indicating the scope of the disclosure. Although the foregoing description is directed to the preferred embodiments of the disclosure, it is noted that other variations and modification will be apparent to those skilled in the art, and may be made without departing from the spirit or scope of the disclosure.

Number	Name	Date	Kind
4024189	Davis	May 1977	A
4371469	Foglia et al.	Feb 1983	A
4683336	Blackhurst	Jul 1987	A
4994620	Fong et al.	Feb 1991	A
5112519	Giacobbe et al.	May 1992	A
5634969	Cody et al.	Jun 1997	A
5677473	Tomifuji et al.	Oct 1997	A
5739087	Dennis	Apr 1998	A
5849960	Singleton et al.	Dec 1998	A
6008181	Cripe et al.	Dec 1999	A
6020303	Cripe et al.	Feb 2000	A
6150322	Singleton et al.	Nov 2000	A
6335312	Coffindaffer et al.	Jan 2002	B1
6462096	Dino	Oct 2002	B1
6946567	Zhang et al.	Sep 2005	B2
7098353	Zhang et al.	Aug 2006	B2
7148375	Edwards et al.	Dec 2006	B2
7342136	Kenneally et al.	Mar 2008	B2
7462730	Raney et al.	Dec 2008	B2
7781390	Singleton et al.	Aug 2010	B2
20040042988	Raney et al.	Mar 2004	A1
20110263884	Ngo et al.	Oct 2011	A1
20110275844	Ngo et al.	Nov 2011	A1

Organoclay compositions for drilling fluids useful to provide substantially constant rheology profiles to such fluids over a wide temperature range

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US Referenced Citations (23)

Non-Patent Literature Citations (11)

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Entry
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