Claims
- 1. A method for conducting a drilling operation in a subterranean formation using a fragile gel drilling fluid comprising:
(a) an invert emulsion base; (b) one or more thinners; (c) one or more emulsifiers; and (d) one or more weighting agents.
- 2. The method of claim 1 wherein said invert emulsion has a continuous base comprised of at least one component selected from at least one of the following groups:
(i) esters prepared from fatty acids and alcohols, esters prepared from olefins and fatty acids or alcohols; (ii) olefins comprising linear alpha olefins, isomerized olefins having a straight chain olefins having a branched structure, isomerized olefins having a cyclic structure; olefin hydrocarbons; (iii) paraffin hydrocarbons comprising linear paraffins, branched paraffins, poly-branched paraffins, cyclic paraffins, isoparaffins; (iv) mineral oil hydrocarbons; (v) glyceride triesters comprising rapeseed oil, olive oil, canola oil, castor oil, coconut oil, corn oil, cottonseed oil, lard oil, linseed oil, neatsfoot oil, palm oil, peanut oil, perilla oil, rice bran oil, safflower oil, sardine oil, sesame oil, soybean oil, sunflower oil; and (vi) naphthenic hydrocarbons.
- 3. The method of claim 2 wherein said thinner is selected from at least one of the following groups:
(i) a compound having the formula: R—(C2H4O)n(C3H6O)m(C4H8O)k—H where R is a saturated or unsaturated, linear or branched alkyl radical having about 8 to about 24 carbon atoms, n is a number ranging from about 1 to about 10, m is a number ranging from about 0 to about 10, and k is a number ranging from about 0 to about 10; and (ii) a non-ionic surfactant, said surfactant being the reaction product of at least one oxide, selected from the group comprising ethylene oxide, propylene oxide and butylene oxide, with C10-22 carboxylic acids or C10-22 carboxylic acid derivatives containing at least one double bond in position 9, 10, 13, or 14 having structural units of the general formula: 3 where R1 is a hydrogen atom, or an OH group, or a group OR2, and where R2 is an alkyl group of about 1 to about 18 carbon atoms, or an alkenyl group of about 2 to about 18 carbon atoms, or a group of the formula: 4 and where R3 is a hydrogen atom, or an alkyl group of about 1 to about 21 carbon atoms, or an alkylene group of about 2 to about 21 carbon atoms.
- 4. The method of claim 1 wherein said operation is drilling a borehole.
- 5. The method of claim 1 wherein said operation is running casing in a borehole.
- 6. The method of claim 1 wherein said operation is cementing a borehole.
- 7. The method of claim 1 wherein said fragile gel is a structure capable of suspending drill cuttings that may be immediately disrupted by movement of said fluid.
- 8. The method of claim 4 wherein said fragile gel reverts to a flowable or liquid state immediately upon resumption of drilling after a period of rest.
- 9. The method of claim 4 wherein no appreciable pressure spike is observed by pressure-while-drilling equipment when said drilling is resumed.
- 10. The method of claim 1 wherein said thinner reduces the viscosity of said drilling fluid at lower temperatures to a greater extent than it reduces the viscosity of said drilling fluid at higher temperatures.
- 11. The method of claim 1 wherein said drilling fluid has a lower yield point at lower temperatures than at higher temperatures.
- 12. The method of claim 1 wherein said drilling fluid is visco-elastic.
- 13. The method of claim 1 wherein the equivalent circulating density of said drilling fluid approximates the surface density of said drilling fluid.
- 14. The method of claim 4 wherein the ECDs are less than about 0.5.
- 15. The method of claim 14 wherein said drilling is in deep water
- 16. The method of claim 14 wherein said fluid is tolerant to contaminants, wherein said contaminants comprise drill cuttings from said drilling.
- 17. The method of claim 1 wherein said fluid does not exhibit sag when at rest.
- 18. A fragile gel drilling fluid comprising:
(a) an invert emulsion base; (b) one or more thinners; (c) one or more emulsifiers; and (d) one or more weighting agents.
- 19. The drilling fluid of claim 18 wherein said invert emulsion has a continuous base comprised of at least one component selected from at least one of the following groups:
(i) esters prepared from fatty acids and alcohols, esters prepared from olefins and fatty acids or alcohols; (ii) olefins comprising linear alpha olefins, isomerized olefins having a straight chain olefins having a branched structure, isomerized olefins having a cyclic structure; olefin hydrocarbons; (iii) paraffin hydrocarbons comprising linear paraffins, branched paraffins, poly-branched paraffins, cyclic paraffins, isoparaffins; (iv) mineral oil hydrocarbons; (v) glyceride triesters comprising rapeseed oil, olive oil, canola oil, castor oil, coconut oil, corn oil, cottonseed oil, lard oil, linseed oil, neatsfoot oil, palm oil, peanut oil, perilla oil, rice bran oil, safflower oil, sardine oil, sesame oil, soybean oil, sunflower oil; and (vi) naphthenic hydrocarbons.
- 20. The drilling fluid of claim 19 wherein said thinner is selected from at least one of the following groups:
(i) a compound having the formula: R—(C2H4O)n(C3H6O)m(C4H8O)k—H where R is a saturated or unsaturated, linear or branched alkyl radical having about 8 to about 24 carbon atoms, n is a number ranging from about 1 to about 10, m is a number ranging from about 0 to about 10, and k is a number ranging from about 0 to about 10; and (ii) a non-ionic surfactant, said surfactant being the reaction product of at least one oxide, selected from the group comprising ethylene oxide, propylene oxide and butylene oxide, with C10-22 carboxylic acids or C10-22 carboxylic acid derivatives containing at least one double bond in position 9, 10, 13, or 14 having structural units of the general formula: 5 where R1 is a hydrogen atom, or an OH group, or a group OR2, and where R2 is an alkyl group of about 1 to about 18 carbon atoms, or an alkenyl group of about 2 to about 18 carbon atoms, or a group of the formula: 6 and where R3 is a hydrogen atom, or an alkyl group of about 1 to about 21 carbon atoms, or an alkylene group of about 2 to about 21 carbon atoms.
- 21. The drilling fluid of claim 19 wherein said drilling fluid comprises a blend of said esters and said olefins, and said thinners and emulsifiers are derived from fatty acids, wherein said esters are selected from the group comprising about C12 to about C14 fatty acids and 2-ethyl hexanol or about C8 fatty acids and 2-ethyl hexanol and said olefins are selected from the group comprising isomerized, or internal, olefins having about 40 to about 70 weight percent C16 and about 20 to about 50 weight percent C18 and wherein said thinners are selected from the group comprising:
thinners having the following general formula:
R—(C2H4O)n(C3H6O)m(C4H8O)k—H, where R is a saturated, linear alkyl radical having about 12 to about 14 carbon atoms, n is a number ranging from about 1 to about 10, m is a number ranging from about 0 to about 10, and k is a number ranging from about 0 to about 10; thinners comprising a non-ionic surfactant which is a reaction product of ethylene oxide, propylene oxide and/or butylene oxide with C10-22 carboxylic acids or C10-22 carboxylic acid derivatives containing at least one double bond in position 9/10 and/or 13/14 having units of the general formula: 7 where R1 is a hydrogen atom or an OH group or a group OR2, where R2 is an alkyl group of about 1 to about 18 carbon atoms, or an alkenyl group of about 2 to about 18 carbon atoms or a group of the formula: 8 where R3 is a hydrogen atom, or an alkyl group of about 1 to about 21 carbon atoms or an alkylene group of about 2 to about 21 carbon atoms; and combinations thereof; and wherein said drilling fluid further comprises at least one additional additive compatible with said ester blend wherein said additive is selected from the group comprising additives for filtration control, additives for high temperature high pressure control, and additives to reduce or control temperature rheology.
- 22. The drilling fluid of claim 18 wherein said drilling fluid forms a structure that is capable of suspending drill cuttings at rest and that is instantaneously disruptible by movement.
- 23. The drilling fluid of claim 18 wherein said fluid forms a fragile gel at rest.
- 24. The drilling fluid of claim 18 wherein the ECDs of said fluid when used in drilling boreholes are less than about 0.5.
- 25. The drilling fluid of claim 18 wherein said fluid is visco-elastic.
- 26. A method for reducing the loss of drilling fluid into a subterranean formation while drilling a borehole in said formation, said method comprising using the drilling fluid of claim 18.
- 27. A method for eliminating or avoiding sag during drilling operations, said method comprising employing the drilling fluid of claim 18 in said drilling operations.
- 28. A method for reducing the loss of drilling fluid into a subterranean formation while drilling a borehole in said formation, said method comprising using the drilling fluid of claim 18.
- 29. A method for preparing a drilling fluid comprising formulating a drilling fluid comprising an invert emulsion base comprising an ester blend and further comprising a thinner compatible with said ester blend such that said fluid builds a structure at rest capable of suspending drill cuttings without appreciable sag and wherein said structure may be immediately disrupted by movement of said fluid without registering an appreciable pressure spike with pressure-while-drilling equipment.
RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent application Ser. No. 09/929,465, filed Aug. 14, 2001, pending, and a continuation-in-part of International Patent Application Nos. PCT/US00/35609 and PCT/US00/35610, both filed Dec. 29, 2000, and pending under Chapter II of the Patent Cooperation Treaty.
Continuation in Parts (3)
|
Number |
Date |
Country |
Parent |
09929465 |
Aug 2001 |
US |
Child |
10175272 |
Jun 2002 |
US |
Parent |
PCT/US00/35609 |
Dec 2000 |
US |
Child |
10175272 |
Jun 2002 |
US |
Parent |
PCT/US00/35610 |
Dec 2000 |
US |
Child |
10175272 |
Jun 2002 |
US |