Patent Application
20100096120
This invention relates to horizontal well liners, and more particularly to well liner segments which permit in situ upgrading of hydrocarbons during recovery from an underground reservoir, a method of manufacture of same, and to a process of in situ upgrading and recovery using such horizontal well segments.
Oil upgrader catalyst, such as a standard hydrotreating/HDS catalyst manufactured by Akzo Chemie Nederaland bv Amsterdam, and identified as Ketjenefine1™ 742-1, 3AQ, has been used in prior art oilfield in situ hydrocarbon upgrading processes of the type described in U.S. Pat. No. 6,412,557. 1 Trademark of Akzo Chemie Nederaland bv Amsterdam for hydrotreating catalyst
Specifically, U.S. Pat. No. 6,412,557 describes a process for upgrading hydrocarbons within a petroleum reservoir by placing such a known hydrotreating catalyst around an exterior periphery of a centrally located perforated pipe situated in the horizontal leg of a horizontal well bore for upgrading and producing oil from a heavy oil (bitumen) formation.
Specifically, as may be understood from the in situ upgrading process of U.S. Pat. No. 6,412,557 and the methodology of the prior art in relation to in situ oil upgrading, a hole is drilled from the surface down to the target reservoir oil zone of the petroleum formation. The hole is curved so that it becomes horizontal when it arrives at the target reservoir oil zone. The horizontal section is typically created near the lowermost base portion of the target reservoir zone, and is extended laterally along the lowermost base portion to create a horizontal well, typically extending for hundreds of meters to the intended toe of the horizontal well. The vertical section of such well is cased. If the reservoir rock is consolidated, the horizontal section may be left open and un-cased, but sometimes a perforated liner is emplaced in the horizontal section to mitigate against the production of sand fines. If the rock is un-consolidated it is imperative to emplace a perforated liner to prevent complete collapse of the hole. Once drilling of the hole is completed a metal pipe is pushed into the hole, typically all the way to the intended toe of the horizontal well. In the horizontal section, this pipe is referred-to as the ‘liner’. The liner will have openings that are sized to allow reservoir fluids to enter the interior of the liner for flowing to the surface, but exclude the entry of sand that could plug the liner or cause operational difficulty with oil treating facilities at the surface. The openings in the liner can be narrow slits, in which case the pipe is called a ‘slotted liner’, or they may be narrow apertures between rows of wire that is wrapped around a pipe having relatively large holes, which are called ‘wire-wrapped screens’. Both slotted liners and wire-wrapped screens are commonplace in the design of horizontal wells. The separation of the liner from the undisturbed reservoir is small, typically in the range of 1-2 inches based on a centralized liner. While the bore hole may be drilled larger by reaming operations to leave more space between the liner and the reservoir, this is an additional expense.
As taught in the prior art and for example U.S. Pat. No. 6,412,557, the 1-2 inch annular interstitial space which exists between an un-reamed hole (typically approximately 12.25 inches in diameter) and the outside diameter of the centralized liner (typically of in the range of about 9.6 inches) is filled with catalyst of the type described above or a similar catalyst, by pumping such catalyst downhole into such interstitial space. The catalyst permits upgrading of the oil immediately prior to entering the perforated well liner so as to increase flowability of the produced oil within the horizontal well to more easily produce such oil to surface.
Disadvantageously, however, with this prior art method, since the resulting vertical path of draining fluids (oil) into the perforated liner is very short, the residence time of the oil in the interstitial space which contains such catalyst is very short, and the Gas and Liquid Hourly Space Velocity (“LHSV”) will be very high. By way of example, for a well of the above dimensions producing 100 m3/day of produced oil having a well 1-inch annular catalyst zone, the LHSV is approximately 2670 hr−1 and the residence time is only approximately 11 seconds. While this short residence time may provide some upgrading, it would be much more desirable to have a catalyst placement design that provides much longer residence times for the oil being exposed to such upgrading catalyst.
Accordingly, a real need exists for a liner design and an improved oilfield in situ hydrocarbon upgrading process which allows increased time of exposure of the produced oil to upgrader catalyst, to thereby improve flowability and increase effective recovery from underground petroleum formations, particularly from bitumen and tar sands formations.
The present invention relates to horizontal well liner designs which allow increased time or extent of exposure in which produced oil is exposed to upgrader catalyst during in situ hydrocarbon production, as well as improved methods for producing hydrocarbons using in situ hydrocarbon production methods, contemplating use of well liner segments containing catalyst to upgrade oil during production.
Specifically, in a broad embodiment of the present invention, a well liner segment for upgrading hydrocarbons during collection is provided, to better allow collection of hydrocarbons from an underground hydrocarbon reservoir. Such liner segment possesses first and second mutually opposite ends and is adapted to be coupled in a horizontal manner at both of said mutually opposite ends to other elongate well liner segments to form an elongate well liner.
Significantly, each well liner segment comprises:
wherein the interstitial space is adapted to be filled with a catalyst to permit upgrading and improve flowability of said hydrocarbon when the hydrocarbon flows through said interstitial passage and thereafter into the inner liner member via said apertures therein.
In a first embodiment, the well liner segment of the present invention is adapted to permit inward radial flow of the produced oil. Specifically, the apertures in the outer and inner members are located so as to permit the oil to travel radially inwardly through apertures in the outer liner member into the interstitial space where such oil contacts the catalyst, and continue directly radially inwardly or alternatively circumferentially about the inner liner and thereafter radially inwardly through radially-aligned apertures in the inner liner and be collected in the inner liner, whereafter such upgraded oil may then be pumped or transferred in an appropriate manner to the surface (hereinafter the so-called “radial flow” configuration).
The increase in exposure time to catalyst which results from such horizontal well liner design can be seen mathematically. For example, in the prior art, where as mentioned above, the diameter of an unreamed horizontal well bore outside diameter is typically 12.25 inches and the tubing diameter of prior art (single tube) well liner being in the range of 9.6 inches, accounting for a well liner thickness of ¼ inch, the effective length of travel of oil through catalyst in the outside space between the horizontal well bore and the well liner is only 1.075 inches (ie [12.25−2×(0.25)−9.6]/2} and the resulting cross-sectional area of such space [π×(11.752−9.62)/4]=36 sq. inches, assuming the well liner is concentrically located in the well bore.
By way of contrast, for a 9.6 inch diameter circular outer well liner segment of the present invention (ie outer liner member diameter equals 9.6 inches) and an inner member outside diameter of 5.0 inches, assuming a tubing thickness of ¼ inches, the effective radial length of travel of oil through catalyst in the resulting interstitial space between the outer member and the inner member centrally located within such outer member, when the thickness of the steel is accounted for, is increased to 2.0 inches (ie [9.6−2×(0.25)−5.0]/2=2.0) and the resulting cross-sectional area of the interstitial space in which catalyst is placed increases accordingly to: [π(9.6−0.25×2)25.02)/4]−45.4 sq. inches. If catalyst is also placed in the interstitial space between the horizontal well bore and the outer liner member, the effective radial length of travel of oil is increased to 3.075 inches (ie 1.075+2.0 inches), thus nearly tripling the radial distance which the oil travels through catalyst and thus likewise similarly increasing the time the oil is exposed to catalyst.
In a second alternative embodiment of the well liner of the present invention which likewise serves to increase the amount and time or extent of exposure to catalyst, apertures are situated in the outer liner relative to the inner liner to allow oil at one end of the outer well liner to flow into the interstitial space and thereafter cause such oil to flow laterally along such interstitial space to apertures in the inner liner member located proximate the opposite end of the well liner segment, before permitting the oil to drain or flow into the inner liner member, so as to thereby increase the time and amount of exposure of such oil to catalyst which is packed in such interstitial space (hereinafter the so-called “lateral flow” configuration). The effect of the lateral flow is to greatly increase the residence time of the draining fluids over the catalyst. For example, if the lateral travel length of oil in the interstitial passage between unaligned apertures of the outer and inner liners is 15 inches, the residence time using a lateral flow design of the present invention will be more than ten times as for the radial flow case in the prior art for identical fluid volumetric flow rates having only a effective length of travel of oil through catalyst of only 1.075 inches. While it may seen desirable to make the slotted segments shorter, for longer residence times, this must be balanced with the expected reduction in volumetric fluid production rates since there are fewer slots open to the reservoir on the outer liner.
Accordingly, in such second alternative embodiment of the well liner of the present invention, the apertures in said outer member are situated proximate a first end of mutually opposite ends of the well liner segment, and the apertures in the inner member are situated proximate an opposite second end of the well liner segment. The particular arrangement of such apertures respectively in the inner and outer liner members, namely positioning the apertures in the outer member proximate said first end thereof, allows said hydrocarbon to enter the interstitial space and to thereafter travel longitudinally along the well liner segment and within said interstitial space towards said second end while simultaneously contacting said catalyst therein so as to be upgraded, and to thereafter pass into said inner member via apertures in said inner member proximate said second end so as to become collected in said inner member of said well liner segment.
Alternatively, a configuration of apertures may be used which combines both a “lateral flow” configuration and a “radial flow” configuration.
In a preferred embodiment, at one end of the well liner segment the outer liner is affixed to the inner liner, and at another end the outer liner is in a slidable relationship to the inner liner (as more fully described below in various contemplated configurations) so as to allow some longitudinal movement of the inner liner member relative to the outer liner member in order to prevent buckling or overstressing of either the outer or inner liner members due to differential thermal expansion of the inner liner relative to the outer liner, which may otherwise arise in in situ production methods where well liner segments of the present invention are used.
Thus in one preferred embodiment, the inner well liner is centrally located in the outer well liner by means of an annular ring at one end, welded to the exterior of the inner well liner and to the interior of the outer well liner. At an opposite end the inner liner is concentrically located within the outer liner by two concentric rings, a first ring welded to the interior of the outer liner, and a second ring mounted to the exterior of the inner liner, which concentric ring arrangement permits thermal growth expansion of the inner liner relative to the outer liner, should uneven heating of the inner and outer liner members occur during use. The annular ring, and the concentric rings both also serve to maintain catalyst within the interstitial area between the inner and outer liners.
In an alternative configuration, there is provided means for slidably coupling the inner liner member to the outer liner member at a corresponding end of each of the inner and outer liner member, to prevent the inner liner member from being displaced from within the outer liner member, but simultanteously allowing some slidable longitudinal movement at one end of the inner liner relative to the outer liner. More particularly, means slidably coupling said inner liner member to said outer liner member at one end is provided, which comprises a first ring member fixedly attached to said outer liner member, which further contacts said inner liner member in slidable engagement therewith so as to permit longitudinal slidable movement of said inner liner member relative to the outer liner member. Alternatively, the means coupling said inner liner member to said outer liner member comprises a first ring member fixedly attached to said inner liner member, which contacts said outer liner member in slidable engagement therewith so as to permit longitudinal slidable movement of said inner liner member relative to the outer liner member.
Still further alternatively, in a preferred embodiment, the means coupling said inner liner member to said outer liner member comprises a first and second pair of ring members situated proximate one end of said well liner segment, said first ring member fixedly coupled to said inner liner member, said second ring member fixedly coupled to said outer liner member, wherein each of said first and second ring members co-operate in a mutual slidable engagement relationship so as to permit longitudinal movement of associated inner and outer liner members relative to each other.
In a further aspect of the present invention, the invention comprises an improved in situ process for upgrading hydrocarbons when collecting said hydrocarbons from an underground hydrocarbon reservoir.
Such improved in situ process of the present invention comprises the steps of:
The catalyst which is provided in the interstitial space is contemplated as comprising a hydrocarbon upgrading catalyst selected from the group of hydrocarbon upgrading catalysts comprising:
wherein such catalyst is of a size sufficient to be substantially be prevented from escaping through any of said apertures in said outer or inner members so as to substantially prevent loss of said catalyst once said catalyst is situated in said interstitial space.
In a preferred embodiment, the oil upgrader catalyst is a hydrodesulphurization catalyst, and in a further preferred embodiment is hydrotreating/HDS catalyst manufactured by Akzo Chemie Nederaland bv Amsterdam, and identified as Ketjenefine2™ 742-1, 3AQ. 2 Trademark of Akzo Chemie Nederaland bv Amsterdam for hydrotreating catalyst
In a further aspect of the present invention, a method of manufacture of a well liner segment having an outer liner and an inner liner located within said outer liner is provided, comprising the steps of:
(i) welding at least one seal ring to at least one of said inner and outer liner member, proximate one end thereof;
(ii) inserting said inner liner within said outer liner; and
(iii) inserting catalyst pellets in an interstitial space created between said inner liner and said outer liner.
In a preferred embodiment, such method comprises the further additional step of:
(iv) inserting an annular member between said inner and outer liners at an end of each opposite said seal ring, so as to thereby encapsulate said catalyst pellets within said interstitial space between said seal ring and said annular member.
Further advantages and permutations will appear from the following detailed description of various non-limiting embodiments of the invention, taken together with the accompanying drawings, in which:
a is a cross-sectional view of the well liner segment shown in
b is a cross-section of a well liner segment of the present similar view to that shown in
Such hydrocarbon recovery system 2 is adapted to direct hydrocarbons, particularly viscous oil 15 which, during the method of such hydrocarbon recovery system 2, drains out of hydrocarbon formation 1, through a catalyst-packed interstitial space 12 within each well liner segment 10, for subsequent recovery to surface 13.
A plurality of well liner segments 10 of the present invention are shown, each threadably coupled to an adjoining other well liner segments 10 so as to form a well liner 6 as shown in
With reference to
A slotted or wire-wrapped inner liner member 22 is provided, concentrically located within outer liner member 20 to form the interstitial space 12, such inner liner member 22 having an inner volume/area 80 for collecting upgraded hydrocarbon and allowing it to be transferred to surface 13 by pumping or other transfer method.
In a preferred embodiment, each of outer liner member 20 and inner liner member 22 of the well liner segment 10 are cylindrical elongate members, adapted to be inserted in a cylindrical horizontal well bore 3 as shown in
In a preferred embodiment, as best shown in
In a first embodiment and as shown in
Alternatively, as seen in
The well liner segment 10 of the “radial-flow” configuration shown in
Interstitial space 12 is typically packed during manufacture of such well liner segment 10 with a hydrocarbon upgrader catalyst 40. One such hydrocarbon upgrader catalyst 40 which is suitable for use in the present invention is standard hydrotreating/HDS catalyst manufactured by Akzo Chemie Nederaland bv Amsterdam, and identified as Ketjenefine3™ 742-1, 3AQ. 3 Trademark of Akzo Chemie Nederaland bv Amsterdam for hydrotreating catalyst
Preferably, hydrocarbon upgrader catalyst 40 when positioned in such interstitial space 12 during manufacture of such well liner segment 10 is of a pelletized or granularized form, of a size nominally greater than the size of apertures 31, to prevent loss of catalyst from interstitial space 12 via apertures 31.
In both the “radial flow” and “lateral flow” embodiments of the well liner 10 of the present invention, and as best shown in
Likewise, at an opposite end 60a of the well liner segment 10 of the present invention, in both the “radial flow” and “lateral flow” embodiments thererof, and as best seen for example in
In a first embodiment, as shown in FIGS. 3 & 5-11, such sliding seal 52 comprises a first (outer) ring member 50 fixedly secured via circumferential welds 72 to outer member 20, and a second (inner) ring member 54 likewise secured via circumferential welds to inner member 22, which ring members 50, 54 together act to concentrically locate inner liner member 22 within outer member 20.
In a second embodiment, a first version of which is shown in
In the embodiments shown in FIGS. 3 & 5-7, and as noted above, a conical ring member 68 may be affixed to each of outer and interior members 20, 22 via circumferential welds 72, to concentrically locate and affix interior member 22 to outer member 20 and to further retain catalyst 40 within interstitial space 12. Alternatively, and as best seen in
Preferably in all embodiments of the well liner 10 of the present invention, each of mutually opposite ends 60a, 60b of outer well liner 20 possess male external threaded end 61 and female (internal) threaded end 62 respectively, to permit threadable connection of respective ends 60a and 60b of separate well liner segments 10 together, as shown in
In another embodiment of the invention, provision may be made for the inner liner members 22 to be coupled together, as shown in
In a still further refinement, and as shown in
Other means of fluidly coupling well liner members 10 together will now be clearly apparent to those of skill in the art, and are further contemplated within the scope of this invention as being other equally viable alternative means of fluidly coupling well liner segments 10 together.
For a horizontal well liner 10 of 414 meters, 69 connected well liner segments 10 each of 6-meter length are required. For an annular interstitial space of 1.5 inches, each well liner segment 10 will contain approximately 300 pounds of catalyst 40.
The following is a description of how oil 15 is able to be collected and upgraded and thereafter pumped to surface 13 using the well liner segments 10 of the present invention in an in-situ hydrocarbon recovery system 2.
Specifically, in an in situ hydrocarbon recovery process 2 as may be seen from
A plurality of elongate well liner segments 10 are coupled together via coupling means comprising exterior male 61 threaded portions and female threaded portions on respect ends 60a, 60b of outer well liners 20, and inserted through horizontal well bore 3 so as to form a horizontal well liner 6 within said horizontal leg 101, as shown in
In the in situ extraction process as shown in
A method for the manufacture of well liner segments 10 of the present invention is set out below.
For the embodiments of the well liner segments 10 shown in
For manufacture of well liner members 10 of the configuration shown in
For the embodiments of the well liner segments 10 shown in
Although the disclosure describes and illustrates preferred embodiments of the invention, it is to be understood that the invention is not limited to these particular embodiments. Many variations and modifications will now occur to those skilled in the art. For a complete definition of the invention and its intended scope, reference is to be made to the summary of the invention and the appended claims read together with and considered with the disclosure and drawings herein.
