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United States Patent Application 20180119533
Kind Code A1
Alhuthali; Ahmed ;   et al. May 3, 2018

Wellbore System With Lateral Wells

Abstract

A well system that intersects a subterranean formation, and which includes a motherbore disposed in a non-producing formation that is between producing zones. Connate fluids in the formation can be produced with the well system; alternatively, fluids can be injected into the formation through the well system. Lateral wellbores extend from the motherbore to depths that are both deeper and shallower than the motherbore. Flow to/from each lateral wellbore can be controlled by an inflow control valve. Wellhead assemblies mounted over an opening of the well system can be at a location that is spaced away from a populated area and far away from the hydrocarbon formation.


Inventors: Alhuthali; Ahmed; (Dhahran, SA) ; AlAlyan; Essam; (Dhahran, SA)
Applicant:
Name City State Country Type

Saudi Arabian Oil Company

Dhahran

SA
Assignee: Saudi Arabian Oil Company
Dhahran
SA

Family ID: 1000002283812
Appl. No.: 15/338064
Filed: October 28, 2016


Current U.S. Class: 1/1
Current CPC Class: E21B 43/305 20130101; E21B 34/06 20130101; E21B 41/0035 20130101; E21B 49/08 20130101
International Class: E21B 43/30 20060101 E21B043/30; E21B 49/08 20060101 E21B049/08; E21B 41/00 20060101 E21B041/00

Claims



1. A wellbore system comprising: a motherbore formed in a non-producing zone of a subterranean formation; a lateral wellbore extending from the motherbore into a shallower producing zone that is at a depth that is more shallow than the non-producing zone; and another lateral wellbore extending from the motherbore into a deeper producing zone that is at a depth that is deeper than the non-producing zone.

2. The wellbore system of claim 1, further comprising inflow control valves provided at intersections between the lateral wellbore and the motherbore, and the another lateral wellbore and the motherbore.

3. The wellbore system of claim 2, wherein the inflow control valves regulate flow from the lateral wellbores into the motherbore.

4. The wellbore system of claim 1, wherein the lateral wellbore comprises a leg having a substantially vertical portion that penetrates the shallower producing zone.

5. The wellbore system of claim 4, wherein the leg has a substantially horizontal portion with an end attached to the vertical portion and an opposing end attached to the motherbore.

6. The wellbore system of claim 5, wherein the leg further comprises a tip portion that has an end attached to an end of the vertical portion distal from the horizontal portion, and that extends substantially horizontally in the shallower producing zone.

7. The wellbore system of claim 1, wherein the another lateral wellbore comprises a leg having a substantially vertical portion that penetrates the deeper producing zone.

8. The wellbore system of claim 7, wherein the leg has a substantially horizontal portion with an end attached to the vertical portion and an opposing end attached to the motherbore.

9. The wellbore system of claim 8, wherein the leg further comprises a tip portion that has an end attached to an end of the vertical portion distal from the horizontal portion, and that extends substantially horizontally in the deeper producing zone.

10. The wellbore system of claim 1, further comprising a primary wellbore that extends from surface and into communication with an end of the motherbore, wherein the motherbore extends along a generally horizontal path.

11. The wellbore system of claim 10, further comprising a wellhead assembly on surface that is in communication with an end of the primary wellbore distal from the motherbore, wherein the motherbore, primary wellbore, shallower lateral wellbore, and deeper lateral wellbore define a well circuit.

12. The wellbore system of claim 11, wherein the well circuit comprises a first well circuit and the primary wellbore comprises a first primary wellbore, the wellbore system further comprising a second well circuit having a second primary wellbore that intersects with the first primary wellbore, so that the second well circuit is in communication with the wellhead assembly.

13. A method of operating a wellbore system comprising: directing a flow of fluid from a producing zone in a subterranean formation into a non-producing zone that is in the subterranean formation; directing another flow of fluid into the non-producing zone and from another producing zone in the subterranean formation that is on a side of non-producing zone opposite from the producing zone; and directing the flow of fluid and the another flow of fluid to surface.

14. The method of claim 13, wherein the flow of fluid and the another flow of fluid are directed into a motherbore in the non-producing zone.

15. The method of claim 14, wherein the flow of fluid and the another flow of fluid flow through lateral bores into the motherbore, and wherein the lateral bores have substantially vertical portions that penetrate the producing zone and the another producing zone.

16. The method of claim 13, further comprising controlling a rate of the flow of fluid from the producing zone into the non-producing zone, and controlling a rate of the another flow of fluid from the another producing zone into the non-producing zone.

17. The method of claim 13, further comprising forming a motherbore in the non-producing zone, forming a lateral bore from the motherbore into the producing zone, and forming another lateral bore into the another producing zone.

18. The method of claim 17, wherein the motherbore is substantially horizontal.

19. The method of claim 17, further comprising forming a primary wellbore from surface and that is in communication with the motherbore.

20. The method of claim 13, further comprising monitoring a composition of fluid making up one or more of the flow of fluid and the another flow of fluid flowing into the non-producing zone, and blocking fluid from entering the non-producing zone having a designated amount of a selected constituent.
Description



BACKGROUND OF THE INVENTION

1. Field of Invention

[0001] The present disclosure relates to producing hydrocarbons from a subterranean formation. More specifically, the present disclosure relates to producing hydrocarbons from separate zones that are at different depths.

2. Description of Prior Art

[0002] Hydrocarbon producing wellbores extend below the Earth's surface where they intersect subterranean formations in which hydrocarbons are trapped. The wellbores generally are created with drilling systems that include drill bits mounted on an end of a drill string, and a drive system above the opening to the wellbore that rotates the drill string and bit. Cutting elements on the drill bit scrape or otherwise impact the bottom of the wellbore as the bit is rotated and excavate material from the formation thereby deepening the wellbore. Drilling fluid is typically pumped down the drill string and discharged from the drill bit into the wellbore. The drilling fluid flows back up the wellbore in an annulus between the drill string and walls of the wellbore. Cuttings produced while excavating are carried up the wellbore with the circulating drilling fluid.

[0003] When forming a wellbore system, the drilling systems penetrate through formation layers located at various depths below the Earth's surface. Wellbore systems typically include a main bore that projects into a target layer within one of the formation layers. Generally, there is no crossflow between the individual formation layers. Thus, the main bores of wellbore systems usually extend into the target layer where the connate fluid to be produced resides. Wellbore systems sometimes include lateral wells that branch from the primary or main bore into different portions of subterranean formation, and often branch at different depths from the main bore. Due to natural or applied stresses in the rock matrix, fractures are usually present in formation layers. The fractures may provide a fluid flow path of downhole or connate fluid that can include hydrocarbons and/or water. Lateral wellbores formed by current drilling methods and systems often intersect these fractures.

[0004] Vertical wells, horizontal wells, multilateral wells, or maximum reservoir contact ("MRC") wells experience deficiencies in tight-fractured reservoir under populated areas. For example, while non-deviated wells can avoid fractures and early water breakthrough, their productivity is very limited in tight reservoirs. A shortcoming with horizontal wells is that although they can enhance well productivity, horizontal wells are more prone to intersect fractures, which may cause early water breakthrough. Multilateral wells and MRC wells have the same drawbacks as the horizontal wells.

SUMMARY OF THE INVENTION

[0005] Disclosed herein is an example of a wellbore system, and which includes a motherbore formed in a non-producing zone of a subterranean formation, a lateral wellbore extending from the motherbore into a shallower producing zone that is at a depth that is more shallow than the non-producing zone, and another lateral wellbore extending from the motherbore into a deeper producing zone that is at a depth that is deeper than the non-producing zone. Inflow control valves are optionally provided at intersections between the lateral wellbore and the motherbore, and the another lateral wellbore and the motherbore. In an example, the inflow control valves regulate flow from the lateral wellbores into the motherbore. The lateral wellbore can include a leg having a substantially vertical portion that penetrates the shallower producing zone. In an alternative, the leg has a substantially horizontal portion with an end attached to the vertical portion and an opposing end attached to the motherbore. In yet another embodiment, the leg further includes a tip portion that has an end attached to an end of the vertical portion distal from the horizontal portion, and that extends substantially horizontally in the shallower producing zone. In one alternative, the another lateral wellbore includes a leg having a substantially vertical portion that penetrates the deeper producing zone. Optionally, the leg has a substantially horizontal portion with an end attached to the vertical portion and an opposing end attached to the motherbore. A tip portion can be included on the leg that has an end attached to an end of the vertical portion distal from the horizontal portion, and that extends substantially horizontally in the deeper producing zone. The wellbore system can further include a primary wellbore that extends from surface and into communication with an end of the motherbore, wherein the motherbore extends along a generally horizontal path. The wellbore system can also optionally include a wellhead assembly on surface that is in communication with an end of the primary wellbore distal from the motherbore, wherein the motherbore, primary wellbore, shallower lateral wellbore, and deeper lateral wellbore define a well circuit. In an alternate embodiment, well circuit is a first well circuit and the primary wellbore is a first primary wellbore, in this example the wellbore system further including a second well circuit having a second primary wellbore that intersects with the first primary wellbore, so that the second well circuit is in communication with the wellhead assembly.

[0006] Also described herein is an example of a method of operating a wellbore system by directing a flow of fluid from a producing zone in a subterranean formation into a non-producing zone that is in the subterranean formation, directing another flow of fluid into the non-producing zone and from another producing zone in the subterranean formation that is on a side of non-producing zone opposite from the producing zone, and directing the flow of fluid and the another flow of fluid to surface. The flow of fluid and the another flow of fluid can be directed into a motherbore in the non-producing zone. Alternatively, the flow of fluid and the another flow of fluid flow through lateral bores into the motherbore, and wherein the lateral bores have substantially vertical portions that penetrate the producing zone and the another producing zone. In one example the method includes controlling a rate of the flow of fluid from the producing zone into the non-producing zone, and controlling a rate of the another flow of fluid from the another producing zone into the non-producing zone. The method can also further include forming a motherbore in the non-producing zone, forming a lateral bore from the motherbore into the producing zone, and forming another lateral bore into the another producing zone. The motherbore can optionally be substantially horizontal. Optionally included with the method is a step of forming a primary wellbore from surface and that is in communication with the motherbore. In one embodiment the method includes monitoring a composition of fluid making up one or more of the flow of fluid and the another flow of fluid flowing into the non-producing zone, and blocking fluid from entering the non-producing zone having a designated amount of a selected constituent.

BRIEF DESCRIPTION OF DRAWINGS

[0007] Some of the features and benefits of the present invention having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which:

[0008] FIG. 1 is a perspective view of an example of a wellbore system having a motherbore with lateral bores.

[0009] FIG. 2 is a perspective view of an alternate example of a wellbore system.

[0010] FIG. 3 is a perspective view of an alternate example of the wellbore system.

[0011] FIG. 4 is a side sectional view of an alternate example of wellbore system.

[0012] FIG. 5 is an end sectional view of an alternate example of wellbore system.

[0013] FIG. 6 is a plan view of an alternate example of a wellbore system.

[0014] FIG. 7 is a plan view of alternate examples of wellbore systems that extend into a reservoir.

[0015] FIG. 8 is a perspective view of an example of forming a wellbore system in accordance with the present disclosure.

[0016] While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF INVENTION

[0017] The method and system of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. The method and system of the present disclosure may be in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout. In an embodiment, usage of the term "about" includes +/-5% of the cited magnitude. In an embodiment, usage of the term "substantially" includes +/-5% of the cited magnitude.

[0018] It is to be further understood that the scope of the present disclosure is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation.

[0019] FIG. 1 shows in a perspective view one example of a wellbore system 10 formed within a subterranean formation 12. Here the wellbore system 10 includes a well circuit 14 that penetrates the formation 12, and has an upper end in communication with a wellhead assembly 16 shown mounted on surface 18. The well circuit 14 is made up of a primary wellbore 20, which is at the upper end of well circuit 14 and proximate to wellhead assembly 16. An end of primary wellbore 20 distal from wellhead assembly 16 connects to a motherbore 22, wherein motherbore 22 extends in generally horizontally within formation 12. A series of lateral bores 24, 26, 28, 30, 32 connect to motherbore 22. Included with lateral bore 24 are legs 34, 36 that project laterally from motherbore 22 in opposite directions from one another. As shown, legs 34, 36 each extend a distance from motherbore 22 in formation 12, and then curve along a path that projects toward surface 18 and in a substantially vertical orientation. Downstream of lateral bore 24 is lateral bore 26, which also includes legs 38, 40 that have portions that project away from one another in a lateral direction and then curve in the formation 12 in a direction away from surface 18. Lateral bores 28, 30, 32 each have a configuration similar to that of lateral bore 26, where lateral bore 28 includes legs 44, 46, lateral bore 30 includes legs 46, 48 and lateral bore 32 includes legs 50, 52. Inflow control valves 54, 56, 58, 60, 62 are shown provided respectively in the intersection of lateral bores 24, 26, 28, 30, 32 with motherbore 22. As will be described in more detail below, inflow control valves 54, 56, 58, 60, 62 selectively control and regulate fluid flow from the lateral bores 22, 24, 26, 28, 30, 32 into motherbore 22.

[0020] In the example of FIG. 1, motherbore 22 is formed in what is referred to as a nonproducing zone 63. In the illustrated example, a nonproducing zone describes a zone or portion of formation 12 from which connate fluids, such as water or other hydrocarbons, are not being produced. In contrast, producing zone 64 is shown adjacent nonproducing zone 63 and at a shallower depth. Producing zone 66 is also shown adjacent nonproducing zone 63 and on a side that is opposite producing zone 64 and at a depth greater than nonproducing zone 63. Producing zones 64, 66 each include connate fluids that are being produced with the wellbore system 10. Further in this example, natural formation occlusions have formed that seal fluid flow between nonproducing zone 63 and either of producing zones 64, 66. Further in the example, legs 34, 36 of lateral bore 24 project vertically into the producing zone 64, and through which connate fluid within producing zone 64 is directed into the motherbore 22. Lateral bores 26, 28, 30, 32 have their respective legs directed vertically deeper and into the producing zone 66, and through which the connate fluid in producing zone 66 is directed into the motherbore 22. From motherbore 22, the fluid received from lateral bores 24, 26, 28, 30, 32 can be directed to the wellhead assembly 16 via primary bore 20, where the fluid can be transferred from wellhead assembly 16 via pipeline (not shown) to transportation vessels, processing facilities, and the like.

[0021] FIG. 2 shows in a side perspective view an alternate embodiment of the wellbore system 10A which includes a well circuit 14A with a primary bore 20A and a motherbore 22A, where motherbore 22A extends generally horizontally and within a nonproducing zone 63A. Nonproducing zone 63A is shown between producing zones 64A, 66A, where producing zone 64A is at a shallower depth than nonproducing zone 63A, and producing zone 66A is at a greater depth than nonproducing zone 63A. Lateral bores 24A, 26A, 28A, 30A, 32A extend from sides of the motherbore 22A, and that have configurations and orientations that are different from the lateral wellbores 24, 26, 28, 30, 32 of FIG. 1. More specifically, lateral bore 24A has legs 34A, 36A that project to a greater depth than motherbore 22A and into producing zone 66A. Moreover, the tips of the legs 34A, 36A within the producing zones 66A curve and follow a generally horizontal path to their terminal ends. Legs 38A, 40A of lateral bore 26A and legs 46A, 48A of lateral bore 30A project to a depth shallower than motherbore 22A and into producing zone 64A. Legs 38A, 40A, 46A, 48A also have tip portions that extend in a generally horizontal path and project laterally away from the sides of motherbore 22A. Legs 42A, 44A of lateral bore 28A and legs 50A, 52A of lateral bore 32A extend from nonproducing zone 63A into producing zone 66A along a generally vertical path, and also have tip portions on their terminal ends that are generally horizontally oriented.

[0022] Another example embodiment of a wellbore system 10B is shown in a perspective view in FIG. 3 and where the wellbore system 10B includes a pair of well circuits 68, 70 in formation 12B. Well circuit 68 includes a primary wellbore 72 that joins a primary wellbore 74 of well circuit 70 to define a branch 76. Where branch 76 is shown disposed at a lower end of primary wellbore 20B, which extends into the formation 12B from surface 18B and is in communication with wellhead assembly 16B. A motherbore 78 is shown making up a portion of well circuit 68 past the terminal end of primary wellbore 72, lateral bores 78, 80, 82, 84, 86, 88 project from the sides of motherbore 78. Lateral bore 80 is shown having legs 90, 92 that extend laterally outward generally horizontally from motherbore 78, and then curve into a substantially vertical direction and towards surface 18B. Lateral bore 82 of FIG. 3 includes legs 94, 96 that extend horizontally from opposing sides of motherbore 78, and then curve into a generally vertical direction deeper from motherbore 78 and away from surface 18B. Lateral bores 84, 86, 88, are configured similar to lateral bore 82, and wherein lateral bore 84 has legs 98, 100 that project in a general horizontal direction adjacent motherbore 78, and whose end portions project vertically away from surface 18. Similarly, legs 102, 104 of lateral bore 86, and legs 106, 108 of lateral bore 88 extend laterally outward and then vertically away from surface 18B.

[0023] Further illustrated in FIG. 3 is motherbore 78 also depicted in a generally horizontal configuration and disposed within a nonproducing zone 109. Nonproducing zone 109 is shown between a pair of producing zones 110, 112, where producing zone 110 is at a depth shallower than nonproducing zone 109 and producing zone 112 is at a depth greater than nonproducing zone 109. In this example the legs 90, 92 of lateral bore 80 terminate within producing zone 110 so that fluid within producing zone 110 is directed into motherbore 78 via legs 90, 92. In contrast, the legs of the lateral bores 82, 84, 86, 88 project into and terminate within the producing zone 112 and provide a communication means for fluid in producing zone 112 to flow into motherbore 78. Inflow control valves 114, 116, 118, 120, 122 are shown disposed within motherbore 78, and respectively at the intersection between motherbore 78 and lateral bores 80, 82, 84, 86, 88.

[0024] Still referring to the example of FIG. 3, well circuit 70 includes a motherbore 124 that connects to a terminal end of primary wellbore 74, and follows a generally horizontal path within formation 12B. Lateral bores 126, 128, 130, 132, 134 all intersect motherbore 124 at different measured depths of motherbore 124. For the purposes of illustration herein, measured depth of a borehole is an indication of a distance from surface to a location in the borehole and through the borehole. A true vertical depth is the shortest distance from surface to the location in the borehole. Because portions of boreholes are often not vertical, measured depth can be different from true vertical depth. In the example of FIG. 3, lateral bore 126 includes legs 136, 138 that project to a shallower depth and having tips that then extend laterally outward from motherbore 124 and in a generally horizontal configuration. Similarly, lateral bore 128 also has legs 140, 142 that change course a vertical distance from motherbore 124 and having tips that extend further laterally out from motherbore 124. Lateral bore 130 includes legs 144, 146, lateral bore 132 includes legs 148, 150, and lateral bore 134 includes legs 152, 154. Each of the legs of lateral bores 130, 132, 134 extend laterally outward and then vertically away from motherbore 124 and then have tips that extend laterally outward again from motherbore 124. Inflow control valves 160, 162, 164, 166, 168 are also included in motherbore 124 and provided respectively at the intersection between motherbore 124 and lateral wellbores 126, 128, 130, 132, 134.

[0025] Motherbore 124 is strategically configured so that it extends within a nonproducing zone 155 of formation 12B and which is between producing zones 156, 158, where the producing zones 156, 158 are sealed from one another and also from nonproducing zone 155. Moreover, the ends of the lateral bores 126, 128, 130, 132, 134 are strategically located within the producing zones 156, 158 so that connate fluid within these zones 156, 158 can directed onto the motherbore 124. Similar to the well system 10 of FIG. 1, the well circuits 68, 70 then can direct fluid from these producing zones 110, 112, 156, 158 onto the wellhead assembly 16B so the fluid produced in formation 12B can be collected and then processed.

[0026] Referring now to FIG. 4, shown in a side sectional view is an alternate embodiment of a wellbore system 10C having a wellbore circuit 14C formed in formation 12C and that provides flow paths for directing fluid in the formation 12C to a wellhead assembly 16C on surface 18C. Wellbore circuit 14C includes a primary wellbore 20C that projects into formation 12C from surface 18C. A horizontally disposed motherbore 22C is shown extending from a terminal end of primary wellbore 20C. Here, the wellbore system 10C is used for producing fluid that is trapped within a cap rock system 170, which in the illustrated example includes a dome-like shaped producing zone 172 that is set adjacent to a cap rock 174. Cap rock 174, which is a non-producing zone, is sandwiched between producing zone 172 and an adjacent producing zone 176 that is on a side of cap rock 174 opposite from producing zone 172. Cap rock 174 is isolated from both producing zones 172, 176. Lateral bores 178, 180, 182, 184, 186, 188, 190, 192, 194, 196 are shown that connect to motherbore 22C and have portions that project vertically away from motherbore 22C into one of the producing zones 172, 176. More specifically, lateral bores 178, 182, 186, 190, 194 each terminate within producing zone 172, and therefore provide a means for producing fluid from within producing zone 172 and back into motherbore 22C. Lateral bores 180, 184, 188, 192, 196 project from motherbore 22C and vertically to the lower depth of producing zone 176, and also present a means for producing fluid back into motherbore 22C. Vertically orienting the lateral bores 180, 184, 188, 192, 196 of FIG. 4 avoids intersection that cracks or fractures 198 shown formed within the producing zone 176. An advantage of avoiding the fractures 198 is the delay or avoidance of water migration being coupled with the hydrocarbons being produced. Inflow control valves 200, 202, 204, 206, 208, 210, 212, 214, 216, 218 are provided within the motherbore 22C and allow for regulating flow from the producing zones 172, 176 and into motherbore 22C.

[0027] FIG. 5 shows in an end sectional view an example of a wellbore system 10D having a wellbore circuit 14D for communicating fluid in formation 12D to a wellhead assembly 16D on surface 18D. In this example, wellbore circuit 14D includes a primary wellbore 20D that extends from surface 18D and has an upper end in communication with wellhead assembly 16D. An end of primary wellbore 20D distal from wellhead assembly 16D merges into a motherbore 22D. Motherbore 22D extends horizontally away from primary wellbore 20D and has lateral wells 220, 222 connected thereto. As illustrated, lateral well 220 intersects a production zone 224 that is set at a depth less than that of the motherbore 22D and makes up part of a cap rock system 226 within formation 12D. Further, at least a portion of motherbore 22D is in cap rock 228, where cap rock 228 is a non-producing zone and that is sealed from communication with the producing zone 224. Adjacent the cap rock 228 is another producing zone 230 which is at a depth lower than cap rock 228 and is also isolated from communication with cap rock 228. Further illustrated are legs 232, 234 of lateral bore 220 first project laterally away from motherbore 22D a distance and then curve vertically to a shallower depth and intersect the producing zone 224. Legs 232, 234 provide a conduit for fluid within producing zone 224 to flow into motherbore 22D. Similarly, legs 236, 238 of lateral bore 222 extend laterally away from motherbore 22D and then vertically into the lower depth production zone 230 for collection of connate fluid within production zone 230. Inflow control valves 240, 242 selectively regulate flow respectively from lateral wells 220, 222 and into motherbore 22D.

[0028] FIG. 6 shows a plan view of another example of wellbore system 10D (FIG. 5) and where primary wellbore 20D transforms into a motherbore 22D. In this example, the tips of legs 232, 234, shown in dashed outline, represent where the legs 232, 234 enter into the production zone 224. Similarly, legs 236, 238 of lateral well 222 have tips depicted in dashed outline indicating where they project into production zone 230. Additional lateral wells 244, 246 are shown connecting to motherbore 22D and which where legs 248, 250 of lateral bore 244 have tips intersecting the production zone 224. Legs 252, 255, which make up lateral bore 246 also have tips that terminate within production zone 224. Inflow control valves 258, 260 within motherbore 22D selectively regulate flow from within lateral wells 244, 246 respectively into motherbore 22D. Lateral bores 262, 264, 266, 268 are shown on a portion of motherbore 22D, and on a side of lateral bore 222 opposite from lateral bore 246. Legs 270, 272 of lateral bore 262 have tips that are shown in dashed outline and project into production zone 230. Similarly, legs 274, 276 of lateral bore 264 also shown having tips in dashed outline are also disposed in production zone 230. Further, lateral bore 266 has legs 278, 280, and legs 282, 284 of lateral bore 268 are within production zone 230. Additional inflow control valves 288, 290, 292, 294 control the flow from lateral wells 262, 264, 266, 268 respectively into motherbore 22D.

[0029] FIG. 7 shows a plan view of one example of wellbore systems 296, 298 and that respectively include well circuits 300, 302 that intersect a reservoir 304. Wellbore systems 296, 298 are for draining and producing hydrocarbons from reservoir 304. Well circuit 300 includes a primary wellbore 306 and motherbore 308 that connects to an end of primary wellbore 306 within reservoir 304. A series of lateral wells 310 are shown projecting from opposing sides of motherbore 308 and into the reservoir 304. Unlike well circuit 300, well circuit 302 includes a primary wellbore 312 that branches into a pair of additional primary wellbores 314, 316. A motherbore 318 extends from an end of primary wellbore 314 within reservoir 304. A series of lateral wells 320 projecting from opposing sides of the motherbore 318 into reservoir 304. A motherbore 322 also couples with primary wellbore 316, where a series of lateral bores 324 extend radially outward from opposing sides of the motherbore 322. The lateral wells 310, 320, 324 that project from motherbores 308, 318, 322 can be configured so that some project into producing zones above and below the zone in which the respective motherbores 308, 318, 322 are formed.

[0030] In the example of FIG. 7, each motherbore 308, 318, 322 is formed in a non-producing zone. Thus, the wellbore systems 296, 298 can have similar configurations to those discussed in the preceding figures. Included with wellbore system 296 is a wellhead assembly 326 on surface that connects to primary wellbore 306. A production line 328 also connects to wellhead assembly 326, and which can be used for directing fluids produced from within reservoir 304 to offsite for transportation, storage, production, processing, and the like. Similarly, a wellhead assembly 330 is included with wellbore system 298 and which also includes a production line 332 for directing fluids produced by wellbore system 298 to offsite. Shown within reservoir 304 is an interface 334 which represents where water and hydrocarbon fluids are in contact and at a time when production from reservoir 304 has initiated. Over time as connate fluid is produced from reservoir 304, the interface 334 moves radially inward, as illustrated by interface 334A. In this example interface 334A intersects with some of the series of lateral bores 310, 320, 324. As discussed above, selective operation and actuation of some of the inflow control valves (not shown) may block flow through individual lateral bores that have ends or that are in a region that has been infiltrated with water. As such, production of water from reservoir 304 can be kept at a minimum thereby reducing the amount of water separation required of the fluid that is produced from reservoir 304.

[0031] FIG. 8 shows in a perspective view an example of forming the wellbore system 10 of FIG. 1. In this example, a drilling system 336 is shown having a derrick 338 on surface 18. Attached to rotating equipment on derrick 338 is an example of a drill string 340, which is made up of a string of drill pipe 342 and a drill bit 344 on a terminal end of the drill string 340. In the illustrated example, the bit 344 is being rotated and used to form leg 52 of lateral bore 32. Examples of steering the bit to form the different shaped bores described herein includes rotary steerable technology (to geosteer deviated portions of the bores), logging while drilling, gyroscopes, and the like. Additionally, it is considered to be well within the capabilities of one skilled in the art to form the wellbore system 10 using drilling technology currently known. Further illustrated is how the knowledge of the producing zones 64, 66 is known, so that the motherbore 22 can be formed between producing zones 64, 66 and remain within the nonproducing zones 63. An advantage to forming the motherbore 22 between producing reservoirs 64, 66 (also referred to as target reservoirs), and concentrating the lateral bores 24, 26, 28, 30, 32 into the target reservoirs provides for a flexible completion of the well circuit 14 and penetrating different reservoirs vertically, horizontally, or deviated, at the same time. Moreover, the multiple lateral bores 24, 26, 28, 30, 32, and the inflow control valves 54, 56, 58, 60, 62 also provide the ability to produce at different rates and at different times.

[0032] The present invention described herein, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While a presently preferred embodiment of the invention has been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the present invention disclosed herein and the scope of the appended claims.

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