Title:
INTERVENTIONLESS PINPOINT COMPLETION AND TREATMENT
Kind Code:
A1


Abstract:
A method of treating a subterranean formation is provided utilizing a system for setting downhole control pressure to select and operate hydraulically activated sleeve valves which are disposed on a casing which is cemented into a well bore, and flowing a first treatment fluid which is capable of dissolving cement through the hydraulically activated sleeve valves.



Inventors:
Prather, Dean (Houston, TX, US)
Application Number:
11/948513
Publication Date:
06/04/2009
Filing Date:
11/30/2007
Primary Class:
Other Classes:
166/53
International Classes:
E21B43/12
View Patent Images:
Related US Applications:



Primary Examiner:
ANDREWS, DAVID L
Attorney, Agent or Firm:
JOHN W. WUSTENBERG (DUNCAN, OK, US)
Claims:
What is claimed is:

1. A system for treating a subterranean formation, comprising: a well bore; a casing within a portion of the well bore; a cement in a portion of an annulus between the casing and the portion of the well bore; a plurality of hydraulically activated sleeve valves connected to the casing; a system for setting downhole control pressure for the plurality of hydraulically activated sleeve valves; and a first treatment fluid which is capable of dissolving the cement.

2. The system of claim 1, further comprising a second treatment fluid.

3. The system of claim 1, wherein at least one of the plurality of hydraulically activated sleeve valves comprises a position indicator.

4. The system of claim 3, wherein the position indicator comprises a pressure bypass conduit.

5. The system of claim 1, wherein at least one of the plurality of hydraulically activated sleeve valves comprises a port alignment system.

6. The system of claim 1, wherein the system for setting downhole control pressure comprises: a control module; one or more control lines; and a pressure control system.

7. The system of claim 6, wherein: at least one of the one or more control lines is at least partially disposed in the annulus; and the pressure control system is disposed external to the well bore.

8. The system of claim 1, wherein the portion of the well bore is substantially horizontal.

9. The system of claim 1, wherein: the first treatment fluid comprises an acid; and the cement is acid-soluble.

10. A system for treating a subterranean formation, comprising: a well bore, wherein: the well bore comprises: a substantially vertical portion; a first substantially horizontal portion; and a second substantially horizontal portion; the substantially vertical portion forms a juncture with each of the first substantially horizontal portion and the second substantially horizontal portion; and the juncture of the substantially vertical portion and the first substantially horizontal portion is physically distinct from the juncture of the vertical portion and the second substantially horizontal portion; a first casing within a portion of the first substantially horizontal portion of the well bore; a second casing within a portion of the second substantially horizontal portion of the well bore; a first cement in a portion of an annulus between the first casing and the portion of the first substantially horizontal portion of the well bore; a second cement in a portion of an annulus between the second casing and the portion of the second substantially horizontal portion of the well bore; a first plurality of hydraulically activated sleeve valves connected to the first casing; a second plurality of hydraulically activated sleeve valves connected to the second casing; a system for setting downhole control pressure for each of the first plurality of hydraulically activated sleeve valves and second plurality of hydraulically activated sleeve valves; and a first treatment fluid which is capable of dissolving the cement.

11. A method for treating a subterranean formation, comprising: providing a casing in a well bore, wherein the casing comprises a plurality of hydraulically activated sleeve valves, at least one of which is connected to a system for setting downhole control pressure; introducing cement into a portion of an annulus between the casing and the well bore; utilizing the system for setting downhole control pressure to open at least one of the hydraulically activated sleeve valves; and flowing a first treatment fluid which is capable of dissolving the cement through the at least one of the hydraulically activated sleeve valves.

12. The method of claim 10, further comprising: utilizing the system for setting downhole pressure to selectively open or close two or more units of the plurality of hydraulically activated sleeve valves; flowing a first treatment fluid which is capable of dissolving the cement through at least one of the selectively opened hydraulically activated sleeve valves; and flowing a second treatment fluid through the at least one of the selectively opened hydraulically activated sleeve valves.

13. The method of claim 10, wherein the system for setting downhole control pressure comprises: a control module; one or more control lines; and a pressure control system.

14. The method of claim 13, wherein: at least one of the one or more control lines is at least partially disposed in the annulus; and the pressure control system is disposed external to the well bore.

15. The method of claim 10, wherein at least a portion of the well bore is substantially horizontal.

16. The method of claim 10, wherein: the first treatment fluid comprises an acid; and the cement is acid-soluble.

17. The method of claim 10, wherein: at least one of the plurality of hydraulically activated sleeve valves comprises a position indicator; the position indicator comprises a pressure bypass conduit; and at least one of the plurality of hydraulically activated sleeve valves comprises a port alignment system.

18. The method of claim 10, wherein the cement is introduced through at least a portion of an interior of the casing prior to being introduced into the annulus.

19. The method of claim 10, wherein the cement is introduced into at least a portion of the annulus prior to being introduced into the interior of the casing.

20. A method for treating a subterranean formation, comprising: providing a well bore, wherein: the well bore comprises: a substantially vertical portion; a first substantially horizontal portion; and a second substantially horizontal portion; the substantially vertical portion forms a juncture with each of the first substantially horizontal portion and the second substantially horizontal portion; and the juncture of the substantially vertical portion and the first substantially horizontal portion is physically distinct from the juncture of the vertical portion and the second substantially horizontal portion; providing a first casing in the first substantially horizontal portion of the well bore, wherein the first casing comprises a first plurality of hydraulically activated sleeve valves, at least one of which is connected to a system for setting downhole control pressure; providing a second casing in the second substantially horizontal portion of the well bore, wherein the second casing comprises a second plurality of hydraulically activated sleeve valves, at least one of which is connected to the system for setting downhole control pressure; introducing cement into a portion of an annulus between the first casing and the first substantially horizontal section of the well bore; introducing cement into a portion of an annulus between the second casing and the second substantially horizontal section of the well bore; utilizing the system for setting downhole control pressure to selectively open or close at least one hydraulically activated sleeve valve in each of the first plurality of hydraulically activated sleeve valves and second plurality of hydraulically activated sleeve valves; flowing a first treatment fluid which is capable of dissolving the cement through the at least one hydraulically activated sleeve valve in the first plurality of hydraulically activated sleeve valves; and flowing the first treatment fluid through the at least one hydraulically activated sleeve valve in the second plurality of hydraulically activated sleeve valves.

Description:

BACKGROUND

The invention relates generally to systems and methods for completion and treatment of subterranean wells and, more specifically, to hydraulic operation of sleeve valves that provide selective and controlled application of fluids in subterranean installations.

Wells drilled for the production of hydrocarbons will often intersect, or traverse several zones to be treated and/or produced. The zones to be treated may be different areas of a single hydrocarbon-bearing formation or may be different formations altogether. The zones may have similar or dissimilar characteristics, and may be in vertical, inclined, or horizontal well bores. It is often necessary to treat the different zones to enhance production. Well treatments include, but are not limited to, fracturing and acidizing. The characteristics of a zone will often determine the required treatment.

Because each intersected zone may require treatment specific to the characteristics of that zone, it is necessary in many cases to isolate the zone being treated from other zones. There are a number of methods used to isolate zones for treatment. For example, a casing can be cemented in a well and then perforated at the zone(s) to be treated, so that treatment fluid can be communicated into the selected zone(s). In such cases, packers are typically lowered into the well and are set in the well to isolate the zone being treated from other zones. Another method uses sliding sleeves in a casing that slide to align openings in the sleeves with casing openings so treatment fluid can be communicated therethrough. Typically, the mechanical sleeve valves are opened or closed by a shifting tool that is placed within the valve housing and manipulated by standard wireline and/or coiled tubing methods. The sleeve, which seal the fluid communication path, can be physically moved from the closed to opened position, and vice versa, by these methods. There also exists hydraulically actuated sleeve valves in which opening and closing of the valve is achieved remotely with the use of hydraulic control lines. In these types of hydraulic sleeve valves, a pressure differential across a defined piston area causes the sleeve to move in the desired direction. In order to reliably operate the hydraulically actuated sleeve valve, an operator should accurately know what pressure is applied downhole to the hydraulically actuated sleeve valve. Note that an “application” of pressure can be an increase in pressure or a decrease in pressure as desired or as required by a particular control system.

Typically, the control lines are very long and have a relatively small flow area, so there is significant resistance to transmission of pressure through the lines. This means that pressure in the lines measured at the surface is not necessarily the same as pressure in the lines at the downhole hydraulically actuated sleeve valve (even when corrected for hydrostatic pressure due to the fluid in the line). Instead, there is a significant time lag between application of a pressure to the lines at the surface and a corresponding change in pressure in the lines at the hydraulically actuated sleeve valve.

Eventually, the pressure at the hydraulically actuated sleeve valve will reach the pressure applied to the lines at the surface (plus hydrostatic pressure in the lines). However, it will take a very long time since the pressure at the hydraulically actuated sleeve valve approaches the pressure applied to the lines at the surface asymptotically.

Yet another complicating factor is that each well installation is different. The control lines may be of different sizes or lengths, the fluid used in the lines may be different, a temperature profile of the well may vary (which affects compressibility of the fluid in the lines), air or other gases can be entrained in the fluid in the lines, etc.

SUMMARY

The invention relates generally to systems and methods for completion and treatment of subterranean wells and, more specifically, to hydraulic operation of sleeve valves that provide selective and controlled application of fluids in subterranean installations.

The present invention provides a system for treating a subterranean formation. In one embodiment of the invention, the system includes a well bore, a casing within a portion of the well bore, a cement in a portion of an annulus between the casing and the portion of the well bore, a plurality of hydraulically activated sleeve valves connected to the casing, a system for setting downhole control pressure for the plurality of hydraulically activated sleeve valves, and a first treatment fluid which is capable of dissolving the cement. In another embodiment of the invention, the system includes a well bore, which itself includes a substantially vertical portion, a first substantially horizontal portion, and a second substantially horizontal portion. In this embodiment, the substantially vertical portion forms a juncture with each of the first substantially horizontal portion and the second substantially horizontal portion, and the juncture of the substantially vertical portion and the first substantially horizontal portion is physically distinct from the juncture of the vertical portion and the second substantially horizontal portion. In this embodiment, the system also includes a first casing within a portion of the first substantially horizontal portion of the well bore, a second casing within a portion of the second substantially horizontal portion of the well bore, a first cement in a portion of an annulus between the first casing and the portion of the first substantially horizontal portion of the well bore, a second cement in a portion of an annulus between the second casing and the portion of the second substantially horizontal portion of the well bore, a first plurality of hydraulically activated sleeve valves connected to the first casing, a second plurality of hydraulically activated sleeve valves connected to the second casing, a system for setting downhole control pressure for each of the first plurality of hydraulically activated sleeve valves and second plurality of hydraulically activated sleeve valves, and a first treatment fluid which is capable of dissolving the cement. The present invention also provides a method for treating a subterranean formation. In accordance with one embodiment of the invention, a casing is provided in a well bore, wherein the casing includes a plurality of hydraulically activated sleeve valves, at least one of which is connected to a system for setting downhole control pressure. Cement is introduced into a portion of an annulus between the casing and the well bore. The system for setting downhole control pressure is utilized to open at least one of the hydraulically activated sleeve valves. A first treatment fluid, which is capable of dissolving the cement, is flowed through the at least one of the hydraulically activated sleeve valves. In accordance with another embodiment of the invention, a well bore is provided, which includes a substantially vertical portion, a first substantially horizontal portion, and a second substantially horizontal portion. The substantially vertical portion of the well bore forms a juncture with each of the first substantially horizontal portion and the second substantially horizontal portion, and the juncture of the substantially vertical portion and the first substantially horizontal portion is physically distinct from the juncture of the vertical portion and the second substantially horizontal portion. Also in accordance with this embodiment of the invention, a first casing is provided in the first substantially horizontal portion of the well bore, wherein the first casing includes a first plurality of hydraulically activated sleeve valves, at least one of which is connected to a system for setting downhole control pressure. A second casing is provided in the second substantially horizontal portion of the well bore, wherein the second casing includes a second plurality of hydraulically activated sleeve valves, at least one of which is connected to the system for setting downhole control pressure. Cement is introduced into a portion of an annulus between the first casing and the first substantially horizontal section of the well bore. Cement is also introduced into a portion of an annulus between the second casing and the second substantially horizontal section of the well bore. The system for setting downhole control pressure is utilized to selectively open or close at least one hydraulically activated sleeve valve in each of the first plurality of hydraulically activated sleeve valves and second plurality of hydraulically activated sleeve valves. A first treatment fluid, which is capable of dissolving the cement, is flowed through the at least one hydraulically activated sleeve valve in the first plurality of hydraulically activated sleeve valves. The first treatment fluid is also flowed through the at least one hydraulically activated sleeve valve in the second plurality of hydraulically activated sleeve valves.

The features and advantages of the present invention will be readily apparent to those skilled in the art. While numerous changes may be made by those skilled in the art, such changes are within the spirit of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These drawings illustrate certain aspects of some of the embodiments of the present invention, and should not be used to limit or define the invention.

FIG. 1 illustrates an embodiment of the invention in a cross-sectional view of a representative well bore with a single horizontal portion.

FIG. 2 illustrates an embodiment of the invention in a cross-sectional view of a representative well bore with multiple horizontal portions.

FIG. 3 illustrates an embodiment of the invention in a cross-sectional view of a representative well bore with a single horizontal portion.

FIG. 4 illustrates an embodiment of the invention in a cross-sectional view of a representative well bore with multiple horizontal portions.

FIG. 5 illustrates an aspect of an embodiment of the invention in a cross-sectional view of a position-indicative hydraulically activated valve.

FIG. 6 illustrates an aspect of an embodiment of the invention in a cross-sectional view of a conventional hydraulically activated valve.

FIG. 7 illustrates an aspect of an embodiment of the invention in a side view of a system for setting downhole control pressure.

DESCRIPTION OF PREFERRED EMBODIMENTS

The invention relates generally to systems and methods for completion and treatment of subterranean wells and, more specifically, to hydraulic operation of sleeve valves that provide selective and controlled application of fluids in subterranean installations.

While the making and using of a number of embodiments are discussed in detail below, it should be understood that the discussion is not limiting. The specific embodiments set forth herein are illustrative and do not limit the scope of the invention.

The improved systems and methods for completing and treating zones in a well bore are described herein and may be utilized in vertical or horizontal well bores. It is understood that the term “vertical well bore” used herein is the portion of the well bore to be completed which is substantially vertical, inclined, or deviated. The term “horizontal” or “lateral” well bore is used to mean the portion of a well bore in a subterranean producing zone which is substantially horizontal. The terms “upper” and “lower” and “top” and “bottom” are relative terms and are intended to apply to respective positions within the well bore. The term “zone” as used herein refers to separate parts of the well bore designated for treatment and may refer to an entire hydrocarbon formation or separate portions of a single formation such as horizontally and/or vertically spaced portions of the same formation. “Down”, “downward”, or “downhole” refer to the direction in or along the well bore from the wellhead into the well. Also, as used herein the terms “seal” and “isolation” are used with the recognition that some leakage may occur and that such leakage may be acceptable. Thus, some embodiments of the present invention may allow for leakage without departing from the scope of the invention and systems that provide for such leakage and fall within the scope of the present invention

Referring now to FIG. 1, according to one embodiment of the invention, a casing is shown lowered into a horizontal or lateral well bore. FIG. 1 discloses a well 10 which may be made up of a vertical well bore 15 or vertical portion 15 which may have casing cemented therein, and a horizontal or lateral well bore or portion 20. A tool string 25 may be lowered into the well 10. Tool string 25 may be lowered in on a tubing 30 and may include a liner hanger 32 such as for example a Halliburton VersaFlex™ Expandable Liner Hanger System.

In this embodiment, a casing 34 extends downwardly from liner hanger 32 and has a lower end 36. Lower end 36 of casing 34 may have float shoe 38 and a float collar 40 of a type known in the art connected therein. Also connected inside casing 34 may be a tubing conveyed perforating device 42 with a hydraulically actuated firing head, and polished bore receptacle 44.

In this embodiment, well 10 and casing 34 define an annulus 46 which is a generally horizontal annulus in horizontal portion 20. Casing 34 has a casing interior 48 that defines a flow passage 50 therethrough. An inner string 52 may be disposed in casing 34 and extend therethrough, so that a lower end 54 thereof extends into and is received in polished bore receptacle 44. A conventional hydraulically actuated opening sleeve 56, explained in more detail below, may be connected in the inner string 52 as well. A plurality of communication subs 58, which may also be referred to as communication subs 58, may be connected to casing 34. The communication subs will be designated with subscripts a-e for identification purposes. Communication subs 58 may be, for example, position-indicative hydraulically activated valves, such as HV Series Interval Control Valves commercially available from WellDynamics of Spring, Tex.

One embodiment of communication subs 58 is shown in FIG. 5. Generally, each of the plurality of communication subs 58 may include a housing 60 having a plurality of housing ports 82 allowing communication between outside the housing 60 and inside the housing 60. A movable sleeve 62 may be sealed to the inside of the housing 60 such that in one position the sleeve 62 prevents flow through the housing ports 82 and in another position flow therethrough is facilitated. The sleeve 62 may be moved from the closed position to the opened position (and vice versa) by a pressure differential, such as that created by control line hydraulic pressure, which may be applied to one or more piston areas associated with the sleeve 62. The communication subs 58 may include one or more position indicators to indicate, for example, that the sleeve 62 has been moved into the fully opened flow condition. Such position indicators may include a pressure bypass conduit that is uncovered (i.e., opened to fluid communication) as the sleeve 62 reaches the fully opened conditioned. When the bypass conduit is uncovered, fluid communication among the open and closed control lines in the communication sub 58 and the pressure control equipment is established. Additionally, once uncovered, the bypass conduit may be used to circulate the actuating fluid, such as hydraulic fluid, through the communication sub 58 and control system to, among other things, remove contaminants such as air, gas, water, or particulates. Still further, the housing 60 and the sleeve 62 may include a port alignment system to maintain the housing ports 82 and sleeve or door ports 80, if any, in a desired flow alignment.

In one embodiment, hydraulic activation of communication subs 58 is provided by a system 710 for setting downhole control pressure, as shown in FIG. 7 and described in detail in U.S. Patent Publication No. 2007/0012455 A1, which is hereby incorporated by reference. A control module 720 may control operation of each of the communication subs 58 in response to pressure levels, sequences of pressures, combinations of pressures, etc. in one or more control lines 722. For clarity and simplicity, only a single control line 722 is shown in FIG. 7, but any number of control lines may be used in keeping with the principles of the invention. The control module 720 could be used to select from among multiple communication subs 58 which particular communication sub 58 is to be operated and/or in what manner the selected communication sub 58 should be operated. Thus, the control module 720 can perform a device selection function as well as a device operating function. However, for simplification in FIG. 7, only a single communication sub 58 is shown using the control module 720, and so in this case no device selection function is performed by the control module 720. Pressure may be applied to the control line 722 by a pressure control system 724 positioned at a location remote from the casing 34. For example, the pressure control system 724 could be positioned at the earth's surface (including on a well platform, a floating rig, at a subsea wellhead or mudline, etc.) and the casing 34 could be installed thousands of feet downhole.

To facilitate installation and operation of the control lines 722, the control lines 722 may be run in grooves on the outside of the casing 34 in a low profile configuration. Subsequent cementing of casing 34 into well 10 may result in additional stability and support for control lines 722. While control lines 722 may be run through the interior of casing 34, placing control lines 722 outside of casing 34 may provide additional interior volume for transmission of fluids or tools through casing 34.

Referring back to FIG. 1, a plurality of communication subs 58 may be included on casing 34. Communication subs 58 may be positioned adjacent the selected zones to be treated.

A plurality of selected zones, for example, zones 100, 102, 104, 106, 108, and 110, may be treated and produced with the systems and methods described herein. The zones may be referred to as extending from the bottom or lowermost zone 100 to the top or uppermost zone 110. The zones may be also referred to as the first selected zone 100 through the final selected zone 110. The zones may be zones in a single formation or may be individual formations to be treated.

After inner string 52 is lowered into well bore 10, cement may be flowed through inner string 52 and out through float collar 40 and/or float shoe 38. As shown in FIG. 3, cement may be flowed therethrough into annulus 46. When the desired amount of cement has been displaced through the well into annulus 46, a foam dart, or wiper plug 113 may be displaced through inner string 52 to seat in float collar 40. Liner hanger 32 may be set in the well, inner string 52 may be removed, and the cement may be allowed to set in annulus 46.

Alternatively, cementing of casing 34 may be achieved via reverse-circulation cementing. Methods and systems for reverse-circulation cementing in subterranean formations are described in detail in U.S. Patent Application 2006/0086499 A1, which is hereby incorporated by reference.

In FIG. 3, the tubing 30 is shown wherein a tool string 114 has been stung through liner hanger 32. To treat the selected zones, openings through the cement in annulus 46 must be created. To do so, a dissolving fluid is displaced into the casing 34 ahead of the treatment fluid. For example, if acid-soluble cement is utilized, acid may be used as the dissolving fluid. The treatment fluid may be, for example, acidizing fluid or fracturing fluid. To treat bottom zone 100, the dissolving fluid is displaced into the casing 34 ahead of the desired treatment fluid. Hydraulic pressure may be applied in the string 114 to cause the firing head in perforating device 42 to fire to create openings in casing 34, or to cause conventional hydraulically actuated sleeve 56 to activate openings in casing 34. Acid will flow through the openings in casing 34, and will create an opening, or openings, through the cement by dissolving the cement in the annulus 46, thus creating a pathway for treatment fluid. The pathway through the cement at bottom zone 100 may be referred to as pathway 130.

As shown in FIG. 6, conventional hydraulically actuated sleeve 56 may be, for example, a sleeve 56 disposed in an outer housing 122. Conventional hydraulically actuated sleeve 56 is detachably connected therein. The application of hydraulic pressure will cause conventional hydraulically actuated sleeve 56 to move so that ports 124 in outer housing 122 are uncovered to allow flow therethrough. One example of the sleeve that may be used is a hydraulically activated sleeve, such as the Delta Stim™ Sleeve commercially available from Halliburton of Houston, Tex. Housing 122 has upper and lower ends 126 and 128, respectively, adapted to be threaded into casing 34.

Once the bottom selected zone 100 has been treated, all or a portion of the remainder of the plurality of selected zones may be treated without the use of packers therebetween. The cement in annulus 46 may separate the zones to be treated and, as such, the current method may be quicker, easier and more efficient than open hole methods which require packers to be set between the zones to be treated.

In this example, the next zone to be treated is second selected zone 102. To treat zone 102, system 710 may open communication sub 58a. Sleeve 62a may move downwardly so that sleeve ports 80a and casing ports 82a are aligned. Acid or other dissolving fluid may be spotted therethrough ahead of treatment fluid in the casing 34. The acid may pass through the aligned sleeve ports and casing ports 80a and 82a, and may create a second pathway 132 through the cement in annulus 46. Treatment fluid may thereafter be flowed into second selected zone 102 through pathway 132. First communication sub 58a may be closed and second communication sub 58b may then be actuated by system 710. Casing ports 82b and sleeve ports 80b may be aligned when sleeve 62b moves upon the application of fluid pressure in casing 34. Dissolving fluid may be spotted therethrough ahead of treatment fluid to create a third set of openings 134, or third pathway 134 through the cement in annulus 46 so that the third selected zone 104 may be treated. This procedure may be followed to treat any and/or all of the selected zones shown in FIG. 1 in any order or combination, including multiple treatments of any given zone. Thus, additional pathways 136, 138 and 140 may be opened so that treatment fluid may be communicated therethrough into each of selected zones 104-110, respectively. The number of zones and sleeves shown in FIG. 1 is not intended to be limiting and is shown only for exemplary purposes. Any desired number of zones may be treated.

The embodiment in FIG. 1 shows a system and a method used in connection with an inner string 52, but an inner string is not required. FIGS. 2 and 4 show multiple horizontal well bores having no inner string.

FIG. 2 schematically discloses well 150 comprising well bore 151, which has a vertical well bore or vertical portion 152, a first horizontal portion 154 and second horizontal portion 156. Vertical portion 152 is preferably cased, and has casing 157 cemented therein.

A liner hanger 158 disposed in well 150 has a first casing 160 extending therefrom into first horizontal portion 154. Casing 160 defines a flow passage 162 therethrough. Annulus 164 is defined between first horizontal portion 154 and casing 160. A second casing 170 may extend from a packer 172, which may be a desired packer of a type known in the art, into second horizontal portion 156. It will be understood that casing 160 and liner hanger 158 will be in place and, if cemented in place, will be cemented in place according to the present method prior to the time casing 170 is disposed in the second horizontal portion 156. First horizontal portion 154 intersects a plurality of zones 173, specifically zones 174, 176, 178, 180, 182 and 184. The zones may be referred to collectively as zones 173 and zones 174-184 will be referred to as the first or bottom selected zone through the sixth or upper selected zone. The number of zones shown in the drawings is exemplary, and is not intended to be limiting.

Casing 160 may be lowered into the well in any manner known in the art. Cement may be flowed therethrough and through the float collar 40 and float shoe 38 so that as shown in FIG. 4, cement may flow into annulus 164. Also connected inside casing 160 may be a perforating device 42 with a hydraulically actuated firing head, and may also include a conventional hydraulic actuated sleeve 56. When the desired amount of cement has been displaced through casing 160 into annulus 164, a foam dart 190, or other wiper may be placed therein at the back edge of the cement. Other types of wipers may be used, but the foam dart is preferred. Foam dart 190 will preferably latch in float collar 40 with a snap ring or other latching means. Alternatively, cementing of casing 160 may be achieved via reverse-circulation cementing techniques.

A dissolving fluid, for example acid, for dissolving the cement in annulus 164 may follow foam dart 190 into casing 160. The cement may be allowed to set and pressure in casing 160 may increase. The pressure increase may cause pressure activated conventional hydraulically actuated sleeve 56 to move thereby uncovering casing ports 124, and/or may cause the firing head on perforating device 42 to actuate. The dissolving fluid utilized to pump the foam dart 190 into the float collar may pass through openings 124 and/or the openings in casing 160 created by the firing head in perforating device 42 to create a first set of openings 192, or first pathway 192, through the cement so that treatment fluid can be communicated therethrough into first selected zone 174.

Thereafter, the procedure discussed with respect to the embodiment of FIG. 1 may be followed. System 710 may align sleeve ports 80a with casing ports 82a. A column of dissolving fluid, for example acid if acid-soluble cement, may be displaced through the casing. The column of acid may pass through aligned openings 82a and 80a after sleeve 62a moves. The acid may dissolve the acid-soluble cement in annulus 164 sufficiently to create second set of openings 194, or second pathway 194, through the cement so that the second selected zone 176 may be treated with a treating fluid, such as fracturing fluid or acid. System 710 may be utilized to close the first seat sleeve 84a and open the second seat sleeve 84b. Acid may then passes through aligned openings to create the third set of openings, or third pathway. In the same manner, any of the remaining sleeves, which in the embodiment shown in FIG. 2 are seat sleeves 84c-84e may be activated so that the desired zones may be treated. For example, treatment fluid would flow, in the embodiment shown, through pathways 196, 198, 200 and 202 to treat zones 178, 180, 182 and 184. It will be understood that dissolving fluids other than acid may be utilized to dissolve the cement in the annulus.

After all desired zones intersected by first horizontal portion 154 are treated, any tubing used to convey cement connected to liner 158 may be disconnected, and zones intersected by second horizontal portion 156 may be treated. Second horizontal portion 156 may have been drilled in a manner known in the art prior to the treatment of zones intersected by first horizontal portion 154.

An annulus 205 may be defined between second horizontal portion 156 and casing 170. Equipment of a type known in the art, such as a packer 206 and a polished bore receptacle 207, may extend from packer 172 so that cement and treatment fluid may be communicated therethrough into casing 170. Other equipment known in the art, for example, crossovers and seal assemblies, can be used as necessary to connect packer 172 to packer 206 and casing 170.

After cement is flowed to substantially fill the annulus 205 and allowed to set, the procedure described with respect to first horizontal portion 154 and with respect to FIG. 1 may be performed. A foam dart 190, which preferably will latch in float collar 40, or other wiper, may be displaced after the cement at the back edge thereof and in front of dissolving fluid. Pressure may be increased to create openings in casing 170 by moving conventional hydraulically activated sleeve 56 to uncover openings 124 and/or by causing the firing head in the perforating device 42 to actuate. The dissolving fluid then may dissolve the cement adjacent thereto to create the first set of openings 210, or first pathway 210, through the cement in annulus 205, and the first selected zone 212 may be treated therethrough. The remainder of zones 214 through 224 may be treated in a manner similar to that already described. System 710 may cause sleeve ports 80a and casing ports 82a to be aligned so that the dissolving fluid and treating fluid will pass therethrough to dissolve the cement and create a second set of openings 226, or second pathway 226, through which second selected zone 214 may be treated. A column of acid may be introduced into the casing 170. After each sleeve ports 80 is aligned with the casing ports 82, and the acid may dissolve the cement to make the third set of openings 228, or third pathway 228, through the desired set of openings, in this case sixth set of openings 234, or sixth pathway 234, and each zone may be treated. After the desired number of zones are treated, any or all of the zones, as selected by system 710, may be produced. In the case of FIG. 2, the zones from both of horizontal portions 154 and 156 may be produced simultaneously. In the embodiment described, acid-soluble cement is referred to for cementing casing, but it is understood that other types of cements may be used that can be dissolved with basic solutions or other solvents.

By utilizing the foregoing methods, an interventionless, packerless method of producing from multiple zones is possible. The method is packerless in that no packers are necessary to be placed between zones, since the cement barrier acts as a separation between the production zones. Thus, hydraulic pressure activated sleeves may be utilized in a casing string to create openings through which treatment fluids may be communicated into the selected zones and through which the zones may be produced. While the illustrated embodiments described herein disclose the use of liner hangers, it is understood that the methods described do not require liner hangers and are useful in wells where liner hangers are not used.

Therefore, the present invention is well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the present invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the present invention. Moreover, the indefinite articles “a” or “an”, as used in the claims, are defined herein to mean one or more than one of the element that it introduces. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee.