Multi-zone Intelligent and Interventionless Single Trip Completion

Abstract

A one trip interventionless method for fracking multiple intervals incorporates a remotely operated passage isolation valve for each interval. A screen backed by a base pipe is provided to route screened production through a shutoff valve before the production reaches the passage in the completion assembly. The shutoff valve is remotely operated as well. The fracking port is associated with a pressure responsive operator such as a j-slot mechanism with a spring return. The j-slot mechanism is behind a rupture disc so that it remains unaffected while other operations are going on in the wellbore. The rupture discs are set at different pressures for the intervals involved. Sequentially, each fracked zone is isolated and the zone above is opened with breaking the rupture disc and applying predetermined number of pressure cycles. The screen valves are remotely operated as needed after the fracking to initiate production from one or more intervals.

Description

FIELD OF THE INVENTION

The field of the invention is multi zone fracturing and production and more particularly for a one trip method to accomplish such a completion without well intervention.

BACKGROUND OF THE INVENTION

Fracturing is done sequentially in an interval, typically from the bottom up, starting with the lowermost zone that has a fracking sleeve opened, generally with a dropped ball on a seat. Pressuring up shifts the seat and the associated sleeve that supports the seat so that open ports are exposed through which fluid at high pressure and high velocity impinges on the formation to initiate fractures. The port for that zone just fractured is closed and after the entire zone is fractured in this manner the production ports are open. These ports are screened so that production does not produce sand or other particulates. During the fracturing the fracking ports of zones just completed are frequently left open and isolated with another and larger ball dropped on a seat above the still open fracking port to isolate it. When the whole interval is fractured in that sequential manner, the balls can be flowed up to the surface on production or the balls can be blown through the seats or allowed to dissolve or otherwise disappear to facilitate the production that then takes place. In some instances the well is put into injection service rather than production from the formation.

In the past methods to accomplish the steps described above have been with well intervention to close sliding sleeves over fracking port or have simply left those opened fracking ports in that condition and isolated them with dropped balls that landed on higher seats. Some relevant examples of the state of the art can be seen in U.S. Pat. Nos. 6,446,729; 6,983,795; 8,127,847 and 8,342,245. What is needed and provided by the present invention is a way to do a fracking job more intelligently and in a single trip without intervention in the wellbore. Along those lines the present invention has a screen assembly in each interval that can be remotely isolated or opened as well as a formation isolation valve that can be remotely and selectively operated. The fracking port is located behind a breakable member such as a rupture disc with the breaking pressure of each interval set at a different value. The rupture discs allow other well operations to take place before the fracking ports are opened. The preferred opening mechanism is a pressure cycle responsive j-slot assembly. The formation isolation valve is preferably a ball or plug valve that is remotely operated preferably by associated hydraulic lines from the surface. These and other aspects of the present invention will be more readily appreciated by those skilled in the art from a review of the detailed description and the associated drawings while recognizing that the full scope of the invention is to be determined from the appended claims.

SUMMARY OF THE INVENTION

A one trip interventionless method for fracking multiple intervals incorporates a remotely operated passage isolation valve for each interval. A screen backed by a base pipe is provided to route screened production through a shutoff valve before the production reaches the passage in the completion assembly. The shutoff valve is remotely operated as well. The fracking port is associated with a pressure responsive operator such as a j-slot mechanism with a spring return. The j-slot mechanism is behind a rupture disc so that it remains unaffected while other operations are going on in the wellbore. The rupture discs are set at different pressures for the intervals involved. Sequentially, each fracked zone is isolated and the zone above is opened with breaking the rupture disc and applying predetermined number of pressure cycles. The screen valves are remotely operated as needed after the fracking to initiate production from one or more intervals.

BRIEF DESCRIPTION OF THE DRAWING

The FIGURE illustrates one bottom hole assembly for a given interval that can be repeated for a one trip interventionless fracking and production method for one or more intervals.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The FIGURE illustrates a wellbore 10 that has a surrounding formation that can be one or more intervals although a single interval 12 is illustrated for clarity and to avoid repetition of components. An isolation valve 14 is in the passage 16 so that an interval or intervals that are already fractured 18 can be isolated. Packer 20 isolates the interval 12 from interval 18 and other packers such as 20 can be used to isolate as many intervals as needed. Valve 14 is preferably remotely operated without an intervention in the passage 16. The operation can be through control lines, power cable, acoustic signal or pressure cycling to name a few options.

A screen 22 is mounted over a tubular 24 with no wall openings so that flow in the screen will all be directed to valve or valves 26 before entering the passage 16. A control line 28 is shown for operating the valve or valves 26 without intervention but as with valves 14 other means of operation are contemplated as described above as well as other known actuation variations.

A burst disc 30 covers a pressure responsive j-slot assembly 32 that after a number of applications and removals of pressure results in opening ports 34. Each zone has a burst disk that is set to different pressures so that the ports 34 in different intervals will become accessible to pressure cycling at progressive higher pressures in a direction toward the surface.

What is shown in the FIGURE is a single interval assembly that can be repeated any number of times to address as many intervals as is desired and the assemblies can also be spaced out as needed. The lowermost interval can be at hole bottom and in that case the valve 14 for that interval will not be required. The illustrated assembly allows for isolation without intervention of any already fracked intervals with valve 14, followed by raising pressure to break the burst disc 30 so that pressure cycling can open ports 34 for fracking to begin while screen 22 is effectively blocked off with valves 26 closed. When the illustrated interval is fracked the other intervals are sequentially fracked by repeating the above process until all intervals are fracked. Thereafter, any one or more screens 22 can be opened without intervention in passage 16 for production flow. Similarly valves 26 can also be selectively closed if an interval produces sand or water.

Those skilled in the art will appreciate that a fracking and production completion can be made in a single trip without well intervention. The bottom hole assemblies that are used for multiple intervals also permit other pressure related activities to occur before the fracking with the fracking ports remaining isolated and closed behind rupture discs. Key components are provided that respond to interventionless signals to make the one trip fracking and production possible.

The configuration is composed of 3 major components placed serially in the tubing string. The first component is a remotely controlled intelligent flow control device. This is followed by a fracturing port tool utilizing a “j-style” mechanism. The last element includes a zonal isolation packing element and a valve capable of blocking the tubing string. These two units can be broken into separate elements. The entire configuration can be incorporated into a single tool or built from individual components. The flow control device can be on/off, discrete or continuous choking. Control can be achieved via hydraulic, electro-mechanical or electro-hydraulic control. For completions utilizing screen, the inlet to the valve should be placed under the screen to allow flow from the screen-tubing annular area to the inside diameter of the production tubing. The fracturing port will allow tubing to annulus fracturing. The port will initially be run closed. Application of pressure will allow communication to a “j-slot” shifting piston through a burst disc or spring loaded check valve. This pressure will shift the “j-slot” to the second position opening the fracturing port. After completion of the frack, high pressure will again be applied via the tubing to shift the “j-slot” to the final position, closing the frack port. The final position will be configured such that the application of additional pressure cycles will not shift the “j-slot”. The burst disc/check valve will be arranged such that the lowest frack port in the string requires the lowest pressure for communication. Higher frack ports will require increase pressure to allow shifting of the “j-slot”. This will allow each frack port to be opened sequentially. The tubing valve will allow for isolation of the tubing string below the frack port being utilized at any point in time. A packing element will allow for annular zonal isolation. The tubing valve will be a ball or butterfly valve (or similar) capable of completely sealing off the lower section of tubing. Control of this valve can be accomplished by pressure/mud pulse or directly via electrical signals form an electro-mechanical/electro-hydraulic flow control valve or from an electric monitoring device. During run-in, the valve will be locked in the open position. An initial signal will cause the valve to close and allow for fracturing through the frack port above the valve. A second signal will cause the valve to open allowing production/communication to lower zones.

Control of the fracturing port can be achieved via low pressure instead of high pressure. The unit can be design such that hydrostatic pressure plus fluid head keeps the valve locked into a position. A decrease of this pressure would cause a shift (pressure would not need to be decreased below formation pressure, removal of some fluid weight or artificially applied pressure is sufficient). Upon reapplication of the pressure, the valve will lock into the next position. The final position will still be a locking position to ensure future pressure cycles do not shift the port.

The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below:

Claims

1. An interventionless completion method for one trip fracking and production from at least one interval, comprising:

running in a bottom hole assembly that comprises at least one set of the following components:

an annular seal;

an isolation valve for selectively closing an internal passage through the assembly;

at least one frack port and associated closure for selective communication with said passage;

a screen with an associated screen valve to selectively allow communication with said passage;

performing, at least one time, the following completion steps without passage intervention with tools and in a single trip:

closing off an annular space with said annular seal;

closing off said passage with said isolation valve;

opening said frack port;

fracking through said now open frack port;

closing said frack port;

opening said screen valve; and

producing through said screen.

2. The method of claim 1, comprising:

running in multiple sets of said components;

locating said sets adjacent a plurality of intervals;

performing said completion steps at each said interval.

3. The method of claim 2, comprising:

performing said completion steps in a sequence that begins furthest from a surface location and moves toward said surface location.

4. The method of claim 1, comprising:

isolating said closure from passage pressures to a predetermined level.

5. The method of claim 4, comprising:

using a breakable member for said isolating.

6. The method of claim 5, comprising:

operating said closure with pressure after breaking said breakable member.

7. The method of claim 6, comprising:

using pressure cycles with a j-slot mechanism for opening and closing said closure.

8. The method of claim 6, comprising:

opening and closing said closure with pressure cycles applied to a spring loaded j-slot mechanism;

disabling said j-slot mechanism from reopening said closure after closing said closure.

9. The method of claim 8, comprising:

opening said screen valve after closing said closure.

10. The method of claim 3, comprising:

isolating said closures from passage pressures to different predetermined levels.

11. The method of claim 10, comprising:

using breakable members for said isolating.

12. The method of claim 11, comprising:

operating said closures with pressure after breaking a respective said breakable member.

13. The method of claim 12, comprising:

using pressure cycles with a j-slot mechanism for opening and closing each said closure.

14. The method of claim 12, comprising:

opening and closing said closures with pressure cycles applied to a spring loaded j-slot mechanism;

disabling said j-slot mechanism from reopening each said closure after closing said closure.

15. The method of claim 14, comprising:

opening at least one said screen valve after closing said closure associated with said screen.

16. The method of claim 10, comprising:

using breakable members set to break at different pressures for said isolating.

17. The method of claim 16, comprising:

using breakable members with progressively higher pressure settings in a direction toward a surface location.