Work over methods and apparatus

Methods and apparatus for isolating the producing zone of a well during workover operations, particularly where the well is equipped with a production string and a submersible electric pump suspended thereon. A packer and isolation valve are set in the well above the producing zone, and a hydraulically operable control suspended on the pipe string below the pump is releasably coupled to the valve and arranged to enable remote control of the valve from the surface by adjusting the pressure of fluids in the production string or in the well annulus.

We claim:

1. Apparatus for isolating an underground earth formation intersected by a well bore, comprising: packer means having an opening therethrough and adapted to be anchored in a sealed but removable manner in the well bore above said formation; valve means connected to the upper end of said packer means, said valve means including a valve body having a flow passage communicating with said opening and with the well bore above said packer means, and a valve element mounted on said valve body and arranged for movement between positions opening and closing said flow passage; and retrievable hydraulically operable valve actuator means fixed to the lower end of a pipe string extending upwardly to the surface, said actuator means including an actuator sleeve that is adapted to be releasably connected with said valve element for moving said valve element between open and closed positions in response to the pressures of fluids in the well above said packer means.

2. The apparatus of claim 1 wherein said actuator means includes piston and cylinder means defining two spaces of variable volume, said piston means being connectable mechanically to said valve element, and means providing fluid communication between one of said spaces and said pipe string and between the other of said spaces and said annulus.

3. The apparatus of claim 2 wherein said fluid communication means includes two hydraulic lines, one of said lines extending from one of said spaces to the interior of said pipe string and the other of said lines extending from the other of said spaces to said annulus.

4. The apparatus of claim 3 wherein said fluid communication means further includes a transfer means associated with each of said hydraulic lines.

5. The apparatus of claim 1 wherein said actuator means is sensitive to the pressure exerted by the liquid filling said pipe string and includes cylinder means having piston means movable therein and defining two spaces of variable volume, said piston means being connected to said actuator sleeve, and means for providing communication between said spaces and two vertically spaced distinct locations in said pipe string.

6. The apparatus of claim 5 wherein said communication providing means include two hydraulic lines, each line connecting one of said spaces with one of said locations in said pipe string.

7. The apparatus of claim 6 wherein said actuator means further includes latch means for releasably connecting said actuator sleeve to said valve element.

8. The apparatus of claim 1 wherein said valve element is constituted by a sleeve member slidably mounted on the exterior of said valve body, said valve body having its lower end fixed to said packer means and its upper end closed in a sealed manner by removable closing means, said valve body having at least one side port adapted to be opened and closed by said sleeve member, and seal means on said valve body above and below said port.

9. The apparatus of claim 8 further including means for releasably connecting said actuator sleeve with said sleeve member, said connecting means including laterally movable latch fingers engageable with detent means in the periphery of said sleeve member.

10. The apparatus of claim 9 wherein said valve means further includes means for protecting said seal means including a protection sleeve slidably mounted on said valve body for covering said seal means in the open position of said sleeve member and means for making said protection sleeve and said sleeve member move together when said sleeve member reaches an intermediate position between its open position and its closed position.

11. In a system for the workover of an oil well of the type including a production string, a pumping assembly fixed to the bottom of the string, an electric power supply cable to connect said pumping assembly to a power source located on the surface, a packer capable of being anchored in the well and having two sealed passages, one to maintain said production string and the other to allow the passage of said electric power cable, the improvement comprising packer means sealably anchored in the well below said pumping assembly, valve means for opening and closing a flow passage through said packer means, and hydraulic means fixed below said pumping assembly and releasably connected with said valve means to enable remote control thereof.

12. The system of claim 11 wherein said hydraulic means is connected to first and second control lines, one of said control lines being in communication with the interior of said production string below said packer and the other of said control lines extending through said packer and being in communication with the annulus space above said packer.

13. The system of claim 12 further including an inertia-type valve means for closing said second control line to upward flow of fluid in the event of the breakage of the line at a point below the packer.

14. The system of claim 11 further including a sliding joint in said production string above said pumping assembly.

15. The system of claim 14 wherein said production string includes at least one drill collar section below said pumping assembly.

16. A method for the workover of a well wherein the production of fluid from a production zone takes place through a production string, comprising the steps of: isolating said producing zone by means of an isolating apparatus including a packer and an isolating valve equipped with a valve sleeve capable of sliding in a direction substantially parallel to the axis of the well and placed in the well above the producing zone by means of a setting tool; attaching at the lower end of a production string a means for hydraulically controlling said isolating valve, said controlling means including two hydraulic lines connected to two couplings of the production string, said controlling means being sensitive to the pressure prevailing in said production string and being, consequently, operable from the surface by means of a liquid filling said production string; placing said production string and said controlling means in the well and releasably connecting said controlling means to said valve sleeve; and operating said controlling means from the surface to move said valve sleeve to its opening position.

17. The method of claim 16 including the further steps of placing a plug in the production string between said two couplings; closing said valve sleeve by adjusting from the surface the pressure of fluid in the production string; closing the communication of the controlling means with the production string to maintain said valve sleeve in its closed position; balancing the pressures between the production string and the annulus; releasing the controlling means from the valve sleeve; and removing said production string and said controlling means from the well, said zone being isolated by said valve sleeve and said packer.

18. A method for the workover of a well wherein the production of luid from a producing zone takes place through a production string, comprising the steps of; isolating said producing zone by means of an isolating apparatus including a packer and an isolating valve equipped with a valve element capable of sliding in a direction substantially parallel to the axis of the well between open and closed positions, said isolating apparatus being places in the well above the producing zone by means of a setting tool; attaching at the lower end of said production string a means for hydraulically controlling said valve element, said controlling means being sensitive to differences in the pressures in production string and the annulus and being, consequently, operable from the surface by means of the liquid filling said production string and said annular space; placing said production string and said controlling means in the well and releasably connecting said controlling means to said valve element; and operating said hydraulic controlling means from the surface to move said valve element into its open position.

19. The method of claim 18 including the further steps of closing said valve element by adjusting from the surface the difference in pressure between the production string and the annulus; closing off communication of the hydraulic controlling means and the production string to maintain said valve element in its closed position; balancing the pressures between the production string and the annulus by opening a circulation valve; obtaining, by fluid circulation, a pressure at the level of said isolating valve higher than the pressure of the producing zone; releasing the controlling means from the valve element; and removing said production string and said valve controlling means from the well, said zone remaining isolated by said isolating valve and by said packer.

20. The method of claim 19 including the further step of after closing off the communication between the hydraulic controlling means and the production string, checking the sealing of the underground-zone-isolating apparatus by increasing the pressure in the annulus above the isolating apparatus.