System, method and apparatus for concentric tubing deployed, artificial lift allowing gas venting from below packers
An artificial lift deployed on concentric tubing allows gas to be vented from below packers in a well. A central flow path is used for the fluid production from the artificial lift system, while an outer concentric tubing allows for the venting and production of gas from below a packer. The gas enters the outer concentric flow path through a perforated sub set that is located below the packer. Sealing of the inner concentric string flow from the outer concentric flow path is achieved with a polished bore receptacle and stinger assembly.
1. A well system, comprising;
a well having casing installed therein and a packer mounted in the casing;
an artificial lift mounted to a tubing string assembly extending from a surface of the well, the artificial lift being located below the packer, the tubing string assembly comprising:
an outer tubing extending to the well surface, the outer tubing having a perforated sub located below the packer and a polished bore receptacle located below the perforated sub;
an inner tubing within the outer tubing, the inner tubing having a stinger that stabs into sealing engagement with the polished bore receptacle, providing a flow path for fluid pumped by the artificial lift through the inner tubing, the perforated sub providing a flow path for gas in the casing to flow up an inner annulus between the inner and outer tubing; and
wherein the artificial lift is secured to the stinger and has an outer diameter smaller than an inner diameter of the outer tubing, so that the artificial lift may be installed by lowering it on the inner tubing through the outer tubing.
2. A well system according to claim l, wherein the artificial lift comprises an electrical submersible pump (ESP) comprising one of a centrifugal and progressive cavity pump.
3. A well system according to claim 1 , further comprising a sub-surface safety valve installed in the inner tubing above the packer, and a sub-surface safety valve installed in the outer tubing above the packer.
4. A well system according to claim 1 , wherein the artificial lift comprises a gas separator for separating gas from the fluid and releasing gas into a casing annulus between the casing and the perforated sub.
5. A well system according to claim 1 , further comprising a sub-surface safety value in the inner tubing and a sub-surface valve in the outer tubing.
6. A well system according to claim 1 , wherein the artificial lift comprises a rod-driven progressive cavity pump (PCP), and the drive rod is within the inner tubing.
7. A well system according to claim 6 , wherein a stator of the PCP is fixed to an end of the inner tubing.
8. A well system according to claim 1 , wherein the inner tubing is coiled tubing.
9. A well system, comprising;
a well having casing installed therein and a packer mounted in the casing;
an artificial lift mounted to a tubing string extending from a surface of the well, the artificial lift being located below the packer; the tubing string comprising:
an axis;
an inner tubing concentric with the axis and providing a fluid flow path from the artificial lift, through the packer, and to the well surface; and
an outer tubing concentric with the axis and the inner tubing, the outer tubing extending from the artificial lift to the well surface, the outer tubing having a perforated sub located below the packer for allowing gas ingress into a lower annulus between the perforated sub and the inner tubing and then to the well surface via an upper annulus between the inner and outer tubing; and
wherein the outer and inner tubing are crossed over to smaller tubing sizes above the packer to make space available for a power cable packer penetrator.
10. A method of operating a well, comprising:
providing a well with casing;
installing an outer tubing in the casing, the outer tubing having a section containing an inlet aperture in its sidewall;
setting a packer between the outer tubing and the casing above the inlet aperture;
securing an artificial lift device to a lower end of a string of inner tubing and running the inner tubing and the artificial lilt device inside the outer tubing, defining an inner annulus between the inner tubing and the outer tubing, and forming an inner annulus seal between the inner tubing and the outer tubing below the inlet aperture; operating the artificial lift device to deliver well fluid through the inner tubing to a surface of the well; and
allowing gas in the casing below the packer to flow into the inlet aperture and up the inner annulus to the surface of the well.
11. A method according to claim 10 , wherein the artificial lift device comprises a progressive cavity pump.
12. A method according to claim 10 , wherein forming an inner annulus seal comprises stabbing a stinger of the inner tubing into a polished bore receptacle mounted in the outer tubing.
13. A method according to claim 10 , further comprising installing a sub-surface safety in the inner tubing above the packer.
14. A method according to claim 10 , wherein the artificial lift device comprises a gas separator for separating gas from the fluid and releasing gas into the casing below the inlet aperture.
15. A method according to claim 10 , wherein the outer and inner tubing are crossed over to smaller tubing sizes above the packer to make space available for an ESP power cable packer penetrator.
16. A method according to claim 10 , further comprising installing a sub-surface safety value in the inner tubing and installing a sub-surface safety valve in the outer tubing.
17. A method according to claim 10 , wherein the artificial lift device comprises a rod-driven progressive cavity pump (PCP), and before operating the lift device, the method further comprises lowering a string of drive rods through the inner tubing to the PCP.
18. A method according to claim 17 , wherein a stator of the PCP is fixed to an end of the inner tubing, and the inner tubing is coiled tubing.