Straddle packer system
View Patent ↗A straddle packer system includes an upper seal member, a lower seal member, an upper equalizing valve configured to equalize pressure across the upper seal member, a lower equalizing valve configured to equalize pressure across the lower seal member, and an anchor. The upper and lower seal members do not move when actuating the upper and lower equalizing valves, respectively, into an unloading position to equalize the pressure across the upper and lower seal members.
1. A straddle packer system, comprising:
an upper seal member;
a lower seal member;
an upper equalizing valve having an upper outer housing, an upper inner mandrel, and a biasing member disposed between the upper outer housing and the upper inner mandrel, wherein the upper outer housing is movable against a bias force of the biasing member and relative to the upper seal member and the upper inner mandrel into a first unloading position to equalize pressure across the upper seal member, wherein the upper seal member does not move when the upper equalizing valve is moved into the first unloading position;
a lower equalizing valve movable into a second unloading position to equalize pressure across the lower seal member, wherein the lower seal member does not move when the lower equalizing valve is moved into the second unloading position; and
an anchor, wherein:
the biasing member biases the upper inner mandrel into a run-in position where one or more ports formed through the upper inner mandrel are positioned within the upper outer housing of the upper equalizing valve;
the one or more ports are positioned outside of an end cap member of the upper outer housing to open fluid communication to an annulus surrounding the one or more ports; and
a c-ring disposed within the upper outer housing is compressed into a groove formed in the upper inner mandrel when the upper outer housing is moved to the first unloading position.
2. The system of claim 1 , wherein the upper equalizing valve is configured to move into the first unloading position before the lower equalizing valve is moved into the second unloading position.
3. The system of claim 1 , wherein the upper equalizing valve and the lower equalizing valves are configured to be simultaneously movable into the first and second unloading positions.
4. The system of claim 1 , wherein the upper inner mandrel has one or more ports, wherein the upper outer housing and the upper inner mandrel are movable relative to each other to a position where the ports open fluid communication to equalize pressure across the upper seal member.
5. The system of claim 1 , wherein the lower equalizing valve includes an inner mandrel movable relative to an outer housing having one or more ports through which fluid communication is opened to equalize pressure across the lower seal member.
6. The system of claim 1 , wherein the upper seal member is a cup seal member that is energized by pressurized fluid, and wherein the lower seal member is a cup seal member that is energized by pressurized fluid or a packer element that is energized by a compression or a tension force.
7. The system of claim 1 , wherein the upper inner mandrel of the upper equalizing valve is pressure volume balanced when the system is pressurized, or biased in a downward direction by pressurized fluid when the system is pressurized.
8. The system of claim 1 , wherein an inner mandrel of the lower equalizing valve is pressure volume balanced when the system is pressurized, or biased in a downward direction by pressurized fluid when the system is pressurized.
9. The system of claim 1 , wherein an inner mandrel of the lower equalizing valve is biased in an upward direction by pressurized fluid when the system is pressurized.
10. The system of claim 1 , wherein the lower equalizing valve includes a biasing member biasing a valve member disposed within a lower outer housing into a run-in position to close fluid flow through one or more ports formed in a flow sub of the lower equalizing valve.
11. The system of claim 10 , wherein a lower inner mandrel is movable against a bias force of the biasing member to move the valve member into the second unloading position to open fluid communication through the one or more ports.
12. The system of claim 11 , further comprising a c-ring that is compressed into a groove formed in the lower inner mandrel when the lower inner mandrel is moved to the second unloading position.
13. The system of claim 1 , further comprising a spacer pipe coupling disposed between the upper equalizing valve and the lower equalizing valve, wherein the spacer pipe coupling is coupled to the lower equalizing valve by a swivel.
14. The system of claim 1 , wherein the upper inner mandrel has a shoulder configured to transmit a compression force to set the anchor.
15. The system of claim 1 , wherein the upper inner mandrel has a shoulder configured to transmit a tension force to unset the anchor.
16. A method of operating a straddle packer system, comprising:
lowering the system into a wellbore;
actuating an anchor of the system into engagement with the wellbore;
energizing an upper seal member and a lower seal member of the system to isolate a section of the wellbore;
equalizing pressure across the upper seal member by applying a tension force to actuate an upper equalizing valve of the system, wherein the upper equalizing valve has an upper outer housing, an upper inner mandrel, and a biasing member disposed between the upper outer housing and the upper inner mandrel, wherein the upper outer housing is movable against a bias force of the biasing member and relative to the upper seal member and the upper inner mandrel to equalize pressure across the upper seal member, wherein the upper seal member does not move when the upper equalizing valve is actuated by the tension force; and
equalizing pressure across the lower seal member by applying the tension force to actuate a lower equalizing valve of the system, wherein the lower seal member does not move when the lower equalizing valve is actuated by the tension force.
17. The method of claim 16 , further comprising actuating the upper equalizing valve before actuating the lower equalizing valve.
18. The method of claim 16 , further comprising simultaneously actuating the upper equalizing valve and the lower equalizing valve.
19. The method of claim 16 , further comprising moving the outer housing of the upper equalizing valve relative to the upper inner mandrel having one or more ports to open fluid communication to an annulus surrounding the ports to equalize pressure across the upper seal member.
20. The method of claim 16 , further comprising moving the upper inner mandrel having one or more ports relative to the upper outer housing of the upper equalizing valve to open fluid communication to an annulus surrounding the ports to equalize pressure across the upper seal member.
21. The method of claim 16 , further comprising moving a valve member of the lower equalizing valve to open fluid communication through one or more ports of a flow sub to equalize pressure across the lower seal member.
22. The method of claim 16 , wherein the upper equalizing valve and the lower equalizing valve are in at least one of an open position and a closed position while the system is lowered into the wellbore.