Sliding sleeve having contracting, ringed ball seat
A sliding sleeve opens with a deployed ball. The sleeve has a seat disposed in the housing, and the seat has segments biased outward from one another with a C-ring or other biasing element. Initially, the seat has an expanded state in the sliding sleeve so that the seats segments expand outward against the housing's bore. When an appropriately sized ball is deployed downhole, the ball engages the expanded seat. Fluid pressure applied against the seated ball moves the seat into the inner sleeve's bore. As this occurs, the seat contracts, which increases the engagement area of the seat with the ball. Eventually, the seat reaches the shoulder in the inner sleeve so that pressure applied against the seated ball now moves the inner sleeve in the housing to open the sliding sleeve's flow port.
1. A sliding sleeve opening with a deployed plug, the sleeve comprising:
a housing defining a first bore and defining a flow port communicating the first bore outside the housing;
an inner sleeve defining a second bore and being movable axially inside the first bore from a closed position to an opened position relative to the flow port, the second bore having a transition shoulder and an engagement shoulder disposed therein; and
a compressible seat disposed in a first axial position engaged against the transition shoulder in the second bore of the inner sleeve,
the compressible seat in the first axial position having an expanded state and engaging the deployed plug with the first contact dimension into which the engaged plug is forced,
the compressible seat moving the inner sleeve axially open in response to fluid pressure applied against the engaged plug,
the compressible seat shifting from the first axial position past the transition shoulder to a second axial position engaged against the engagement shoulder and contracting from the expanded state to a contracted state in response to the applied fluid pressure,
the compressible seat transitioned to the contracted state in the second axial position compressing with the second contact dimension, narrower than the first contact dimension, wedged against the engaged plug forced into the compressible seat.
2. The sleeve of claim 1 , further comprising an attachment holding the inner sleeve in the closed position and being disengageable to permit movement of the inner sleeve from the closed position.
3. The sleeve of claim 1 , wherein an edge of the compressible seat in the expanded state defines a first contact area, and wherein the compressible seat in the contracted state defines a second contact area greater than the first contact area.
4. The sleeve of claim 1 , wherein the compressible seat comprises a split ring.
5. The sleeve of claim 1 , wherein the compressible seat moves the inner sleeve open axially when the compressible seat is at least partially engaged with the transition shoulder.
6. A sliding sleeve opening with a deployed plug, the sleeve comprising
a housing defining a first bore and defining a flow port communicating the first bore outside the housing; and
an inner sleeve defining a second bore and being movable axially inside the first bore from a closed position to an opened position relative to the flow port, the second bore having a transition shoulder and an engagement shoulder disposed therein; and
a compressible seat disposed in the inner sleeve and being movable axially from a first axial position engaged against the transition shoulder to a second axial position engaged against the engagement shoulder,
the compressible seat comprising means for engaging the deployed plug in an expanded state in the first axial position engaged against the transition shoulder, the compressible seat in the expanded state having a first contact dimension into which the engaged plug is forced,
the inner sleeve comprising means for opening in response to fluid pressure applied against the plug engaged in the compressible seat and forced into the first contact dimension,
the compressible seat further comprising means for transitioning from the expanded state to a contracted state toward the second axial position engaged against the engagement shoulder, and
the compressible seat even further comprising means for compressing in the contracted state having a second contact dimension, narrower than the first contact dimension, wedged against the engaged plug forced into the compressible seat.
7. The sleeve of claim 6 , further comprising means for disengageably holding the inner sleeve in the closed position.
8. The sleeve of claim 6 , wherein the transition shoulder in the inner sleeve comprises means for engaging the compressible seat at least partially.
9. The sleeve of claim 6 , wherein the compressible seat in the expanded state in the first axial position comprises means for engaging the deployed plug with a first contact area.
10. The sleeve of claim 9 , wherein the compressible seat in the contracted state toward the second axial position comprises means for engaging the engaged plug with a second contact area, the second contact area being greater than the first contact area.
11. The sleeve of claim 6 , wherein the compressible seat in the second axial position engages the engagement shoulder in the second bore of the inner sleeve.
12. A fluid treatment method for a wellbore, the method comprising:
deploying a plug downhole to a sliding sleeve in the wellbore;
engaging the deployed plug against a compressible seat engaged against a transition shoulder and in an expanded state in a first axial position in an inner sleeve of the sliding sleeve;
applying fluid pressure against the engaged plug in the compressible seat in the expanded state having a first contact dimension into which the engaged plug is forced;
moving the inner sleeve axially open in the sliding sleeve in response to the applied fluid pressure;
contracting the compressible seat from the expanded state into a contracted state by moving the compressible seat axially against an engagement shoulder in the inner sleeve; and
compressing the engaged plug with the compressible seat in the contracted state having a second contact dimension, narrower than the first contact dimension, wedged against the engaged plug forced into the compressible seat.
13. The method of claim 12 , further comprising disengageably holding the inner sleeve in the closed position.
14. The method of claim 12 , wherein moving the inner sleeve axially open in the sliding sleeve comprises engaging the compressible seat in the first axial position against the transition shoulder within the inner sleeve.
15. The method of claim 12 , wherein engaging the deployed plug against the compressible seat expanded in the sliding sleeve comprises engaging the deployed plug with a first contact area of the expanded seat.
16. The method of claim 15 , wherein contracting the compressible seat into the contracted state comprises engaging the plug with a second contact area of the contracted seat, the second contact area being greater than the first contact area.
17. The method of claim 15 , wherein contracting the compressible seat into the contracted state by moving the compressible seat axially in the inner sleeve comprises transitioning the compressible seat past the transition shoulder in the inner sleeve.