초록 ▼

Downhole tools comprise a housing chamber with an expandable member disposed therein. An interior of the expandable member is in fluid communication with an outside environment so that hydrostatic pressure can act on an inner wall surface of the expandable member. The outer wall surface of the expan

Downhole tools comprise a housing chamber with an expandable member disposed therein. An interior of the expandable member is in fluid communication with an outside environment so that hydrostatic pressure can act on an inner wall surface of the expandable member. The outer wall surface of the expandable member partially defines a sealed chamber within the housing chamber such that expansion of the expandable member due to an increase in hydrostatic pressure causes the volume within the sealed chamber to decrease, thereby energizing the sealed chamber. Thus, an increase in hydrostatic pressure within an outside environment is compensated. Further, when the hydrostatic pressure within the outside environment decreases, the energized sealed chamber causes contraction of the expandable member, thereby compensating for the decrease in hydrostatic pressure.

대표청구항 ▼

1. A downhole tool comprising: a tubular member comprising an outer wall surface;a housing disposed on the tubular member, the housing comprising a housing chamber;an expandable member disposed in the housing chamber, the expandable member comprising an interior portion, an outer wall surface, a con

1. A downhole tool comprising: a tubular member comprising an outer wall surface;a housing disposed on the tubular member, the housing comprising a housing chamber;an expandable member disposed in the housing chamber, the expandable member comprising an interior portion, an outer wall surface, a contracted position, and an expanded position the outer wall surface of the expandable member partially defining a sealed chamber within the housing chamber; andat least one port disposed through the housing, the at least one port being in fluid communication with the interior portion of the expandable member and an outside environment,wherein the expandable member moves from the contracted position toward the expanded position due to a pressure increase within an annulus of a wellbore outside of the tubular member, and the expandable member moves from the expanded position toward the contracted position due to a pressure decrease within the annulus of the wellbore outside of the tubular member. 2. The downhole tool of claim 1, wherein the sealed chamber comprises a fluid pressure exerting a force on an outer wall surface of the expandable member. 3. The downhole tool of claim 1, wherein the sealed chamber is charged with a gas at a fluid pressure, the fluid pressure exerting a force on an outer wall surface of the expandable member. 4. The downhole tool of claim 3, wherein the fluid pressure is an operational fluid pressure. 5. The downhole tool of claim 3, wherein the sealed chamber is charged with the gas when the expandable member is in the contracted position. 6. The downhole tool of claim 1, wherein the housing comprises a housing outer wall surface having a portion that inflects inwardly when the expandable member is in the expanded position. 7. The downhole tool of claim 1, wherein the at least one port is disposed through a lower end of the housing. 8. The downhole tool of claim 1, wherein an anti-extrusion device is disposed at an upper end and a lower end of the expandable member. 9. A pressure relief device for compensating for a change in pressure within an isolated outside environment within a wellbore, the pressure relief device comprising: a tubular member having an outer wall surface and an inner wall surface defining a bore;a housing disposed on the outer wall surface of the tubular member, the housing having a housing outer wall surface, a housing inner wall surface, a port disposed through the housing outer wall surface, and a housing chamber, the port being in fluid communication with an isolated outside environment outside of the tubular member;an expandable member disposed within the housing chamber, the expandable member comprising an upper end, a lower end, an outer wall surface, and an inner wall surface, the inner wall surface defining an interior portion of the expandable member, the interior portion being in fluid communication with the port, and the outer wall surface of the expandable member and the housing inner wall surface defining a sealed chamber,wherein the expandable member expands within the housing chamber due to an increase in pressure within the isolated outside environment outside of the tubular member. 10. The pressure relief device of claim 9, wherein the expandable member contracts within the housing chamber due to a decrease in pressure within the isolated outside environment. 11. The pressure relief device of claim 9, wherein the housing comprises a plurality of ports disposed through the housing outer wall surface, each of the plurality of ports being in fluid communication with the interior portion of the expandable member. 12. The pressure relief device of claim 11, wherein a filter is disposed within each of the plurality of ports. 13. The pressure relief device of claim 9, wherein the housing outer wall surface comprises a portion that inflects inwardly when the expandable member expands within the housing chamber due to the increase in pressure within the isolated outside environment. 14. The pressure relief device of claim 9, wherein the sealed chamber is charged with a gas at a fluid pressure, the fluid pressure exerting a force on an outer wall surface of the expandable member. 15. The pressure relief device of claim 14, wherein the gas is nitrogen. 16. The pressure relief device of claim 15, wherein the expandable member is secured to the tubular member at the upper and lower ends of the expandable member and an anti-extrusion device is disposed at the upper and lower ends of the expandable member. 17. A method of reducing pressure within an isolated wellbore annulus, the method comprising the steps of: (a) disposing a tubular string within a wellbore, the tubular string comprisinga tubular member having a housing, the housing having a port and an inner wall surface defining a housing chamber,an expandable member disposed within the housing chamber, the expandable member comprising an interior portion in fluid communication with the port, an outer wall surface of the expandable member and the inner wall surface of the housing defining a sealed chamber,a first wellbore barrier operatively associated with the tubular member, anda second wellbore barrier operatively associated with the tubular member, the second wellbore barrier being disposed below first wellbore barrier,(b) establishing an isolated wellbore annulus with the first and second wellbore barriers, the port being in fluid communication with the isolated wellbore annulus; and(c) expanding the expandable member within the housing chamber due to an increase in pressure within the isolated wellbore annulus causing the sealed chamber to have a reduced volume, thereby reducing pressure within the isolated wellbore annulus. 18. The method of claim 17, further comprising the step of: (d) contracting the expandable member due to a decrease in pressure within the isolated wellbore annulus. 19. The method of claim 18, wherein step (d) is facilitated by a compressed gas contained within the sealed chamber. 20. The method of claim 18, wherein step (d) is facilitated by atmospheric pressure contained within the sealed chamber.