Pressure limiter for a downhole pump and testing apparatus
First Claim
1. A pressure limiter for use in a tool string having a pump and an inflatable packer, said pressure limiter comprising:
- housing means for positioning in said tool string between said pump and packer, said housing means defining a central opening therethrough and an outlet to the annulus of the well in communication with said central opening;
mandrel means for positioning in said central opening of said housing means;
port means on said housing means in communication with a discharge portion of said pump for providing a flow path in said housing means;
valve means disposed between said housing means and mandrel means for providing communication between said port means and said outlet when in an open position in response to an outlet pressure of said pump, said valve means further having a closed position; and
biasing means for biasing said valve means toward said closed position.
1 Assignment
0 Petitions
Accused Products
Abstract
A pressure limiter for use with a positive displacement pump and an inflatable packer. The pressure limiter includes an outer housing with an inner mandrel disposed therein. Slidably disposed between the mandrel and housing is a generally annular piston. A spring biases the piston toward a closed position. Packer pressure acts upwardly on the piston tending to move it to an open position in which pump discharge pressure is relieved to a well annulus. A check valve prevents premature relief of pressure of the packer. Once the piston is in an open position, packer pressure will maintain it in the open position until pressure is relieved from the packer.
40 Citations
18 Claims
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1. A pressure limiter for use in a tool string having a pump and an inflatable packer, said pressure limiter comprising:
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housing means for positioning in said tool string between said pump and packer, said housing means defining a central opening therethrough and an outlet to the annulus of the well in communication with said central opening; mandrel means for positioning in said central opening of said housing means; port means on said housing means in communication with a discharge portion of said pump for providing a flow path in said housing means; valve means disposed between said housing means and mandrel means for providing communication between said port means and said outlet when in an open position in response to an outlet pressure of said pump, said valve means further having a closed position; and biasing means for biasing said valve means toward said closed position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A pressure limiter for a pump used to inflate an inflatable packer, said pressure limiter comprising:
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a housing connectable to said pump and packer and defining a central opening therethrough with a housing outlet to the annulus of the well in communication with said central opening; a mandrel disposed in said housing and connectable to said pump and packer such that a flow passage is defined from said pump to said packer; a piston annularly disposed between said mandrel and said housing and in communication with said flow passage, said piston being movable to an open position in response to pump discharge pressure, said open position being such that said housing outlet is in communication with a pump outlet whereby fluid pumped by said pump is bypassed through said housing outlet, said piston further having a closed position; and check valve means for controlling flow through said flow passage and maintaining packer pressure on said piston for holding said piston in said open position. - View Dependent Claims (11, 12, 13, 14, 15, 16)
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17. A downhole tool comprising:
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a pump; an inflatable packer disposed below said pump and adapted for inflation thereby; and a pressure limiter disposed between said pump and packer and comprising; means for bypassing pump discharge pressure to a well annulus above said packer when said pump discharge pressure reaches a predetermined level, said means for bypassing including an annular piston in said pressure limiter and biased toward a closed position, said piston having a differential area thereon against which said pump pressure acts for overcoming a biasing force on said piston when said predetermined level is reached; and means for maintaining said pressure limiter in a bypassing position such that an outlet of said pump is in substantially constant communication with said well annulus until pressure is relieved from said packer, said means for maintaining said pressure limiter in a bypassing position includes a check valve adjacent said piston whereby pressure is maintained on said differential area at a level substantially as high as said predetermined level, even when said pump discharge pressure drops as a result of being bypassed to said well annulus. - View Dependent Claims (18)
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Specification