Cement control ring
AssigneeBaker Hughes Incorporated
InventorGrant R. Thompson
Life of this patent
Estimating the term…
Abstract
A sealing system for a flow tube keeps cement from getting around it to the flapper when the safety valve is in the open position. Seals are provided at opposed ends of the flow tube so that the power spring and the flapper will not get fouled with cement pumped through the flow tube in wells that are completed through a production string with the safety valve in place. The seals may be mounted to the flow tube or the surrounding body. A unique seal construction separates cement from the flapper behind the flow tube. The force acting on the flow tube to hold the valve open also helps to apply a force against the lower seal adjacent the flapper.
Claims22
A safety valve for downhole use, comprising:
- a body having a passage extending through it, a flapper pivotally mounted to selectively close said passage, a flow tube to selectively operate said flapper and pass in front of it to open said passage, said flow tube biased away from said flapper by a closure spring mounted in a cavity defined by said body and the outside of said flow tube;
- at least one seal between said outside of said flow tube and said body;
- said at least one seal is mounted to at least one of said body and said flow tube at or between opposed ends of said flow tube;
- said at least one seal isolates said cavity from said passage when said flapper is open;
- said at least one seal comprises an upper and a lower seal spaced apart along said flow tube.
A safety valve for downhole use, comprising:
- a body having a passage extending through it, a flapper pivotally mounted to selectively close said passage, a flow tube to selectively operate said flapper and pass in front of it to open said passage, said flow tube biased away from said flapper by a closure spring mounted in a cavity defined by said body and the outside of said flow tube;
- at least two seals between said flow tube and said body;
- and
- said seals isolate said cavity from said passage when said flapper is open.
A safety valve for downhole use, comprising:
- a body having a passage extending through it, a flapper pivotally mounted to selectively close said passage, a flow tube to selectively operate said flapper and pass in front of it to open said passage, said flow tube biased away from said flapper by a closure spring mounted in a cavity defined by said body and the outside of said flow tube;
- at least two seals between said flow tube and said body to isolate said cavity when said passage is open;
- said at least one seal further comprises an end seal energized when said flow tube is moved to a position where its lower end approaches said housing to displace said flapper, whereupon fluids passing through said flow tube are sealed off from said flapper by said end seal.
Dependencies are inferred from the claim text.