Hydraulic shock absorber for sliding sleeves

摘要

A sliding sleeve has an associated shock absorber to limit shock loading to the shifting apparatus when the end of travel is reached. An adjacent sleeve defined an annular cavity in a manner that does not reduce the drift dimension of the shifting sleeve. The cavity has a fluid in it and the movement of the shifted sleeve causes the movement of the shock absorber sleeve to reduce the fluid volume in the annular cavity. The volume reduction forces fluid through a restriction to regulate the speed of the sliding sleeve as a travel stop is reached. The fluid can be a gas, an incompressible fluid or grease. The restriction can be temporarily covered such as with a rupture disc. Room to compensate for thermal expansion can be provided in the annular space.

主权项

1. An assembly of a sliding sleeve and a shock absorber for use in a subterranean location comprising:
a housing having at least one selectively covered open wall opening by a sliding sleeve surrounding a passage through said housing, said passage defined by a drift dimension that is the smallest dimension for tool passage through said housing; a hydraulic shock absorber surrounding said passage actuated by initial movement of said sliding sleeve into contact with said hydraulic shock absorber to then move said shock absorber to absorb the impact from said sliding sleeve; said shock absorber defining a variable volume adjacent said passage; said variable volume is formed between a sleeve movable upon impact from said sliding sleeve and said housing, movement of said sleeve directly reduces said variable volume; said sleeve and said sliding sleeve have an internal diameter at least as large as said drift dimension.