Double-acting shock damper for a downhole assembly

摘要

A downhole assembly, including a downhole tool, a downhole force-creating device, and a shock damper. The shock damper includes a hollow housing including an annular shoulder near each end and extending radially inward from the housing. The damper also includes a mandrel located at least partially inside the housing to form an annulus between the mandrel and the housing, the mandrel including an annular shoulder near each end and extending radially outward from the mandrel. A spring is located in an annular cavity formed by the annulus and between both the housing shoulders and the mandrel shoulders. The mandrel is movable relative to the housing to an expanded position in one direction and to a compressed position in the other direction.

主权项

1. A downhole assembly, including:
a downhole tool; a downhole force-creating device; and a shock damper including:
a hollow housing including an annular housing shoulder near each end and extended radially inward from the housing;a mandrel located at least partially inside the housing to form an annulus between the mandrel and the housing, the mandrel including an annular mandrel shoulder near each end and extended radially outward from the mandrel;a spring located in an annular cavity defined by the annulus and between both the annular housing shoulders and the annular mandrel shoulders;a first annular piston located in the annular cavity between a first end of the spring and one annular housing shoulder, wherein the first annular piston is configured to seal against the housing and the mandrel;a second annular piston located in the annular cavity between a second end of the spring and the other annular housing shoulder, wherein the second annular piston is configured to seal against the housing and the mandrel;the mandrel being movable relative to the housing to an expanded position in one direction and to a compressed position in the other direction;the spring being compressible by one of the annular housing shoulders on one end and one of the annular mandrel shoulders on the opposite end as the mandrel moves between the expanded and compressed positions, the compression of the spring resisting relative movement between the mandrel and the housing and absorb the force moving the mandrel;wherein the first annular piston or the second annular piston includes a check valve configured to allow one way fluid communication through the first annular piston or the second annular piston into the annular cavity; andwherein the first annular piston or the second annular piston includes a port configured to allow fluid communication into and out of the annular cavity.