Wear resistant downhole piston
AssigneeSchlumberger Technology Corporation
InventorAnan Noel
Life of this patent
Estimating the term…
Abstract
A piston for use in a rotary steerable system includes a body formed from a first material. A sealing surface extends around the circumferential wall of the body. The sealing surface is formed from a plurality of layers of a second material. The second material is harder than the first material. The piston can be within a downhole piston assembly that also includes a housing, and the piston being longitudinally movable in a bore in the housing. A method for producing a piston includes preparing a piston formed from a first material, with the piston including a first end. A sealing surface is applied to the piston using laser cladding, with the sealing surface including a second material harder than the first material. The sealing surface is finished to a sealing surface diameter.
Claims18
A piston for use in a downhole tool, comprising:
- a body formed of a first material, the body including a first end, a second end, and a circumferential wall;
- a radially outwardly facing, circumferential sealing surface formed by laser cladding a second material to the body extending around the circumferential wall, the second material being harder than the first material, the circumferential sealing surface having a sealing surface diameter, the sealing surface diameter having a tolerance of less than or equal to 0.02 mm;
- and
- a housing including a housing bore and an inner surface, the body being positioned at least partially in the housing bore and the circumferential sealing surface of the second material forming a tolerance seal between the inner surface and the circumferential sealing surface.
A downhole piston assembly, comprising:
- a piston, the piston including:
- a body including a first end, a second end, a circumferential wall, and an extension axis, the body having a first diameter and including a first material;
- and
- a sealing surface formed by laser cladding extending around the circumferential wall, the sealing surface being perpendicular to the extension axis, the sealing surface being a radially outwardly facing circumferential surface having a second diameter greater than the first diameter, the sealing surface having an outer edge at an outer edge distance relative to the first end of the body and having an inner edge distance relative to the second end of the body, the outer edge distance being between 10% and 50% of a length of the piston and the inner edge distance being less than 30% and greater than 0% of the length of the piston, the sealing surface including a second material, the second material being harder than the first material;
- and
- a housing including a housing bore and an inner surface, the piston being longitudinally movable in the housing bore along the extension axis, the sealing surface forming a tolerance seal between the inner surface of the housing and the sealing surface of the second material.
A method for manufacturing a piston, comprising:
- preparing a piston, the piston including a first end, the piston having a body of a prepared diameter and being formed from a first material;
- applying a sealing surface to the piston using laser cladding, the sealing surface including a radially outwardly facing circumferential surface of a second material harder than the first material;
- finishing the sealing surface to a sealing surface diameter greater than the prepared diameter, the sealing surface diameter having tolerances of less than or equal to 0.02 mm;
- and
- placing the piston in a housing bore of a housing, the housing including an inner surface forming a tolerance seal with the second material of the radially outwardly facing circumferential surface.
Dependencies are inferred from the claim text.