Apparatus and method for centralizing pipe in a wellbore
AssigneeConoco Inc.
InventorsDennis R. Wilson, Jack H. Cole, Wilber R. Moyer, Larry K. Moran
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Abstract
A system for centralizing casing pipe in a wellbore includes lateral pistons in the side wall of the casing string which are movable by forces applied to their inner end, from a retracted position within the maximum exterior profile of the casing pipe string to a predetermined extended position which will move the casing pipe string toward a central position in the borehole. Various well operations can be performed using the pistons in addition to the centralizing function.
Claims21
An apparatus for spacing a casing pipe string from the walls of a wellbore wherein the wellbore is established for use in producing hydrocarbons from earth formations, the apparatus comprising:
- a plurality of casing pipe sections together with collars making up the casing pipe string;
- said collars interconnecting said pipe sections, said collars being comprised of short joints of casing pipe having threads for interconnecting with adjacent ends of pipe sections, said collars further having a greater peripheral wall thickness than said pipe sections, the outside diameter of said collars representing the maximum exterior profile of said pipe string;
- a plurality of piston guides in the peripheral wall of said casing pipe string, said piston guides being within the maximum exterior profile of said casing pipe string;
- pistons mounted in said piston guides for movement from a retracted position in said piston guides to an extended position wherein the outer end of said pistons are in contact with the wall of the wellbore, the extended position of said pistons being a predetermined single position;
- means for deploying said pistons from said retracted position to said predetermined single fixed extended position wherein the inner end of said pistons are substantially clear of an interior bore within said casing pipe string, said piston guides also being substantially clear of the interior bore of said casing pipe string so that when said piston means is in said extended position, said bore in said casing pipe string is substantially fully open.
Apparatus for spacing a casing pipe string from the walls of the borehole, comprising:
- a plurality of piston guides laterally arranged in the wall of pipe sections making up the casing pipe string, such guides extending between the exterior wall of the casing pipe and a longitudinal bore in the casing pipe;
- pistons arranged for sliding movement in said guides from a retracted position, where the outer end of the piston does not extend outwardly beyond the piston guide, to a single predetermined discrete extended position where the outer end of the piston may be moved outwardly from the guide to only one predetermined position;
- said guides and retracted pistons being arranged so that they are within the maximum exterior profile of the casing pipe string;
- said guides and extended pistons being arranged so that they are substantially clear of the bore in the casing pipe to provide a full opening within the casing pipe bore when said pistons are in said extended position.
A method for centralizing a casing pipe string from the walls of a wellbore wherein the wellbore is established for use in a well system involved in the production of hydrocarbons from earth formations, wherein the pipe string is provided with transverse piston guides in the walls of the pipe string and pistons are mounted in the piston guides for movement from a retracted position where the outer end of the pistons are inside the piston guide to an extended position where the outer end of the pistons extends outwardly beyond the piston guides toward the wellbore, and wherein the pipe string is made up of casing pipe sections with casing collars interconnecting the pipe sections, the collars having a greater peripheral wall thickness and a greater outside diameter than the pipe sections so that the collars represent the maximum exterior profile of the pipe string, the method comprising;
- moving the pistons from said retracted position to said extended position, wherein in the retracted position an inner end of the piston extends into a bore within the pipe string and an outer end of the piston is within the maximum exterior profile of the pipe string, wherein the piston guides are within the maximum exterior profile of the pipe string and do not extend substantially into the bore of the pipe string so that the bore of the pipe string is open when the piston is moved to an extended position, and wherein in the extended position the outer ends of the pistons are moved to a predetermined single position for contact with the wall of the wellbore and the inner end of the piston is substantially clear of the bore of the pipe string to render the bore of the pipe string full open.
Dependencies are inferred from the claim text.