Norton Christensen, Inc.

Eastman Christensen Company

J Stanley Davis

Steven R Radford

Kelly Knighton

Jamming caused by absorbent members in sponge core barrels or loss of coring information caused by oil wipes in oil field boreholes in which sponge core coring tools are disposed can be avoided by employing a method and tool wherein the absorbent member is formed in placed in contact about the core after the has been cut and disposed within the inner tube. In the illustrated embodiment, a liquid foam is catalytically formed from two constituent parts. The constituent parts are hydraulically forced from longitudinal chambers defined within the inner tube walls into an area in the throat of the bit where the parts meet and exothermically generate a liquid foam. The liquid foam rises into a plurality of longitudinal open chambers defined within the inner tube. Each of the open chambers has a longitudinal slot defined therethrough which communicates the chamber with the axial bore in which the core is disposed. The liquid foam flows into the longitudinal chambers and into the annular space between the inside surface of the inner tube and the core. Ultimately, the core is totally immersed in the liquid foam. Thereafter, within a predetermined curing time, the liquid foam cures to form a sponge-like solid. The oil bearing core may not be retrieved to the well surface. As the core is depressurized during retrieval, oil forced from the core by escaping water and gas is retained within the sponge for later analysis.

Method and apparatus for coring with an in situ core barrel sponge

An axial bore is defined throughout the hydraulic lift inner barrel. This axial bore is communicated with the interior of the inner tube thereby allowing the interior of the inner tube to be flushed prior to initiation of the coring operation. When the coring operation is begun, flow of drilling fluid to the interior of the inner tube is prevented by allowing a ball dropped within the drill string to seat within a plug through which the communicating axial bore is defined. Once the flow of drilling fluid to the interior of the inner tube is stopped, the coring operation can begin. After the coring operation is completed, a second ball is dropped and allowed to seat within an inner mandrel through which the axial bore of the coring tool is also defined. Once the axial bore of the inner mandrel is closed, drilling fluid is forced into an expansion chamber within a telescopic piston disposed circumferentially outside of the inner mandrel. The piston is connected to the inner tube. Diversion of drilling fluid into the expansion chamber causes the piston to be longitudinally displaced upward with respect to the inner mandrel, and hence with respect to the outer tube of the drill string. The inner tube is thus similarly lifted within the drill string, thereby activating core catchers or any other downhole mechanism coupled directly or indirectly to the inner tube.

Hydraulic inner barrel in a drill string coring tool

A core spring type core catcher and a full closure core catcher are completely concealed from the core within a coring tool. The full closure catcher is reliably actuated to assume a closed configuration without dependence upon gravity or an interference diametrical fit with the core by use of a cam ring which is longitudinally displaced downwardly within the core barrel by a preloaded compression spring. The full closure core catcher is comprised of a plurality of flapper valves circumferentially disposed outside of the inner tube and concealed by the inner tube or a terminal extension of the inner tube. Disposed above the plurality of flapper valves, and also circumferentially disposed outside of and concentric with the inner tube is a cam ring. Similarly circumferentially disposed outside of and concentric with the inner tube is a preloaded coil compression spring bearing against the cam ring. The cam ring in turn is in sliding contact with a rear surface of each one of the plurality of flapper valves. When the inner tube is longitudinally displaced with respect to the flapper valves to uncover the flapper valves, the flapper valves are then rotated inwardly within the inner barrel of the coring tool by virtue of the downward longitudinal drive of the cam ring as powered by the preloaded compression spring.

Self activating, positively driven concealed core catcher

A fragmented or unconsolidated core can be cut and retained within a coring tool without substantial disturbance of the core by the use of a shrouded core catcher. A core catcher is concentrically disposed within the coring tool and outside of a smooth, cylindrical sleeve telescopically disposed inside of the core catcher. The core catcher in turn is coupled to a lower assembly which can be selectively longitudinally fixed within the coring tool, but which is otherwise temporarily coupled to the sleeve. As the sleeve is longitudinally pulled upward after the completion of the coring operation, the lower assembly becomes longitudinally fixed within the coring tool and the sleeve, which heretofore has fully covered and concealed the core catcher, begins to be withdrawn from the core catcher, leaving it unconcealed. Ultimately, the core catcher is at least partially uncovered, thereby permitting activation and contact between the core catcher and the core disposed within the coring tool. However, at all times during the coring operation, the core catcher remains concealed behind the cylindrical sleeve which extends in the coring tool throughout the substantial length of the core.

Shrouded core catcher

Downward displacement of an inner tube with respect to the outer tube in a coring tool is effectuated by an apparatus comprising a bearing assembly, a cylinder, a piston telescopically disposed within the cylinder, and a mechanism for selectively applying an hydraulic force to the piston. The bearing assembly is longitudinally fixed with respect to the outer tube while providing rotational freedom with respect to the outer tube. A cylinder is axially disposed within the coring tool, is connected to the bearing assembly, and hence is rotationally free with respect to the outer tube. The piston, which is telescopically disposed within a cylinder, is downwardly longitudinally displaceable within the cylinder, and hence with respect to the outer tube. A mechanism is incorporated within the coring tool for selectively applying a hydraulic force to the piston in order to longitudinally displace the piston downwardly within the cylinder. The inner tube, being coupled to the piston, is thus downwardly displaced within the coring tool.

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Sandy, UT, United States of America

J Stanley Davis