Christensen, Inc.

Other

Norton Christensen, Inc.

Japan National Oil Corporation

Energy Ventures, Inc.

James T Aumann

Craig R Hyland

David S Rowley

Steven R Radford

Haraldur Karlsson

Michael Filshtinsky

Jimmy L Carroll

Lothar H Waldes

Harold G White

A pressure and temperature core sampler comprises a tool for recovering cores specifically enabling the evaluation of methane hydrate resources. Because methane hydrate tends to decompose under conditions of pressure decrease and/or temperature increase as the samples are retrieved to the surface, a coring tool in accordance with the present invention provides a self-contained system for retrieving core samples at or near in situ pressure while cooling the core sample. The coring tool is preferably a wire line retrievable device that provides for nearly continuous coring during the drilling operation.

Method and apparatus for recovering core samples under pressure

Apparatus for recovering core samples at in situ conditions

Method and apparatus for transferring core sample from core retrieval chamber under pressure for transport

Apparatus for recovering core samples under pressure

A pressure and temperature core sampler comprises a tool for recovering cores specifically enabling the evaluation of methane hydrate resources. Because methane hydrate tends to decompose under conditions of pressure decrease and/or temperature increase as the samples are retrieved to the surfaces a coring tool in accordance with the present invention provides a self-contained system for retrieving core samples at or near in situ pressure while cooling the core sample. The coring tool is preferably a wire line retrievable device that provides for nearly continuous coring during the drilling operation.

The invention is a coring device which has features to seal off from the well fluids prior to taking of the specimen. The apparatus can be hydraulically or pneumatically actuated to move an inner string which is connected to a core barrel. Prior to moving the core barrel, an outer tube is sealingly pushed into the formation. Once the outer tube has been set into the formation, the inner tube drives the core barrel into the formation, leaving behind a rabbit. A clam shell is located at the forward end which stays open as the core barrel is driven into the formation and closes as the core barrel is withdrawn into the outer tube to retain the core. The pneumatic or hydraulic pressure continues to be applied to the inner string as the core barrel is withdrawn into the outer tube. Upon full retraction of the core barrel into the outer tube, a ball valve is actuated to seal off the core barrel. At that time, the hydraulic or pneumatic pressure is removed and the apparatus is pulled to the surface. The core barrel has a venting feature to allow any gas in the core barrel to escape as the core barrel fills with the core sample.

Method and apparatus for taking an undisturbed core sample

An improved bearing system for the driven shaft of a downhole motor is shown that provides a main thrust and radial bearing system having means for sealing the bearings in oil at equal or slight pressure above that of the drilling mud inside the drill pipe and insulating the fluid seals and bearings from all possibility of contact with cuttings and debris from the drilling operation. A durable seal having a restricted flow path permitting slow leakage is positioned below the main bearing system in such a relationship to the drilling fluid distribution path that the seals for the oil bath for the bearings are subjected to essentially the same pressure on all sides.

Bearing system for a downhole motor

A coring tool, which includes a flexible wire mesh in which the core is disposed, includes a mechanism for maintaining tension on the wire mesh sleeve which then seizes the core disposed within the sleeve, and which serves to retain the core and maintain it under tension. The sleeve is maintained under tension by tensile force transmitted to the sleeve through a stripper tube. The stripper tube is axially disposed through a piston ratchet assembly connected to a piston slidable within the drill string. The piston is resiliently urged upward within the drill string by a return spring but is longitudinally forced downward within the drill string and advanced downwardly with respect to the stripper tube by an increase in pressure within the drill string thereby compressing the return spring. The piston ratchet assembly prevents the piston from moving longitudinally upward with respect to the stripper tube and thereby allows the resilient force of the preloaded spring to be applied through the piston and piston ratchet assembly to the stripping tube as a tensile force on the wire mesh sleeve. A fixed ratchet assembly is provided within the coring tool to prevent any downward movement of the stripper tube through the fixed ratchet assembly thereby maintaining tension on the stripper tube while the piston is being advanced in response to an increase in fluidic pressure.

Hydraulically pulsed indexing system for sleeve-type core barrels

An improved coring device that incorporates a nonrotatable inner barrel disposed within the outer driving structure of the drill string which is coupled to a coring bit. A woven metal mesh sleeve is circumferentially mounted outside the inner barrel and tucked around its lower end. The lower end of the mesh sleeve in the inner barrel is in turn connected to a stripper tube which is pulled upwardly during the coring operation. As the core is cut by the coring bit and enters the inner barrel, the woven metal mesh sleeve is disposed about the core and constricts about the core when pulled upwardly by the stripper tube. The opposing end of the woven metal mesh sleeve is connected to a weight which serves to compress the metal sleeve when outside the inner barrel, thereby increasing its diameter to prevent binding or jamming.

Coring device with an improved core sleeve and anti-gripping collar

Coring device with an improved weighted core sleeve and anti-gripping

A multi position safety valve retainable within an internal portion of a drill string casing (s) and responsive to the greater differential pressure in an internal fluid passage to displace a valve head (32) relative to a valve seat (VS) from its normal partially open position to either a wide open or a closed position. The valve head (32) is attached to a valve stem (30) that extends through a valve chamber and slideably mounted in opposite closed ends of a valve body and returnable to and maintained in the partially open position by opposing compression springs (34) (36) situated between opposite ends (22) of the valve body (VB) and one side of an intermediate abutment (30c) of the valve stem (30) and an intervening disc (38) on the opposite side thereof. The disc 38 is moveable into and out of seating engagement with an intermediate stop (20a) by one spring (34) and the intermediate abutment (30c) of the valve stem respectively.

Drill string safety valve

A composite drill collar for drilling bore holes in earth formations including a structural steel outer jacket having a lower end secured to a lower coupling connectable to a drill bit and an upper end secured to an upper coupling connectable to an adjacent drill collar thereabove. An annular heavy metal core of sintered tungsten is disposed in the jacket and is held in compression therein by preloading the lower and upper couplings against the ends of the core, which places the jacket in tension, causing the jacket to contract and grip the periphery of the core. The structural steel jacket has a thick wall to carry the bending, torsion, compression, tension and impact loads encountered in the drilling operation, so that such loads are not carried through the core, which has the purpose of increasing the overall density and mass of the composite drill collar, lessening considerably the tendency for a deviated well bore to be produced.

Composite heavy metal drill collar

This invention relates to improvements in pressure core barrels of the type described in U.S. Pat. No. 3,548,958 wherein a controlled pressure is maintained on a core sample during surfacing. Among the improvements provided by the present invention are an improved arrangement of the pressure control valve, a device for positively latching the assembly (both in the open and closed positions) and the provision of a hydraulic assist for moving the outer barrel to the sealing position. Another particular feature provides an improved device for flushing drilling mud from the core barrel mechanism with sealing valve open and while the core sample is maintained substantially at a pressure at which it was sealed in the bore hole and to facilitate subsequent freezing and removal of the core sample therefrom for analysis.

Pressure core barrel flushing system

This invention relates to improvements in pressure core barrels of the type described in U.S. Pat. No. 3,548,958 wherein a controlled pressure is maintained on a core sample during surfacing. Among the improvements provided by the present invention are an improved arrangement of the pressure control valve, a means for positively latching the assembly (both in the open and closed positions) and the provision of a hydraulic assist for moving the outer barrel to the sealing position. Another feature provides an improved device for flushing of the mud from the core sample while it is under high pressure to facilitate the further sampling of the core after freezing of the section.

Pressure core barrel

A drill string shock absorber has a dual spring system for absorbing vibrations and shock loads during rotary well bore drilling operations. A first spring acts in compression when sufficient weight is set down on the drill bit through the shock absorber to overcome the fluid pressure forces tending to extend the shock absorber, and a second spring acts in compression when the weight applied to the bit through the shock absorber does not overcome the fluid pressure forces. A splined connection transmits torque to the shock absorber during drilling operations, and seals are provided between the telescopic shock absorber components for confining therein a body of lubricant, the pressure of which is equalized with the pressure of drilling fluid flowing through the shock absorber.

Growing community of inventors

Salt Lake City, UT, United States of America

James T Aumann