Chevron Research Company

Dean C Barnum

William Charles Corea

Frank L Campbell

In accordance with the present invention, rotation of the inner barrel relative of the axis of symmetry of the core barrel (indicative of core twist off or core sand erosion during coring operations) is detected by a novel sensor combination. The sensor includes a reed switch mechanically imbedded in a support sleeve of a custom safety sub attached to the outer core barrel and electrically actuated by an adjacently positioned signature magnet fitted to the inner barrel to connect a power source uphole from the core barrels with a driver valve of a mud pulser system. During coring, circumferential passage of the reed switch adjacent to the signature magnet (during rotation of the outer core barrel to generate a core), allows the power source to periodically activate the valve driver to produce a series of mud pulses of constant repetition rate. But with the occurrence of rotation of the inner core barrel irregular repetition rates are produced at uphole indicating equipment. Result: sticking and jamming of the core can be immediately detected and uphole parameters modified to ease unsafe conditions.

Means and method for facilitating measurements while coring

In accordance with the present invention, rotation of the inner barrel relative of the axis of symmetry of the core barrel (indicative of core twist off or core sand erosion during coring operations) is detected by a novel sensor combination comprising a battery-powered Hall-effect device fitted to the inner barrel imbedded in a support sleeve of a custom safety sub attached to the outer core barrel adjacent to a single signature magnet. During coring, circumferential passage of the Hall-effect device adjacent to the signature magnet (during rotation of the outer core barrel to generate a core), produces a series of signals of constant repetition rate. But with the occurrence of rotation of the inner core barrel irregular repetition intervals are produced at uphole indicating equipment connected to the Hall-effect device through conventional downhole telemetering and power generating equipment. Result: sticking and jamming of the core can be immediately detected and uphole parameters modified to ease unsafe conditions. Use of a battery pack to power the Hall-effect device, simplifies operations, especially where the present invention is used in conjunction with the MWC mud pulse telemetering equipment.

Battery powered means and method for facilitating measurements while

In accordance with the present invention, rotation of the inner barrel relative of the axis of symmetry of the core barrel (indicative of core twist-off or core sand erosion during coring operations) is detected by a novel sensor combination comprising a Hall-effect device imbedded in a support sleeve of a custom safety sub attached to the outer core barrel adjacent to a single signature magnet fitted to and carried by a special support ring attached to the inner barrel. In releasably attaching the inner and outer core barrels together, the special support ring is made to be locking through operation of a series of compression strings acting between the lower surface of the ring and the inner core barrel as to wedge the upper surface of the support ring against an annular stopper ring. Result: the inner core barrel does not rotate relative to the outer core barrel during the trip down to the bottom of the well bore. Before coring commences, the Hall-effect device can be pretested since the signature magnet is locked in circumferential side-by-side relationship with and hence detectable by the Hall-effect device. Increases in mud pressure at the core site, causes release of the support ring (and the magnet) relative to the outer core barrel.

Locking means for facilitating measurements while coring

In accordance with the present invention, rotation of the inner barrel relative of the axis of symmetry of the core barrel (indicative of core twist off or core sand erosion during coring operations) is detected by a novel sensor combination comprising a Hall-effect device imbedded in a support sleeve of a custom safety sub attached to the outer core barrel adjacent to a signature magnet fitted to the inner barrel. During coring, circumferential passage of the Hall-effect device adjacent to the signature magnet (during rotation of the outer core barrel to generate a core), produces a series of signals of constant repetition rate. But with the occurrence of rotation of the inner core barrel irregular repetition rates are produced at uphole indicating equipment connected to the Hall-effect device through conventional downhole telemetering and power generating equipment. Result: sticking and jamming of the core can be immediately detected and uphole parameters modified to ease unsafe conditions.

Growing community of inventors

Fullerton, CA, United States of America

Dean C Barnum