Battery powered means and method for facilitating measurements while coring

摘要

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.