초록 ▼

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 i

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.

대표청구항 ▼

Apparatus for monitoring detrimental conditions associated with extraction of a core from an earth formation penetrated by a well bore using a core barrel having a rotatable outer cylindrical barrel attached to and operationally rotated by, a drill string, and drilling fluid circulating within said

Apparatus for monitoring detrimental conditions associated with extraction of a core from an earth formation penetrated by a well bore using a core barrel having a rotatable outer cylindrical barrel attached to and operationally rotated by, a drill string, and drilling fluid circulating within said well bore as said core is extracted, wherein rotation of a usually stationary inner core barrel coaxial of the outer core barrel during said extraction of said core and its placement thereof within the cylindrical inner barrel, is used to indicate said associated detrimental coring conditions, comprising; first means mechanically attached to said core barrel and operationally fitted between said outer and inner core barrels for generating a series of signals indicative of relative rotation of the inner core barrel relative to the outer core barrel during extraction of said core from the formation; second means uphole from said first means and operational connected thereto for responding to said series of signals indicative of said relative inner barrel rotation wherein occurrence of said relative inner barrel rotation, causes operations to be initiated to overcome any associated detrimental condition within said well bore.