Method and apparatus for orientating core sample and plug removed from sidewall of a borehole relative to a well and formations penetrated by the borehole
First Claim
1. A method of determining the position in space of a formation sample comprising the steps of:
- (a) moving sensors from the surface via a wireline cable along a well borehole from the well head to a specified depth in a well wherein the movement along the well is sensed by determining gravity or magnetic field measurements during movement and the gravity or magnetic field measurements are resolved into coordinate components;
(b) from the coordinate components, determining the location of the tool along the well borehole; and
(c) cutting a formation core sample at that location wherein the relative position of the sample with respect to the tool is known so that the location of the tool determined with the measurements as the tool moves along the well borehole provides a description in three variables of the formation sample in space with respect to the well borehole.
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Abstract
A method and apparatus for determining the location in space of a formation sample is set forth. This involves a tool which is typically run on a wireline in a well, the tool supporting orthogonal positioned magnetometers and similar orthogonal accelerometers for measuring movement of the tool along the well borehole whereby components of the magnetic field and gravity field are measured to enable determination of the well in space. The tool supports an axially positioned centrally located core cutting apparatus and a laterally projecting plug cutting apparatus; scribe marks formed on the formation samples orient the samples relative to the tool and the tool is located in space from the above mentioned measurements so that the position of formation samples can be determined.
34 Citations
18 Claims
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1. A method of determining the position in space of a formation sample comprising the steps of:
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(a) moving sensors from the surface via a wireline cable along a well borehole from the well head to a specified depth in a well wherein the movement along the well is sensed by determining gravity or magnetic field measurements during movement and the gravity or magnetic field measurements are resolved into coordinate components; (b) from the coordinate components, determining the location of the tool along the well borehole; and (c) cutting a formation core sample at that location wherein the relative position of the sample with respect to the tool is known so that the location of the tool determined with the measurements as the tool moves along the well borehole provides a description in three variables of the formation sample in space with respect to the well borehole. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An apparatus for determining the location in a well borehole of a sample obtained from a formation along the well borehole comprising:
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(a) sample cutting means suspended by a wireline cable in a well borehole and having an elongate housing and including cylindrical sample receiving means; and (b) gravity sensor means mounted for movement with said housing, said gravity sensor means measuring acceleration movement of said housing as said housing moves along a well borehole from a well head toward the bottom of a well borehole, said sensor means forming a gravity vector signal providing the location of the well borehole in space defined by three orthogonal coordinate dimensions. - View Dependent Claims (17, 18)
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Specification