Formation resistivity imaging in conductive boreholes
AssigneeBaker Hughes Incorporated
InventorsRANDY GOLD, Stanislav W. Forgang, Dinesh P. Shah
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Abstract
An apparatus for providing an image of a resistivity property of an earth formation surrounding a borehole is provided. The apparatus, in one aspect, may include a plurality of measure electrodes that are configured to convey an electrical current into the earth formation. In one aspect, each measure electrode may be substantially surrounded by an associated insulator that extends away from a tool body in a manner that blocks at least a portion of a vertical current flowing in a conductive fluid when the tool is operated to log the borehole. A processor provides an image of the resistivity property of the earth formation using the current in plurality of measure electrodes.
Claims17
An apparatus configured to provide an image of a resistivity property of an earth formation, the apparatus comprising:
- a logging tool configured to be conveyed in a borehole having a conductive fluid therein;
- at least one measure electrode on a pad of the logging tool configured to sense an electrical current in the earth formation;
- at least one return electrode;
- an associated insulator surrounding at least one of the at least one measure electrode and the at least one return electrode and limiting a current path between the at least one measure electrode and the at least one return electrode;
- and
- at least one processor configured to provide an image of the resistivity property using the current sensed by the at least one measure electrode.
A method of imaging a resistivity property of an earth formation, the method comprising:
- conveying a logging tool into a borehole having a conductive fluid therein;
- using at least one measure electrode on a pad of the logging tool to sense an electrical current in the earth formation;
- reducing a flow of current in the fluid in the borehole by surrounding at least one of the at least one measure electrode and the at least one return electrode with an associated insulator that limits a current path between the at least one measure electrode and the at least one return electrode;
- and
- providing an image of the resistivity property using the current sensed by the at least one measure electrode.
A non-transitory computer-readable medium product having stored thereon instructions that when read by at least one processor cause the at least one processor to perform a method, the method comprising:
- providing an image of a resistivity property of an earth formation using a current sensed by at least one measure electrode on a logging tool of an apparatus, the apparatus further including at least one return electrode, the logging tool conveyed in a borehole with a conductive fluid therein, an associated insulator surrounding at least one of the at least one measure electrode and the at least one return electrode.
Dependencies are inferred from the claim text.