Logging tool with electric dipole source and magnetic sensor for forward and lateral imaging
First Claim
1. A method of operations in a borehole comprising:
- generating a first electric dipole in the borehole that is parallel with an axis of the borehole, and generating a second electric dipole in the borehole that is transverse to the axis of the borehole, the electric dipoles forming an electromagnetic field in a formation that surrounds the borehole;
using a coil in the borehole at a location spaced axially away from the electric dipoles to sense magnetic flux that is generated by the electromagnetic field; and
based on the step of sensing magnetic flux, identifying a distance and a direction from the first electric dipole and the second electric dipole to a bed boundary that is in the formation.
2 Assignments
0 Petitions
Accused Products
Abstract
A logging method and system for imaging forward and lateral sections of a subterranean formation. An electric dipole source generates electromagnetic field in the formation that is sensed with magnetic flux sensor that is spaced a distance away from the electric dipole source. The resulting electric dipoles can be axial or transverse, and magnetic flux sensors can sense magnetic fields oriented axially or orthogonally. The axial and transverse electric dipoles can be collocated, and magnetic flux sensors that sense axial or orthogonal magnetic fields can be collocated. Analyzing changes in the magnitude of signals sensed by magnetic flux sensors can indicate the presence and distance of bed boundaries that are ahead and lateral to the electric dipole source.
7 Citations
19 Claims
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1. A method of operations in a borehole comprising:
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generating a first electric dipole in the borehole that is parallel with an axis of the borehole, and generating a second electric dipole in the borehole that is transverse to the axis of the borehole, the electric dipoles forming an electromagnetic field in a formation that surrounds the borehole; using a coil in the borehole at a location spaced axially away from the electric dipoles to sense magnetic flux that is generated by the electromagnetic field; and based on the step of sensing magnetic flux, identifying a distance and a direction from the first electric dipole and the second electric dipole to a bed boundary that is in the formation. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of operations in a borehole comprising:
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generating a magnetic field in a formation that surrounds the borehole by generating electric dipoles in the borehole that are respectively oriented axially and transverse to an axis of the borehole; measuring magnetic flux in the borehole at a location that is spaced axially away from the electric dipoles; and identifying a bed boundary in the formation based on the step of measuring magnetic flux. - View Dependent Claims (12, 13)
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14. A tool for use in a borehole comprising:
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a means for forming electric dipoles that generate magnetic fields in a formation surrounding the borehole, the means being coupled to a housing of the tool, and the magnetic fields being oriented transverse to one another; a means for sensing magnetic flux generated by the electric dipoles; a housing disposable in the borehole that is coupled to the means for forming electric dipoles and coupled to the means for sensing magnetic flux; and a means for identifying the presence of a bed boundary in the formation in a direction spaced axially and radially from the housing. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification