Well logging apparatus for obtaining azimuthally sensitive formation resistivity measurements
First Claim
1. A logging while drilling resistivity tool comprising:
- a substantially cylindrical, electrically conductive tool body including first and second longitudinally opposed ends, the tool body disposed to be operatively coupled with a drill string and deployed in a subterranean borehole such that the logging while drilling tool may acquire resistivity measurements without removing the drill string from the borehole;
at least one magnetically permeable ring deployed about the tool body between the first and second longitudinally opposed ends thereof, an AC voltage supply electrically connected to the first and second ends of the tool body, at least one connecting conductor deployed exterior to an outer surface of the magnetically permeable ring; and
a receiver.
3 Assignments
0 Petitions
Accused Products
Abstract
An apparatus for making azimuthally sensitive resistivity measurements of a subterranean formation is disclosed. The apparatus includes a magnetically permeably ring deployed about an electrically conductive tool body. An AC voltage supply is coupled to the tool body on opposing sides of the magnetically permeable ring, with at least one connecting conductor crossing outside the ring. Exemplary embodiments of this invention may further include one or more current sensing electrodes deployed in and electrically isolated from an outer surface of the tool body and may be utilized to make azimuthally resolved formation resistivity measurements
118 Citations
29 Claims
-
1. A logging while drilling resistivity tool comprising:
-
a substantially cylindrical, electrically conductive tool body including first and second longitudinally opposed ends, the tool body disposed to be operatively coupled with a drill string and deployed in a subterranean borehole such that the logging while drilling tool may acquire resistivity measurements without removing the drill string from the borehole;
at least one magnetically permeable ring deployed about the tool body between the first and second longitudinally opposed ends thereof, an AC voltage supply electrically connected to the first and second ends of the tool body, at least one connecting conductor deployed exterior to an outer surface of the magnetically permeable ring; and
a receiver. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A logging while drilling tool comprising:
-
a substantially cylindrical, electrically conductive tool body including first and second longitudinally opposed ends;
at least one magnetically permeable ring deployed about the tool body between the first and second longitudinally opposed ends thereof;
an AC voltage supply electrically connected to the first and second ends of the tool body, at least one connecting conductor deployed exterior to an outer surface of the magnetically permeable ring;
at least one current sensing electrode deployed in an outer surface of the tool body. - View Dependent Claims (10, 11, 12, 13)
-
-
14. A logging while drilling tool comprising:
-
a substantially cylindrical, electrically conductive tool body including first and second longitudinally opposed ends;
at least one magnetically permeable ring deployed about the tool body between the first and second longitudinally opposed ends thereof;
an electrically conductive, rigid sleeve deployed about the magnetically permeable ring;
an AC voltage supply electrically connected to the first end of the tool body and the sleeve;
at least one electrode deployed in an outer surface of the tool body, an outer surface of the electrode electrically isolated from the outer surface of the tool body; and
at least one current measurement module disposed to measure electrical current in the electrode. - View Dependent Claims (15, 16, 17, 18, 19, 20)
-
-
21. A logging while drilling tool comprising:
-
a substantially cylindrical, electrically conductive tool body including first and second longitudinally opposed ends;
longitudinally spaced first and second magnetically permeable rings deployed about the tool body, a central region of the tool body located between the first and second magnetically permeable rings;
at least AC voltage supply disposed to provide an AC voltage difference between the central region of the tool body and the longitudinally opposed ends of the tool body, at least one connecting conductor deployed exterior to an outer surface of each of the rings;
at least one electrode deployed in an outer surface of the central region of the tool body, an outer surface of the electrode electrically isolated from an outer surface of the tool body; and
at least one current measurement module disposed to measure electrical current in the electrode. - View Dependent Claims (22, 23, 24)
-
-
25. A downhole tool comprising:
-
a substantially cylindrical, electrically conductive tool body including first and second longitudinally opposed ends, the tool body including a blade deployed thereon, the blade configured to extend outward from the tool body;
at least one magnetically permeable ring deployed about the tool body between the first and second longitudinally opposed ends thereof;
an AC voltage supply electrically connected to the first and second ends of the tool body;
at least one current sensing electrode deployed in an outer surface of the blade. - View Dependent Claims (26)
-
-
27. An inductive choke for a logging while drilling tool, the inductive choke comprising:
-
an electrically conductive drill collar;
an electrically conductive, rigid sleeve mechanically and electrically coupled to the drill collar; and
a magnetically permeable ring deployed between the sleeve and the drill collar. - View Dependent Claims (28, 29)
-
Specification