COMBINED PROPAGATION AND LATERAL RESISTIVITY DOWNHOLE TOOL
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Accused Products
Abstract
A combined resistivity tool incorporating both induction/propagation antennas and lateral resistivity antennas disposed in recesses of downhole tubulars, in which a lateral resistivity antenna includes an insulating base layer disposed in the recess; a toroidal antenna disposed over the insulating base layer; and a shield disposed over the recess.
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Citations
55 Claims
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1-41. -41. (canceled)
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42. A lateral resistivity sensor disposed in a recess in a tubular having a longitudinal axis and adapted for subsurface disposal, comprising:
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an insulating base layer disposed in the recess; a toroidal antenna disposed over the insulating base layer; and a shield disposed over the recess and adapted to prevent electric current flow along the shield in a direction parallel to the longitudinal axis of the tubular near the toroidal antenna.
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51. A resistivity logging tool, comprising:
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an elongated conductive first tubular having a central bore and an insulated circumferential opening along its wall to prevent current flow across the opening; an elongated conductive second tubular having a lateral resistivity sensor mounted thereon; wherein the second tubular is disposed within the first tubular such that the lateral resistivity sensor is positioned near the insulated circumferential opening in the first tubular; and wherein a current path is formed between the first and second tubular on either side of the insulated circumferential opening when the second tubular is disposed within the first tubular.
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53-1. The resistivity logging tool of claim 23, further comprising a non-conductive shield disposed over the insulated circumferential opening on the exterior of the first tubular.
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54. A method for mounting a lateral resistivity sensor on a section of a tubular having a longitudinal axis and adapted for subsurface disposal, comprising:
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creating a recess on an outer wall of the tubular section; forming a base layer of an insulating material in the recess; forming a toroidal core by wrapping a magnetically permeable material over the base layer; winding a conductive wire around the toroidal core to form a toroidal antenna; and installing a shield assembly over the recess, the assembly adapted to prevent electric current flow in the shield in a direction parallel to the longitudinal tubular axis near the toroidal antenna.
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55-2. The method of claim 27, further comprising adapting the recess with a pressure compensating mechanism.
Specification