초록 ▼

A gap collar for an electromagnetic communication unit of a downhole tool positioned in a wellbore is provided. The downhole tool communicates with a surface unit via an electromagnetic field generated by the electromagnetic communication unit. The gap collar includes a first collar having a first e

A gap collar for an electromagnetic communication unit of a downhole tool positioned in a wellbore is provided. The downhole tool communicates with a surface unit via an electromagnetic field generated by the electromagnetic communication unit. The gap collar includes a first collar having a first end connector and a second collar having a second end connector matingly connectable to the first end connector. The gap collar further includes a non-conductive insulation coating disposed on the first and/or second end connectors, and a non-conductive insulation molding positioned about an inner and/or outer surface of the collars. The insulation molding moldingly conforms to the shape collars. The connectors are provided with mated threads modified to receive the insulation coating. Measurements taken by the downhole tool may be stored in memory, and transmitted to the surface unit via the electromagnetic field.

대표청구항 ▼

What is claimed is: 1. A method of providing downhole information from a downhole evaluation tool located in a wellbore to a surface unit, the wellbore formed by advancing a drilling tool into the earth, the method comprising:positioning the downhole evaluation tool in the wellbore, the downhole eva

What is claimed is: 1. A method of providing downhole information from a downhole evaluation tool located in a wellbore to a surface unit, the wellbore formed by advancing a drilling tool into the earth, the method comprising:positioning the downhole evaluation tool in the wellbore, the downhole evaluation tool having an electromagnetic telemetry system adapted to communicate via an electromagnetic field with the surface unit, wherein the electromagnetic telemetry system comprises a pair of collars matingly connected with a non-conductive insulation coating therebetween, the non-conductive insulating coating defining a gap, and wherein the electromagnetic telemetry system further comprises a non-conductive insulation member extending across the gap about one of an inner surface of the collars, an outer surface of the collars and combinations thereof, the insulation member conforming to the shape thereof;measuring downhole data using sensors positioned in the downhole tool;storing the downhole data in a memory unit positioned in the downhole tool; andtransmitting at least a portion of the downhole data to the surface via the electromagnetic field.