Methods and apparatus for generating electromagnetic telemetry signals
AssigneeEvolution Engineering Inc.
InventorsAaron W. LOGAN, Daniel W. AHMOYE, David A. SWITZER, Justin C. LOGAN, Patrick R. DERKACZ, Mojtaba KAZEMI MIRAKI
Life of this patent
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Abstract
An electromagnetic telemetry signal generating assembly comprises a first section of drill string, a second section of drill string, a gap sub configured to insulate the first section from the second section, and a power source configured to provide a first voltage to a control circuit. The control circuit is configured to drive a second voltage between the sections of drill string. The gap sub provides a gap of at least 12 inches (30 cm). The second voltage may be different than the first voltage.
Claims20
An apparatus useful for drilling, the apparatus comprising a probe;
- a section of drill string;
- a gap sub in the section of drill string;
- and a rod;
- wherein:
- the rod is connected to support the probe;
- the rod passes through at least a portion of a bore in the gap sub;
- and
- a diameter of the rod is less than a diameter of the probe.
An apparatus useful for drilling, the apparatus comprising:
- a gap sub coupled between a tubular uphole drill string section and a tubular downhole drill string section, the gap sub electrically insulating the uphole drill string section from the downhole drill string section, the gap sub comprising a bore providing fluid communication between bores of the uphole drill string section and the downhole drill string section, at least a portion of the bore of the gap sub being a smaller-diameter section wherein, in the smaller-diameter section the bore of the gap sub has a cross sectional area smaller than cross sectional areas of the bores of the uphole and downhole drill string sections;
- a probe supported in the bore of the lower drill string section by a rod extending from an uphole end of the probe through the smaller-diameter section of the bore of the gap sub to a support above the smaller-diameter section of the bore of the gap sub, the rod having a cross sectional area smaller than that of the probe.
Dependencies are inferred from the claim text.