Drill bit assembly having electrically isolated gap joint for electromagnetic telemetry

摘要

A drill bit assembly having an electrically isolated gap joint for electromagnetic telemetry comprises a drill bit, a pin body, an electrically insulating gap joint therebetween, and an electrical conductor extending across the gap joint. The bit head has a cutting end and an opposite connecting end with an engagement section. The pin body has a tubular body with an axial bore therethrough, and comprises a connecting end with an engagement section. The pin body connecting end is connected to the bit head connecting end such that the engagement sections overlap. The electrically insulating gap joint fills an annular gap between the bit head and pin body engagement sections such that the bit head and pin body are mechanically connected together at the connecting ends but are electrically separated. The electrical conductor has one end electrically contacting one of the bit head and pin body, and the other end communicable with electronics equipment.

主权项

1. A drill bit assembly comprising
an electrically conductive bit head having a cutting end, and an opposite connecting end with an engagement section; an electrically conductive pin body having a tubular body with an axial bore therethrough, and comprising a connecting end with an engagement section, the pin body connecting end positioned relative to the bit head connecting end such that the engagement sections overlap with an annular gap therebetween; an electrically insulating gap joint filling the annular gap between the bit head and pin body engagement sections such that the bit head and pin body are mechanically connected together at the connecting ends but electrically separated; an electrical conductor extending across the gap joint and having one end electrically contacting one of the bit head and pin body, and the other end communicable with electronics equipment; an electronics housing in at least one of the bit head and pin body, and having a communications port for the conductor to extend therethrough and communicate with electronics equipment in the electronics housing; and electronics equipment in the electronics housing and communicative with the conductor, the electronics equipment including electromagnetic telemetry circuitry, wherein the electromagnetic telemetry circuitry includes a processor, a digital/analog converter communicative with the processor for converting digital data from the processor into an analog data signal, a power amplifier communicative with the converter to amplify the signal and apply a resulting voltage of the signal across the insulated gap joint, thereby transmitting the signal upstring.