HIGH-POWER WELL LOGGING METHOD AND APPARATUS

摘要

A system and method for safely and economically providing up to 1800 watts to downhole equipment is shown in the figure. In one embodiment, the system uses a standard multiconductor logging cable (20) which supports orthogonal signal transmission modes on circumferentially spaced insulated conductors (1, 2, 3, 6, 7). A high-powered power source on the surface (M1, M2. M3, M4) is coupled to the insulated conductors in the cable to drive a power signal on the lowest impedance signal transmission mode. Safety may be enhanced by the addition of a reliable current imbalance detector configured to shut down all power source when currents in the insulated conductors do not add to zero. The system may further include multiple power sources operating on different independent signal transmission modes, and may also include multiple telemetry channels which share the power transmission modes via multiplexing.