Measurement-while-drilling system using mud-pulse valve for data transmission

摘要

A measuring tool for collecting down hole information, which essentially has a sensor sub including plural data collecting sensors secured at a forward portion of a drilling pipe and a sonde movable in the drilling pipe. Both the sensor sub and sonde employ a set of loop antennas to effect radiocommunication between them to thereby certainly send data detected by means of the sensors to the sonde. A metering valve for producing mud-pulse used in the measuring tool, wherein there is provided a changeover means switching the main mud-flow stream from one of the detour/interference passages and the straight/open passage to the other. IMAGE