CA2268444A1 - Apparatus and method for drilling boreholes - Google Patents

Abstract

The present invention provides a drilling system (10) for drilling of boreholes. The drilling system contains a drill string (20) having a drill bit (50) driven by a mud motor (55). Sensors placed at selected locations in the drill string continually measure various downhole operating parameters, including the diffential pressure across the mud motor, rotational speed of the mud motor, torque, temperature, pressure differential between the fluid passing through the mud motor and the annulas between the drill string and the borehole, and temperature of the circulating fluid. A downhole control circuit processes signals from these sensors and transmits the processed data uphole to a surface control unit (40), which is programmed to operate the drilling system or aid an operator to control the drilling operations in various operating modes. The system also provides means for monitoring the wear condition of the mud motor and to estimate the remaining life of the mud motor during the drilling operations. The drill string also preferably contains formation evaluation and testing devices, such as a resistivity device for determining the formation resistivity, gamma ray device for determining the gamma ray intensity of the formation, an inclinometer for determining the inclination of the drill string near the drill bit and means for determining the drill string azimuth.