Patent ID: 6100696
Filing Date: 2000-08-08
Classification: G01V

Abstract:
A directional instrument for measuring while drilling electrical properties of rock formations adjacent to a borehole, comprising:a) a transmitter coil coupled to a signal generator for providing to the transmitter coil an oscillating voltage at a frequency of between 1 KHz and 200 KHz;b) at least one receiver coil disposed coaxially to the transmitter coil, the axis of the coils defining the axis of the instrument, the at least one receiver coil being coupled to a signal processing circuit for determining an electrical property of the rock formation from signals received; andc) a conductive reflector spaced from the transmitter coil, the reflector being generally parallel to the axis of the instrument, the transmitter coil, the at least one receiver coil, and the conductive reflector included in a side pocket of a conductive collar in a drill string including a drill bit so the directional measuring instrument can perform measurement while drilling.