METHOD IS CASED WELL INCLINOMETER SURVEYING Russian patent published in 2000 - IPC

FIELD: geophysical technique; applicable in oil and gas industry for control over position in space of axis of cased wells. SUBSTANCE: downhole instrument of inclinometer is located at wellhead inside casing string. Downhole instrument body is centered in lowered casing string and stabilized from azimuth turning by location on its surface of spring- loaded members with formation of their contact with internal surface of casing string. Size of contact along axis of casing is as large as possible. Downhole instrument is equipped with piston system. Taken for reference point of values of azimuth angles of well axis is position of azimuth-stabilized body of downhole instrument. Prior to lowering of downhole instrument into well, azimuth position of turning angle transducer of downhole instrument body round its longitudinal axis is determined. Downhole instrument is uniformly moved inside casing string due to building up of excessive pressure above or under it. Motion of downhole instrument to bottom of casing string is restricted by limiter. In course of motion of downhole instrument, values of zenith angles of well axis are determined by zenith angle transducer, and values of azimuth angles of well axis are determined by transducer of turning angles of downhole instrument body round its longitudinal axis, and recorded by memory of downhole instrument. Values of zenith and azimuth angles of well axis are read-out from memory after completion of round trips and withdrawal of downhole instrument from well. Reference of obtained values of zenith and azimuth angles of well axis to well depth is accomplished by uniform distribution of these values over measured internal of well. EFFECT: higher accuracy on inclinometer surveying of cased directional wells. 3 dwg, 1 dwg