METHOD OF AUTOMATIC CHECKING FOR WEAR OF DRILLING PIPE THREADED JOINTS Russian patent published in 1999 - IPC

FIELD: drilling equipment. SUBSTANCE: this relates to checking taper thread joints of drilling pipes for wear in oil and gas production industry, primarily in drilling deep bore-holes. According to method, drilling pipe to be checked is screwed in master coupling and nipple, acoustic oscillations are generated in drilling pipe body, and these oscillations are received by sensors installed on master coupling and nipple. Signals received by sensors are processed. Then, threshold signal is formed corresponding to standard threaded joint. Processed signal is compared with threshold signal and according to results of comparing aforesaid signals, conclusion is drawn about operability of threaded joint for further operation of drilling pipe. Receiving, processing of signals obtained from sensors from both threaded joints of drilling pipe, comparing them with threshold signal are effected simultaneously or successively. Used as criterion in comparison are correlation or autocorrelation functions of acoustic oscillations which passed through master joint under control. Compared are values of these functions or their parameters. Application of aforesaid method improves reliability of bore-hole drilling process due to less probable emergency situations caused by condition of threaded joints in drilling string. EFFECT: higher efficiency. 3 cl