| The depth is used to record the position of the logging probe by the measurements of the cable or drill pipe.Due to the borehole environment,cable stretch,drill pipe stretch and other errors,the measure depth can’t match the depth of true depth,if the depth is not accurate,the logging data lost the geological significance and physical meaning and can’t describe stratum information.To improve the accuracy of logging depth,the paper gives a detail information on the depth correction of the cable magnetic mark depth system,image logging acceleration correction and LWD depth system.The first the paper describes the method of the measurement of the various depth system,In terms of construction,hardware and software,it analyzed the depth error caused by various factors.,For wireline logging and LWD(logging while drilling),the biggest factor is cable and drill pipe stretch,To solve these depth errors,in the terms of the operation and hardware,the paper puts forward practicable controlling measures.The purpose of depth correction is to calculation the depth offset,after that,it is to operate the curve of tensile or compression.The second the paper describes the cable magnetic mark depth system,it explains how to detect the magnetic mark automatically by artificial intelligence syntactic pattern.The method to extract the primitives of the logging magnetic mark curve by the same internal,then accept input pattern and to recognize the magnetic mark by pattern recognition.It has the advantage of the recognition speed and simple operation.Finally,the magnetic mark is used to correct depth automatically.After the description of the wireline logging depth correction,next the paper describes the acceleration correction of imaging logging in detail.The basement of the FMI imaging logging instrument and measurement principle and deduces the instrument motion equation.It analyzes the factors that causes the ‘yo-yo’ phenomenon and instrument sticking,so it develops the algorithm for recognizing the sticking.For various motion state,the paper uses Kalman filter algorithm and double integral method to accept the optimal estimation of depth and to accept the true depth,and to resample the plate data by Akima interpolation algorithm for recover fault image.Finally,the paper describes the development of the LWD.The LWD depth system is different from the wireline longing depth system,it records drill bit by the position of the hook and the length of drill pipe.In terms of ground system,drilling process and time-depth conversion,it describes the LWD depth system and the factors in detail,in order to lay the foundation for further research on the depth correction. |
