A Research Of Multi-arm Caliper Logging Data Processing And Interpretation Method

Due to formation environment variation and various measures to increase production crustal stress would be broken. It can result in uniform casing stress and excessive yield strength,even casing damage. Electrochemical corrosion is also one of the most serious causes of casing damage. Casing damage types contains many factors, included deformation, corrosion, rupture and fault, which will undoubtedly give the normal production of the oil field a great impact. By the end of 2007, more than 22000 casing damage wells have been found in national oil fields.At present, the detection methods for casing damage wells, including mechanical well diameter detection, electromagnetic detection and acoustic detection. This paper mainly considers processing and interpretation of multi-arm caliper logging data and sums up the main advantages, including evaluation method for multi-arm caliper logging and three-dimensional image.Multi-arm caliper logging tool included X-Y caliper, eight-arm caliper, thirty-six-arm caliper, and forty-arm caliper, the measurement accuracy is related to the number of the measuring arms. Forty-arm caliper can measure 40 different directions of well diameter, and provide the maximum diameter and minimum diameter. This thesis will study the optimization and evaluation parameters of the multi-arm caliper logging data in two aspects based on the measurement and principle of logging. Optimization data is mainly maximum and minimum well diameter, and the evaluation parameters, including offset of center point, rate of ellipse, variation of diameter rate, variation of wall thickness and so on. On the basis of this, analyzing the qualitative evaluation criteria for casing and then the computer visualization technique is introduced to image the multi-arm caliper data.OpenGL as a leader in computer visualization technology, provides a lot of very practical function in image processing. Therefore, in this paper, the imaging aspects use C++combined with OpenGL development environment. Each set of data of the multi-arm caliper logging is a section of the casing. So the three-dimensional reconstruction of the casing will be first to use interpolation method to restore the casing section, then using triangle patches to process upper and lower layers in order to restore the shape of the casing. Calculating the color according to the degree of casing damage and using the rotation and zoom function of OpenGL to deal with 3D image can finish the program.According to the interpretation of practical data in oil fields, the method can be applied to evaluate the casing damage. The casing damage can be easily found by the means of logging curves and three dimensional imaging result makes the casing damage more intuitive.