两端金属体对阵列感应测量数据的影响研究

Two-end Metal Effects on the Measurement Accuracy of Array Induction Log

两端金属体对阵列感应测量数据的影响对测井仪器设计和准确测量具有重要实际意义。在考虑线圈系和金属体有限大小及不同地层电导率情况下,通过数值计算详细分析了两端金属体长度和距离变化对阵列感应测井仪器的影响规律。地层电导率大于0.1S/m,金属体距离大于0.3m时,可以忽略金属体的影响,否则需要考虑金属体的影响。以地层电导率等于0.001S/m为例,分析金属体长度和距离变化对阵列感应测井仪器的影响规律。当间距小于1.3m时,子阵列6一侧的金属影响比子阵列8一侧的影响大。

The study of effects of two-side metals on measurement of array induction log has important role in design of the log tools and tools measurement accuracy. By considering the limits of coil and metal and different formation conductivities, we analyze in detail the influences of the length of metal and distance from the nearest subarray on array induction log data with finite element method. The results show that we can ignore the metal body effects when formation conductivity is greater than 0. 1 S/m and the distance is over 0. 3 m. Otherwise we need to consider the effects. Based on the situation that the formation conductivity is equal to 0. 001 S/m, we analyze the effect on the measurement through changing lengths of metal bodies and distance between metal bodies and the array induction log instrument. When the distance is less than 1.3 m, we find that the measurement of the sixth subarray is more serious influenced than the eighth subarray.