瞬变电磁法过套管测井技术分析

Research of cased-hole logging with transient electromagnetics

瞬变电磁感应测井是一种以瞬变电磁理论为基础的新型感应测井技术,其在发射机理、频率选择、发射方式、信号提取等方面不同于传统的感应测井,具有零直耦、小线圈距,高信噪比、频率丰富、处理简单等优点。通过分析瞬变电磁场传播机理、与连续电磁场的差异、测试信息的提取,研究电磁探伤测井原理,探寻过套管测井的实现方式。瞬变电磁法过套管测井与过去的电极法过套管测井相比施工简便、时效高、可连续测量,是一种进行过套管剩余油检测的有效手段。

Cased-hole logging with Transient electromaganetics(TEM) is a new type of induction logging techniques based on TEM theory, however, it is quite different from conventional method of induction logging with continuous electromagnetics when it comes to mechanism of electromagnetic emission, frequency selection, transmitting mode, signal extraction. Logging with TEM has the advantages of banishing directly coupling signal, much smaller transmitter-receiver spacing, high signal-to-noise ratio, abundant frequency information, and simple processing. By analyzing the transmission mechanism of transient electromagnetics,the difference from continuous electromagnetic field,the methods of information extraction, and studying the electromagnetic inspection instrument that has already been used for detecting the condition of casing damages, the realization of cased-hole logging is explored by using TEM method. Logging with TEM in cased-hole has the advantages of convenient operation, high time efficiency, continuous measurment compared with electrode method. Therefore, it is an effective way for detecting the remaining oil through casing.