近地表岩溶探测方法

在钻井过程中，井下地层中的岩溶使钻井液在井下地层中有了流通条件，会出现漏失。井漏会造成钻井的停顿或中断甚至更严重的事故，因此，在钻井施工前，根据地质预测，在有可能存在岩溶的区块要尽量将岩溶资料收集齐全。本文根据探区的地质情况，针对近地表300m以内采用瞬变电磁法和对称四极法组合进行岩溶探测研究，将反演结果与地质资料相结合进行解释，以降低近地表岩溶对油气井钻井施工的潜在威胁。研究证明瞬变电磁法与对称四极组合能较有效地探测近地表岩溶的分布。

iversity,Changsha,Hu'nan 410083,China An integrated geophysical method for near-surface karst survey

In the drilling process, the leakage of drilling fluid will occur when the drilling bit encounter karst strata.This kind of well leakage causes drilling interruptions or even serious accidents.Therefore, before drilling, complete karst strata information should be collected based on geological prediction.Based on the geological prediction of the exploration area, we use the transient electromagnetic (TEM) method and the symmetrical four-pole sounding method to detect near-surface karst (up to 300 meters depth), and interpret inversion results with the constraint of geological information to determine near-surface karst strata and ensure well drilling.Our application proves that the proposed approach can effectively detect near-surface karst strata.