摘要
The identification of igneous rock in sedimentary basins serves as the basis for the exploration of igneous oil and gas reservoirs.The implementation of magnetic exploration in the identification and delineation of igneous rock can often achieve good results.However,when igneous rock and deep magnetic layers are under the influence of remanence,the reduction to the pole of magnetic anomaly and conventional magnetic inversion methods,which require clear magnetization directions,is limited,and special magnetic anomaly processing and inversion methods are necessary.We present a case study on igneous rock imaging through a strategy involving the joint use of a preferential filtering method and amplitude inversion affected by remanence in the Qikou depression in China.We first extract the weak anomalies of igneous rock from the observed total-field anomaly via preferential filtering and calculate their amplitude data.We then perform amplitude inversion to determine the underground three-dimensional magnetism distribution and propose a reasonable interpretation by combining seismic and other data.This work demonstrates the feasibility and effectiveness of the above strategy in delineating the igneous rock buried deep in sedimentary basins.
沉积盆地火成岩识别是火成岩油气藏勘探的基础,利用磁异常来识别和圈划火成岩体往往可以取得较好的效果。但当火成岩体及深部磁性层受剩磁影响时,化磁极及常规磁异常反演方法的应用受到限制,需要采用特殊的磁异常处理与反演方法。本文以岐口凹陷火成岩识别为例,利用优化滤波方法与磁异常模量反演方法相结合,提取火成岩弱异常并计算其模量异常,利用磁异常模量反演给出地下三维等效磁化率分布,结合地震等资料对强磁性分布区进行了分析解释。研究表明,优化滤波方法和磁异常模量反演方法的应用,对埋藏深度大的火成岩弱异常提取和受剩磁影响的火成岩磁性反演可以取得良好的效果。
基金
supported by the National Natural Science Foundation of China(No.41074095)
the Scientific Research Foundation of China University of Petroleum(Beijing)at Karamay(NO:XQZX20230005).
