位场方法在非常规油气勘探中的应用

Application of potential field method in the unconventional oil and gas exploration

在常规油气勘探领域,高精度的重磁资料能够非常好的完成油气资源的远景评价,为地震勘探和钻井提供指导.在非常规油气勘探领域,重磁勘探方法显得尤为重要.因为非常规油气资源的地质结构、圈闭条件、储层评价、成藏机理、渗流特征等方面更加复杂和未知,地震勘探和钻井难以直接开展,亟需非地震方法的优选规划.由于重磁位场方法并不能"特异性"的揭示地下页岩分布和页岩气的资源潜力,从某种程度上说,重磁位场方法在常规油气和非常规油气的勘探技术是没有多大区分的,核心都是"综合"二字.其中,对重磁资料的处理要经过常规的延拓、剩余重力异常提取和磁异常化极等,以及重力异常剥皮、park反演、梯度反演等关键处理,能够获取特定地层的厚度与埋深和断裂信息.本文以页岩气资源的重磁位场勘探技术为中心,通过调研国内外重磁方法在非常规油气勘探阶段的应用实例,总结规律,构建利用位场方法开展页岩气等资源勘探的技术体系与流程.

In the field of conventional oil and gas exploration, high-precision gravity and magnetic data can be very good to complete the prospective evaluation of oil and gas resources, and provide guidance for the seismic exploration and drilling. While in the field of unconventional oil and gas （UOG） exploration, Gravity and magnetic exploration methods carry a particularly important duty. More complex and unknown are UOG＇s geological structure, trap conditions, reservoir evaluation, reservoir mechanism, percolation characteristics, seismic exploration and drilling are difficult to be directly carried out. In this case, it is urgent to take use of the optimization and plan of non-seismic methods. Gravity and magnetic potential field method is believed that it fails to ＂specifically＂ reveal the underground shale distribution and resource potential of shale gas, in a way, exploration technology of the gravity and magnetic potential field methods applied in conventional oil ＆ gas and unconventional oil ＆ gas have no much distinction, both of which are the core of ＂COMPREHENSIVE＂. Processing the gravity and magnetic data goes through a series of steps, such as traditionally, continuation, gravity anomalies residualizing and magnetic reduction to the pole, as well as gravity anomaly peeling, Park inversion and gradient inversion, which can get specific stratigraphic thickness and depth, with basement faults information. After researching the application of gravity and magnetic methods in shale gas exploration stage at home and abroad, this paper is centered in the exploration technology of the gravity and magnetic potential field in shale gas resource, building technology system on using the gravity and magnetic potential field methods for exploring shale gas.