马尔可夫随机场反演在火山岩储层预测中的应用  

Application of Markov random field inversion in the prediction of volcanic reservoirs

作　　者：曹磊[1] 张达[1] 李宁[1] 荆锡贵 CAO Lei;ZHANG Da;LI Ning;JING Xigui(Reservoir and Fluid Prediction Group of Northeast Petroleum Branch of Sinopec,Changchun 130062,China)

机构地区：[1]中国石油化工股份有限公司东北油气分公司储层预测团队,吉林长春130062

出　　处：《石油物探》2021年第1期167-174,共8页Geophysical Prospecting For Petroleum

基　　金：中国石油化工股份有限公司科技重大项目“东部探区油气聚集规律与精细评价关键技术”(ZDP17014);重点科技项目“松南断陷火山岩气藏分布规律及关键技术”(P19027-5)共同资助。

摘　　要：常规反演方法识别火山岩储层通常会因为地质模型与地下地质情况差异较大而导致反演结果准确率不高。针对火山岩储层预测的难点,将波阻抗与测井曲线进行贝叶斯分级划分的岩相作为随机变量,分角度叠加地震数据作为连续变量,通过马尔可夫随机场模型建立两者的关系,并将其引入到火山岩地震叠前反演算法当中。该方法克服了叠前同时反演方法必须建立低频模型的缺点。利用楔形模型进行反演测试,反演结果与模型吻合且边界收敛。将该方法应用于长岭龙凤山火山岩内幕储层预测,通过合理的划分岩相,绕开了对火山岩的岩性预测而直接进行物性预测。预测结果表明,反映火山岩物性的密度体与实钻井结果吻合度高。The exploration and development of volcanic rock reservoirs has been a focus in the oil and gas geophysics community.The conventional inversion of volcanic rock reservoirs are usually inaccurate due to the large difference between the geological model and the underground geological conditions.In this study,the lithofacies divided by Bayes classification of impedance and log curves were regarded as the random variable,whereas angle stacking seismic data was regarded as the continuous variable.The two variables were related by the Markov random field model and then introduced into the algorithm of seismic pre-stack inversion of volcanic rocks.This process helped successfully overcome the dependence of the simultaneous inversion method on the low-frequency model,which was demonstrated by the test on a wedge model.The inversion results were more consistent with the model,while the boundary was more convergent.This method was applied to the prediction of the inner reservoirs of volcanic rock in Longfengshan,Changling.The performance of physical property prediction bypassed that of the lithology prediction,through a reasonable division of lithofacies.The prediction results showed that the density body that reflects the physical properties of the volcanic rock was highly consistent with the actual drilling results.

关 键 词：马尔可夫随机场 叠前反演 火山岩 低频模型 Bayes理论 楔形模型 

分 类 号：P631[天文地球—地质矿产勘探]