煤层气物性参数随埋深变化规律研究

Study on Variation Law of Coalbed Methane Physical Property Parameters with Seam Depth

针对深部煤层煤层气的'高地应力、低渗透性'特性导致开发难度大的问题,分析了沁水盆地南部煤层气井岩心试验数据和测井、试井、压裂、生产等实际资料,研究了主要储层物性参数与埋深的关系。研究结果表明:不同储层物性随埋深变化规律各不同,具有跃变式变化特征;拐点变化值并不是一个确定埋深。利用BP神经网络模拟物性参数变化拐点的结果表明:选取的关键参数不同,得到的物性随埋深变化拐点值是不一致的。以力学参数为关键参数的深部煤层埋深拐点为1 043 m;侧重物性参数的埋深拐点为659~950 m;以产能因素为关键参数的埋深拐点为927~1 171 m。

According to high difficult development caused by high geostress and low permeability features of the coalbed methane in deep seam,the paper analyzed the rock core test data of the coalbed methane well in the south part of Qinshui Basin and the logging,well test, fracturing,production and other actual informations of the coalbed methane well and studied the relationship between the physical property parameters of main reservoir and depth.The study results showed that the variation law of different reservoir with seam depth would be different and would have jumped type variation features.The variation value of the inflection point would not be a certain buried depth value. The results of the changed inflection point of the physical property parameter simulated with BP neural network showed that due to the selected key parameters different,the obtained physical property with the changed inflection point of the depth would be different.The inflection point value of the deep seam depth with the mechanics parameters as the key parameters was 1 043 m.The deep seam depth inflection point value of the particular physical property parameters was 659~950 m.The deep depth inflection point value with production factors as the key parameters was 927~1 171 m.