辽河东部凸起C—P页岩气聚集地质条件

通过对辽河坳陷东部凸起已钻探井的录井、测井及岩芯资料的系统分析,结合目的层段样品的有机地化及实验测试结果分析,认为东部凸起上古生界石炭—二叠系暗色泥岩单层厚度较大,空间分布广泛稳定,有机质类型以III型干酪根为主,丰度指标高(TOC>2.0%),热演化程度高(Ro=1.5%～2.6%),具备形成页岩气藏的源岩条件;暗色泥岩有机碳含量高为吸附态页岩气提供了丰富的载体,微裂缝的发育为游离态页岩气提供了良好储集空间;同时泥岩石英矿物含量高(平均SiO2>40%),岩性较脆易形成裂缝,符合工程压裂条件要求,部分已钻探井在石炭系—二叠系暗色泥岩段普遍存在气测全烃异常,预示东部凸起上古生界石炭—二叠系具有较大的页岩气勘探潜力。

East Uplift of C-P Shale Gas Accumulation Geological Condition Analysis

The analysis of the East uplift well’s logging and core data,and the results of the organic geochemistry and the experiment analysis about the intended interval samples reveal that the East uplift of Upper Paleozoic Carboniferous-Permian mudstone has larger thickness,spreads widely and stably,with maintype III kerogen,abundance index(TOC>2.0%),andhigh thermal evolution(Ro=1.5%～2.6%),which means there has mother rock conditions of shale gas reservoir.Dark mudstone with high organiccarbon content for adsorption states of shale gas provides abundant carrier,and microfracture development provides excellent reservoir space for the free state of shale gas.At the same time,high quartz mineral conten(t average SiO2>40%),makes the lithology brittle and easy to form crack,which comply with in accordance with engineering fracture condition.Some drilled wells in the Carboniferous-Permian mudstone section have the prevalence of gas logging total hydrocarbon anomaly,which indicate that the East uplift of Upper Paleozoic carboniferous-Permian has larger shale gas exploration potential.