四川盆地下古生界筇竹寺组与龙马溪组页岩气勘探优选区预测

四川盆地下寒武统筇竹寺组和下志留统龙马溪组为盆地内重要的气源岩，在常规气田勘探中发现广泛的油气显示,表明其具有页岩气勘探的良好前景。在页岩气勘探初期，应该先进行优先层段优先区块的深入研究。目前，多名学者对筇竹寺组、龙马溪组的特征和页岩气发育的有利区位做出了预测，但使用方法不完善、不统一，评价指标比较混乱。在系统分析Fort Worth盆地Barnett页岩优选区块特征的基础上，参照美国地质调查局对Barnett页岩的选区原则，结合四川盆地自身的特征，选取页岩层总厚度、TOC、Ro、埋藏深度4个指标确定了2套岩层的页岩气优选区与延展区。研究认为，筇竹寺组有利区与外围延展区均在成都—乐山—资阳—内江为界的区域内部，龙马溪组有利区与外围延展区均在自贡—宜宾一带。

Shale gas favorable area prediction of the Qiongzhusi Formation and Longmaxi Formation of Lower Palaeozoic in Sichuan Basin, China

The Qiongzhusi Formation of the Lower Cambrian and Longmaxi Formation of the Lower Silurian are important gas source rocks in Sichuan Basin, with widespread gas shows in conventional oil exploration. Previous research has shown a bright future of shale gas development of the two reservoirs. Furthermore, in the early stage of exploration, deep research about the favorable area of the reservoir instead of the whole area can not be exaggerated. At present, many researchers have studied the reservoir characteristics and predicted the prospective area used methods which are imperfect and inconsistent. The purpose of this paper is to select the good exploration area using the method that had been used in Barnett shale by the U.S. Geological Survey in 2004. After systematically studying the details of the selected area of Barnett shale in Fort Worth Basin and considering the characteristics of Sichuan Basin, this paper chose thickness, totol organic carbon content, vitrinite reflectance and burial depth to determine the favorable area and extended area of the two reservoirs in Sichuan Basin. The result of this study indicated that both the best exploration area and the extended area of the Qiongzhusi Formation are within the border of Chengdu-Leshan-Ziyang-Neijiang and that of Longmaxi Formation are located around Zigong-Yibin area.