下寺湾油气田延长组长7段页岩气藏浅析

摘要

Xiasiwan oil-gas field is close to the center of Ordos Basin.In the study area,the chang7 member of Yan-chang Formation of Mesozoic was developed in the massive thick black shale.Combined with the study results of domestic and foreign experts and scholars,by analyzing various conditions for shale gas accumulation,such as distribution,burial depth,and microstructure of shale,abundance and thermal evolution of organic matter,porosity,permeability,microfrac-ture,etc.,it was indicated that the chang7 member of Yanchang Formation of Mesozoic in the study area has the conditions for shale gas accumulation.The major geologic parameters for evaluation and identification of exploration targets are mainly focused on the thickness and burial depth of shale,TOC,maturity,development degree of microfracture,and abnormal indi-cation of gas logging.According to the reservoir-forming conditions of shale gas and the distribution of abnormal indica-tion of gas logging in drilling,it was indicated that the area of Liuluoyu is the most favorable area for the shale gas accumu-lation,which is the main area for next step exploration and development.%下寺湾油气田位于鄂尔多斯盆地中部，研究区中生界三叠系延长组长7段发育大套黑色油页岩。结合国内专家学者研究成果，通过对研究区页岩分布，页岩埋藏深度、厚度及微构造，有机质丰度和有机质热演化程度，孔隙度，渗透率，微裂缝等成藏条件进行分析认为：该区中生界三叠系延长组长7段页岩具备了页岩气成藏的条件；该区页岩气勘探选区评价的关键地质参数主要包括页岩埋藏深度及厚度、有机碳含量、成熟度、微裂缝发育程度和气测异常显示等。根据页岩气藏成藏条件及勘探过程中钻井气测异常的分布情况，预测下寺湾油气田西南部柳洛峪一带为页岩气藏最有利发育区，是下一步勘探开发的重点区域。