湘中及湘东南地区上泥盆统佘田桥组页岩气勘探前景

摘要

The Devonian Shetianqiao Formation in central and southeastern Hunan area has perfect shale gas reservoiring conditions, thus a shale gas exploration prospective area. Taking the gas-bearing shale in the formation with advantageous geological condition and apparent characteristics as the main subject investigated, carried out analysis on shale gas reservoiring characteristics and exploration, exploitation potential. The investigation has shown that the gas-bearing shale is widely distributed with high organic carbon content (mean TOC 0.61%), high thermal evolution degree (mean Ro 2.71%), low porosity and permeability (0.7%and less than 0.04×10-3μm2 respectively) as well as strong adsorptivity. The distribution of gas-bearing shale thickness in depression basins has formed a unique“thin middle thick both ends”pattern. Combined with reservoiring characteristics and physicochemical indices marked out four advan-tageous areas with large shale gas potential.%湘中及湘东南地区泥盆纪佘田桥组具有良好的页岩气成藏条件，为页岩气勘探远景区。选取地质条件优越、页岩气特征明显的泥盆纪佘田桥组含气页岩作为主要研究对象，对页岩气储气特征和勘探开发潜力进行了分析。研究表明：含气页岩层分布面积广、有机碳含量高（TOC均值0.61%）、热演化程度高（Ro均值2.71%），低孔低渗（孔隙度为0.7%，渗透率小于0.04×10-3μm2），且吸附能力强。含气页岩层厚度展布在凹陷盆地形成独特的“中心薄边缘厚”格局，结合其成藏特征和物化指数，划分出页岩气潜力较大的四个有利区。