川西坳陷陆相天然气勘探新思考

New thoughts of continental gas exploration in Western Sichuan Depression

王鹏 李瑞 刘叶

Wang Peng Li Rui Liu Ye

油气藏地质及开发工程国家重点实验室(成都理工大学), 成都610059 2. 中国石油化工股份有限公司西南石油局第二物探大队, 四川德阳618500

National Key Laboratory of Oil & Gas Reservoir Geology and Exploitation(Chengdu University of Technology), Chengdu, Sichuan 610059, China 2. Second Geophysical Prospecting Crew, Southwest Petroleum Bureau, SINOPEC, Deyang, Sichuan 618500, China

位于龙门山逆冲推覆带前缘的川西坳陷上三叠统—侏罗系为1套陆相致密—超致密碎屑岩含气层系,通过长期勘探,构造及与构造相关的各类复合型圈闭气藏基本探明。通过应用"连续型"气藏理论对该区进行分析,认为川西侏罗系属"远源"气藏,不具备"连续型"气藏成藏条件;须家河组具备"连续型"气藏成藏条件和特征,特别是须五段及部分须四段埋深相对较浅,泥页岩发育,有机质丰度高,成熟度高,生气量大,与砂岩广泛大面积接触,具备页岩气、致密砂岩气并探的优势,剩余勘探潜力巨大,是目前经济技术条件下最现实的开发领域。针对川西须家河组这一老勘探对象,开展"连续型"气藏富集规律研究,利用地质—测井—地震技术联合预测优势,尤其注重依托高精度三维地震资料,开展叠前储层、裂缝和含气性检测新技术的应用,配套先进的钻井、储层改造和保护等工程工艺技术和设施,预期仍然可取得具有重要价值的新突破。

Located on the edge of Longmengshan thrust-napped belt,the western Sichuan Depression from the Upper Triassic to Jurassic is a set of continental tight-super tight gas-bearing clasolite.Long-term exploration has proven structures and various types of composite traps.Applying the theory of continuous gas reservoir to analyze the target zone,it has been found out that Jurassic in the western Sichuan is a "distal" gas pool and does not have continuous gas reservoir forming conditions.The Xujiahe Formation possesses accumulation conditions and characteristics of continuous gas reservoir.This is particularly true for T3x5 and part of T3x4 which are characterized by shallow burial depth,well-developed pelite,high organic richness,high maturity,large amount of gas generation and general contact with sandstone.Therefore,with the advantages of exploration for both shale gas and tight gas,they possess large exploration potential and are the most practical development areas under current economical and technical conditions.In view of the high exploration degree of the Xujiahe Formation,the enrichment regulation study for continuous gas reservoir is carried out by the combined prediction of geology-logging-seismic technologies,especially with the high-precision 3D seismic data.The application of new techniques such as pre-stack reservoir,fracture gas-bearing property and advanced engineering technologies of drilling,reservoir stimulation and protection is expected to achieve significant breakthroughs.

https://doi.org/10.11781/sysydz201204406