四川盆地二叠系海陆过渡相页岩气地质条件及勘探潜力

四川盆地二叠系海陆过渡相页岩气

地质条件及勘探潜力

郭旭升　胡东风　刘若冰　魏祥峰　魏富彬

中国石化勘探分公司

摘　要　上二叠统龙潭组海陆过渡相泥页岩是四川盆地重要的烃源岩层系，前期的研究工作主要集中于烃源岩评价，而针对页岩气成藏方面的研究则较少。为此，通过对龙潭组取心井——东页深1井分析测试结果的解剖，结合邻区的钻探成果，对龙潭组富有机质泥页岩的分布特征、地化特征、储层特征、含气特征及顶底板条件等进行了研究，并与具有相似沉积背景且已获得良好页岩气显示的页岩层系展开了对比分析，明确了龙潭组页岩气形成的地质条件及勘探潜力。研究结果表明：①川东南地区龙潭组海陆过度相富有机质泥页岩发育，厚度大于40 m、脆性矿物含量较高、孔隙度较高、有机碳含量高、热演化程度适中、含气性较好，具备页岩气形成的有利地质条件；②较之于国内外其他已获得良好页岩气显示的海陆过渡相泥页岩，川东南地区龙潭组孔隙度、有机碳含量、有机质成熟度、含气量等关键参数更优；③有机质类型是影响龙潭组泥页岩中有机质孔隙发育程度的主要因素，页岩气勘探选层应避开煤层富集段。结论认为：在综合考虑富有机质泥页岩发育程度及夹层厚度、埋深、保存等条件下，綦江—赤水一带是四川盆地龙潭组海陆过渡相页岩气勘探的最有利地区。

关键词　四川盆地　晚二叠世　龙潭期　海陆过渡相　泥页岩　有机碳含量　热演化成熟度　含气量　页岩气勘探潜力

DOI: 10.3787/j.issn.1000-0976.2018.10.002

Geological conditions and exploration potential of Permian marine–continent transi-

tional facies shale gas in the Sichuan Basin

Guo Xusheng, Hu Dongfeng, Liu Ruobing, Wei Xiangfeng & Wei Fubin

(Sinopec Exploration Company, Chengdu, Sichuan 610041, China)

NATUR. GAS IND. VOLUME 38, ISSUE 10, pp.11-18, 10/25/2018. (ISSN 1000-0976; In Chinese) Abstract: Marine–continent transitional facies shale of the Longtan Fm, Upper Permian is an important source rock stratum in the Sich-uan Basin. The previous researches on it mainly focus more on source rock evaluation, but less on shale gas accumulation. In this paper, the test and analysis results of Well DYS1, the coring well of Longtan Fm were dissected. Combined with the drilling results of its ad-jacent area, the organic rich shale in the Longtan Fm were studied from the aspects of distribution, geochemical, reservoir, gas-bearing characteristics and roof and floor conditions, and then compared with the shale strata with similar sedimentary background and good shale gas shows. And accordingly, its geological conditions for the formation of Longtan shale gas and its exploration potential were made clear. And the following research results were obtained. First, in the southeastern Sichuan Basin, the organic rich shale of transitional facies of Longtan Fm is developed with a thickness of more than 40 m. It is characterized by high brittle mineral content, high porosity, high total organic carbon (TOC), moderate thermal evolution (R o) and good gas-bearing property. Therefore, it is geologically favorable for the formation of shale gas. Second, compared with the existing transitional facies shales at home and abroad, the Longtan shale is better in terms of porosity, TOC, R o, gas content and other key parameters. Third, the type of organic matters is the main reason for the low development degree of organic pores in the Longtan shale. And during its shale gas exploration and selection, the coal seam enriched sections shall be avoided. In conclusion, considering the development degree, interlayer thickness, depth and preservation conditions of organic rich shale comprehensively, the Qijiang–Chishui area is the best exploration area for the transitional facies shale gas of Longtan Fm in the Sichuan Basin.

Keywords: Sichuan Basin; Late Permian; Longtan Fm; Marine-continent transitional facies; Shale; Total organic carbon; Thermal evolu-tion maturity; Gas content; Shale gas exploration potential

基金项目：国家科技重大专项“页岩气区带目标评价与勘探技术”（编号：2017ZX05036）。

作者简介：郭旭升，1965年生，教授级高级工程师，博士；本刊第八届编委会委员；主要从事石油地质综合研究及勘探管理工作。地址：（610041）四川省成都市高新区吉泰路688号。ORCID：0000-0001-7378-7594。E-mail: guoxs.ktnf@ 通信作者：刘若冰，1973年生，研究员，博士；主要从事油气田勘探开发研究与技术管理工作。地址：（610041）四川省成都市高新区吉泰路688号。ORCID：0000-0003-2245-6861。E-mail: liurb.ktnf@