四川盆地侏罗系大安寨段湖相页岩油气形成地质条件及勘探方向  

Geological conditions to form lacustrine facies shale oil and gas of Jurassic Daanzhai Member in Sichuan Basin and exploration directions

作　　者：杨跃明[1] 黄东[2] 杨光[2] 李育聪 戴鸿鸣 白蓉[2] Yang Yueming;Huang Dong;Yang Guang;Li Yucong;Dai Hongming(PetroChina Southwest Oil & Gasfield Company, Chengdu, Sichuan 610051,China;Exploration and Development Research Institute, PetroChina Southwest Oil & Gasfield Company, Chengdu, Sichuan 610041,China;School of Geoscience and Technology, Southwest Petroleum University, Chengdu, Sichuan 610500,China)

机构地区：[1]中国石油西南油气田分公司 [2]中国石油西南油气田分公司勘探开发研究院 [3]西南石油大学地球科学与技术学院

出　　处：《天然气勘探与开发》2019年第2期1-12,共12页Natural Gas Exploration and Development

基　　金：国家科技重大专项“四川盆地致密油资源潜力、甜点区预测与关键技术应用”(编号:2016ZX05046-006-008)

摘　　要：随着认识的不断深入和工程技术的进步,页岩油气已经正式进入我国储量序列,正在有序开发。通过岩心、露头、钻井、测井以及大量的分析化验资料,对四川盆地侏罗系大安寨段湖相页岩油气的形成地质条件和资源潜力进行系统分析和评价。研究结果表明:①大安寨段湖相页岩主要发育在大一三亚段浅湖、半深湖泥,有机碳含量平均为1.15%,有机质类型均以Ⅱ型干酪根为主,镜质体反射率介于0.8%~1.4%,处于成熟—高成熟阶段,页岩厚度大,生烃能力强,具备形成页岩油气的物质基础。②大安寨段页岩以黑色、灰黑色页岩与生物介壳灰岩不等厚互层为主,脆性矿物平均含量为63.4%含量较高;页岩孔隙度平均为5.92%,储集条件好,储层发育微米—纳米级孔隙,具备储集页岩油气的储集空间,有利于页岩储层的改造。③大安寨段湖相页岩油气具有埋藏浅、保存条件好、压力系数高等优越条件,按照有机碳含量大于1.5%的范围,计算页岩油资源量为70×10^8 t,页岩气的资源量为3.5×10^12 m^3,结合大安寨段页岩油气评价指标,优选出射洪—遂宁—南充—蓬安—仪陇—南部页岩油气勘探有利区近1×10^4 km^2,并建议在公山庙、龙岗地区开展先导试验工作。With continuous deepening understandings and advancing engineering technologies, shale oil and gas formally comes into the domain of China’s reserves and has been developed in good order. Some geological conditions to form lacustrine facies shale oil and gas of Jurassic Daanzhai Member, Sichuan Basin, and resource potential were analyzed and evaluated systematically based on core, outcrop, drilling, and well-logging data. Results show that(1) this lacustrine-facies shale of Daanzhai Member is mainly developed in the shallow and semi-deep lake mud of J1dn31, with the TOC of 1.15% on average, the main type Ⅱ kerogen, and the Ro of 0.8%-1.4%, indicating that it is in the stage of mature-high maturity with thick shale and strong hydrocarbon-generating capacity,also providing the material base to form shale oil and gas;(2) the shale of Daanzhai Member is mainly composed of black and grayish black shale interbedd with biological shell limestone in different thickness. Its content of fragile minerals is higher, averaging 63.4%.Its porosity averages 5.92%. Its reservoir conditions are good with developed micro-and nano-scale pores to act as reservoir space,which is favorable for the stimulation;and(3) this lacustrine facies shale oil and gas is superior with shallower burial depth, better preservation conditions, and higher pressure coefficient. In view that the TOC is lower than 1.5%, the calculated shale oil and gas resources achieve 70×108 t and 3.5×1012 m3, individually. Combined with some evaluation indexes, one favorable belt with about 10000 km2, Shehong-Suining-Nanchong-Peng’an-Yilong-Nanbu area, is selected for shale-oil and shale-gas exploration. What’s more, it is recommended to carry out pilot tests in two areas of Gongshanmiao and Longgang.

关 键 词：四川盆地 早侏罗世-大安寨期 湖相 页岩油气 地质条件 资源量 有利区 先导试验 

分 类 号：P618.13[天文地球—矿床学]