柴达木盆地德令哈坳陷石炭系页岩气系统评价  

Carboniferous shale gas system evaluation for the Delingha depression in Qaidam Basin

作　　者：刘成林[1,2] 张旭[1,2] 杨元元[1,2] 李英杰[3] 郑策[4] 马寅生[2] 王国仓[5] 李宗星[2] 康艳丽[2] 代昆[4] 

机构地区：[1]中国地质科学院页岩油气调查评价重点实验室,北京100081 [2]中国地质科学院地质力学研究所,北京100081 [3]中国地质大学(北京)水资源与环境学院,北京100083 [4]中国石油大学(北京)地球科学学院,北京102249 [5]中国科学院地质与地球物理所兰州油气资源研究中心,甘肃兰州730000

出　　处：《地学前缘》2016年第5期135-145,共11页Earth Science Frontiers

基　　金：国家自然科学基金项目(41272159;41572099);中国地质调查局地质调查项目(1212011120964)

摘　　要：石炭系是柴达木盆地油气勘探的新层系，油气勘探程度低，但发育厚度大的高有机质丰度泥页岩，具有很好的页岩气资源潜力。通过对德令哈坳陷石炭系露头剖面进行实测和钻井岩心分析，明确石炭系泥页岩空间展布特征。测定样品有机地球化学参数、孔渗特征，并且进行等温吸附和渗流实验，分析其储集特征。结合德参1井盆地模拟分析，研究石炭系页岩气成藏事件，划分德令哈坳陷石炭系页岩气系统。研究表明：石炭系泥页岩广泛发育，埋深较大但未发生变质；泥页岩有机质丰度较高，有机质类型主要为Ⅱ2型和Ⅲ型，处于成熟一高成熟演化阶段；上石炭统泥页岩发育优于下石炭统；泥页岩表现为低孔低渗特征，孔隙度在1．89％～5．48％，渗透率为（O．115--2．7）×10-7μm2；上覆地层发育厚层泥页岩可以提供良好的盖层条件；古近纪末现今为页岩气系统形成的关键时期；上石炭统克鲁克组钻遏天然气显示，证实了德令哈坳陷石炭系页岩气系统的存在。在泥页岩厚度、埋深、TOC含量、成熟度等条件综合评价基础上，将德令哈坳陷划分为德令哈页岩气系统与埃北页岩气系统。As one of petroleum exploration frontier formations in Qaidam Basin, Carboniferous has great shale gas source potentialities but at a relatively immature exploration stage presently. Based on field geological survey and drilled well analyses, the distribution of Carboniferous shale for the Delingha depression in Qaidam Basin was clarified. The characteristics of organic geochemistry, porosity and permeability for Carboniferous shale samples were tested. We also made isothermal adsorption tests and seepage experiments for studying the shale accumulation conditions. Combined with basin modeling analysis of Well Decan 1, this paper evaluated Carboniferous shale gas system for the Delingba depression in Qaidam BasirL Carboniferous shale is widely distributed in the depression with various thickness and buried depth. Most shale has higher organic matter richness and organic matter types of 1I e and HI, and is at the thermal stage of maturity and high maturity. Upper Carboniferous shale has large thickness and organic matter richness than that of Lower Carboniferous. Carboniferous shale shows the reservoir characteristics of low porosity of 1. 89%- 5. 48% and low permeability of （0. 115 - 2. 7） ×10 -7μm2. Thick shale of overlying formations provides favorable cap condition for Carboniferous shale gas. Basin modeling indicates that from the end of the Paleogene to present is the critical moment for the Carboniferous shale gas system in the Delingha depression. Natural gas shows of Keluke Group of Upper Carboniferous indicate that Carboniferous shale gas system exists in the Delingha depression. In light of shale thickness, buried depth, TOC, thermal maturity and other geological conditions comprehensive evaluation, this paper divided the Deiingha depression into two shale gas systems, i. e., Delingha shale gas system and Aibei shale gas system.

关 键 词：页岩气系统 石炭系 德令哈坳陷 柴达木盆地 

分 类 号：P618.13[天文地球—矿床学]