烃源岩排烃期与储层致密期匹配关系的确定及意义--以准噶尔盆地吉木萨尔凹陷芦草沟组致密油为例  

Determination and Significance of Matching Relationship between Phase of Hydrocarbon Expulsion and Sandstone Reservoir Densification: Tight Oil of Lucaogou Formation in Jimsar Sag,Junggar Basin

作　　者：白桦 庞雄奇[4] 王绪龙[5] 张建国 刘树根[2] 卢立泽 王贺华 BAI Hua;PANG Xiong-qi;WANG Xu-long;ZHANG Jian-guo;LIU Shu-gen;LU Li-ze;WANG He-hua(ZhenHua Oil Company Beijing 100031,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploration (Chengdu University of Technology) Chengdu 610059,China;Chengdu North Petroleum Exploration and Development Technology Company Limited Chengdu 610051,China;College of Geosciences,China University of Petroleum (Beijing) Beijing 102249,China;Xinjiang Oilfield Company,PetroChina Karamay 834000,China)

机构地区：[1]振华石油控股有限公司,北京100031 [2]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 [3]成都北方石油勘探开发技术有限公司,成都610051 [4]中国石油大学(北京)地球科学学院,北京102249 [5]中国石油新疆油田分公司,克拉玛依834000

出　　处：《科学技术与工程》2018年第28期15-25,共11页Science Technology and Engineering

基　　金：国家“973”项目(2011CB201100);国家重点基金(U1262205)资助。

摘　　要：烃源岩排烃期与储层致密期匹配关系是致密砂岩油气成藏机理及富集规律研究中尚未得到很好解决的关键问题。在大量数据统计分析的基础上,结合排烃门限理论、孔隙度演化规律和构造演化背景,以有机质成熟度Ro为纽带,探讨了烃源岩排烃期与储层致密期之间的匹配关系。通过对准噶尔盆地吉木萨尔凹陷芦草沟组烃源岩有机质丰度、类型和成熟度等特征的分析,认为芦草沟组烃源岩为一套较好-好的烃源岩,以Ⅱ型干酪根为主,处于成熟演化阶段。应用生烃潜力法对芦草沟组烃源岩的排烃特征进行了研究,结果表明其Ro达到约0.73%(埋深约3 200 m)后,烃源岩进入排烃期,开始大量排烃。鉴于芦草沟组砂泥岩互层特征以及Ro与埋深的正相关性,用烃源岩Ro的演化来反映紧邻(互层的)地层的埋深变化。通过对实测岩心孔隙度随埋深演化的统计分析,结果表明在埋深超过约2 700 m(对应Ro约0.6%)后,芦草沟组孔隙度普遍小于10%,整体进入致密期。考虑到Ro的不可逆性,认为芦草沟组致密油具有"先致密,后排烃(成藏)"的特征,该特征在一定程度上为芦草沟组致密油的近源成藏(充注)过程提供了有利地质条件,烃源岩排烃条件决定了宏观上致密油富集区域。The relationship between reservoir tightening time and hydrocarbon expulsion period is the key issue which has not been well solved in studies on the tight oil and gas accumulation mechanism and enrichment regularity.On the basis of a large amount of data statistical analysis,combined with the theory of hydrocarbon expulsion threshold,porosity evolution and tectonic evolution background,discusses the new method of matching relationship between the stage with a large amount of hydrocarbon expulsion of hydrocarbon source rock and reservoir dense phase.The analysis of organic matter abundance,organic matter type and maturity of Lucaogou formation source rock in Junggar Basin Jimsar sag,suggesting that Lucaogou formation source rock is a set of fair to good hydrocarbon source rocks,mainly dominated by type II kerogen and at the mature stage.According to the hydrocarbon expulsion modelling,the source rocks reached the hydrocarbon expulsion threshold at 0.73%R o(buried depth about 3 200 m),and begin to expulse a great quantity of hydrocarbon.In view of Lucaogou formation of sandstone and mudstone interbedded frequently feature,this paper uses the R o of source rocks evolution to reflect the buried depth of adjacent(interbedded)strata.Through to statistical analysis of measured core porosity with depth evolution,it is found that in the depth of more than about 2 700 m(corresponding R o approximately 0.6%),Lucaogou formation porosity is generally less than 10%,generally the whole stratum into the dense phase.Considering the irreversibility of R o evolution that Lucaogou formation tight oil is characterized by“tightening before expulsion”or“tightening before accumulation”which provides a favorable geological condition for near-source charging characteristics of Lucaogou tight oil.Hydrocarbon source rock expulsion conditions determine the tight oil accumulation area.

关 键 词：排烃期 致密期 致密油 芦草沟组 吉木萨尔凹陷 

分 类 号：P618.13[天文地球—矿床学]