玛湖凹陷西南地区二叠系油气藏相态类型及凝析油气地球化学特征  

Geochemical characteristics of Permian condensate oil and gas and phase types in southwest of Mahu Sag

作　　者：王义凤[1,2] 田继先 李剑[1,2] 乔桐 刘成林[3,4] 张景坤 沙威 沈晓双[5] WANG Yifeng;TIAN Jixian;LI Jian;QIAO Tong;LIU Chenglin;ZHANG Jingkun;SHAWei;SHEN Xiaoshuang(Research Institute of Petroleum Exploration&Development,PetroChina,Beijing 100083,China;Key Laboratory of Gas Reservoir Formation and Development,CNPC,Langfang 065007,Hebei,China;State Key Laboratory of Petroleum Resources and Engineering,China University of Petroleum(Beijing),Beijing 102249,China;College of Geosciences,China University of Petroleum(Beijing),Beijing 102249,China;Research Institute of Petroleum Exploration&Development,PetroChina Qinghai Oilfield Company,Dunhuang 736200,Gansu,China)

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]中国石油天然气集团有限公司天然气成藏与开发重点实验室,河北廊坊065007 [3]中国石油大学(北京)油气资源与工程全国重点实验室,北京102249 [4]中国石油大学(北京)地球科学学院,北京102249 [5]中国石油青海油田公司勘探开发研究院,甘肃敦煌736200

出　　处：《岩性油气藏》2024年第6期149-159,共11页Lithologic Reservoirs

基　　金：中国石油天然气股份有限公司前瞻性基础性重大科技项目“大气田(区)成藏规律与勘探关键技术研究”下设03课题“凝析油与轻质油形成机制、成藏条件及资源潜力研究”(编号:2021DJ0603)资助。

摘　　要：利用PVT相态模拟软件恢复了玛湖凹陷西南地区二叠系油气藏原始储层流体组分,综合经验统计法与相图判别法对已发现油气藏的相态类型进行了判识,通过油气地球化学分析方法,明确了不同相态类型油气的来源及成因。研究结果表明:①玛湖凹陷西南地区二叠系油气藏主要分布在风城组和上乌尔禾组,油气藏的相态类型多样,以黑油油藏为主,挥发性油藏和凝析气藏(带油环的凝析气藏和近临界态凝析气藏)次之,凝析气藏主要发育在风城组,储层流体组分以甲烷为主,C7+烃类含量较少。②研究区二叠系不同相态原油的母质类型为偏腐泥型,均为风城组烃源岩成熟阶段的产物,凝析油的成熟度略高于其他相态类型原油,比其他相态类型原油物性更好,具有低黏度、低凝固点和低含蜡量的特点。③研究区二叠系天然气的组分以烃类气为主,其中甲烷的平均摩尔分数为86.21%,非烃类气含量低,成熟度差异较大,R_(o)为0.52%~2.39%;主要为风城组腐泥型烃源岩的产物;上乌尔禾组油气藏中天然气成熟度更高,平均R_(o)值为1.99%,风城组油气藏和凝析气藏中的天然气成熟度较低,平均R_(o)值分别为0.71%和0.85%。④受风城组烃源岩的热演化程度和储层物性影响,研究区二叠系发育2套含油气系统,分别为风城组的源内自生自储型油气藏和上乌尔禾组的源外下生上储型油气藏。The genetic types and its source of condensate oil and natural gas in Permian Formation,in southwest of Mahu Sag,is under controversy,the type of fluid phases is complex,which restricts the further expansion of deep oil and gas exploration in Mahu Sag.In this study,PVT phase simulation software was used to recover original reservoir fluid components oil and natural gas in Permian Formation,in southwest of Mahu Sag,combined empirical statistical methods with P-T phase diagram to determine the phase types of discovered oil-gas reservoirs.The source and genetic types of different phase types of oil and gas is clarified by multiple means of geochemical analyses.The results show that:(1)The Permian oil and gas reservoirs in southwest of Mahu Sag are mainly distributed in Fengcheng and upper Urho Formation.The phase types of oil-gas reservoirs are multiple,black oil reservoir comes first,near critical high volatile reservoir and condensate gas reservoir(condensate gas reservoirs with oil rings and near-critical condensate gas reservoirs)comes second.Condensate gas reservoirs are mainly developed in Fengcheng Formation.The reservoir fluid components are mainly methane,and the content of C7+hydrocarbons is relatively small.(2)The parent organic matter type of the different phases oil in the Permian are slightly sapropelic,all of which are the products of the mature stage source rocks in the Fengcheng Formation.The condensate oil maturity is slightly higher than the other phase oil,and its physical properties are better than others,with the characteristics of low viscosity,low freezing point and low wax content.(3)The natural gas components in the Permian are mainly hydrocarbon gas,of which the average methane mole fraction is 86.21%,the non-hydrocarbon gas content is low,the maturity varies greatly,the value of R_(o) is 0.52%-2.39%.It is mainly the product of sapropelic source rocks in the Fengcheng Formation.The maturity of natural gas of the upper Urho Formation is higher,with an average R_(o) value of 1.99%,while the

关 键 词：流体相态 凝析气藏 油源对比 腐泥型烃源岩 甲烷 风城组 上乌尔禾组 二叠系 玛湖凹陷 

分 类 号：TE122.1[石油与天然气工程—油气勘探] P618.13[天文地球—矿床学]