玛湖凹陷二叠系风城组烃源岩地球化学特征及页岩油“甜点”评价  

Geochemical characteristics of source rocks and evaluation of shale oil“sweet spot”of Permian Fengcheng Formation in Mahu Sag

作　　者：白玉彬 李梦瑶 朱涛[3] 赵靖舟 任海姣 吴伟涛 吴和源 BAI Yubin;LI Mengyao;ZHU Tao;ZHAO Jingzhou;REN Haijiao;WUWeitao;WU Heyuan(School of Earth Sciences and Engineering,Xi’an Petroleum University,Xi’an 710065,China;Shaanxi Key Laboratory of Petroleum Accumulation Geology,Xi’an 710065,China;Research Institute of Exploration and Development,PetroChina Xinjiang Oilfield Company,Karamay 834000,Xinjiang,China)

机构地区：[1]西安石油大学地球科学与工程学院,西安710065 [2]陕西省油气成藏地质学重点实验室,西安710065 [3]中国石油新疆油田公司勘探开发研究院,新疆克拉玛依834000

出　　处：《岩性油气藏》2024年第6期110-121,共12页Lithologic Reservoirs

基　　金：国家自然科学基金面上项目“流体活动与自生矿物形成转化及有机质热演化对页岩孔隙发育和烃类赋存的影响”(编号:42372155)资助。

摘　　要：通过岩石薄片、总有机碳(TOC)、岩石热解、氯仿沥青“A”、镜质体反射率(R_o)等多种岩石学及有机地球化学分析资料,对准噶尔盆地玛湖凹陷二叠系风城组烃源岩特征进行了评价,并建立了页岩油“甜点”评价标准,以典型井为例系统刻画了研究区“甜点”的分布特征。研究结果表明:①玛湖凹陷二叠系风城组烃源岩矿物组成主要为石英、长石和白云石,其次为方解石和黏土矿物,岩石类型包括灰质泥岩、砂质泥岩、云质泥岩与泥岩。②不同岩性烃源岩的有机质丰度存在一定的差异,TOC平均为0.75%;有机质类型以生油Ⅱ型为主,其次为Ⅰ型和少量的Ⅲ型;处于低成熟—成熟演化阶段,以中等—极好烃源岩为主。③优选TOC、氯仿沥青“A”、游离烃S_(1)和R_o作为页岩油“甜点”评价参数,将其划分为富集、中等富集、低效与无效共4种资源类型。④典型井玛页1井的页岩油“甜点”评价结果显示,高TOC、高氯仿沥青“A”和S_(1)、高油饱指数(OSI)的层段页岩油勘探潜力最好;相对贫有机质、S_(1)较高的层段,页岩油也具有一定的勘探潜力。The source rock characteristics of the Permian Fengcheng Formation in Mahu Sag were defined based on a variety of petrographic and organic geochemical data,such as rock slices,total organic carbon(TOC),rock-eval pyrolysis,chloroform bitumen“A”and vitrinite reflectance(Ro).The evaluation standard of shale oil“sweet spot”was established,and the distribution characteristics of“sweet spot”in the study area were systematically described by taking typical wells as examples.The results show that:(1)The source rocks of Permian Fengcheng Formation in Mahu Sag are mainly composed of quartz,feldspar and dolomite,followed by calcite and clay minerals.The rock types include calcareous mudstone,sandy mudstone,dolomitic mudstone and mudstone.(2)The abundance of organic matter in source rocks with different lithologies is different,and TOC is 0.75%on average.The organic matter type is mainly typeⅡ,which is the main source of oil generation,followed by typeⅠand a small amount of typeⅢ.It is in the low maturity to mature evolution stage,and dominated by medium to very high-quality source rocks.(3)TOC,chloroform bitumen“A”,free hydrocarbon S_(1) and Ro were selected as evluation parameters for shale oil“sweet spot”and divided into four resource types:enriched,medium enriched,low efficiency and ineffective.(4)The evaluation results of shale oil“sweet spot”in typical well Maye 1 show that the shale oil exploration potential is the best in the layers with high TOC,chloroform bitumen“A”,S_(1),and oil saturation index(OSI).In addition,shale oil also has exploration potential in the relatively organic-poor interval with high S_(1).

关 键 词：烃源岩 有机地球化学 页岩油 “甜点”评价 有机质类型 有机质丰度 有机质成熟度 风城组 二叠系 玛湖凹陷 准噶尔盆地 

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]