珠江口盆地西江凹陷XJ-A构造古近系储层特征及对油气成藏的影响  

Conditions of XJ-A structure of the Paleogene reservoir in the XijiangDepression and their influence on hydrocarbon accumulation

作　　者：冯进 马永坤 贾培蒙 史玉玲 邱欣卫 牛胜利 梁浩然 FENG Jin;MA Yongkun;JIA Peimeng;SHI Yuling;QIU Xinwei;NIU Shengli;LIANG Haoran(CNOOC Deepwater Development Limited,Shenzhen 518054,China;China National Of fshore Oil Corporation Shenzhen Branch,Shenzhen 518054,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]中海石油深海开发有限公司,广东深圳518054 [2]中海石油(中国)有限公司深圳分公司,广东深圳518054 [3]油气藏地质及开发工程全国重点实验室(成都理工大学),成都610059

出　　处：《成都理工大学学报（自然科学版）》2024年第3期392-402,共11页Journal of Chengdu University of Technology: Science & Technology Edition

基　　金：中海石油(中国)集团公司“十四五”重大科技项目(KJGG2022-0403)。

摘　　要：西江凹陷位于珠江口盆地北部珠一坳陷西南部,与紧邻的惠州凹陷相比,其勘探程度相对较低,研究工作较为薄弱。近期的研究揭示,西江凹陷古近系恩平组和文昌组也具有足够的生排烃与勘探开发潜力。为了明确西江凹陷古近系储层条件对油气成藏的影响,本文选择位于西江主洼的XJ-A构造,利用储层物性、沉积相、薄片鉴定及包裹体测试资料等,对研究区的储层宏观条件和微观特征进行了详细的分析。研究结果表明XJ-A构造古近系沉积相以滨浅湖、中深湖和辫状河三角洲相为主,其中恩平组发育了大套以滨浅湖相为主的泥岩,文昌组则以辫状河三角洲相的砂岩为主,形成了“恩平富泥、文昌富砂”的特点;恩平组砂岩多为长石、石英类砂岩,而文昌组以长石类砂岩为主;恩平组砂岩孔隙度集中在5%~15%,而文昌组砂岩分布于10%~15%,它们的渗透率集中分布在(1~10)×10-3μm 2范围内,均属于低/特低孔、低渗储层;储层的成岩作用主要包括压实、自生矿物沉淀、溶蚀、交代和充填作用。结合该地区砂岩储层捕获的包裹体均一温度、有机质镜质体反射率和伊利石/蒙脱石混层中蒙脱石质量分数等,综合判断XJ-A构造的砂岩储层处于中成岩阶段的A 2期。综合分析表明,XJ-A构造古近系发育有良好的储层条件,同时古近系砂体也为油气运移提供了有效的横向运移通道,并且可以与研究区断裂相配合输导油气,为油气在斜坡带圈闭内聚集成藏提供保障。The Xijiang Depression is located in the southwest of the Zhuyi Depression in the north of the Pearl River Mouth Basin.It has been poorly explored in research compared with the adjacent Huizhou Depression.Recent research has revealed that the Enping and Wenchang Formations in the Xijiang Depression from the Paleogene have adequate potential for hydrocarbon generation,expulsion,and exploration and development.To clarify the impact of the conditions of the Paleogene reservoir on oil and gas accumulation in the Xijiang Depression,we considered the XJ-A structure located in the main depression of Xijiang,and used data on the physical properties of the reservoir,sedimentary facies,the identification of thin sections,and inclusion testing to analyze its macroscopic and microscopic characteristics.The results showed that the Paleogene sedimentary facies of the XJ-A structure were dominated by shore shallow-lake,middle deep-lake,and braided river-delta facies.The Enping Formation developed a large volume of mudstone that was dominated by shore shallow-lake facies,while the Wenchang Formation was dominated by sandstone from the braided river-delta facies such that the former was rich in mud while the latter was rich in sand.The sandstone of the Enping Formation primarily consisted of feldspar and quartz sandstone,while the Wenchang Formation mainly featured feldspar sandstone.The porosity of sandstone in the Enping Formation ranged from 5%~15%,that of sandstone in the Wenchang Formation ranged from 10%~15%,and their permeabilities ranged from(1~10)×10-3μm 2.They all belonged to reservoirs with low/ultra-low porosity and low permeability within the squared-meter range.The diagenesis of the reservoir mainly featured compaction,the precipitation of authigenic minerals,dissolution,and replacement and filling.In conjunction with the homogenization temperature of inclusions captured by the sandstone reservoir in this area,the vitrinite reflectance of organic matter,and the percentage content of montmorillonite in the illite/m

关 键 词：砂岩储层 成岩作用 油气成藏 古近系 西江凹陷 

分 类 号：TE121[石油与天然气工程—油气勘探] TE822