摘要
中央洼陷带是东海盆地西湖凹陷重要的油气勘探开发区域之一,寻找优质储层发育区、明确优质储层主控因素是油气勘探开发深入的关键。本文综合运用钻井岩心、薄片鉴定、扫描电镜、物性分析等技术方法,结合钻探成果,分析西湖凹陷中央洼陷带花港组储层特征,探讨了优质储层主控因素。认为中央洼陷带花港组发育辫状河—辫状河三角洲—湖泊沉积体系,优质储层主要受沉积微相和有机酸溶蚀双重控制,多期叠置水道储层厚度大、粒度粗、分选好、杂基低,孔候连通性好,物性较好;花港组储层主要岩性为长石岩屑砂岩、岩屑长石砂岩,下伏平湖组煤系烃源岩早期产生的有机酸和晚期生成的CO2顺断层向上运移至花港组砂岩储层中,大量长石和碳酸盐胶结物被溶蚀,形成大量铸模孔和粒间溶蚀,有效改善了砂岩储层的渗流能力。
The central depression is an important oil and gas exploration and development area in the Xihu Sag of the East China Sea Shelf Basin.Identifying high-quality reservoir development areas and identifying the main controlling factors of high-quality reservoirs are key to the further exploration and development of oil and gas.In this study,core,thin section identification,scanning electron microscopy,physical property analysis,and other technical methods were used to analyze the reservoir characteristics of the Huagang Formation in the central sag of the Xihu Depression.Additionally,the main controlling factors of high-quality reservoirs were discussed,and it was considered that the developed braided-river delta-lake sedimentary system is developed in the Huagang Formation in the central depression.High-quality reservoirs were mainly controlled by sedimentary microfacies and organic acid dissolution.The multi-stage superimposed channel reservoir was characterized by large thickness,coarse grain size,good sorting,low impurity base,good connectivity,and good physical properties,and the Huagang Formation reservoir was mainly composed of feldspar lithic sandstone and lithic arkose,which were easily dissolved by organic acids produced in the early stage of coal measure source rocks and CO2.The organic acids and CO2 migrated upward along the fault to the sandstone reservoir of the Huagang Formation.Feldspar and carbonate cements were dissolved and mold pores and intergranular corrosion were formed,which effectively improved the seepage capacity of sandstone reservoirs.
作者
侯凯文
张彦振
HOU Kaiwen;ZHANG Yanzhen(Research Institute of Shanghai Branch of CNOOC Ltd.,Shanghai 200330,China)
出处
《上海国土资源》
2021年第1期13-18,共6页
Shanghai Land & Resources
基金
“十三五”国家科技重大专项“东海深层低渗-致密天然气勘探开发技术”(2016ZX05027001)。
关键词
海洋地质
西湖凹陷
中央洼陷带
花港组
储层特征
主控因素
marine geology
Xihu sag
central depression
Huagang formation
reservoir characteristics
controlling factor
