Acta Petrolei Sinica ›› 2023, Vol. 44 ›› Issue (10): 1612-1623,1649.DOI: 10.7623/syxb202310003

Previous Articles     Next Articles

Genesis and evolution of Lower Cretaceous silicified carbonate reservoirs in southern Campos Basin

Xiong Lianqiao1, Xie Xiaojun1, Deng Yougen2, Tang Wu1, Zhang Chunyu1, Bai Haiqiang1, Liu Ziyu1, Liao Jihua1   

  1. 1. CNOOC Research Institute Co., Ltd., Beijing 100028, China;
    2. Tuha Downhole Service Company, CNPC Xibu Drilling Engineering Company Limited, Xinjiang Shanshan 838200, China
  • Received:2022-10-20 Revised:2023-05-15 Online:2023-10-25 Published:2023-11-03

坎波斯盆地南部下白垩统硅化碳酸盐岩储层成因及演化

熊连桥1, 谢晓军1, 邓有根2, 唐武1, 张春宇1, 白海强1, 刘子玉1, 廖计华1   

  1. 1. 中海油研究总院有限责任公司 北京 100028;
    2. 中国石油西部钻探工程有限公司吐哈井下作业公司 新疆鄯善 838200
  • 通讯作者: 熊连桥,男,1986年10月生,2018年获中国石油勘探开发研究院博士学位,现为中海油研究总院有限责任公司高级工程师,主要从事沉积与储层地质研究。
  • 作者简介:熊连桥,男,1986年10月生,2018年获中国石油勘探开发研究院博士学位,现为中海油研究总院有限责任公司高级工程师,主要从事沉积与储层地质研究。Email:xionglq2@cnooc.com.cn
  • 基金资助:
    中国海洋石油集团有限公司"十四五"科技重大项目(KJGG2021-0100)资助。

Abstract: It is generally considered that the reservoir properties will be destroied once silicification occurs in carbonate reservoirs, leading to difficulty in the storage of oil and gas. However, some scholars have found that siliceous rocks originated from completely corroded carbonates can also develop dissolved pores, where oil and gas have also been discovered. There still lack systematic studies on the genesis of silica in the Lower Cretaceous lacustrine carbonate rocks of Campos Basin, relationship between silica and reservoir space, and evolution law of the reservoir space. After the silicification of carbonate rocks, it is difficult to grasp the changes in the evolution of reservoir porosity. Based on previous studies and the analyses of microscopic rock characteristics under microscope and geochemical characteristics, the paper investigates the petrologic features, reservoir space types, silica source and storage space evolution law of Lower Cretaceous silicified carbonate reservoirs in Campos Basin. The results suggest that dissolved siliceous rocks can act as reservoirs; silica in carbonates was formed due to metasomatism, and silica-rich hydrothermal fluid flowed into the carbonate formations through major faults, producing a cementation and metasomatism on the carbonate rocks; there were multi-stage hydrothermal fluid activities, including the dissolution of original carbonate rocks, cementation and metasomatism of silica, and dissolution of the siliceous rocks from completely corroded carbonate rocks. In general, the reservoir space evolution of the silicified carbonate rocks can be divided into five stages, including carbonate rocks with high porosity, siliceous carbonate rocks with medium porosity, carbonate siliceous rocks with low porosity, siliceous rocks with medium porosity, and siliceous rocks with high porosity. In addition, fractured-cavity type reservoirs with better physical properties can be found in siliceous rocks distributed along major faults.

Key words: lacustrine carbonate rock, siliceous rock, silicification, reservoir, Lower Cretaceous, Campos Basin

摘要: 通常认为,碳酸盐岩储层中一旦出现硅化现象,储层物性就会遭到破坏,难以存储油气。但有学者发现,由碳酸盐岩完全蚀变而成的硅质岩同样发育溶蚀孔洞,并且有油气发现。坎波斯盆地下白垩统湖相碳酸盐岩中硅质来源、硅质与储集空间的关系及储集空间演化规律等问题尚无系统研究,碳酸盐岩发生硅化后,储层孔隙度如何变化很难回答。基于前人研究成果,结合岩石镜下微观特征、地球化学特征分析,对坎波斯盆地下白垩统硅化碳酸盐岩储集层的岩石学特征、储集空间类型、硅质来源及储集空间演化规律等开展研究,研究结果表明发生溶蚀的硅质岩可以作为储集层。碳酸盐岩中的硅质主要为交代成因,富硅质的热液从基底通过大断裂进入碳酸盐岩地层,对原始碳酸盐岩进行溶蚀,产生硅质胶结、交代作用以及对碳酸盐岩蚀变而来的硅质岩进一步溶蚀;总体上,硅化碳酸盐岩的储集空间演化可划分为①碳酸盐岩高孔阶段、②硅质碳酸盐岩中孔阶段、③碳酸盐质硅质岩低孔阶段、④硅质岩中孔阶段、⑤硅质岩高孔阶段5个阶段;热液活动存在多期性,在沿大断裂分布的硅质岩中可以找到物性较好的裂缝-孔洞型储集层。

关键词: 湖相碳酸盐岩, 硅质岩, 硅化作用, 储层, 下白垩统, 坎波斯盆地

CLC Number: