海相油气地质2025，Vol.30Issue(5)：435-446,12.DOI:10.3969/j.issn.1672-9854.2025.05.005
巴西桑托斯盆地下白垩统Barra Velha组微生物碳酸盐岩储层特征及主控因素
Characteristics and main controlling factors of microbial carbonate reservoirs of the Lower Cretaceous Barra Velha Formation in the Santos Basin,Brazil
摘要
Abstract
The microbial carbonates of the Lower Cretaceous Barra Velha Formation in the Santos Basin,Brazil,primarily formed in a high-salinity alkaline depositional environment,and have recently become a hotspot for hydrocarbon exploration and development in deep-water areas.However,research on the characteristics of microbial carbonate reservoirs formed in such unique environment is relatively limited and controlling factors of reservoir formation remains poorly understood.Based on integrated core samples,thin sections,well logs,and petrophysical test data,this study systematically investigates the lithofacies,reservoir space types,and physical properties of microbial carbonates in the basin.It clarifies the diagenetic sequence and pore evolution of the reservoirs and explores the main controlling factors and models for the development of high-quality reservoirs.The research results show that:(1)The main rock types of microbial carbonate reservoirs of the Lower Cretaceous Barra Velha Formation in the Santos Basin include stromatolite,spherulitite,laminite,rudstone,grainstone and breccia.The formation can be divided into two third-order sequences,primarily consisting of four microfacies types:microbial reef,grain shoal,microbial spherulitic shoal,and inter-shoal deposits.(2)The reservoir space is mainly composed of biological framework pore,framework dissolution pore,intergranular pore,intergranular dissolution pore,intragranular dissolution pore,intercrystalline pore,and dissolution fracture.Porosity and permeability generally exhibit a positive correlation,indicating the dominance of pore-type reservoirs.Statistics show that the microbial reef and grain shoal microfacies have better reservoir properties,while the microbial spherulitic shoal and inter-shoal microfacies show relatively poorer reservoir quality.(3)The diagenetic sequence and pore evolution of microbial carbonate reservoirs have been clarified.In the early diagenetic stage,meteoric water dissolution and dolomitization played constructive roles in reservoir evolution.In contrast,mid-to-late hydrothermal activity led to silica filling of reservoir pores particularly in areas adjacent to faults,which not only damaged the reservoir but also increased reservoir heterogeneity.(4)Paleoclimate,paleo-water condition,sequence stratigraphy,and sedimentary microfacies types are the main factors controlling the development and distribution of high-quality microbial carbonate reservoirs.Combined with diagenetic evolution,an evolution model of microbial carbonate reservoirs has been established in this study.关键词
微生物碳酸盐岩/储层特征/成岩作用/储层发育模式/桑托斯盆地/巴西Key words
microbial carbonates/reservoir characteristics/diagenesis/reservoir development model/Santos Basin/Brazil分类
石油、天然气工程引用本文复制引用
朱奕璇,张忠民,胡宗全,鲍志东,张淘..巴西桑托斯盆地下白垩统Barra Velha组微生物碳酸盐岩储层特征及主控因素[J].海相油气地质,2025,30(5):435-446,12.基金项目
本文受中国石油化工股份有限公司科技攻关项目"哈萨克斯坦52区块勘探潜力及目标优选"(编号:P24120)、中国石油化工股份有限公司科技攻关项目"伊拉克美索不达米亚盆地中生界勘探潜力与目标优选"(编号:P25150)联合资助 （编号:P24120）
