巴西桑托斯盆地下白垩统Barra Velha组微生物碳酸盐岩主要形成于高盐碱沉积环境，是近年深水领域油气勘探开发的热点。然而对于这种特殊环境及成因形成的微生物碳酸盐岩储层特征及其发育主控因素的研究相对薄弱。通过岩心、薄片、测井和物性测试等资料，系统研究了盆地微生物碳酸盐岩的岩相、储集空间类型和物性，明确了储层成岩序列以及孔隙演化特征，并探讨优质储层发育的主控因素与模式。研究表明：①桑托斯盆地下白垩统Barra Velha组微生物碳酸盐岩储层主要岩石类型包括叠层石灰岩、球粒微生物岩、层纹岩、砂屑灰岩、砾屑灰岩和角砾灰岩。纵向上可划分为2个三级层序，主要发育微生物礁、颗粒滩、微生物球粒滩、滩间等4种沉积微相。②储集空间主要为生物格架孔及生物格架溶孔、粒间孔及粒间溶孔、粒内溶孔、晶间孔以及溶蚀缝，孔隙度和渗透率整体呈正相关关系，以孔隙型储层为主。微生物礁和颗粒滩沉积微相的储层物性较好，微生物球粒滩和滩间沉积微相的储层物性相对较差。③明确了微生物碳酸盐岩储层成岩序列及孔隙演化。早成岩阶段，大气水溶蚀、白云石化对储层演化起到建设性作用；中—晚期热液作用下，断裂附近储层孔隙被硅质充填，对储层起到破坏性作用的同时也增加了储层的非均质性。④古气候、古水介质、层序及沉积微相类型是控制微生物碳酸盐岩优质储层发育和分布的主要因素；结合成岩演化，建立了微生物碳酸盐岩储层发育模式。

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.