缝洞型碳酸盐岩气藏多类型储集层孔隙结构特征及储渗能力——以四川盆地高石梯-磨溪地区灯四段为例

为全面表征缝洞型碳酸盐岩气藏多类型储集层的孔隙结构特征及储渗能力，借助多种测试技术对四川盆地高石梯-磨溪地区灯四段储集层样品进行分析与研究。首先利用铸体薄片和扫描电镜技术定性刻画了储集层的岩性、物性、储集空间和喉道特征，然后根据高压压汞得到的毛管压力曲线对储集层进行分类，最后基于多尺度CT扫描定量表征了3类样品的二维、三维孔隙结构特征。结果表明：研究区储集空间既有受组构控制的粒间溶孔、粒内溶孔和晶间溶孔等，又有不受组构控制的溶洞、溶缝和构造缝；喉道以缩颈、片状和管束状为主；根据毛管压力曲线特征，储集层可划分为缝洞型、孔洞型和孔隙型；缝洞型大孔隙与溶洞发育，分布均匀且连通性好，喉道粗大且数量较多，微裂缝与溶洞串接呈串珠状分布，沟通了孤立的储集空间，具有最好的储渗能力；孔洞型多尺度孔隙与溶洞发育，储集能力强，喉道粗大但数量较少，连通性较差，各储集空间无法有效沟通，渗流能力受限；孔隙型细小孔隙发育且分布不均，大部分区域被岩石骨架占据，喉道数量少且连通性极差，储渗能力弱。

Pore Structure Characteristics and Storage-Seepage Capability of Multi-Type Reservoirs in Fracture-Cavity Carbonate Gas Reservoirs: A Case Study of Deng-4 Member in Gaoshiti-Moxi Area,Sichuan Basin

In order to comprehensively characterize the pore structure and storage-seepage capability of multi-type reservoirs in fracture-cavity carbonate gas reservoirs, a series of test techniques were used to study the samples from the Deng 4 Member in Gaoshiti-Moxi block of Sichuan basin. At first, the lithology, physical property, storage space and throat of the reservoirs were qualitatively described by thin section and scanning electron microscope. Then, the reservoirs were classified according to the capillary pressure curves obtained by high pressure mercury injection. Finally, the two and three dimensional pore structure characteristics of three types of samples were quantitatively determined based on multi-scale CT scans. The study results show that:The storage space is composed of intergranular dissolved pores, intra-granular dissolved pores, inter-crystalline dissolved pores, solution cavities, solution fractures, and structural fractures; the throat type mainly contains necking throat, punctual throat, and control shape throat; the reservoirs can be classified to fracture-cavity type, cavity type, and pore type; in fracture-cavity-type reservoirs, large pores and cavities are developed, uniformly distributed, and connected well,and coarse throats are numerous, micro-fractures and dissolution cavities are beaded in series, which are connected with the isolated storage space and has the best storage and seepage capability; in cavity-type reservoirs multi-scale pores and cavities are developed with strong storage capability, throats are coarse but few and poorly connected with limited seepage capability; in pore-type reservoirs, small pores are developed and unevenly distributed, and most of the spaces are occupied by rock skeleton with few throats and poor connectivity, leading to weak storage-seepage capability.