塔里木盆地哈拉哈塘地区奥陶系储层古岩溶作用及其与裂缝的关系

塔里木盆地哈拉哈塘地区奥陶系为碳酸盐岩裂缝溶洞型储层，通过野外露头考察、岩心观察、薄片分析、扫描电镜-阴极发光谱分析、扫描电镜-X射线能谱分析等多种分析手段，综合分析了奥陶系储层的古岩溶作用类型及特征。通过野外露头类比，在西克尔露头识别出了粗粒垮塌杂乱角砾岩、细粒搬运杂乱角砾岩、高度扰动地层和未扰动地层等4种古洞穴相；通过岩心观察，在奥陶系不同层位均识别出了与古洞穴相关的杂乱角砾岩。奥陶系储层经历了准同生期岩溶、风化壳岩溶和埋藏岩溶3种不同的岩溶作用，形成的溶孔内部胶结物表现出不同的阴极发光谱特征。储层内部大量发育的裂缝对于埋藏岩溶作用具有重要影响，一方面可沟通缝合线系统，促进岩溶作用；另一方面直接沟通深部热液，导致岩溶作用的发生。

Paleo-karstification of the Ordovician carbonate reservoirs and the relationship with fractures in the Halahatang area of Tarim Basin

The Ordovician reservoirs in the Halahatang area of Tarim Basin are carbonate reservoirs and the storage space is karstic vugs and fractures. Types and characteristics of paleo-karstification in the Ordovician carbonate reservoirs were comprehensively analyzed by outcrop study, core observation, thin section analysis, SEM-CL spectrum and SEM-EDS analysis. Coarse-clast collapsed chaotic breccia facies, fine-clast transported chaotic breccia facies, highly disturbed strata facies and undisturbed strata facies were identified in the Xikeer outcrop by outcrop analog. Chaotic breccia related to paleo-caves was found in different formations of the Ordovician under core observation. The Ordovician reservoir experienced three types of paleo-karstification, including penecontemporaneous karstification, weathering karstification and buried karstification. Different karstic vugs demonstrated different SEM-CL spectrums. Widely developed fractures in the reservoir have a significant influence on burial karstification. On one hand, factures promoted karstification by connecting stylolite networks; on the other hand, fractures induced karstification by carrying deep hydrothermal fluids into the reservoir.