新疆塔河油田下奥陶统碳酸盐岩储层成因类型与评价

The genetic classification and evaluation of the Lower Ordovician carbonate reservoirs in the Tahe Oil Field, Xinjiang

塔河油田油气主要产自下奥陶统碳酸盐岩地层中 ,储渗空间和储层类型研究对油田的勘探开发有重要意义。笔者通过岩芯及铸体薄片的详细观察 ,结合钻井资料和测井曲线 ,对下奥陶统碳酸盐岩的储渗空间特征进行了成因类型划分 ,并在储渗空间发育分布状况、物性和油气测试资料分析的基础上 ,对各成因类型储层的储集性进行了评价。研究表明 ,大型洞穴发育比较普遍 ,相应的洞穴型储层是区内下奥陶统最主要的储层类型 ,是储集性能好、油气高产的首要目标 。

The oil and gas in the Tahe Oil Field, Xinjiang mostly occur in the Lower Ordovician carbonate (reservoirs). The study of the storage spaces and reservoir types is believed to be significant for the exploration and development of the oil field. The present paper deals with the genetic classification of the Lower Ordovician (carbonate) reservoirs in the Tahe Oil Field on the basis of the examination of boreholes, cast thin sections and well logs, and the evaluation of the reservoir quality has been made on the basis of the development of storage spaces, porosity and permeability, and other analytical data of the carbonate reservoirs. The results of research have disclosed that: (1) five types of storage spaces are recognized, i.e. solution pores, solution spaces, caves, weathered fissures and structural fissures; (2) five genetic types consist of shoal grainstone solution pores-type reservoirs, weathered (fissure)-type reservoirs, cavity-type reservoirs, surficial fissure- and pore space (pore)-type reservoirs and structural fissure-type reservoirs, and (3) the cavity-type reservoirs are interpreted as the main target due to their high quality and high production. In addition, the structural fissure-type and weathered (fissure)-type reservoirs have been found to be very significant in the Lower Ordovician carbonate reservoirs in the study area.