Controlling effects of the Ordovician carbonate pore structure on hydrocarbon reservoirs in the Tarim Basin, China

作     者：Wu Guanghui Yang Haijun Li Haowu Sun Lixia 

作者机构：School of Marine Sciences Sun Yat-sen University PetroChina Research Institute of Petroleum Exploration and Development PetroChina Tarim Oilfield Company 

出 版 物：《Petroleum Science》 (石油科学（英文版）)

年 卷 期：2013年第10卷第3期

页      面：282-291页

核心收录：

学科分类：081803[工学-地质工程] 08[工学] 0818[工学-地质资源与地质工程] 

基　　金：supported by the National Basic Research Program of China (973 Program Grant No.2011CB201106) 

主　　题：Carbonate throat radius critical hydrocarbon column unconventional reservoir mechanism 

摘      要：The Ordovician carbonate reservoirs in the Tarim Basin with secondary dissolution pores and vugs have complicated pore structures. The weathering crust reservoirs mainly consist of large cavities or vugs connected by fractures, but most of the reef-shoal reservoirs have complex and small throats among matrix pores. The pore structure can be divided into four types： big pore and big throat, big pore but small throat, small pore and small throat, and fracture type. Most of the average throat radius falls between 0.03 and 0.07μm, close to that of unconventional reservoirs except in local areas with developed fractures. Fluid driving force analysis shows that the differentiation of fluid is mainly controlled by the throat radius in two kinds of mechanism separated by the critical throat radius about 0.1 μm. There is obvious fluid differentiation and oil/gas/water contact in fracture-cavity reservoirs with big throats. However, most of reservoirs under the critical throat radius have high capillary pressure, which resulted in incomplete differentiation of gas/oil/water, and complicated fluid distribution and fluid properties in the unconventional reservoirs.