川东北宣汉-达县地区长兴组-飞仙关组礁滩储层特征及其控制因素

川东北宣汉-达县地区是我国重要的气藏发育区块。为了深入探索储层特征、物性与岩石类型，成岩作用的相关性，运用薄片鉴定、扫描电镜等技术手段，结合物性测试数据，测井资料和压汞数据，对储层的岩石类型，孔隙类型，孔隙结构、物性特征以及储层展布进行分析。研究表明，川东北宣汉-达县地区优质储层为生物礁白云岩及鲕粒白云岩，经历过重结晶及多期溶蚀，粒间溶孔最为发育。长兴组储层孔隙度平均值为5．4％。渗透率平均值为93．41×10^-3μm^2；飞仙关组储层平均孔隙度为8％，平均渗透率为132，76×10^-3μm^2，孔喉结构良好。沉积相控制储层的岩石类型和展布，成岩作用尤其是溶蚀作用控制着储层的物性，而构造作用对储层的形成则有双重影响。

Characteristics and controlling factors of the reef shoal reservoirs from the Changxing Formation-Feixianguan Formation in the Xuanhan-Daxian zone, northeastern Sichuan

The Xuanhan-Daxian zone in northeastern Sichuan is believed to be an important locality for the development of gas pools in China. The present paper deals, in detail, with the rock type, porosity type, porosity structure, physical property and distribution of the reef shoal reservoirs in terms of physical data, well logs and pressure-injection data with the aid of thin section examination and SEM techniques. The high-quality reservoirs in the study area consist of biohermal dolostone and oolitic dolostone characterized by the enrichment of intergranular solution openings due to recrystallizarion and polystage dissolution. The average porosity equals to 5.4% and average permeability equals to 93.41 ×10^-3μm^2 for the Changxing Formation reservoirs, while the average porosity equals to 8% and average permeability equals to 132.76 ×10^-3μm^2 for the Feixianguan Formation reservoirs. Sedimentary facies tends to control rock types and distribution, whereas diagenesis especially the dissolution tends to control the physical properties of the reservoirs. The fissures caused by structural processes may have dual impacts on the carbonate reservoirs.