四川盆地西南部雷口坡组储层特征及控制因素

四川盆地西南部中三叠统雷口坡组气藏主要的储层类型为碳酸盐颗粒滩储层。其主要发育两种储渗形式：砂屑云岩储层以残余粒间孔和粒间溶孔为储集空间，喉道以缩颈喉道和管束状喉道为主，孔喉配置关系较好，储层多表现为中孔中渗的特征；鲕粒灰岩储层和残余生屑云岩储层以粒内溶孔、铸模孔和生物体腔孔为储集空间，喉道欠发育，储层多表现为中孔、渗透率偏低的特征。进一步对储层的控制因素分析表明，颗粒滩为储层提供了早期的物质来源；单滩体的厚薄控制着储层的储渗形式；原生粒间孔的保存和同生期大气淡水淋溶作用分别是形成这两种储渗形式的颗粒滩储层的关键。

Characteristics and Dominating Factors of Reservoirs in Leikoupo Formation,Southwest Sichuan Basin

On the basis of comprehensive analysis of drilling, logging and core data, it is considered that carbonate reservoir of grain shoal is an important reservoir type in Leikoupo Formation, Middle Triassic, southwest Sichuan Basin. The reservoir types of two different patterns of porosity and permeability have been mainly developed:(1) Dolarenite reservoirs are dominated by residual intergranular pores and intergranular dissolved pores in the reservoir space, and are possessed of well developed throats with neck down and shaped tube, and are characterized by the good reservoir capability with medium porosity and permeability;(2) Oolitic limestone and residual bioclastic dolomite reservoirs are dominated by isolated intragranular dissolved, moldic and organisms pores in the reservoir space, and are possessed of less developed throats which mainly are miniature in the dimension, and manifest as medium porosity and low permeability. Analysis to the controlling factors of these reservoirs suggests as follows: (1)Grain shoals lay the foundation to the reservoir; (2)Reservoir pattern is controlled by the thickness of a single shoal; (3)The preservation of primary intergranular pores is the key to dolarenite reservoirs, while syndiagenetic meteoric leaching is crucial to reservoirs of oolitic limestones and residual bioclastic dolomites.