滇黔川地区灯影组储层特征及其主控因素

Reservoir characteristics of Dengying Formation in Dian-Qian-Chuan area and their control factors

滇黔川地区灯影组时代老、埋藏深,经多期构造运动改造,成岩演化复杂。为摸清灯影组储层特征及优质储层发育的控制因素,利用宏观露头-岩心及微观薄片、储层物性测试及地球化学资料对储层进行系统分析。综合研究表明:滇黔川地区优质白云岩储层岩石类型主要为藻丘亚相的藻纹层云岩、藻云岩,浅滩亚相的藻砂屑云岩,云坪亚相的粉-中晶白云岩;主要的储集空间为溶蚀孔洞、粒内孔和粒间溶孔、晶间孔和晶间溶孔及微裂缝与溶缝,整体上表现为低孔低渗特征;优质储层受控于沉积相、岩溶作用及构造破裂作用的叠加效应。藻丘、浅滩及云坪亚相的有利岩相为储层发育提供物质基础。岩溶作用是优质储层形成的重要机制,灯二段与灯四段上部受大气淡水与混合水改造形成有效的次生溶蚀孔洞缝,从而改善了储层的储集品质。

The Sinian Dengying Formation in Dian-Qian-Chuan area has old geologic age and great buried depth.It experienced a number of tectonic movements,so its diagenetic evolution process is very complicated,In order to understand the reservoir characteristics of the Dengying Formation and the controlling factors of high-quality reservoir,the petrophysical and geochemical characteristics of the reservoir are analyzed based on the thin slice data and the cathodoluminescence data of the outcrops and cores,and it is shown that;the rock types of high-quality dolomite reservoir in Dian-Qian-Chuan area are mainly algae laminated dolomite,algae dolomite,algae grain dolomite and power-medium size crystal dolomite;the main reservoir space is dissolved pores,intragranular and intergranular dissolved pores,intercrystalline pores and dissolved pores,micro-cracks and dissolved fractures;the overall characteristic of the reservoir is low porosity and low permeability;the high-quality reservoir is controlled by the superposition effect of sedimentary fades,karstification and tectonic fracture.The favorable facies of alga mound,shoals and tidal flat subfacies deposits provide material basis for the development of reservoir;karst process is an important mechanism of high-quality reservoir formation,and in the upper part of the second member and the fourth member of the Dengying Formation,the secondary dissolved pores and fractures were produced because of the effect of atmospheric water and mixed water,which improves the quality of the reservoir.