火山岩储集空间影响因素分析

Analysis of influential factors on volcanic reservoir space

火山岩储集空间按照结构成因分类法分为原生孔隙、次生孔隙和裂缝3大类型,并具有复杂的"孔缝双重结构",火山岩相、喷发模式、裂缝系统、不整合面、成岩作用及其后生环境是影响其成分、结构和构造的5大要素。其中,火山岩相、喷发模式是储集空间形成和发育的基本动力条件,相态和喷发幅度控制孔缝成因结构;裂缝系统、不整合面、成岩作用及其后生环境是储集空间改造和保存的重要地质因素:多期次构造裂缝构成储集空间的主体,火山岩顶部或侧翼距不整合面的距离影响储集空间带的分布,成岩及其后生作用使得原生孔隙被次生充填或加剧溶蚀孔、缝的形成。那些经历过溶蚀作用和水上喷发的正交密集型裂缝系统,将成为最有利的储集空间体。

Volcanic reservoir space can be divided into 3 categories including primary pore, secondary pore and fractures according to configuration and origin, and has complicated 'dual configuration of pore and fractures'. Volcanic facies, patterns of volcanic eruption, network of fractures, unconformity, diagenism and its post diagenetic environment are essential factors affecting the composition, configuration and structure of reservoir space. Among these factors, the first two are basic dynamic conditions for formation and development of the reservoir space, and the configuration and structure of pore-fracture are controlled by facies and eruption scale. The other factors are important for reconstruction and preservation of r.eservoir space. The structural fractures of multiphase had constituted reservoir space. The distance from volcanic top or flank to unconformity had influenced the distribution of reservoir space. Diagenism and post diagenetic effect had resulted in primary pore being charged at later stage, or had boosted the formation of eroded pores and fractures. Those orthogonal dense fracture systems which had experienced denudation and overwater eruption will be the most favorable reservoir spaces.