磨溪气田嘉二段鲕粒灰岩储层特征及成因机制

OOLITIC LIMESTONE RESERVOIR CHARACTERISTICS AND ITS GENETIC MECHANISM OF JIA2 MEMBER IN MOXI GAS FIELD

储层特征定量描述及其成因机制分析是储层分布预测、勘探目标选择和开发方案设计的前提和基础。以川中磨溪气田嘉二2A层非层状碳酸盐岩鲕粒灰岩储层为例,从储层的沉积岩石学特征着手,定量分析了储集空间类型、微观孔喉结构、物性分布及孔渗关系等储层的基本特征,分析了嘉二2A层鲕粒滩储层的成因机制,建立了其滩体迁移模式。结果表明,该套储层的形成和分布受区内微地貌的次一级分异和海侵-海退旋回的共同控制,在局部微地貌高地,海退持续时间长,沉积物充分暴露,大气淡水对储层的淋溶改造进行得较为彻底,储层厚度较大,质量较好。

Quantitative description of reservoir characteristics and its genetic mechanism analysis are prerequisite and foundation of reservoir distribution prediction,exploitation target selection and exploitation plan design.Starting from sedimentary lithology characteristics of the reservoir,the authors quantitatively analyze its basic properties including reservoir pore space type,microcosmic pore throat structure,physical property distribution and poroperm relation by taking non-layered carbonate oolitic limestone reservoir of Jia22 A Bed,Moxi Gas Field in Middle Sichuan as an example.The genetic mechanism of oolitic bank reservoir is also studied,and its beach body migration model is established.The study indicates that the formation and distribution of the reservoir is under the associated control of the secondary differentiation of microtopography and transgression-regression cycle in the area.On local microtopography altitude,regression lasted for a long period,sediments were completely exposed,and eluviation of atmosphere freshwater on reservoir was therefore thoroughly conducted,leading to a comparatively thicker reservoir with better quality.