应用大视域拼接扫描电镜技术定量评价页岩孔隙结构——以川南深层渝西区块龙马溪组储层为例

doi:10.13809/j.cnki.cn32-1825/te.2021.04.013

摘要/Abstract

摘要：

受乐山—龙女寺水下古隆起和多期构造挤压的影响,渝西区块龙马溪组页岩由北往南沉积水体逐渐加深,具有I类储层厚度变化大、孔隙度总体偏低（小于4.5 %）的特征。对优质页岩孔隙结构开展精细研究至关重要。通过一种优化的基于MAPS图像的页岩孔缝特征分析方法,能够在有效识别和统计页岩有机孔缝和无机孔缝的前提下,大幅降低算法的时空复杂度。区内页岩有机孔缝的表征视域边长约300 μm;无机孔缝的表征视域边长在500 μm以上,MAPS图像探测到的区内有机孔缝的直径开度范围多介于0~100 nm,无机缝开度最高可达500 nm以上,有机孔缝密集但体积小,无机孔缝稀疏但体积大。有机孔对页岩储集空间贡献最大,影响也最大;无机孔对储集空间有一定贡献,但影响较小;有机缝对页岩储集空间贡献很小,影响也可忽略;无机缝对页岩储集空间贡献不固定,影响较大。

关键词: 页岩储层, 微观孔隙, 控制作用, 龙马溪组, 川南地区

Abstract:

Influenced by the underwater paleouplift and multi-stage structural extrusion of Leshan-Longnyusi, Yuxi Block gradually deepens from north to south, and has the characteristics of large thickness change of type I reservoir and low porosity（less than 4.5 %）, it is very important to study the pore structure of high quality shale. Traditional shale pore analysis technology has weak identification ability for different types and sizes of micro nano pores. Through an optimized analysis method based on maps image, it can reduce the space-time complexity of the algorithm and improve the applicability on the premise of effectively identifying and statistics the organic and inorganic pore fractures of shale. Characterization of organic pore fractures in Longmaxi formation is about 300 μm, inorganic pore seam with a visual field of view length of 500 μm. The diameter or opening range of organic pore gap detected by maps image is mostly between 0~100 nm. The organic matter content and organic matter porosity are different, and the abundance of organic matter is not the only control factor for the development of organic matter pores.

Key words: shale reservoir, micro-pore type, control function, Longmaxi Formation, South Sichuan area

中图分类号:

TE135

李仲,赵圣贤,冯枭等. 应用大视域拼接扫描电镜技术定量评价页岩孔隙结构——以川南深层渝西区块龙马溪组储层为例[J]. 油气藏评价与开发, 2021, 11(4): 569-576.

Zhong LI,Shengxian ZHAO,Xiao FENG, et al. Application of large field splicing scanning electron microscopy on quantitatively evaluation of shale pore structure: A case study of Longmaxi Formation reservoir in deep western Chongqing Block to southern Sichuan[J]. Petroleum Reservoir Evaluation and Development, 2021, 11(4): 569-576.

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样品号	井号	层位	测试日产量（m³）
BH32-1	H3-2	五峰组	57
BH42-1	H2-1	五峰组	76
BH42-2	H2-1	龙马溪组1小层	138
BH42-4	H2-1	龙马溪组3小层	105
H332-1	H3-2	龙马溪组1小层	110
H332-2	H3-2	龙马溪组4小层	54