Title

Shale reservoir characteristics and their influencing factors in the Lucaogou Formation,southeastern margin of the Junggar Basin,China

单位

1.国土资源部矿山地质环境重庆南桐野外基地,重庆401120;2.国土资源部页岩气资源勘查重点实验室,重庆401120;3.重庆地质矿产研究院,重庆401120;4.中国地质调查局成都地质调查中心,四川成都610081

Organization

1.Chongqing Nantong Field Base,Mine Geological Environment of Ministry of Land and Resources,Chongqing 401120,China;2.Key Laboratory of Shale Gas Exploration,Ministry of Land and Resources,Chongqing 401120,China;3.Chongqing Institute of Geology and Mineral Resources,Chongqing 401120,China;4.Chengdu Institute of Geology and Mineral Resources,China Geological Survey,Chengdu 610081,China

摘要

通过野外地质调查、剖面实测、页岩气调查井(ZY3井)资料采集和样品测试,分析了芦草沟组沉积相、岩相特征,从矿物组成、孔渗特征和岩石力学参数等角度研究了芦草沟组页岩储层特征及主要储集空间类型,并探讨了其影响因素。结果显示:芦草沟组页岩储层整体呈特低孔(平均值0.98%)、特低渗(平均值0.04mD,1mD≈0.987×10-3μm2)的特征;微观孔隙以连通性、吸附性较差的微米级基质粒间孔为主,主要储集空间类型为裂缝和微裂缝,气体多以游离态赋存;页岩样品的柏松比(平均值0.22)与杨氏弹性模量(平均值1.34×104MPa)交会图以及高脆性矿物含量(平均值66.98％)均指示其具有良好的可压裂性和天然裂缝发育条件。认为芦草沟组页岩储层发育主要受沉积环境、矿物组成和成岩作用影响。

Abstract

In order to analyze the characteristics of the lithofacies and sedimentary facies of the Lucaogou Formation,we investigated a number of samples collected from the well drilling ZY3 and from the outcrop in the field.Furthermore,we analyzed the mineral composition,porosimetry and permeability,microstructure of pores and fractures,and mechanical parameters of the rock,and we discussed the factors influencing them.The shale reservoir in the Lucaogou Formation exhibits ultra-low porosity (0.98% in average) and permeability (004mD in average).The microporosity is mostly constituted by matrix intergranular pores at μm scale,which confer poor connectivity and adsorption capacity.The main types of reservoir spaces are the cracks and microcracks,where the shale gas can be reserved in dissociated state.The cross-plot of the Poissons ratio (0.22 in average) and Youngs modulus (1.34 × 104MPa in average),as well as the content of brittle minerals (66.98% in average),suggest that the shale reservoir in the Lucaogou Formation has a high degree of brittleness and offers favorable conditions for natural fracture development.The development of the shale reservoir in the Lucaogou Formation is mainly influenced by the sedimentary environment,mineral composition,and diagenesis.

关键词：

准噶尔盆地; 芦草沟组; 页岩; 储层特征; 沉积相;孔渗特征; 矿物组成; 岩石力学参数;

Keywords:

Junggar Basin;; Lucaogou formation;; shale;; reservoir characteristics;; sedimentary facies;; poroperm characteristics;; mineral composition;; rock mechanics parameter;

基金项目

新疆维吾尔自治区地勘基金项目“新疆准噶尔盆地南缘重点远景区页岩气调查评价”(N13-4-XJ02)资助。

DOI

10.3969/j.issn.1000-1441.2020.04.009

准噶尔盆地东南缘芦草沟组页岩储层特征及其影响因素