东北石油大学学报2025，Vol.49Issue(2)：1-18,18.DOI:10.3969/j.issn.2095-4107.2025.02.001
致密砂岩气藏孔喉结构和渗流特征差异及其对水锁的影响
Differences in pore-throat structure and seepage characteristics of tight sandstone gas reservoirs and their effects on water-blocking:a case study of Shanxi,Taiyuan and Shihezi Formations in Shenmu Gas Field,Ordos Basin
摘要
Abstract
The main tight sandstone reservoirs in the Shenmu Gas Field,located in the Eastern Ordos Basin,exhibit differences in pore-throat structure and permeability.Closed-coring tests confirm the presence of water-blocking damage,and the decrease in gas relative permeability affects the productivity performance of individual wells.Based on methods such as thin slice observation,SEM observation,high-pressure mercury injection,nuclear magnetic resonance(NMR),and gas-water phase permeability experiments,this study analyzes the impact of differences in pore-throat structures and flow characteris-tics on water-blocking damage,as well as the controlling factors involved.The results show that the pore-throat size in the Taiyuan Formations of the Shenmu Gas Field is relatively large and homogene-ous,which contributes to its higher permeability.In contrast,the pore-throat structures of the Shanxi Formation and the He 8 Member are similar,with the Shanxi Formation having smaller pore-throat si-zes,better connectivity,and higher homogeneity,resulting in slightly higher permeability.The Taiyuan Formation contains the highest amount of movable fluids,followed by the Shanxi Formation,with the He 8 Member having the least movable porosity.The distribution of bound water saturation follows a similar trend.The He 8 Member has the highest average water saturation,the most severe water-blocking damage,and the lowest relative permeability.The Shanxi Formation exhibits slightly better common seepage capacity than the Taiyuan Formation,but it is more affected by bound water,resulting in a lower volume of movable gas.The quality of pore-throat structures determines the storage of movable fluids and governs the relative permeability of gas and water phases.High-quality pore-throat conditions facilitate the presence of more movable fluids,enhance fluid flow,and result in rela-tively lower water-blocking damage.The difference in seepage capacity controlled by capillary pressure in pore-throat structures is the primary factor governing water-blocking damage.Production pressure difference and the reservoir formation process also have a certain impact on water-blocking.During the development stage,balancing capillary pressure and controlling the decline in gas relative permeability are key strategies to mitigate water-blocking damage.These findings provide a basis for evaluating the seepage characteristics of tight sandstone gas reservoirs and optimizing production enhancement strate-gies.关键词
鄂尔多斯盆地/神木气田/山西组/太原组/石盒子组/致密砂岩气藏/孔喉结构/气—水相相对渗流/水锁伤害Key words
Ordos Basin/Shenmu Gas Field/Shanxi Formation/Taiyuan Formation/Shihezi Forma-tion/tight sandstone gas reservoir/pore-throat structure/gas-water relative permeability/water-bloc-king damage分类
石油、天然气工程引用本文复制引用
强小龙,文开丰,王德龙,范海润,贾连超,杨国平,杜静,沈欣岚,姚合法..致密砂岩气藏孔喉结构和渗流特征差异及其对水锁的影响[J].东北石油大学学报,2025,49(2):1-18,18.基金项目
国家科技重大专项(2016ZX05050-006) （2016ZX05050-006）
国家自然科学基金项目(41802140) （41802140）
陕西省自然科学研究基础计划项目(2019JQ-257) （2019JQ-257）
