鄂尔多斯盆地清涧地区上古生界致密砂岩孔喉结构对天然气渗流能力的影响OA

In view of the large number of low-production wells and the widespread occurrence of water production in the Qingjian area,constant-rate mercury injection and gas-water relative permeability experiments were carried out to investigate the petrophysical properties and pore characteristics of tight sandstone gas reservoirs in the He 8 and Shan 2 members in the study area.The study clarified the controlling effects of key parameters,including pore size,distribution,throat morphology,and connectivity,on natural gas flow capacity.The results show that the reservoirs in the study area are characterized overall by low porosity and low permeability.Among them,samples from the Shan 23 Submember with permeability greater than 1.00 mD occur at a higher frequency than those from the He 8 Member,and their rock type,interstitial materials and pore-throat structure are all superior to those of the He 8 Member.The study confirms that porosity is the decisive factor governing hydrocarbon enrichment,whereas the structural matching between pores and throats directly determines reservoir flow capacity.At the same time,reservoir tightness is posi-tively correlated with bound water saturation,which directly weakens natural gas flow capacity.This study provides an important technical basis for the evaluation and development of regional tight sandstone gas reservoirs.