Characteristics and pattern construction of bedrock gas reservoir in Dongping area of Qaidam Basin

Through comprehensive analysis of bedrock gas reservoir in Dongping area,such as source-reservoir-caprock assemblage,accumulation model,gas reservoir characteristics and productivity evaluation,it was found the bedrock gas reservoir was close to gas kitchen and the reservoirs were well developed.Besides that,the good communication between the big fracture and the deep Jurassic hydrocarbon source rocks,as well as the hydrocarbon secondary migration,provided a good source-reservoir-caprock assemblage.Controlled by development degree of the structure and fracture,the distribution of gas reservoir was a block bedrock gas reservoir with bottom water.The reservoir was of dual pore space structure(fractures and dissolved pores),and it was affected by fracture distribution,lithology changes and reservoir heterogeneity.Based on seismic and logging fluid identification,the oil-water interface of the bedrock gas reservoir was determined,which provided a basis for reserves calculation and the efficient development of gas field in the next step.