Study on Integration Construction Technology of Natural Gas Gravity Drive to EOR and Oil Reservoir Underground Gas Storage

Abstract

AbstractCompared with other countries, the construction of UGS in China started late. Even more, construction experiences lacks. China has a single type of UGS, mainly gas reservoir, which further limits the scale development of UGS construction. How to break through the limits of conventional UGS types and expand the construction of oil-reservoir UGS is one of the urgent problems to solve during China’s rapid development of UGS construction. This paper depicts the laboratory and simulation results of the new model of cooperative development of natural gas flooding to EOR and construction of reservoir-type UGS. The core of this technology lies in the reasonable conversion timing among the oil displacement phase, the coordination phase and the gas storage phase, as well as the upper and lower pressure limits during the production of different phases. In recent years, the field tests of natural gas EOR and UGS has been committed to exploring together in China, which has created a new field of UGS construction. At present, 400 mcm of natural gas have been stored at the top of the reservoirs, which have some capacity of peak shaving and strategic supply guarantee. The program prediction shows that the oil recovery will increase by more than 25% by natural gas injection at the top of the reservoir, which is double the recovery degree of water flooding, and the peak annual oil production is more than 1 million tons. By comparing with gas reservoir, salt hole and water reservoir type UGS, the advantages and disadvantages of UGS-EOR cooperative construction are analyzed in detail from four aspects: period of building, profit model, operation mode and risk assessment. Combined with the field practice, the prospect of the technology is prospected. This paper has a good guiding significance for improving the oil recovery and peak shaving capacity of gas storage.KeywordsNatural gas gravity driveIntegration ConstructionEnhance Oil Recovery (EOR)Underground Gas Storage (UGS)Quality improvement and efficiency improvement