Reservoir Evaluation and Development ›› 2018, Vol. 8 ›› Issue (5): 56-59.

• Petroleum Engineering • Previous Articles     Next Articles

Feasibility analysis about taking CO2 as cushion gas for gas storage rebuilt upon depleted gas reservoirs

Hu Shuyong1,Hu Xinrui1,Li Yongkai2,Ma Junxiu3   

  1. 1. State Key Laboratory of Oil & Gas Reservoir Geology Exploitation Engineering, Southwest Petroleum University, Chengdu, Sichuan 610500, China;
    2. CCDC Sulige Project Management Department, Ordos, Inner Mongolia 017000, China
    3. Engineering technology research institude, Xinjiang Oilfield Company,PetroChina, Karamay, Xinjiang 834000, China
  • Received:2017-08-10 Online:2018-10-26 Published:2018-12-05


The underground gas storage is one of the major storage and peak-shaving means in the world. It needs the cushion gas to keep the reservoir pressure, prevent the water intrusion and ensure the stability of the gas storage. The cushion gas volume generally accounts for 30 % to 70 % of the total volume of the gas storage. If we just took the natural gas as the cushion gas, a considerable amount of natural gas would not be mined when the storage was abandoned, and a large amount of natural gas would be wasted. The study of thermodynamic properties and the mixed experiments of CO2 and natural gas show that taking CO2 as the cushion gas for gas storage rebuilt upon the depleted gas reservoirs is feasible, because CO2 is in the critical state under the operating pressure and temperature. Its physical properties of “high density” and “high viscosity” make itself separate from the natural gas, rather than mix.

Key words: depleted gas reservoirs, underground natural gas storage, cushion gas, feasibility analysis

CLC Number: 

  • TE822