Volcanic gas reservoirs are hard to tap due to their complex geology. CNPC has marshaled resources from multiple disciplines in relevant studies and developed nine fully-copyrighted, breakthrough technologies on the exploration and development of deep volcanic gas reservoirs:

• Lithology and lithofacies identification of volcanic reservoirs;
  
  
• Identification and prediction of effective reservoirs and fractures in volcanic gas reservoirs;
  
  
• Evaluation of storage-seepage characteristics in volcanic reservoirs;
  
  
• Evaluation of gas reserves and productivity of volcanic gas reservoirs;
  
  
• Productivity appraisal of volcanic gas reservoirs;
  
  
• Optimization of well location and well pattern for volcanic gas reservoirs;
  
  
• Numerical simulation in double-porosity media for fractured volcanic gas reservoirs;
  
  
• Matching technologies for speeding up penetration rate in volcanic rocks and protecting reservoirs in Xushen gas field;
  
  
• Optimization of staged fracturing of horizontal wells in volcanic reservoirs.

These innovative technologies provide strong support for the identification and efficient tapping of proven reserves in deep, complex, lithostratigraphic gas reservoirs, and offer important guarantees in the development of volcanic gas reservoirs.

The new technologies have been successfully applied and delivered notable achievements in developing volcanic gas reservoirs in the Songliao Basin and the Northern Xinjiang region. More than 2 billion cubic meters of natural gas can be produced annually from Xushen gas field in Daqing, Changling-1 gas field in Jilin, and Kelameili gas field in Xinjiang.