Oil & Gas Geology ›› 2011, Vol. 32 ›› Issue (5): 787-791.doi: 10.11743/ogg20110518

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A new method of productivity prediction for high CO2-content gas wells

Yan Jin, Liu Chuanxi   

  1. SINOPEC Petroleum Exploration and Production Research Institute,Beijing 100083,China
  • Received:2010-09-25 Revised:2011-09-01 Online:2011-10-28 Published:2011-12-16

Abstract:

Productivity of gas wells in Songnan volcanic gas reservoir is difficult to predict as high CO2 content has great influences on PVT of natural gas,resulting in large difference between the measured and predicted productivity.Based on laboratory experiments,this paper studied the effects of temperature,pressure and CO2 content on PVT of gas with high CO2 content and established the relational expressions of gas viscosity and Z-facto to pressure for gas with different CO2 contents.A new prediction model considering PVT variations of gas with high CO2 content was built based on gas percolation theory.The case study results indicate that the productivity reduces with the CO2 content increasing;the effect of μZ factor changes on productivity prediction should be considered when CO2 content is above 20%;and the impacts of CO2 content on productivity lowers to a level that can be neglect in late production period.The new method is accurate and practical for the high CO2-content gas reservoirs.

Key words: productivity, gas well, CO2 content, natural gas, Songliao Basin

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