摘要
由于CO2气体与常规天然气性质存在较大差异,使得富含CO2的气藏与常规气藏相态特征不同,导致CO2含量影响气藏的开发指标的变化。为此,以校正过相态的计算模型为基础,研究了等温条件下不同CO2含量天然气相态变化特征、不同温度下含CO2天然气相态变化特征及相态变化对开发指标的影响。结果认为:无论是气藏渗流还是井筒流动过程中,富含CO2的火山岩气藏的相态计算都必须考虑偏差因子、黏度和密度随CO2含量的变化;在压力小于30 MPa时,井筒流动要考虑体积系数的变化;气藏的稳产期、稳产期末采出程度和预测期末采出程度随CO2含量的增加不断降低。该研究成果对富含CO2天然气藏的开发具有指导意义。
Phase behaviors of gas reservoirs with a high CO2 content are different from those of conventional gas reservoirs due to a big difference in properties between CO2 and natural gas. As a result, the contents of CO2 will influence the variation of development index of such gas reservoirs. Based on the phase-correction models, a study is conducted on the phase behavior change of natural gas with different CO2 contents at the same temperature, phase behavior change of natural gas containing CO2 at different temperatures,and the impacts of phase behavior change on the development indexes. The following conclusions are obtained. (1) For volcanic gas reservoirs with high CO2 contents, the changes of the deviation factor, viscosity, and density with the CO2 contents must be taken into account in phase calculation no matter it is percolation in the reservoirs or flow in wellbore. (2) When the wellbore flow pressure is below 30 MPa, the change of volume factor should be considered for gas flow in wellbore. (3) The recovery percents of reserves during or by the end of stable production, and even at the end of the prediction period, all decrease progressively along with the increase of CO2 contents. These understandings can guide the development of volcanic gas reservoirs with high CO2 contents.
出处
《天然气工业》
EI
CAS
CSCD
北大核心
2011年第8期69-72,135,共4页
Natural Gas Industry
基金
国家科技重大专项"含CO2天然气藏开发技术"(编号:2008ZX05016-001)
关键词
火山岩气藏
CO2
含量
相态
状态方程
开发指标
影响因素
volcanic gas reservoir, CO2 content, phase, state equation, development index, influential factor
