摘要
低渗气藏在我国天然气勘探开发中占有较大的比重。由于低渗气藏具有低渗、低孔的特点,使得这类气藏难以直接获得商业开发,必须通过储层压裂改造才能经济有效开发。大量实验研究表明,在低渗气藏生产中存在着启动压力梯度、滑脱效应、应力敏感和高速非达西流,目前关于低渗压裂气井的产能研究中,大多只考虑了单一因素的影响,综合考虑多种因素的研究相对较少。根据气井压裂后流体渗流规律的变化,利用气藏渗流理论,建立了综合考虑启动压力梯度、滑脱效应、应力敏感和高速非达西流的压裂气井稳态产能计算方法,应用新产能计算方法对某低渗气藏进行了实例分析,证明了新方法的可靠性。研究结果表明:启动压力梯度和应力敏感会使气井的产能越低,应力敏感的影响更大;在低压阶段,滑脱效应会使得气井产能有小幅度增加;对低渗致密气藏,要注意控制生产压差,保持适度稳产。
The low permeability gas reservoirs account for large proportion in gas reservoir exploration and development of China.The low permeability gas reservoir has the characteristics of low permeability and low porosity,which makes it difficult to obtain commercial development directly.So it is necessary to improve the development by fracturing.A large number of experimental studies have testified the existence of threshold pressure gradient,slippage effect,stress sensitivity and high velocity non Darcy flow.At present,most of the productivity researches of low permeability fractured gas wells are mainly based on a single factor,and the study of multiple factors is relatively small.According to the changes of fluid seepage law of gas wells after fracturing,using the fluid mechanics theory of gas reservoirs,a new steady-state productivity calculation method of fractured gas well has been established,which considers threshold pressure gradient,slippage effect,stress sensitivity and high velocity non Darcy flow.An example of a low permeability gas reservoir is analyzed by using the new method and the new method is proved to be reliable.The results show that the threshold pressure gradient and stress sensitivity will reduce the gas well productivity,the stress sensitivity is greater;the slippage effect will reduce productivity slightly in the low pressure stage;we should pay attention to control the production pressure difference to maintain a moderate stable production in the low permeability gas reservoir development.
出处
《天然气地球科学》
EI
CAS
CSCD
北大核心
2018年第1期151-157,共7页
Natural Gas Geoscience
基金
中国石油科技创新基金项目(编号:2015D-5006-0207)资助
关键词
低渗气藏
压裂气井
启动压力梯度
滑脱效应
应力敏感
高速非达西流
产能
Low permeability gas reservoir
Fractured gas wells
Threshold pressure gradient
Slippageeffect
Stress sensitivity
High velocity non Darcy flow
Productivity
