摘要
针对低渗气藏经压裂后形成水平裂缝,基于稳定流理论,利用等值渗流阻力法,推导建立了气井压裂后产生水平裂缝条件下,综合考虑启动压力梯度、滑脱效应、应力敏感共同影响下低渗气藏有限导流水平裂缝井产能预测模型,通过实例分析其产能特征。研究结果表明:启动压力梯度和应力敏感使气井产能下降,且启动压力梯度和应力敏感系数越大,气井产能下降幅度越大,而滑脱效应使气井产能增大,且滑脱因子越大,气井产能增加幅度越大;在一定的裂缝导流能力下,水平裂缝的长度对气井压裂后产能影响呈上升趋势,而在一定水平裂缝的长度下,裂缝导流能力中存在一个最佳值,且增加水平裂缝的长度比增加裂缝导流能力更易实现;在高流压阶段,启动压力梯度对气井产能影响显著;而在低流压阶段,应力敏感效应对气井产能影响更大。
In view of the low permeability gas reservoir after fracturing developing horizontal fracture,based on the steady seepage theory,using the equivalent flowing resistance method,with the influence of the start-up pressure gradient,slippage effect and stress sensitivity in the low-permeability oil reservoirs taken into account,a prediction model for fracturing stimulation recovery was established for the horizontal fracture wells,and the productivity characteristic was discussed by analyzing and calculating examples.The result shows that the gas well productivity decline is caused by start-up pressure gradient and stress sensitivity,and along with start-up pressure gradient and deformation coefficient of permeability enlargement,the gas well production continues to decline.While the slippage effect leads to increasing in gas well production,and along with slippage factor enlargement,the gas well production continues to increases.Under a fracture diversion capacity,productivity increases with the increasing of the horizontal fracture length.Under a certain crack length,there is an optimum fracture diversion capacity,and increasing the crack length is more important than increasing the fracture diversion capacity,and also easy to realize.While in the low flowing pressure stage,the stress pollution caused by stress-sensitivity is more serious,the influence of the productivity for gas well is more.
出处
《新疆石油天然气》
CAS
2013年第2期47-50,3+2,共4页
Xinjiang Oil & Gas
基金
西南石油大学研究生创新基金项目"非线性渗流下低渗气藏产能特征研究"(编号:GIFSS0701)
关键词
低渗气藏
水平裂缝
启动压力梯度
滑脱效应
应力敏感
产能特征
low permeable gas reservoir
horizontal fracture
start-up pressure gradient
slippage effect
stress sensitivity
productivity characteristic
