不共面裂缝气藏水平井产能预测模型

考虑到实际压裂水平井得到的裂缝左右两翼并不完全在同一个平面上,为使产能方程预测结果能更切合实际的产量,重点研究气藏压裂水平井裂缝左右两翼与水平井筒形成不同夹角时的产能方程。根据点源累加求和的思想将裂缝的左右翼分成n等份,求出地层中任意点的压降模型,进而推导出裂缝左右两翼与水平井筒成不同夹角时的产能方程,并利用该产能方程分析了左右两翼形成的不同角度组合对产能的影响。结果表明:裂缝与水平井筒所形成的夹角越小,其压裂增产效果越差;当裂缝左右两翼都垂直或接近于垂直于水平井筒时,其压裂增产效果最好。因此,建议在气藏水平井压裂过程中,应在工艺许可范围内尽量压出与水平井筒垂直的裂缝。 

Productivity Prediction Model of Horizontal Gas Wells with Noncoplanar Fractures

Because two wings of a fracture in a fractured horizontal well are not certainly in a line,it’s necessary to calculate the production from a fractured horizontal well that fractures in the two wings has varied orientation with the borehole in order to make the prediction more practical.Based on a point source summation,two wings of fractures were divided into n parts then pressure drop model of every point in the formation were built and finally the deliverability equation of a fractured horizontal well was deduced.By analyzing the effects of different angles between the wings and the wellbore,it turned out that the smaller the angles between the fractures and the wellbore,the worse the stimulation results;when the fractures are vertical to the horizontal wellbore,the stimulation effect is optimal.So if possible,fractures perpendicular to horizontal wellbore are preferred.