非达西渗流边水气藏水平井见水时间预测

对边水气藏水平井的见水时间进行合理预测，有利于气藏的合理开发和更好地进行气藏评估。在目前的预测模型中，一般都假设地层中气体渗流为达西流动，但对于高产水平井，地层中流体渗流的非达西效应对见水时间的影响不可忽略。为研究更加符合实际生产情况的边水气藏水平井见水时间，在多孔介质流体质点渗流规律研究的基础上，采用椭球型水平井渗流模型，综合考虑了高产水平井气体渗流非达西流动效应、水平井距初始气水界面距离、水平段长度和气井产量等因素对见水时间的影响，推导出了具有近似直线供给边界的边水气藏见水时间的预测公式。对某一具体水平井见水时间进行了实例计算，并分析了相关影响因素。由计算结果可知，边水突破时间随着水平段长度的增加而变长；见水时间随着气井产量的增大而减小，且减小的速度逐渐变快；与未考虑气体非达西效应的气井见水时间预测公式相比，本文公式计算精度更高，更符合实际生产情况。该研究成果对科学、高效地开发边水气藏具有指导作用。

Prediction of water breakthrough time for horizontal well in non-Darcy flow edge water gas reservoirs

Reasonable prediction of water breakthrough time of horizontal wells in edge water gas reservoirs is beneficial to rational development of gas reservoirs and evaluation of gas reservoirs. In current prediction models, gas seepage in formation is generally assumed to be Darcy flow,but for high-yield horizontal wells,the non-Darcy effect of fluid seepage in formation on water breakthrough time cannot be ignored. In order to study water breakthrough time more coincident with actual production,based on particle seepage law of porous media fluid,an ellipsoidal horizontal well seepage model was adopted to comprehensively consider the effects of non-Darcy flow effect of gas seepage in high-yield horizontal wells,the distance between horizontal well and initial gas-water interface,the length of horizontal section and the production of gas wells on water breakthrough time,and a formula for predicting water breakthrough time of edge water gas reservoirs with approximate linear supply boundary was derived. The water breakthrough time of a specific horizontal well was calculated,and the related influencing factors were analyzed. The results show that the breakthrough time of edge water increases with the increase of the length of horizontal section;the breakthrough time decreases with the increase of gas well production,and the speed of reduction increases gradually. Compared with the prediction formula of water breakthrough time of gas wells without considering non-Darcy effect,the calculation accuracy of this formula is higher and more coincident with actual production. The research results have a guiding role in the scientific and efficient development of edge water gas reservoirs.