变形介质稠油油藏底水突破时间预测方法

目前稠油油藏底水锥进没有考虑介质变形、幂律特征、启动压力梯度等问题,基于稠油油藏的渗流特征及储集层介质的压力敏感性等特点,推导出了考虑多因素影响的稠油油藏底水突破时间预测数学模型。分析了幂律指数、介质变形系数、启动压力梯度及产量对底水突破时间的影响。研究表明：随着启动压力梯度的增加,井底压力降低,底水与井底之间的压力差越大,底水突破时间提前；幂律指数的大小也影响底水的锥进,幂律指数越大,底水突破时间延长；介质变形系数越大,底水突破越早；油井见水时间随着产量的增加而提前。对于介质变形油藏而言,生产井存在最优的生产压差,在实际生产设计中应考虑变形介质的具体特点进行优化设计,尽量延长油井无水采油期。

PREDICTION METHOD FOR BOTTOM WATER BREAKTHROUGH TIME IN HEAVY OIL RESERVOIR WITH DEFORMED MEDIA

The current equation to calculate the bottom water breakthrough time of heavy oil reservoir with edge and bottom water can not consider the impact of deformed medium, power law feature and starting pressure gradient. Based on the pressure sensitive property of deformed medium and the seepage theory of heavy oil reservoirs, the breakthrough time prediction model was derived for the generalized bingham fluid type of heavy oil reservoir with edge and bottom water in deformed medium. The factors including power law index, media deformation factor, starting pressure gradient and production which impact the breakthrough time were analysed. With the increase of starting pressure gradient, the bottom hole pressure is lower. The breakthrough time is earlier when the pressure difference between bottom water and bottom hole is bigger. When the power law index is increasing, the breakthrough time is prolonged. And when the media deformation factor get bigger, the time is shorten. The time comes earlier as well as the production is increasing. There is an optimal pressure draw down for the producers in deformed media, and should be considered in actual production to prolonged water free production period.