带油环凝析气藏地层压力预测方法

Reservoir pressure prediction of gas condensate reservoir with oil rim

关键词:  凝析气藏  地层压力  凝析油  溶解气  岩石流体膨胀

Key words:  gas condensate reservoir  reservoir pressure  condensate oil  dissolved gas  expansion of rock and fluid

摘要:

带油环凝析气藏气顶油环协同开发过程中,地层压力的不断降低导致气顶发生反凝析现象,油环中的溶解气不断逸出,同时还伴随着原生水蒸发、岩石流体膨胀、边底水侵入等变化。综合考虑以上影响因素,在烃类流体物料守恒原理的基础上,建立带油环凝析气藏地层压力预测方法。将该方法应用于某实际带油环凝析气藏中。计算结果表明:该方法得到的地层压力与关井实际测压数据吻合较好,具有一定的可靠性;在衰竭开采方式下,气顶采气速度和油环采油速度的增加都会加速地层压力的下降;在气顶孔隙体积大于油环的孔隙体积条件下,气顶采气速度的增加更容易加快地层压力的下降,从而气顶的采气速度不能太大以免地层能量过早枯竭。

Abstract:

During the concurrent development of condensate gas cap and oil rim, retrograde condensation, escape of dissolved gas, connate water evaporation, expansion of rock and fluid and external water invasion would occur with the decline of reservoir pressure. Taking the above factors into consideration, a reservoir pressure prediction method for gas condensate reservoir with oil rim was proposed based on the material balance principle. The computational method for reservoir pressure was used in an actual gas condensate reservoir with oil rim. The application results show that the reservoir pressure obtained by this method coincides with the actual measurement, which proves the effectiveness of the method. Meantime, the increase of gas recovery rate or oil recovery rate can speed up the decline of reservoir pressure under depletion development. When the pore volume of gas cap is larger than that of oil rim, the increase of gas recovery rate can deplete the reservoir pressure more easily than oil recovery rate, which indicates that gas recovery rate can 't be too large.