一种适合于塔河缝洞型油藏的综合流动方程

A Kind of Comprehensive Flow Equation for Fractured-vuggy Reservoir in Tahe Oilfield

缝洞型碳酸盐岩油藏以大型溶洞、溶蚀孔洞及裂缝为主要储集空间,非均质性极强,流体在其间的流动形式以管流、渗流混合流动模式为主。传统的碎屑岩产能方程未考虑地层能量变化对裂缝导流能力的影响,无法有效表征流体在缝洞体中的流动过程。基于对塔河油田采油井液面恢复数据进行规律统计,通过验证复合型油藏压恢试井方程,发现其流动过程仍然符合传统圆形地层平面径向流特征,利用液面变化与油套环空截面建立流量与时间的关系,对压恢试井方程进一步解析,明确得出压差与流量存在指数关系,从而建立缝洞体综合流动方程,补充了缝洞型油藏在油藏产能方程理论方面的的空白。结果表明：在缝洞型油藏中流体流动没有启动压差的概念,同时地层能量的变化对裂缝通道导流能力的影响是巨大的。综合流动方程的建立为缝洞型储层流体流动表征及储量动用提供理论基础,在合理采速指定、选泵选型及裂缝通道改造需求方面提供了参考依据。

The main reservoir space with sever heterogeneity of the fractured-vuggy carbonate reservoir are large caves,solution pore-vugs and fractures,and the fluid in them flows as mixed-pattern giving priority to seepage and pipe.Without taking the influence of formation energy change on fracture conductivity into account,the traditional clastic rock productivity equation cannot effectively characterize the process of fluid flow in the fracture-cave.Based on regularity statistics on data of liquid level recovery of the oil wells in Tahe Oilfield,it found that the flow process still accords with characteristics of traditional plane-radial flow in traditional circular formation after pressure buildup test equation of the composite reservoirs was verified.Relationship be-tween flow rate and time was established according to the liquid level change and tubing-casing annulus section.The pressure buildup test equation was analyzed further and an exponential relationship was found be-tween pressure difference and flow rate.Then comprehensive flow equation for the fractured-vuggy reservoirs was set,which fills the blank in reservoir productivity equation of the fractured-vuggy reservoir on the theory.The results show that there is no concept of start-up pressure difference during the fluid flow in the frac-tured-vuggy reservoir,and the change of the formation energy has a great influence on the conductivity of the fracture channel.This new equation provides a theoretical basis for the characterization of fluid flow and reserves producing in the fractured-vuggy reservoir,and provides important reference for the designation of reasonable production speed,selection of pump or pump types and the transformation of the fracture channels.