层内非均质储层内部窜流规律实验研究——以大庆喇嘛甸油田为例

Experimental study of internal channeling law of intra-layer heterogeneous reservoir:A case study of Lamadian Oilfield in Daqing

大庆喇嘛甸油田厚油层以多段多韵律为主要特征,深入认识窜流规律对于进一步挖潜剩余油至关重要。为此,采用层内非均质岩心,对层内非均质储层内部窜流规律实验展开研究。结果表明,在注入量为0~0.4 PV水驱阶段,高渗透层注入端分流率略低于采出端,中、低渗透层则相反;在注入量为0.4 PV至水驱结束阶段,高渗透层采出端分流率大幅度增加,中渗透层分流率大幅度降低,低渗透层分流率小幅度减小。随岩心渗透率级差增大,采出端与注入端各小层窜流程度减小,层间干扰作用减小。随水驱开发的不断进行,层间窜流程度先减小后增大。随注入速度增加,高渗透层采出端与注入端分流率差值增加,窜流程度增强。采取提高水井注入速度的方式可以达到增大注入压力的目的,但由于高渗透层吸液量增幅远大于中、低渗透层,加之储层内部窜流作用的影响,扩大波及体积效果并不十分明显,同时提高水井注入速度还对注入端、采出端和地面设备能力提出更高的要求,因此采取增加高渗透层渗流阻力措施才是提高注入压力的有效技术途径。

The thick oil layers of Lamadian Oilfield in Daqing are mainly characterized by multiple intervals and multiple rhythms.Deeply understanding the channeling law is crucial for further tapping the potential of the remaining oil.There⁃fore,intralayer heterogeneous cores were used to study the internal channeling law of intra-layer heterogeneous reservoirs experimentally.The results show that in the stage of water flooding with an injection volume of 0-0.4 PV,the diversion rate at the injection end is slightly lower than that at the production end in the high-permeability layer,which is opposite to those observed in the medium-and low-permeability layers;in the stage from water flooding with an injection volume of 0.4 PV to the end of water flooding,the diversion rate at the production end of the high-permeability layer greatly increases,while the diversion rate in the medium-permeability layer significantly reduces and that in the low-permeability layer slightly decreases.With the increase in the core permeability ratio,the channeling degree between the sublayers at the pro⁃duction end and the injection end decreases,and the same goes with the interlayer interference.As water flooding contin⁃ues,the channeling degree of interlayer first decreases and then increases.As the injection rate goes up,the diversion rate difference between the production end and the injection end of the high-permeability layer increases,hence the channeling degree rising.Increasing the injection rates of water wells can achieve the purpose of raising the injection pressure.Never⁃theless,because the increase in fluid absorption in the high-permeability layer is much greater than those in the medium and low-permeability layers,besides the influence of channeling inside the reservoir,the effect of expanding the swept vol⁃ume is not distinct.Moreover,increasing the injection rates of water wells also puts forward higher requirements on the ca⁃pabilities of equipment at the injection end and the production end and that on the surface.Therefore,increasing the flow resistance of the high-permeability layer is the effective technical way of increasing the injection pressure.