薄差储层复合暂堵重复压裂技术应用研究

Application of Compound Temporary Plugging Re-fracturing Technology to Thin and Poor Reservoirs

L油田老区目前水驱挖潜的重点已转入三类薄差储层,该类储层油层多且薄、物性差、纵向上分布跨距大、剩余油分布零散,常规重复压裂工艺针对性不强、增产幅度小,有效动用难度大。研发的新型暂堵剂承压强度高、封堵效果好、易降解,为了提高薄差层动用程度以及油井产能,提出采用机械封隔与化学暂堵剂封隔相结合的复合暂堵重复压裂工艺,从而实现在纵向上产生多条主裂缝,并在平面上产生多条分支裂缝,最大程度沟通剩余油区域。模拟得到暂堵重复压裂的最优支撑半缝长为28~35m,穿透比为0.2~0.3,加砂规模为9~15m^3/层。薄差储层复合暂堵重复压裂技术在某开发区的2口老井得到了成功应用,其中A井压后生产6个月,平均日增油8.79t,累计增油1582.16t,且持续有效。与常规压裂相比,该技术大幅增加了剩余油的动用程度,增产效果显著,应用价值广泛。

The focus of water flooding potential in the old areas of Oilfield L has been transferred to the third class reservoir which is characterized as multi-thin oil layers,poor physical properties,large vertical span,and scattered remaining oil distribution.The conventional re-fracturing technology is not available well with small production increase and being difficult to produce effectively.The developed new temporary plugging agent has the characteristics of high bearing strength,good plugging effect and easy degradation.In order to improve the producing degree of thin and poor reservoirs and oil well productivity,it is proposed to apply compound temporary plugging re-fracturing by the combination of mechanical seal and chemical temporary a-gent.Multiple main fractures in the longitudinal direction and multiple branch fractures in the horizontal direc-tion are generated after this technology is applied,and the remaining oil areas may be connected at great degree.The simulation results of temporary plugging re-fracturing are:the optimal propped half-length of hy-draulic fracture is 28-35 m,the penetration ratio is 0.2-0.3,and the proppant usage is 9-15 m^3 per layer.The technology of compound temporary plugging re-fracturing for the thin and poor reservoirs has been successful-ly applied to 2 old wells in Oilfield L.During the first 6 months after the fracturing in Well A,average daily oil production increased by 8.79 t and cumulative oil production increased by 1582.16 t.The oil productivity of Well A is considered to be of great potential.Compared with conventional fracturing,the technology proposed in this paper is able to increase the producing of remaining oil and enhance the stimulation effect,which has a value of broad popularization and application.