纤维暂堵转向压裂技术在裂缝性储层的应用

Application of Fiber Temporary Plugging Fracturing Technology in Fractured Reservoirs

长垣南部葡萄花外围台肇、敖南储层受东西向天裂缝发育影响,裂缝方向性水淹问题严重。生产中为避免注水沿裂缝方向快速突进,在井网设计上以线性注采关系为主,但该方式易形成注采空白剩余油富集的区域,导致区块采出程度低,而对于这类储层利用常规压裂方式形成的双翼缝,无法在空白区域形成有效裂缝系统,难以达到挖潜剩余油的目的。利用“纤维+基液+支撑剂”的暂堵压裂工艺,在砂比为35%~40%的阶段,加入质量浓度为0.4%~1.4%的纤维时,缝内净压差达到5~12MPa。结合储层应力条件研究,该差值满足开启分支裂缝的应力条件,并根据储层物性特点,对施工规模、裂缝条数、裂缝长度及转向时机等参数进行优化,结合现场试验摸索形成了纤维暂堵转向压裂的设计标准。现场应用表明,形成“主缝+分支缝”的裂缝系统在剩余油富集的空白区域建立有效渗流通道,可提高裂缝控制体积,达到裂缝性储层的挖潜效果。

Due to the development of east-west natural fractures,the directional flooding of the fractures is serious in Taizhao and Aonan reservoirs of Putaohua peripheral reservoirs in the southern part of Daqing placanticline.Well pattern was on the linear injection-production relationship mainly for preventing rapid ad-vance of water injection along the fractures.But a blank residual oil accumulation area may be formed under this pattern resulting in low recovery percent of reserves in the block.However,the double-wing fractures formed by conventional fracturing in such reservoirs are difficult to form an effective fracture system in the blank area,and it is difficult to tap the potential of the residual oil.So temporary plugging fracturing technol-ogy of "fiber+base fluid+proppant" was proposed. When the fiber with mass concentration of 0. 4-1. 4% was added at the stage of sand ratio of 35%-40%,the net pressure difference in the fracture can reach 5-12 MPa.Combined with the study of reservoir stress conditions,the difference meets the stress conditions for opening branch fractures.According to the physical properties of the reservoir,operation scale,number of fractures,fracture length and diverting time and other parameters were optimized,and the design criteria for the fiber temporary plugging fracturing were set up through field tests.Field application shows that an effective flow channel may be formed in the blank residual oil accumulation area of the fracture system of "main fracture +branch fracture",and the volume controlled by fractures may be increased and the potential of the fractured reservoirs may be tapped.