顺北油田上浮剂封堵及泵注参数实验研究

塔里木盆地顺北油田碳酸盐岩储层埋藏深、温度高且厚度大,采用常规酸压工艺难以实现有效纵向改造及安全高效开发,为此提出了上浮剂隔挡控缝高酸压工艺。基于现场地质参数及酸压施工要求,优选了漂珠作为目标工艺的上浮剂;利用上浮剂隔板性能评价装置,明确了颗粒组合和最优质量比;基于大型可视化平行板颗粒运移铺置模拟装置,优化了相应的泵注参数。结果表明:优选堆积密度为0.4~0.8 g/cm^3的漂珠作为耐高温上浮剂,颗粒(20~40,100~120,180~200目)的最优质量比为1.0∶2.0∶5.2,封堵厚度15.9 cm,可以满足10 MPa的最高暂堵压力要求。采用低黏度滑溜水压裂液时,建议以0.350~0.625 m/s的线性流速泵注上浮剂,质量分数应控制在5%左右,注入后仅需停泵1次,各级颗粒混合注入即可。研究成果为顺北油田及相关缝高控制改造工艺的有效实施提供了技术支撑。

Experimental study on plugging performance and pumping parameters of floating agent in Shunbei Oilfield

The carbonate reservoirs in Shunbei of Tarim Basin are characterized by deep burial,high temperature and large thickness.It is difficult to realize the effective longitudinal transformation and safe development by using the conventional acid fracturing.Therefore,the fracture height controlled acid fracturing with floating agent plugging is put forward.Based on the field geological parameters and the construction requirement,the floating beads were selected as the floating agent.The particle combination and its optimal mass ratio were obtained by using the self-developed experimental device for evaluating the floating agent plugging,and the pumping parameters were optimized with the large-scale visualization parallel-plate stimulating device for particles migration and placement.The results indicate that the floating beads with a density of 0.4-0.8 g/cm^3 is suitable for the floatation agent with high temperature resistance.The optimal particle mass ratio of 20-40,100-120 and 180-200 mesh is 1.0∶2.0∶5.2.The placement thickness of 15.9 cm can meet the maximum sealing pressure requirement of 10 MPa.It is recommended to use low viscosity slippery water fracturing fluid to pump the floating agent at the linear flow rate of 0.350-0.625 m/s,with the concentration of the floating agent controlled at about 5%.The pump should be stopped only once after injection,and the third rank particles can be mixed injected.The research provides experimental support for the effective implementation of fracture height controlled fracturing in Shunbei Oilfield.