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鄂尔多斯盆地东缘致密砂岩岩石类型以岩屑石英砂岩和岩屑砂岩为主,平均孔隙度2%~10%,平均渗透率0.01~1 md,压力系数0.73~1.09,储层具有低孔、致密-低渗、黏土矿物含量高等特点,需要进行必要的储层改造措施以达到经济有效开发。本文通过室内压裂液体系优选及评价,开发了一套携砂能力强、低温环境下破胶彻底、返排率高、增产效果好等特点的低温低浓度压裂液体系;针对储层厚度薄、储隔层应力差异小、上下煤层发育等实际问题,针对性的优化了控缝高措施、防砂堵措施,现场应用近百井次。实践结果表明,优化的压裂液体系和工艺参数适应于该类低温致密储层,施工成功率高,压后增产效果明显。
The tight sandstone in the eastern margin of Ordos Basin is dominated by lithic quartz sandstone and lithic sandstone with an average porosity of 2% -10%, an average permeability of 0.01-1 md and a pressure coefficient of 0.73-1.09. The reservoirs have low porosity and dense - Low permeability, high clay mineral content, and the need for necessary reservoir modification measures to achieve cost-effective development. In this paper, we have developed a set of low-temperature and low-concentration fracturing fluid system with good sand carrying capacity, thorough gel breaking in the low temperature environment, high backflow rate and good stimulation effect through the optimization and evaluation of the indoor fracturing fluid system. According to the reservoir thickness Thin, stress difference of reservoir layer is small, the upper and lower coal seam development and other practical problems, targeted to optimize the control seam height measures, sand control measures, on-site application of nearly 100 wells. The practice results show that the optimized fracturing fluid system and process parameters are suitable for such low temperature and tight reservoirs, with high success rate of construction and obvious increase of yield after pressure.