Abstract: CO2 dry sand fracturing technology is superior for fracturing development of the strong water-sensitive and water-lock formations, bringing unconventional oil and gas reservoirs like tight gas and shale gas under effective development. The core equipment of technology is the CO2 enclosed sand mixing device. Based on the technological requirements and years of research efforts, the CO2 enclosed sand mixing device with independent intellectual property is developed to break the foreign technological monopoly. It reached the world’s advanced level in terms of technological functions. Field applications indicated that this device can mix the proppant and liquid CO2 in the proportion of the service requirements under the conditions of closed pressure and transmit the fluid into the fracturing vehicles, meeting the requirements designed as high reliability and safety. Application has achieved a good performance in stimulation of production. The yield from a well with a sand injection of less than 10m3 is increased by 20-30 percent on average. The open flow capacity of the well with a maximum sand injection reached 247,560 cubic meters and the productivity of the well was raised by more than 50 percent as compared to a conventionally fractured well, laying a firm foundation for wider application of CO2 dry sand fracturing technology.

Key words: CO2, enclosed sand mixing, dry sanding, unconventional oil and gas reservoir, proportional mixing

摘要： CO2 干法加砂压裂技术针对强水敏、强水锁地层的压裂开采具有明显优势, 可使储量巨大的致密气、页岩 气等非常规油气藏得到有效开发, 其核心装备是CO2 密闭混砂装置。根据工艺技术要求, 经过多年研究, 研发出具有 自主知识产权的CO2 密闭混砂装置, 打破了国外的技术垄断, 技术性能达到国际先进水平。多次现场应用表明, 该装 置可在密闭带压条件下将支撑剂与液态CO2 按施工要求的比例混合后输送给压裂车, 具有高可靠性、安全性, 达到了 设计要求。应用后显示增产效果好, 加砂量小于10m3 的井, 平均增产20% ~30%; 最大加砂量20m3 的井无阻流量达 24. 756×104m3, 较常规压裂对比井产能提高50%以上, 为CO2 干法加砂压裂技术的进一步推广应用奠定了坚实的基础。

关键词: CO2; 密闭混砂; 干法加砂; 非常规油气藏; 比例混合