非常规油气CO_2压裂技术进展及应用实践

Progress and application of CO_2 fracturing technology for unconventional oil and gas

非常规油气是我国重要的接替资源,由于油气储层物性普遍较差,大规模水力压裂是目前比较有效的储层改造技术,但存在耗水量大、储层伤害大、环境污染等问题。CO_2压裂技术充分利用CO_2自身扩散能力强、储层配伍性好、可增加地层能量等特点,具有节水、保护环境、埋存CO_2以及增产等优势。室内实验及现场实践证明,CO_2压裂技术可有效降低储层伤害、改善储层物性,降低岩石起裂压力,促进形成复杂缝网,同时可以高效置换吸附气、降低原油黏度,提高单井产量,CO_2压裂技术相对于水力压裂,压后返排率可提高25%以上,平均单井产量可提高1.9倍以上。通过进一步优化工艺技术,研发配套设备及制定相关标准,探索区块整体开发模式,CO_2压裂技术必将极大地促进我国非常规油气绿色和高效开发。

Unconventional oil and gas are very important superseding resources in China,for poor porosity and permeability,reservoir simulation technology is necessary and large-scale hydraulic fracturing is very effective,but some consequent problems such as high water consumption,high reservoir damage and environmental pollution are inevasible. CO2 fracturing technology,which fully used the CO2 characteristics of easy to diffusion,good formation compatibility and increasing the formation energy,has advantages of saving water,protecting environment,burying CO2 and increasing oil and gas production. Laboratory experiment and field practice indicate that CO2 fracturing technology can effectively reduce reservoir damage,improve reservoir properties,reduce rock initiation pressure,form complex fracture network,replace CH4 and reduce crude oil viscosity. Compared with hydraulic fracturing technology,it can improve backflow rate above 25%,and improve the average single well production above 1.9 times. By further optimizing of technology,developing matching equipment and relevant standards,exploring the overall development of blocks,CO2 fracturing technology will greatly promote the green and efficient development of unconventional oil and gas in China.