CO_2泡沫压裂在煤层气井中的适应性

Adaptability of CO_2 foam fracturing operation in coal-bed methane wells.

CO2泡沫压裂液由于对储层伤害小、返排能力强、滤失量小和携砂能力强等特点,在油气田,特别在低压、水敏性储层中得到应用。CO2泡沫压裂液与常规水基压裂液最大的差异是交联环境的不同。常规水基压裂液是在碱性环境下交联、酸性环境下破胶,而CO2泡沫压裂液则要求在酸性环境下交联。为使稠化剂在酸性条件下能形成良好的冻胶,开发研制出了AC8酸性交联剂,并通过室内研究,形成了CO2泡沫压裂的配套技术。现场应用表明,CO2泡沫压裂液是一种优质低伤害压裂液体系,该体系粘度高,滤失量低,能够清洁裂缝,对地层损害小,易返排,能够满足煤层气井的压裂施工。

Due to the advantages of CO 2 foam fracturing operation such as less damage to the formation, strong flow back ability, less filtration and good proppant carrying property, the fluid has won wide application in oil/gas fields, especially in the formation of low pressure and water sensitivity. The largest difference between the CO 2 foam fracturing fluid and the conventional hydraulic fracturing fluid lies in the different cross linking environment, that is, the former cross links in an acidic or basic surrounding, while the latter only reacts in an acidic condition. To produce gel with good properties, an acidic cross linking agent AC-8 was developed, and the necessary technology was formed based on a lot of experiments. Field using showed that CO 2 foam fracturing fluid was an excellent system with little damage to the reservoir. By virtue of its low viscosity, less filtrate into the formation, strong fracture cleaning ability and easy flowing back, the fluid is a good candidate for fracturing job in coal-bed gas wells.