气体对阴离子表活剂压裂液破胶实验研究

摘要

Anionic surfactant fracturing fluid (ASFF) is a kind of clean fluid,and research of breaking mechanism of crude oil and formation water as well as the experiments had been fully developed.However,the research of influence of gas on fracturing fluid breaking can be hardly traced nowadays.In order to eliminate the obstacle of the appliance of anionic surfactant fluid in fracturing,a set of experimental procedures have been employed to evaluate the influence of natural gas,nitrogen and carbon dioxide on anionic surfactant fracturing fluid.According to the experiment,the viscosity decreasing extent of the three different gases on anionic surfactant fracturing fluid varies sharply.Among the three gases,the CO2 produces the biggest viscosity decreasing extent for ASFF,and it can break the fluid thoroughly;the natural gas produces relative small viscosity decreasing extent on ASFF while the nitrogen cast nearly no influence on viscosity of ASFF.However,nitrogen and natural gas can foam the fluid,which does good for flowing back.The result of the experiment provide the basis for optimizing fracturing fluid design,therefore,the success possibility of field operation can be enhanced.%阴离子表活剂压裂液是新型清洁压裂液,原油和地层水对其破胶机理与实验研究已相当充分,但气体对其破胶作用至今研究很少.为解决阴离子表活剂压裂液在压裂应用中的障碍,研究采用一套实用的实验流程,评价了天然气、氮气、二氧化碳三种常见气体对阴离子表活剂压裂液的影响.实验证明,三种不同的气体对阴离子表活剂压裂液的降粘幅度存在较大的差别,其中,二氧化碳气体对阴离子清洁压裂液降粘幅度最大,可使交联液体彻底破胶,天然气对阴离子型表活剂压裂液降粘幅度较小,氮气对阴离子压裂液的粘度几乎没有影响,氮气和天然气可以使液体泡沫化,从而有利于返排.实验结果为优化压裂设计提供了依据,可有效提高现场压裂施工成功率.