低碳烃无水压裂液稠化剂的制备与性能评价

Preparation and performance evaluation of thickener with low carbon used in waterless fracturing fluid

采用两步法合成了无水压裂液交联剂烷基磷酸酯,其最佳合成条件为:磷酸三乙酯和P2O5、混合醇的投料摩尔比为1∶1∶4,在80℃时反应5 h,产物二烷基磷酸酯的产率高达71.3%。采用络合铁水溶液作为活化剂,其配方为:柠檬酸钠30%,乙二醇10%,硫酸铁30%,去离子水30%。利用正己烷为基液,烷基磷酸酯PA-2为交联剂,络合铁水溶液FC-1为活化剂,制备出低碳烃无水压裂液,并探究了交联剂与活化剂的添加量对压裂液性能的影响。结果表明,随着交联剂PA-2用量的增加,成胶时间显著缩短,粘度逐渐增大。当交联剂PA-2用量为2.5%,活化剂FC-1用量为4%时,成胶时间为116 s,压裂液的粘度高达440.5 m Pa·s。在80℃、剪切速率170 s-1的条件下剪切1 h,该压裂液粘度仍在100 m Pa·s以上,表明该压裂液的耐温耐剪切性能良好。

The alkyl phosphate ester as fracturing fluid crosslinking agent was compounded with two-steps.And the optimum reaction condition was obtained. Triethylphosphate,phosphorus pentoxide and mixed alcohol reacted for 5 h at 80 ℃,with the mole ratio of 1∶ 1∶ 4. The yield of target product,two alkyl phosphate,was 71. 3%. Then activating agent,complexing iron solution was prepared,including 30% trisodiun citrate,10% ethanediol,30% ferric sulfate and 30% deionized water. Finally the alkyl phosphate ester（ PA-2） as crosslinking agent and the activating agent（ FC-1） were added in to the n-hexane to obtain waterless fracturing fluid with low carbon. It was concluded that the gelation time shortened obviously and the viscosity improved gradually as the increasing amount of crosslinking agent（ PA-2）. When the amount of crosslinking agent（ PA-2） and activating agent（ FC-1） was 2. 5% and 4% respectively,the gelation time was 116 seconds and viscosity was 440. 5 m Pa·s at room temperature. Shearing for 1 h at the shear rate of 170 s- 1,the viscosity of the fracturing fluid was still over 100 m Pa·s as temperature increased from 40 ℃ to 80 ℃. This was showed that the heat and shear tolerance of the fracturing fluid were good.