氟苯甲酸盐示踪剂分段压裂测试室内适应性研究

Laboratory compatibility research of fluorobenzoic acid salt tracers in multi-stage fracture test

示踪剂技术目前在水平井压裂测试中广泛使用,通过将不同水溶性示踪剂与压裂液混合注入到不同段内,返排阶段测试各种示踪剂浓度,可以获得各段的返排率以及产水贡献比例。针对常用的稀土微量物质示踪剂种类不够,无法满足十几段甚至更多段压裂测试要求的问题,开展了氟苯甲酸盐类示踪剂与瓜胶压裂液体系的配伍性实验,重点考察了氟苯甲酸盐示踪剂对压裂液各项性能的影响,并评价了示踪剂在压裂液体系中的热稳定性能以及静态吸附性能,同时利用驱替装置模拟压裂液与氟苯甲酸盐示踪剂返排过程,研究了示踪剂返排浓度与返排液流量间的关系。实验结果表明,氟苯甲酸盐示踪剂在1000mg/L以下时,对瓜胶压裂液体系性能无影响,示踪剂在瓜胶压裂液体系中70℃条件下60d后的浓度保留率大于95%。另外,驱替实验证明了氟苯甲酸盐示踪剂返排浓度与返排液流量成正比,可准确测试返排情况。氟苯甲酸盐适合作为分段压裂测试用示踪剂使用。

Tracer technology has been widely applied in multi-stage fracture of horizontal well.In which,different kinds of water tracers will be injected into different stages with fracture liquid respectively,clean up ratio and water production contribution of each stage could be obtained after detection and interpretation of tracer concentrations.Aiming at the problem that number of common used rare earth micro-element tracers was not enough,which could not meet the requirement of test for more than dozens of stages fracturing,the compatibility experiments of fluorobenzoic acid salt tracers with guar gum fracturing fluid have been completed in this research,including influence of fluorobenzoic acid salt tracers on performance of fracturing fluid and heat stability,absorption performance of tracers in fracturing fluid system.Meanwhile,flooding equipment was used to simulate flowing back process of fracture fluid and fluorobenzoic salt tracers to study the relationship between tracer concentration and flow back rate.It was concluded from experiments,tracers with concentration below 1000 mg/L had no influence on fracturing fluid,concentration retention ratio of tracers in guar gum fracturing fluid was more than 95% under 70℃ after 60 days.In addition,flooding experiments results proved tracer concentration of fluorobenzoic acid salt tracer was in direct proportion to the flow rate in same stage.The fluorobenzoic acid salt tracers could be used to test flow back after fracturing accurately.In conclusion,fluorobenzoic acid salt tracer was a good choice for fracturing test.