长效颗粒示踪剂在水平井压裂监测中的应用

Application of long-acting particle tracer in horizontal fracturing monitoring

为解决水平井分段压裂监测过程中,使用液体示踪剂监测周期短、扩散作用较大影响测试精度的问题,针对性地研发了长效颗粒示踪剂。通过实验评价了室温下多孔陶瓷颗粒对稀土元素示踪剂的吸附能力,并优化出示踪剂溶液浓度、颗粒与示踪剂比例以及吸附时间等参数。同时,利用支撑剂导流能力评价装置开展了长效颗粒示踪剂对裂缝导流能力的影响实验。进一步对长效颗粒示踪剂进行冲刷实验,综合评估其长期释放性能,分析冲刷水量与示踪剂释放量之间的关系。结果表明,多孔陶瓷颗粒在稀土元素示踪剂溶液中吸附3h可达到浓度平衡;示踪剂溶液配制浓度为10%,溶液与多孔陶瓷颗粒质量比为5的情况下,颗粒吸附率最高,可达131.7mg/g;颗粒示踪剂占支撑剂质量比例不大于0.5%时不会对支撑剂导流能力造成影响,其在冲刷10倍以上裂缝体积后仍可有效释放,且释放量与冲刷水量呈正比。将该类示踪剂应用到国内某致密砂岩气藏水平井分段压裂监测中,实现了3个月的有效测试。长效颗粒示踪剂能够为水平井分段压裂监测提供更加有效且可靠的方法,对后续压裂方案的优化及水平井的生产管理有一定的指导价值。

In order to solve the issue about monitoring cycle not long enough and low test accuracy caused by high diffusion effect using liquid tracers in horizontal multi-stage fracturing monitor project,long-acting particle tracers have been targeted and developed.Adsorption ability of porous ceramic particles with rare earth element tracers have been evaluated through experiment,parameters such as tracer solution concentration,mass of particles,adsorption duration have meanwhile been optimized.Then,proppant conductivity test equipment was utilized to check whether long-acting particle tracers have influence on fracture conductivity.Furthermore,flush experiment has been conducted to assess long term releasing performance of particle tracers and studied correlation of water flush rate and tracer releasing rate.It was concluded from series experiments,it could reach concentration balance three hours after adding porous ceramic particles into tracer solution.Under the condition that tracer solution concentration 10%,mass ratio of solution and particles 5,adsorption ratio was highest about 131.7mg/g.Particle tracers has no effect on proppant conductivity under mass ratio 0.5%,which could keep releasing effectively after 10times fracture volume flush.A valuable result was confirmed that tracer releasing rate was proportional with water flush rate.At last,this kind of tracer developed has been applied to multi-stage monitor of one horizontal well in a tight sandstone gas field in China,the valid test procedure last more than three months.The long-acting particle tracers provide a more effective method for fracturing test,which could give more valuable information to support fracture scheme optimization and production management of horizontal wells.