预防支撑剂回流的纤维增强技术实验研究

LAB. STUDY ON FIBER ENHANCED PROPPANT TO PREVENT FLOWBACK AFTER FRACTURING

支撑剂回流对压裂井有着不利影响,油气田上提出了多种方法来消除或减少支撑剂的回流,其中以纤维增强支撑剂技术最具发展潜力。通过配伍性实验,从5种纤维材料中筛选出了在压裂液中分散性好、不影响压裂液性能的纤维材料A样。把A样纤维和支撑剂混合后,进行了不同闭合压力、不同压裂液粘度和不同纤维浓度的支撑剂充填层稳定性测量实验,并优选出合适的纤维加量为0.9%-1.2%。实验结果表明,加入纤维后,支撑剂充填层的临界出砂流速提高了10倍以上,明显增强了支撑剂充填层的稳定性,对预防支撑剂回流返吐非常有效;同时纤维对支撑剂导流能力的影响可以忽略不计,即不会降低压裂井的增产效果。

Proppant flowback has a bad effect on hydraulic fractured wells on field, and many methods which are put forward can avoid or reduce proppant flowback, where fiber enhanced proppant is regarded as the most potential technology. Through compatibility experiment, fiber A which has good performance of dispersivity in fracturing fluids and can' t influence the property of fracturing fluids, has been selected from five kinds of fiber. Fiber A was mixed into proppant, and then the stability experiments of the compacted mixture have been done in different closure pressure, different fluids viscosity, and different fiber concentration. Experiment data shows that appropriate fiber concentration in proppant is 0. 9 % - 1. 2 % . Experiment results indicates that the proppant compacted zone which mixed with fiber have an evident effect on preventing proppant flowback, where the critical fluids velocity at the moment of sand production from the compacted mixture, has increased at least 10 times, thus the stability of prop-pant compacted zone has been enhanced obviously. Experiment results also indicates that the adverse influence of fiber on flow conductivity of proppant can be ignored, thus the production increase of fractured wells can' t be reduced.