纤维对支撑剂回流影响实验研究

Experimental Study on the Effect of Fibers in Controlling Proppant Flowback

摘要: 支撑剂回流对压裂井有着不利影响，为消除或减小回流的影响，油气田上提出许多种办法，其中纤维控制支撑剂回流技术具有工艺简单，压后简单，压后快速返排的特点。为此开展纤维对支撑剂回流影响的实验研究。本文通过室内回流实验，系统研究了不同浓度纤维对40/70目陶粒和30/50目石英砂支撑剂回流临界流量的影响规律。实验在5~45 MPa闭合压力范围内进行模拟实验。结果表明：纤维的加入能显著提升两种支撑剂的抗回流能力。对于40/70目陶粒，当纤维浓度为0.3%时，其抗回流性能最优，在5 MPa闭合压力下临界流速可达0.80 m/s。对于30/50目石英砂，纤维浓度在0.1%~0.2%时效果较好，继续增加浓度提升效果不明显。纤维的稳定效果在低闭合压力下更为显著。本研究为水力压裂施工中优化纤维加量以控制支撑剂回流、维持裂缝导流能力提供了实验依据。

Abstract: Proppant flowback exerts an adverse impact on fractured wells. To eliminate or mitigate such impact, a variety of approaches have been proposed in oil and gas fields, among which the fiber-based proppant flowback control technology is featured by simple processes, easy post-fracturing operations and rapid post-fracturing flowback. For this reason, an experimental study on the influence of fibers on proppant flowback was conducted. In this paper, through laboratory flowback experiments, the influence laws of fibers with different concentrations on the critical flowback rates of 40/70 mesh ceramic proppants and 30/50 mesh quartz sand proppants were systematically investigated. Experiments were performed under simulated closure pressures ranging from 5 MPa to 45 MPa. The results indicate that the addition of fibers significantly enhances the flowback resistance of both types of proppant. For 40/70 mesh ceramic proppant, the optimal flowback resistance was achieved at a fiber concentration of 0.3%, with a critical flow velocity reaching 0.80 m/s under a closure pressure of 5 MPa. For 30/50 mesh quartz sand, a fiber concentration between 0.1% and 0.2% yielded the best improvement in flowback resistance, while further increasing the concentration showed no significant additional benefit. The stabilizing effect of fibers was more pronounced under lower closure pressures. This study provides experimental evidence for optimizing fiber dosage in hydraulic fracturing operations to control proppant flowback and maintain fracture conductivity.