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为研究非常规天然气开采过程中支撑剂的运移规律,自主研发水力加砂压裂试验装置。该装置主要由岩石三轴试验机、压裂液泵压伺服控制系统、声发射监测系统3个部分组成,且具有以下特点:1可以模拟不同地应力、不同排量条件下携砂压裂试验;2压裂液注入可以通过流量模式和压力模式控制;3改进的声发射探头具有耐高油压性能,能够用于三轴室内。采用该装置进行了不同地应力、不同排量以及携砂条件下水力压裂试验,结果显示:地压力越大、排量越大红色砂岩起裂压力越大;携砂压裂后的压裂面离裸眼越远,支撑剂浓度越低且支撑剂并不是遍布所有压裂面;声发射累计计数在初期比较稳定,呈线性增加,在起裂前迅速增多。
In order to study the migration of proppant during unconventional gas exploration, a self-developed hydraulic sand fracturing device was developed. The device is mainly composed of rock triaxial testing machine, hydraulic control system of fracturing fluid pump and acoustic emission monitoring system. The device has the following features: 1 It can simulate the effect of sand loading and fracturing under different ground stress and displacement conditions ; 2 fracturing fluid injection through the flow mode and pressure mode control; 3 improved acoustic emission probe with high oil pressure performance, can be used for three-axis chamber. The device was used to carry out hydraulic fracturing tests under different stresses and different displacements as well as sand carrying conditions. The results showed that the greater the ground pressure and the larger the displacement, the greater the cracking pressure of red sandstone; The farther the farther away from the naked eye, the lower the concentration of the proppant and the proppant is not spread over all fractured surfaces. The cumulative acoustic emission counts are relatively stable and linearly increased in the early stage, increasing rapidly before initiation of cracking.