水力喷射压裂工具材料的冲蚀性能研究

发布时间：2018-10-17 07:47

【摘要】：近年来,随着大规模压裂技术在页岩气、致密油气以及低渗、超低渗透油气田的推广实施,水力喷射压裂过程中砂含量和泵的排量变得越来越大,压裂工具将不可避免的承受液固两相流高速冲蚀作用。本文对水力喷射压裂工具常用材料35Cr Mo和钴基合金进行了抗冲蚀性能的研究。利用喷射式实验装置研究了35Cr Mo材料和钴基合金材料在0.2%的羟丙基瓜尔胶溶液和石英砂组成的液、固两相流体中的冲蚀规律,利用失重法计算冲蚀速率并结合扫描电镜对冲蚀形貌进行了分析。实验结果表明:35Cr Mo材料的冲蚀速率随冲击角度的增加先增大后减小,冲刷溶液的冲击角度为45°时,35Cr Mo试样表面冲蚀磨损最严重;35Cr Mo材料和钴基合金材料的冲蚀速率随流速的增加均增大,但是35Cr Mo的增长趋势比钴基合金的更加明显;35Cr Mo材料冲蚀速率随入射流体流速增高过程中存在临界值,此临界速率大约为8.2m/s,当流速高于此临界值时,冲蚀速率随入射流速增高而迅速上升;石英砂含量在50kg/m3~100kg/m3内,35Cr Mo材料的冲蚀速率随着砂含量的增加而增大,当砂含量达到100kg/m3时,冲蚀速率达到最大,随着石英砂含量的继续增加,35Cr Mo材料冲蚀速率开始趋于稳定,钴基合金材料的冲蚀速率随着砂含量的增加稳定缓慢增加。液固混合溶液对35Cr Mo材料的冲蚀作用主要表现为机械冲刷磨损,材料的损伤机理为“微切削”与“冲击锻打”两种机理并存,小角度入射时以微切削为主,大角度入射时以冲击锻打为主。钴基合金的损失形式表现为石英砂的不断冲击使材料表面形成疲劳裂纹,在随后的冲蚀过程中裂纹扩展,进而导致材料损失。
[Abstract]:In recent years, with the popularization and implementation of large-scale fracturing technology in shale gas, tight oil and gas fields and low permeability and ultra-low permeability oil and gas fields, sand content and pump discharge during hydraulic jet fracturing have become larger and larger. Fracturing tools will inevitably withstand high-speed erosion of liquid-solid two-phase flow. In this paper, the erosion resistance of commonly used materials 35Cr Mo and cobalt based alloys for hydraulic jet fracturing tools is studied. The erosion behavior of 35Cr Mo and cobalt-based alloy materials in 0.2% hydroxypropyl guar gum solution and quartz sand was studied by using a jet apparatus. The erosion rate was calculated by weightlessness method and the erosion morphology was analyzed by SEM. The experimental results show that the erosion rate of 35Cr Mo increases first and then decreases with the increase of impact angle. When the impact angle of the scour solution is 45 掳, the erosion wear on the surface of 35Cr Mo specimen is the most serious, and the erosion rate of 35Cr Mo material and cobalt-based alloy material increase with the increase of flow rate. However, the growth trend of 35Cr Mo is more obvious than that of cobalt-based alloy, and the critical value of erosion rate of 35Cr Mo material is about 8.2 m / s in the process of increasing the flow rate of incident fluid, when the flow rate is higher than this critical value, The erosion rate of 35Cr Mo material increases with the increase of sand content in 50kg/m3~100kg/m3, and the erosion rate of 35Cr Mo material increases with the increase of sand content. When the content of sand reaches 100kg/m3, the rate of erosion increases rapidly, and the erosion rate reaches the maximum when the content of sand reaches 100kg/m3, and the rate of erosion increases with the increase of sand content in 50kg/m3~100kg/m3. With the increase of quartz sand content, the erosion rate of 35Cr Mo materials tends to be stable, and the erosion rate of cobalt-based alloy materials increases slowly with the increase of sand content. The erosive effect of liquid-solid mixed solution on 35Cr Mo material is mainly manifested by mechanical erosion and wear. The damage mechanism of the material is the coexistence of "micro-cutting" and "impact forging", and micro-cutting is the main mechanism when the incidence of small angle is small. When large angle incidence, the main impact forging. The loss form of cobalt-based alloy is that the continuous impact of quartz sand causes the fatigue crack on the surface of the material, and the crack propagates during the subsequent erosion process, which leads to the loss of the material.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE934.2

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