基于正交试验设计的压裂管线冲蚀磨损参数效应分析

Parameter effects analysis of erosion wear of fracturing pipelines based on an orthogonal experimental design

冲蚀磨损是水力压裂过程中管道、设备损坏的重要原因之一。目前仿真模拟的冲蚀研究多是探讨特定因素对冲蚀结果的影响,缺乏各因素间作用效果的横向分析比较。本文基于正交试验设计方法研究了多种因素与管线冲蚀磨损结果之间的显著性关系,比较得出各因素对冲蚀磨损结果的影响力排序,为工程管线抗冲蚀磨损方案设计中各控制因素、操作步骤的优先级设置提供依据。案例分析选取了压裂过程影响管线冲蚀磨损结果的具有代表性的试验因素(管径、弯头圆角半径、支撑剂粒径、入口流速),以及可用于衡量管线冲蚀磨损严重度的试验指标(径向流速、切向流速、管壁总压力、管壁最大冲蚀磨损率)进行四因素四水平正交试验分析,基于均值主效应分析和方差分析结果探究了各参数与冲蚀磨损结果的显著性关系。针对本文案例选定的四项试验指标研究表明,入口流速因素均值主效应排序均为第1,且与各试验指标存在显著性关系,最大置信度为95%,影响力最显著;弯头圆角半径因素均值主效应排序三项第2,且与三项试验指标存在显著性关系,最大置信度为95%,则影响力其次;支撑剂粒径影响力最不显著。工程设计时可优先考虑控制流速和管线弯头形态,以提升管线的抗冲蚀磨损性能。

Erosion is one of the important causes of pipeline and equipment damage during hydraulic fracturing. In current research based on erosion simulation, the impact of specific factors on the evaluation of erosion wear has been discussed, while the horizontal comparison of the effects of multiple factors has been ignored. Thus, a method based on an orthogonal experimental design was proposed to study the significant relationship between multiple factors and severity. This can provide the effect ranking of each factor by comparison, and then provide the basis for priority setting of multiple controlling factors and operation steps in the engineering design on pipeline erosion wear resistance. In this case, representative test factors which had impacts on severity (including diameter of pipe, radius of elbow, particle size of proppant, inlet velocity) and test indexes which could measure the severity (including radial velocity, axial velocity, total pressure on pipe wall and maximum erosion rate of pipe wall) were selected. The four factors with a four-level orthogonal experimental design was established and analyzed, and the significant relationship between multiple factors and severity based on the results of mean main effect analysis and variance analysis was studied. The inlet velocity ranked first in all mean main analysis, and had a significant relationship with all four test indexes (the maximum confidence level was 95%), which illustrated that inlet velocity had the largest impact. The elbow radius ranked second in three sets of mean main analysis, and had a significant relationship with three test indexes (maximum confidence level was 95%), which illustrated that the elbow radius had the second largest impact. And the particle size of proppant had the least significance, so that engineering design could give priority to considering the flow velocity and the shape of the elbow to improve the erosion wear resistance of pipelines.