Experimental study on erosion behavior of fracturing pipelines involving fluctuating stress

Abstract

Erosive wear due to particle impact serves as the main cause of pipeline failure. During hydraulic fracturing, fracturing pipelines inevitably suffer erosion damage under high fluctuating stress. In this study, a novel erosion test rig was developed in order to reproduce erosion scenes under complicated fracturing conditions. Then the erosion experiments involving fluctuating stress were carried out for the first time, and the erosion characteristics under varying conditions were obtained. In the erosion tests, the impact angles of the slurry flow varied from 15° to 90°, the flow velocities varied from 7.5 m/s-20 m/s, the solid particle concentration was 10% (in wt.%). The target material was 35CrMo steel, and the flat tensile specimens of 4 mm thickness were used in all erosion tests. Furthermore, the erosion mechanism with consideration of applied stress was subsequently revealed according to micro-structural characterization as well as the rheological spring-slider model. The complex erosion behavior of fracturing pipelines under severe conditions was well unraveled at the laboratory scale.