水力压裂冲蚀磨损对连续管剩余寿命影响研究

Study on effect of erosion wear to residual life of coiled tubing for hydraulic fracturing

针对水力压裂中连续管内壁冲蚀磨损严重和连续管易失效的问题,基于液-固两相流和冲蚀理论,建立了连续管内部砂砾冲蚀模型。采用Grant和Tabakoff模型求解砂砾冲蚀速率,借助实验数据验证了CFD数值模型。利用该模型研究了连续管在不同弯曲度、砂砾粒度、压裂液注入量、质量流量、压裂液粘度对连续管内壁的冲蚀特性。研究表明:弯曲连续管比直连续管冲蚀磨损严重,且弯曲度对连续管内壁的冲蚀磨损影响较大。随着注入量的增加,壁厚平均损失值和壁厚损失峰值呈现快速递增趋势。支撑剂固体颗粒的粒度对连续管内壁的冲蚀磨损影响较大,粒度为40目时连续管冲蚀速率最大。随质量流量的增加,连续管剩余寿命呈线性下降。随压裂液粘度的增加,连续管内壁冲蚀速率总体呈现下降趋势。

Aiming at the problems that the erosion wear of internal wall in coiled tubing is serious and the coiled tubing is easy to fail in hydraulic fracturing, an internal sand erosion model of coiled tubing was established based on liquid -solid two-phaseflow and erosion theory.The sand erosion rate was solved by using Grant and Tabakoff model , and the CFD numerical model was verified by the experimental data .The erosion characteristics of different curvature , particle size of sand, injection volume, mass flow and viscosity of fracturing fluid on internal wall of coiled tubing were studied by using this model .The re-sultsshowed that the erosion of curving coiled tubing is more serious than that of straight coiled tubing , and the curvature has a larger influence on the erosion wear of internal wall in coiled tubing .With the increase of injection volume, the average loss and peak loss of wall thickness present the trend of rapid increasing .The size of solid particle in support agent has a larger influence on the erosion wear of internal wall in coiled tubing , with the maximum erosion rate of coiled tubing when the size is 40 mesh.With the increase of mass flow, the residual life of coiled tubing presents a linear decrease .With the increase of viscosity, the erosion rate of internal wall in coiled tubing presents a decreasing trend as a whole .