Failure Pressure Assessment for Oilfield Water Injection Pipeline Considering Interaction between Corrosion Defects in Internal and External Walls

Finite element analysis software ABAQUS was used to study the interaction between corrosion defects in internal and external walls for the water injection pipeline in Shengli Oilfield and influencing factors. Through the study of the failure pressure of the pipeline with single corrosion defect, the characteristic dimensions affecting the pipeline failure pressure were determined, and the effects of internal and external corrosion defects on the pipeline failure pressure were analyzed in comparison. On this basis, in the case of co-existence of internal and external defects, the influence of corrosion defect size parameters (relative depth, relative length) and axial spacing on pipeline failure pressure was explored, and the interaction limit distance between internal and external corrosion defects was obtained in combination with 5% interaction rule. The results show that the internal corrosion defects had a greater influence on the failure pressure of pipelines. With the increase of the axial spacing between internal and external corrosion defects, the failure pressure of pipelines with different corrosion defect depth and length increased until it tended to a fixed value. With the increase of the depth and length of double corrosion defects, the interaction limit distance of internal and external corrosion defects increased significantly. The size and spacing of internal and external corrosion defects were important factors affecting the interaction between internal and external corrosion defects.