Abstract
Downhole drilling, production, and servicing equipment is lowered, raised, and held in the well using the drilling system, the primary working element of which is the drilling line. During long-term operation, drilling lines undergo fretting corrosion damage, the mechanisms of action and development of which require additional research. The purpose of this study was to analyse the degradation processes by evaluating the features of fretting wear and fretting corrosion of wires, rods, and cores of drilling lines of lifting mechanisms of drilling rigs and their impact on the occurrence and development of damage. The analysis of publications on the selected topic in the research cycle, problem statement, collection of primary data on visual and non-destructive testing of lines from literature sources and examination data to assess their technical condition and study the impact of fretting corrosion damage was carried out. The methodology of research of drilling lines covered a complex of theoretical and practical approaches aimed at studying their characteristics, assessing their technical condition, predicting durability and ensuring operational safety. It was established considering the relevance and practical necessity based on data from literature sources characterised by high citation, the requirements of international standards for the study of line damage in conditions of corrosion and wear effects. Some features of the abrasive effect of oxides on the condition of wires, rods, and cores of drilling lines were revealed. The residual stress-strain state of conjugated surfaces in lines due to the kinematics features of multilayer line winding on the drum was analysed. The analysis of external and internal fretting wear and fretting corrosion damage for drilling lines of lifting mechanisms of the UPA-60x mobile drilling rig was carried out. The prerequisites for the occurrence of a critical condition of the surfaces of drilling line elements due to fretting and corrosion damage were established. Considering the features and potential hazards of damage and destruction of elements of drilling lines due to fretting corrosion phenomena, practical recommendations for the use of lines with polymer-coated cores were given for further operation. The use of these lines in the oil and gas industry will help to: prevent water and dust from entering the cores, reduce the friction forces of the rods to the core and internal stresses, improve the stability of the line shape; absorb fluctuations in dynamic loads