DEVELOPMENT OF MATHEMATICAL MODELS FOR ESTIMATING THE TRACTION FORCE REQUIRED FOR A STEEL PIPELINE EXTRACTING FROM A WELL USING THE DIRECTIONAL DRILLING METHOD

This study presents two universal mathematical models for estimating the traction force required for steel pipeline extracting from a well during the construction of crossings over natural and artificial obstacles using the directional drilling method. The relevance of the study arises from frequent emergency situations during the steel pipeline tract process. Furthermore, the proposed methodology serves as a replacement for existing pipeline repair methods as pipe bursting, sliplining, spot repair, and many others, which often cause environmental degradation, traffic disruption, and damage to surrounding infrastructure. Besides that, extracting defective or old steel pipelines for repair or replacement allows reuse of the same well without drilling a new one.In this study, the first mathematical model determines traction force based on the full steel pipeline segment length in the well as well as resistance from the already extracted pipeline’s actual weight. The second mathematical model accounts for the diminishing ratio of each steel pipeline segment length during the extraction process. An example of the theoretical study was conducted on a five-segment well profile of 792,993 m length using the first mathematical model. The required initial traction force was approximately 707 kN. However, when only the last pipeline segment of 140,771 m length remained in the well, the required traction force dropped to approximately 150 kN, representing a 79 % reduction.