Modelos teóricos de torque e arraste (drag) em poços de óleo e gás: revisão bibliográfica

Abstract

Torque and drag models are used to support well planning and assist in predicting and preventing operational problems during drilling, completion, and interventions. In drilling, these models are typically used during well planning stage to ensure that the proposed project is viable and proposed trajectory can be drilled smoothly within the mechanical limits of the equipment available for drilling. In completion and workovers, these models are used to verify whether the pipes, equipment, and tools are properly sized to withstand torque and drag generated during well activities. Within the literature, there are several theoretical models for calculating axial friction force, and each of them yields different friction force values. Frequently applied models are Robert Mitchell, Bill Mitchell, Drilling Manual, and Soft-String models. Therefore, this work aims to analyze some of the most used theoretical torque and drag models in the oil and gas well drilling and completion engineering to make comparisons among them. Furthermore, a case study is presented to compute and compare drag forces from the different models, aiming to identify the cause of results discrepancy. Based on the content presented in this work and the case study, it was concluded that the number of intervals/sections in the well may have a significant impact on differences in results of accumulated friction force among various models. The more sections applied, the more the values tend to converge, depending on the applied model. The work provided a literature review of the theoretical models of torque and drag typically applied in well engineering, aiming to facilitate the expansion of this content in electronic media.