Finite Element Modeling of the Cutting Process of Drillpipes using a Blowout Preventer

Fábio Vinicius Castilho¹; Paulo Pedro Kenedi¹; Pedro Manuel Calas Lopes Pacheco¹

¹ CEFET/RJ - Department of Mechanical Engineering

doi:10.20906/CPS/COB-2015-0746

Resumo

The exploitation of oil and gas in deepwater has introduced several operational difficulties and the necessity for the development of new technologies. The drilling of oil wells should avoid accidents with damage to persons, environment and materials. In this context, various equipment in drilling of wells are essential to maintain the safety of the operation. The Blowout Preventer (BOP) is a device that has the function of closing the well in an emergency to prevent the fluid leakage from the well to the environment. An important component of the BOP is the blind-shear ram whose function is to cut the pipe and provide sealing. In an emergency, BOP is the last safety barrier and the shear ram is essential to allow the closure of the well safely. The cutting process is composed by a pipe crushing stage followed by a blanking process stage. Although some simple analytic models based on metal cutting and blanking are used to estimate the main parameters of the process as the cutting force, more complete analysis using numerical models must be used to obtain a more complete understanding of the whole process and to estimate the main parameters with greater accuracy. In this work a tridimensional elastoplastic finite element model with contact and large displacements is used to access the stress distribution and the load-displacement behavior developed during the cutting process. An erosion parameter is used to model the separation process of the drillpipe during the cutting stage. Numerical results show a good agreement with experimental data indicating that the numerical model captures the main characteristics of the process.

Palavras-chave: Blowout Preventer; Drillpipes; Finite Element Method; Numerical Simulation; Modeling