An alternative approach for fast oil well drilling simulations in pre-salt

Resumo

This work proposes an alternative approach for fast oil well drilling in pre-salt. Under high stress and
temperature conditions, salt rocks develop a progressive time-dependent deformation, called creep. This behavior
promotes the borehole closure over time, leading to stuck pipe and well drilling delay. Thus, numerical simulations
of the salt rock behavior can be used to assist in oil well design and also along drilling operation. Currently, these
simulations are based on the finite element method. The classical approach performs a full plane axisymmetric
analysis considering the whole domain, but, in general, these simulations demand a high computational cost. As
observed, large zones of well-behaved salt rocks can be represented by a faster one-dimensional axisymmetric
formulation without loss of accuracy of results. Moreover, the division of the original domain into sub-sections
of independent analysis, considerably reduces the total computational cost. Therefore, aiming to speedup the
solution, case study scenarios are defined for elaboration of spatial subdivision rules, combining the two mentioned
formulations. Finally, the results obtained are compared to the classic reference approach. It’s expected that
the proposed strategy can lead to good approximations of reference results, making possible to carry out faster
simulations to assist in oil well drilling.