Flow Parameter Evaluation During the Occurrence of a Gas Kick in a Petroleum Drilling Using Turbulence Models: A Numerical Study

Abstract

The drilling of petroleum wells demand large investments and the use of highly skilled personnel in the operation to be viable economically. In extreme situations, drilling requires strict process control. One of the most important tasks in this process is controlling the pressure within the well to avoid the influx of formation fluids into the well, i.e. a kick. A kick consists of an unwanted formation fluid flow due to a pressure difference in the pit. To better understand this process, a simplified kick simulator using the ANSYS CFX software was developed and implemented to analyze the behavior of some variables inside the pit during the occurrence of a gas kick. In this model, the behavior of dynamic variables such as mud volume fraction, densities, and pressure of fluids inside the tube is evaluated during drilling using two types of drilling fluids and testing four different turbulence models: k-epsilon, RNG-k-epsilon, k-omega and SST. In these tests one can note that for both fluids analyzed, when using the SST model, there was a more rapid invasion of the gas. However, using the RNG k-epsilon model, a greater resistance to invasion was observed, and both fluids exhibited similar behavior when using the same turbulence model. One can also observe that the SST allows a greater pressure drop along the stretch of the well examined in the final moment of the simulation, while the RNG k-epsilon model is one that showed a lower pressure drop.