Semester of Graduation
Master of Science in Petroleum Engineering (MSPE)
As wells become more complex and drilling conditions to reach targets prove even more challenging, being able to detect influx event early and safely handle these influxes has become one of the most important focus areas for improvement in well control safety. The high solubility of formation gas in non-aqueous drilling fluids however makes kick detection and safe handling of kicks more complicated. Recent studies are beginning to incorporate desorption kinetics in well control models to simulate the transient multiphase flow phenomenon associated with gas kicks in non-aqueous drilling fluids to foster safe handling of kicks. However, there is currently an inadequate understanding of gas evolution from non-aqueous fluids to correctly integrate desorption kinetics in these models. Therefore, the aim of this thesis was to improve the understanding of gas evolution in non-aqueous fluids by developing a controlled depressurization experiment that accurately simulate desorption during well control events. Gas evolution experiments were conducted in a custom-made apparatus using methane as the gas phase with various liquid phases. Different parameters such as initial saturation pressure, depressurization rate, oil-water ratio, presence of surfactant, different base fluids, and viscosity, that could influence the behavior of gas desorbing from solutions have been investigated. All these parameters except for the presence of surfactant were found to influence gas evolution. From these studies, the time dependency of the desorption process was presented for methane in olefins. Desorption coefficient results obtained from this study are instrumental in incorporating the desorption kinetics in models to understand its impact on riser/wellbore unloading. The improved understanding of the gas evolution process will ultimately enhance the current practices of safely handling influxes in non-aqueous drilling muds.
Ojedeji, Damilola, "GAS EVOLUTION PHENOMENON OF METHANE IN BASE FLUIDS OF NON-AQUEOUS DRILLING MUDS UNDER CONTROLLED DEPRESSURIZATION" (2021). LSU Master's Theses. 5420.