Modelagem de um medidor do teor de CO2 em escoamento multifásico de óleo e gás

Abstract

Measuring high levels of CO2 in pre-salt production flows is still a technological challenge not fully addressed by the literature. There is significant complexity in accurately identifying the percentage of CO2 in production streams due to its thermodynamic behavior dependent on pressure and temperature, it is largely affected by the way in which CO2 interacts with the other components in the multiphase flow. Therefore, the existence of a method or equipment that can adequately inform the actual CO2 content in the aforementioned production streams would allow for a more efficient management of oil and gas production. The general objective of this work is to subsidize the development of adequate instrumentation for monitoring the percentage of CO2 in an oil and gas production chain between the producing well and the platform through the modeling of the thermodynamic behavior of the produced fluid. To this end, a computational model was created that uses the state equations in the ASPEN HYSYS® program. The modeling results indicate that the pressure-temperature (P-T) behavior presents linearity with slopes that increase according to increases in CO2 content, which is characteristic of many pre-salt production fields. The model successfully reproduced published experimental data for an isochoric process, endorsing the opportunity to estimate CO2 contents only using instrumentation to measure pressure and temperature of multiphase currents, heating systems and considering knowledge of the composition of the fluids: oil, gas and contaminants (mainly produced water and CO2).