Modelado del Proceso de Gas Washing en Objetivos Petroleros Profundos

Abstract

In the present work, the gas washing modeling in deep petroleum targets by combining state equation models (Peng-Robinson) and equilibrium phases (ELV) through isothermic flash and adiabatic flash computations in their rigorous form (non-ideal systems and composition-depending Ks) was made to predict the phase behavior and the composition of different compounds that conform the washed crude oil. The aforementioned models, which were programmed in FORTRAN language, can be used as a computing tool to minimize the uncertainty in both exploration and exploitation of oil. The changes of the P and T variables can be related directly to the depth at which the oil reservoir is located. Thus, by definition, P and T will be minor at shallow depths and will be increased with depth increments. The state equation computations can be used to estimate the alteration effects during migration, reservoir filling and production. Once the modeling and the corresponding programming were obtained, five sceneries at different P, T and washing gas quantity were simulated. The original oil was named Maya Crude and its composition was calculated by PVT analysis. The simulated sceneries were: 1. Gas washing in an oil reservoir at constant T and P. One mol of liquid plus five mol of washing gas were considered. 2. Gas washing in an oil reservoir divided into six levels. Each level had different T and P; T was considered to be constant throughout every level, both vertically and horizontally. One mol of liquid plus one mol of washing gas were considered. 3. Gas washing in an oil reservoir divided into seven levels. T was the same in every level and P was different in each level. One mol of liquid plus five mol of washing gas were considered. 4. Gas washing in an oil reservoir divided in seven levels. The process was a function of both P and the washing gas quantity. T was considered to be constant. 5. Gas washing in an oil reservoir that was considered as an adiabatic flash chamber, dividing the reservoir into seven levels, considering variable T and P in all the levels. One mol of liquid plus five mol of washing gas were considered. This work shows the importance of the support provided by Chemical Engineering to Geology (particularly Geo-Chemistry) because the combination of phase equilibrium and state equation models creates an excellent tool that allows to know, predict and evaluate the oil composition once it has been altered by the gas washing process in the subsurface. The aforesaid will offer more certainty and strengthen the decision-making process during the execution of exploration and reservoir exploitation projects.