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Abstract:
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In the past thirty years , the development of compositional reservoir simulators using
various equations of state (EOS ) has been addressed in the literature . However , the
development of compositional thermal simulators in conjunction with EOS formulation has
been ignored , in particular . Therefore in this work , a fully implicit , parallel , compositional
EOS -based simulator has been developed . In this model , an equation of state is used for
equilibrium calculations among all phases (oil , gas , and aqueous ) . Also , the physical
properties are calculated based on an equation of state , hence obviating the need for using
steam tables for calculation of water /steam properties . The governing equations for the
model comprise fugacity equations between the three phases , material balance , pore volume
constraint and energy equations . The governing partial differential equations are solved
using finite difference approximations . In the steam injection process , the solubility of oil in
water -rich phase and the solubility of water in oil phase can be high . This model takes into
account the solubility of water in oil phase and the solubility of hydrocarbon components in water -rich phase , using three -phase flash calculations . This simulator can be used in various thermal flooding processes (i .e . hot water or
steam injections ) . Since the simulator was implemented for parallel computers , it is capable
of solving large -scale thermal flooding problems . The simulator is successfully validated
using analytical solutions . Also , simulations are carried out to compare this model with
commercial simulators .
The use of an EOS for calculation of various properties for each phase automatically
satisfies the thermodynamic consistency requirements . On the other hand , using the K -value
approach , which is not thermodynamically robust , may lead to results that are
thermodynamically inconsistent . This simulator accurately tracks all components and mass
transfer between phases using an EOS ; hence , it will produce thermodynamically consistent
results and project accurate prediction of thermal recovery processes .
Electrical heating model , Joule heating and in -situ thermal desorption methods , and
hot -chemical flooding model have also been implemented in the simulator . In the electrical
heating model , electrical current equation is solved along with other governing equations by
considering electrical heat generation . For implementation of the hot -chemical heating
model , first the effect of temperature on the phase behavior model and other properties of the
chemical flooding model is considered . Next , the material and energy balance and volume
constraints equations are solved with a fully implicit method . The models are validated with
other solutions and different cases are tested with the implemented models . |