Coupling Equation-of-State Compositional and Surfactant Models in a Fully Implicit Parallel Reservoir Simulator Using the Equivalent-Alkane-Carbon-Number Concept

SPE Journal ◽  
2009 ◽  
Vol 14 (02) ◽  
pp. 302-310 ◽  
Author(s):  
Choongyong Han ◽  
Mojdeh Delshad ◽  
Gary A. Pope ◽  
Kamy Sepehrnoori
Keyword(s):  
Equation Of State ◽  
Carbon Number ◽  
Coupling Equation ◽  
Number Concept ◽  
Fully Implicit ◽  
Reservoir Simulator

A Fully Implicit, Parallel, Compositional Chemical Flooding Simulator

SPE Journal ◽  
2007 ◽  
Vol 12 (03) ◽  
pp. 322-338 ◽  
Author(s):  
Choongyong Han ◽  
Mojdeh Delshad ◽  
Kamy Sepehrnoori ◽  
Gary Arnold Pope
Keyword(s):  
Equation Of State ◽  
Interfacial Tension ◽  
Phase Behavior ◽  
Hybrid Approach ◽  
Material Balance ◽  
Chemical Flooding ◽  
Balance Equations ◽  
Cubic Equation ◽  
Fully Implicit ◽  
Simulation Results

Summary A fully implicit, parallel, compositional reservoir simulator has been developed that includes both a cubic equation of state model for the hydrocarbon phase behavior and Hand's rule for the surfactant/oil/brine phase behavior. The aqueous species in the chemical model include surfactant, polymer, and salt. The physical property models include surfactant/oil/brine phase behavior, interfacial tension, viscosity, adsorption, and relative permeability as a function of trapping number. The fully implicit simulation results were validated by comparison with results from our IMPEC chemical flooding simulator (UTCHEM). The results indicate that the simulator scales well using clusters of workstations. Also, simulation results from parallel runs are identical to those using a single processor. Field-scale surfactant/polymer flood simulations were successfully performed with over 1,000,000 gridblocks using multiple processors. Introduction Chemical flooding is a method to improve oil recovery that involves the injection of a solution of surfactant and polymer followed by a polymer solution. The surfactant causes the mobilization of oil by decreasing interfacial tension, whereas the polymer increases the sweep efficiency by lowering the mobility ratio. Chemical flooding has the potential to recover a very high fraction of the remaining oil in a reservoir, but the process needs to be designed to be both cost effective and robust, which requires careful optimization. Several reservoir simulators with chemical flooding features have been developed as a tool for optimizing the design (Delshad et al. 1996; Schlumberger 2004; Computer Modeling 2004). The University of Texas chemical flooding simulator, UTCHEM (Delshad et al. 1996) is an example of a simulator that has been used for this purpose. However, because UTCHEM is an Implicit Pressure and Explicit Concentration (IMPEC) formulation and in its current form cannot run on parallel computers, realistic surfactant/polymer flooding simulations are limited to around 100,000 gridblocks because of small timestep restrictions and insufficient memory. Recently, the appropriate chemical module was added to the fully implicit, parallel, EOS compositional simulator called GPAS (General Purpose Adaptive Simulator) based on a hybrid approach (John et al. 2005). GPAS uses a cubic equation of state model for the hydrocarbon phase behavior and the parallel and object-based Fortran 95 framework for managing memory, input/output, and the necessary communication between processors (Wang et al. 1999; Parashar et al. 1997). In the hybrid approach implemented in GPAS, the material balance equations for hydrocarbon and water components are solved implicitly first. Then, the material balance equations for the aqueous components such as surfactant, polymer, and electrolytes are solved explicitly using the updated phase fluxes, saturations, and densities.

scholarly journals Development of an equation of state fully implicit compositional model.

2000 ◽  
Vol 65 (4) ◽  
pp. 342-351
Author(s):  
Toshinori Nakashima ◽  
Nario Arihara ◽  
Hideaki Takeda ◽  
Kozo Sato ◽  
Nintoku Yazawa
Keyword(s):  
Equation Of State ◽  
Compositional Model ◽  
Fully Implicit

Tie-Simplex-Based Phase-Behavior Modeling in an IMPEC Reservoir Simulator

SPE Journal ◽  
2013 ◽  
Vol 19 (02) ◽  
pp. 327-339 ◽  
Author(s):  
M.. Rezaveisi ◽  
K.. Sepehrnoori ◽  
R.T.. T. Johns
Keyword(s):  
Stability Analysis ◽  
Phase Behavior ◽  
Single Phase ◽  
Potential Method ◽  
Phase Region ◽  
Behavior Modeling ◽  
Computational Time ◽  
University Of Texas ◽  
Fully Implicit ◽  
Reservoir Simulator

Summary Recently, tie-simplex-based phase-behavior modeling in reservoir simulators has been applied and investigated as a potential method for improving the computational speed of equation-of-state (EOS) -based reservoir simulators. We implemented compositional-space adaptive tabulation (CSAT), the most promising tie-simplex-based method, in UTCOMP, the University of Texas' in-house IMPEC compositional reservoir simulator, to investigate its computational efficiency compared with the phase-behavior algorithm in UTCOMP. The results show that applying CSAT only to skip stability analysis does improve computational time, but only when a significant portion of the gridblocks are in the single-phase region and no other technique for avoiding stability analysis is used. However, in most cases, there is little or no computational advantage to use of CSAT when the simple option in UTCOMP is used where stability analysis is skipped for blocks surrounded by single-phase regions. We explore in detail the performance of CSAT, which depends significantly on the specific gas flood modeled, and the number of tie-lines generated during adaptive tabulation. The results shed light on applicability of CSAT in the IMPEC-type compositional reservoir simulators and show that the advantages of CSAT in this type of simulator are not as great as are reported in the literature for fully implicit or adaptive implicit formulations.

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