Performance Analysis of a Modified Black-Oil Model for a Rich Gas Condensate Reservoir

2005 ◽  
Author(s):  
B. Izgec ◽  
M.A. Barrufet
Keyword(s):  
Performance Analysis ◽  
Gas Condensate ◽  
Black Oil ◽  
Condensate Reservoir ◽  
Black Oil Model

scholarly journals Reservoir Simulation Analysis of Pressure Depletion Performance in Gas-Condensate Reservoirs: Black-Oil and Compositional Approaches

2021 ◽  
pp. 119-137
Author(s):  
Akinsete O. Oluwatoyin ◽  
Anuka A. Agnes
Keyword(s):  
Relative Permeability ◽  
Reservoir Simulation ◽  
Gas Condensate ◽  
Productivity Index ◽  
Liquid Density ◽  
Gas Condensate Reservoirs ◽  
Compositional Model ◽  
Pressure Depletion ◽  
Black Oil ◽  
Black Oil Model

Pressure depletion in gas-condensate reservoirs create two-phase flow. It is pertinent to understand the behavior of gas-condensate reservoirs as pressure decline in order to develop proper producing strategies that would increase gas and condensate productivity. Eclipse 300 was used to simulate gas-condensate reservoirs, a base case model was created using both black-oil and compositional models. The effects of three Equation of States (EOS) incorporated into the models were analysed and condensate dropout effect on relative permeability was studied. Analysis of various case models showed that, gas production was maintained at 500MMSCF/D for about 18 and 12 months for black-oil and compositional models, respectively. However, the compositional model revealed that condensate production began after a period of two months at 50MSTB/D whereas for the black oil model, condensate production began immediately at 32MSTB/D. Comparison of Peng-Robinson EOS, Soave-Redlich-Kwong EOS and Schmidt Wenzel EOS gave total estimates of condensate production as 19MMSTB, 15MMSTB and 9MMSTB and initial values of gas productivity index as 320, 380 and 560, respectively. The results also showed that as condensate saturation increased, the relative permeability of gas decreased from 1 to 0 while the relative permeability of oil increased from 0.15 to 0.85. The reservoir simulation results showed that compositional model is better than black-oil model in modelling for gas-condensate reservoirs. Optimal production was obtained using 3-parameter Peng-Robinson and Soave-Redlich-Kwong EOS which provide a molar volume shift to prevent an underestimation of liquid density and saturations. Phase behaviour and relative permeability affect the behaviour of gas-condensate reservoirs.

APPLICATION OF THE BLACK OIL PVT REPRESENTATION TO SIMULATION OF GAS CONDENSATE RESERVOIR PERFORMANCE

1987 ◽  
Vol 27 (1) ◽  
pp. 370
Author(s):  
W.H. Goldthorpe ◽  
J.K. Drohm
Keyword(s):  
Oil And Gas ◽  
Volatile Oil ◽  
Gas Condensate ◽  
Phase Behaviour ◽  
Dew Point ◽  
Pressure Drops ◽  
Gas Condensate Reservoirs ◽  
Reservoir Performance ◽  
Black Oil ◽  
Condensate Reservoir

Special attention must be paid to the generation of PVT parameters when applying conventional black oil reservoir simulators to the modelling of volatile oil and gas-condensate reservoirs. In such reservoirs phase behaviour is an important phenomenon and common approaches to approximating this, via the black oil PVT representation, introduce errors that may result in prediction of incorrect recoveries of surface gas and condensate. Further, determination of production tubing pressure drops for use in such simulators is also prone to errors. These affect the estimation of well potentials and reservoir abandonment pressures.Calculation of black oil PVT parameters by the method of Coats (1985) is shown to be preferred over conventional approaches, although the PVT parameters themselves lose direct physical meaning. It is essential that a properly tuned equation of state be available for use in conjunction with experimental data.Production forecasting based on simulation output requires further processing in order to translate the black oil surface phase fluxes into products such as sales gas, LPG and condensate. For gas-condensate reservoirs, such post-processing of results from the simulation of depletion or cycling above the dew point is valid. In principle it is invalid for cycling below the dew point but in practice it can still provide useful information.

scholarly journals Evaluation of black-oil PVT-model applicability for simulation of gas-condensate reservoirs

2020 ◽  
pp. 43-48
Author(s):  
O. V. Burachok ◽  
D. V. Pershyn ◽  
S. V. Matkivskyi ◽  
O. R. Kondrat
Keyword(s):  
Phase Transitions ◽  
Phase Equilibrium ◽  
Phase Behavior ◽  
Oil And Gas ◽  
Gas Condensate ◽  
Potential Yield ◽  
Model Application ◽  
Compositional Model ◽  
Black Oil ◽  
Black Oil Model

Creation of geological and simulation models is the necessary condition for decision making towards current development status, planning of well interventions, field development planning and forecasting. In case of isothermal process, for proper phase behavior and phase transitions two key approaches are used: a) simplified model of non-volatile oil, so called “black oil” model, in which each phase – oil, water and gas, are represented by respective component, and solution to fiow equations is based on finding the saturations and pressures in each numerical cell, and change of reservoir fiuid properties is defined in table form as a function of pressure; b) compositional model, in which based on equation of state, phase equilibrium is calculated for hydrocarbon and non-hydrocarbon components, and during fiow calculations, apart from saturations and pressures, oil and gas mixture is brought to phase equilibrium, and material balance is calculated for each component in gas and liquid phase. To account for components volatility, the classic black oil model was improved by adding to the formulation gas solubility and vaporized oil content. This allows its application for the majority of oil and gas reservoirs, which are far from critical point and in which the phase transitions are insignificant. Due to smaller number of variables, numerical solution is simpler and faster. But, considering the importance and relevance of increasing the production of Ukrainian gas and optimization of gas-condensate fields development, the issue of simplified black oil PVT-model application for phase behavior characterization of gas-condensate reservoirs produced under natural depletion depending on the liquid hydrocarbon’s potential yield. Comparative study results on evaluation of production performance of synthetic reservoir for different synthetically-generated reservoir fiuids with different С5+ potential yield is provided as plots and tables. Based on the results the limit of simplified black oil PVT-model application and the moment of transition to compositional model for more precise results could be defined.

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