Rmbal Package

mbal_time() arguments

• x: A vector or sequence of times/dates.
• unit: A unit system for input vector x.

mbal_optim_param_oil() arguments

• input_unit: A unit system for parameters, only the character string ‘Field’ is accepted.
• output_unit: A unit system for properties, only the character string ‘Field’ is accepted.
• unknown_param: A character string showing the unknown parameter(s). One of the following options: ‘N’, ‘m’, ‘We’, or ‘N_m’.
• aquifer_model: Defaulted to NULL, otherwise must be a character string, one of the following eight options: ‘uss_rad_edge’, ‘uss_rad_bottom’, ‘uss_lin_edge’, ‘uss_lin_bottom’, ‘pss_rad_edge’, ‘pss_lin_edge’, ‘pss_lin_bottom’, ‘pot’. For further information about each model, please see ‘Raquifer’ package reference manual (https://CRAN.R-project.org/package=Raquifer).
• N: Original oil in place, STB. If unknown, a NULL value must be assigned.
• m: Ratio of original gas cap volume to original oil leg volume, a numeric. If unknown, a NULL value must be assigned.
• phi: Reservoir porosity, a numeric fraction.
• swi: Initial water saturation in the reservoir, a numeric fraction.
• Np: Cumulative oil production, STB.
• Rp: Ratio of cumulative produced gas to cumulative produced oil.
• Wp: Cumulative water production, STB.
• Gi: Cumulative gas injection, SCF.
• Wi: Cumulative water injection, STB.
• We: Cumulative aquifer water influx, BBL. If unknown, a NULL value must be assigned.
• pb: Bubble point pressure, a numeric value, psi.
• p: Average reservoir pressure, a numeric vector, psi.
• pvt: A data frame of PVT properties including pressure ‘p’ in ‘psi’, oil formation volume factor ‘Bo’ in ‘bbl/stb’, solution gas-oil ratio ‘Rs’ in ‘scf/stb’, oil viscosity ‘muo’ in ‘cp’, volatilized oil-gas ratio ‘Rv’ in ‘stb/scf’, gas formation volume factor ‘Bg’ in ‘bbl/scf’, gas viscosity ‘mug’ in ‘cp’, water formation volume factor ‘Bw’ in ‘bbl/stb’, and water viscosity ‘muw’ in ‘cp’.
• cf: Formation compressibility, a numeric value or vector, 1/psi.
• phi_a: Aquifer porosity, a numeric fraction.
• perm_h_a: Aquifer horizontal permeability, md. Used in ‘uss_rad_edge’, ‘uss_rad_bottom’, ‘uss_lin_edge’, ‘pss_rad_edge’, ‘pss_lin_edge’ and ‘pot’ aquifer models.
• perm_v_a: Aquifer vertical permeability, md. Used in ‘uss_rad_bottom’, ‘uss_lin_bottom’, ‘pss_rad_bottom’, and ‘pss_lin_bottom’ aquifer models.
• h_a: Aquifer height, ft.
• r_a: Aquifer radius, ft. Used in ‘uss_rad_edge’, ‘uss_rad_bottom’, ‘pss_rad_edge’, and ‘pot’ aquifer models.
• r_R: Reservoir radius, ft. Used in ‘uss_rad_edge’, ‘uss_rad_bottom’, ‘pss_rad_edge’, and ‘pot’ aquifer models.
• w_a: Aquifer width, ft. Used in ‘uss_lin_edge’, ‘uss_lin_bottom’, ‘pss_lin_edge’, and ‘pss_lin_bottom’ aquifer models.
• l_a: Aquifer length, ft. Used in ‘uss_lin_edge’, ‘uss_lin_bottom’, ‘pss_lin_edge’, and ‘pss_lin_bottom’ aquifer models.
• tetha: Fraction of reservoir encircled by the aquifer, degrees. Used in ‘uss_rad_edge’, ‘pss_rad_edge’, and ‘pot’ aquifer models.
• muw_a: Aquifer water viscosity, cp.
• cw_a: Aquifer water compressibility, a numeric value, 1/psi.
• cf_a: Aquifer formation compressibility, a numeric value, 1/psi.
• wf: Weight factor, a numeric vector of zeros and ones. A zero value excludes the entire row of reservoir history data at a particular time from the material balance analysis.
• sorg: Residual oil saturation in gas invaded zone (gas cap expansion or gas injection), a numeric fraction.
• sorw: Residual oil saturation in water invaded zone (aquifer encroachment or water injection), a numeric fraction.
• mult_len: A numeric vector of initial estimates for the ‘aquifer_model’ parameters. A vector of length one for the ‘pot’ aquifer model. It applies as a multiplier to the radius of the aquifer. A vector of length two for the ‘uss_rad_edge’, and ‘pss_rad_edge’ aquifer models. The first parameter is applied as a multiplier to the aquifer radius, and the second parameter is applied as a multiplier to the aquifer horizontal permeability. A vector of length two for the ‘uss_lin_edge’, and ‘pss_lin_edge’ aquifer models. The first parameter is applied as a multiplier to the aquifer length, and the second parameter is applied as a multiplier to the aquifer horizontal permeability. A vector of length two for the ‘uss_lin_bottom’, and ‘pss_lin_bottom’ aquifer models. The first parameter is applied as a multiplier to the aquifer height, and the second parameter is applied as a multiplier to the aquifer vertical permeability. A vector of length three for the ‘uss_rad_bottom’ aquifer model. The first parameter is applied as a multiplier to the aquifer radius, the second parameter is applied as a multiplier to the aquifer horizontal permeability, and the third parameter is applied as a multiplier to the aquifer vertical permeability.
• lower: An optional numeric vector of lower bounds for the ‘aquifer_model’ parameters. See ‘minpack.lm’ package for details.
• upper: An optional numeric vector of upper bounds for the ‘aquifer_model’ parameters. See ‘minpack.lm’ package for details.
• control: An optional list of control settings. See ‘minpack.lm’ package for details.

mbal_optim_oil() arguments

• optim_lst: A list object of class ‘optimization_oil’.
• time_lst: A list object of class ‘time/date’.

mbal_optim_oil() outputs

It returns a list object with the following elements and a class according to the ‘optim_lst’ inputs:

• input_unit: A unit system for parameters.
• output_unit: A unit system for properties.
• N: Original oil in place, STB.
• m: Ratio of original gas cap volume to original oil leg volume.
• phi: Reservoir porosity.
• swi: Initial water saturation in reservoir.
• pb: Bubble point pressure.
• p: Average reservoir pressure vector.
• cf: Formation compressibility.
• pvt: A data frame of PVT properties including pressure ‘p’ in ‘psi’, oil formation volume factor ‘Bo’ in ‘bbl/stb’, solution gas-oil ratio ‘Rs’ in ‘scf/stb’, oil viscosity ‘muo’ in ‘cp’, volatilized oil-gas ratio ‘Rv’ in ‘stb/scf’, gas formation volume factor ‘Bg’ in ‘bbl/scf’, gas viscosity ‘mug’ in ‘cp’, water formation volume factor ‘Bw’ in ‘bbl/stb’, and water viscosity ‘muw’ in ‘cp’.
• prod: A data frame of production data, Np, Rp, and Wp.
• inj: A data frame of injection data, Gi, and Wi.
• We: A vector of aquifer encroached water into the reservoir.
• aquifer: A list of aquifer parameters and its class.
• wf: Weight factor.
• sorg: Residual oil saturation in gas invaded zone (gas cap expansion or gas injection).
• sorw: Residual oil saturation in water invaded zone (aquifer encroachment or water injection).
• p_est: Estimated pressures from the material balance analysis.

mbal_perform_param_oil() arguments

• input_unit: A unit system for parameters, only the character string ‘Field’ is accepted.
• output_unit: A unit system for properties, only the character string ‘Field’ is accepted.
• aquifer_model: Defaulted to NULL, otherwise must be a character string, one of the following eight options: ‘uss_rad_edge’, ‘uss_rad_bottom’, ‘uss_lin_edge’, ‘uss_lin_bottom’, ‘pss_rad_edge’, ‘pss_lin_edge’, ‘pss_lin_bottom’, ‘pot’. For further information about each model, please see ‘Raquifer’ package reference manual (https://CRAN.R-project.org/package=Raquifer).
• N: Original oil in place, STB.
• m: Ratio of original gas cap volume to original oil leg volume, a numeric fraction.
• phi: Reservoir porosity, a numeric fraction.
• swi: Initial water saturation in the reservoir, a numeric fraction.
• Np: Cumulative oil production, STB.
• Rp: Ratio of cumulative produced gas to cumulative produced oil.
• Wp: Cumulative water production, STB.
• Gi: Cumulative gas injection, SCF.
• Wi: Cumulative water injection, STB.
• We: Cumulative aquifer water influx, BBL.
• pb: Bubble point pressure, a numeric value, psi.
• p: Average reservoir pressure, a numeric vector, psi.
• pvt: A data frame of PVT properties including pressure ‘p’ in ‘psi’, oil formation volume factor ‘Bo’ in ‘bbl/stb’, solution gas-oil ratio ‘Rs’ in ‘scf/stb’, oil viscosity ‘muo’ in ‘cp’, volatilized oil-gas ratio ‘Rv’ in ‘stb/scf’, gas formation volume factor ‘Bg’ in ‘bbl/scf’, gas viscosity ‘mug’ in ‘cp’, water formation volume factor ‘Bw’ in ‘bbl/stb’, and water viscosity ‘muw’ in ‘cp’.
• cf: Formation compressibility, a numeric value or vector, 1/psi.
• phi_a: Aquifer porosity, a numeric fraction.
• perm_h_a: Aquifer horizontal permeability, md. Used in ‘uss_rad_edge’, ‘uss_rad_bottom’, ‘uss_lin_edge’, ‘pss_rad_edge’, ‘pss_lin_edge’ and ‘pot’ aquifer models.
• perm_v_a: Aquifer vertical permeability, md. Used in ‘uss_rad_bottom’, ‘uss_lin_bottom’, ‘pss_rad_bottom’, and ‘pss_lin_bottom’ aquifer models.
• h_a: Aquifer height, ft.
• r_a: Aquifer radius, ft. Used in ‘uss_rad_edge’, ‘uss_rad_bottom’, ‘pss_rad_edge’, and ‘pot’ aquifer models.
• r_R: Reservoir radius, ft. Used in ‘uss_rad_edge’, ‘uss_rad_bottom’, ‘pss_rad_edge’, and ‘pot’ aquifer models.
• w_a: Aquifer width, ft. Used in ‘uss_lin_edge’, ‘uss_lin_bottom’, ‘pss_lin_edge’, and ‘pss_lin_bottom’ aquifer models.
• l_a: Aquifer length, ft. Used in ‘uss_lin_edge’, ‘uss_lin_bottom’, ‘pss_lin_edge’, and ‘pss_lin_bottom’ aquifer models.
• tetha: Fraction of reservoir encircled by the aquifer, degrees. Used in ‘uss_rad_edge’, ‘pss_rad_edge’, and ‘pot’ aquifer models.
• muw_a: Aquifer water viscosity, cp.
• cw_a: Aquifer water compressibility, a numeric value, 1/psi.
• cf_a: Aquifer formation compressibility, a numeric value, 1/psi.
• wf: Weight factor, a numeric vector of zeros and ones. A zero value excludes the entire row of reservoir history data at a particular time from the material balance analysis.
• sorg: Residual oil saturation in gas invaded zone (gas cap expansion or gas injection), a numeric fraction.
• sorw: Residual oil saturation in water invaded zone (aquifer encroachment or water injection), a numeric fraction.

mbal_perform_oil() arguments

• mbal_lst: A list object of class ‘mbal_oil’.
• time_lst: A list object of class ‘time/date’.

mbal_perform_oil() outputs

It returns a data frame with the following columns:

• P (psia): Average reservoir pressure.
• Eo (bbl/STB): Oil expansivity.
• Eg (bbl/SCF): Gas expansivity.
• Ew (bbl/STB): Water expansivity.
• Ef (bbl/bbl): Rock expansivity.
• Eowf (bbl/STB): Composite expansivity.
• Egwf (bbl/SCF): Composite expansivity.
• Et (bbl): Total reservoir expansion.
• F (bbl): Net fluid withdrawal.
• We: Aquifer encroached water.
• Igd: Gas-cap-drive index.
• Isd: Solution-gas-drive index.
• Inwd: Natural-water-drive index.
• Ifwd: Compaction-connate_water-drive index.
• Iawd: Artificial-water-drive index.
• Itot: Total-drive index.
• RF_oil: Oil recovery factor.
• RF_gas: Gas recovery factor.
• SOo: Average oil saturation in the oil leg.
• SGo: Average gas saturation in the oil leg.
• SWo: Average water saturation in the oil leg.
• SOT: Average oil saturation in the tank.
• SGT: Average gas saturation in the tank.
• SWT: Average water saturation in the tank.
• qo (STB/day): Average oil rate within the period.
• qg (SCF/day): Average gas rate within the period.
• qw (STB/day): Average water rate within the period.
• fg: In-situ free-gas fractional flow.
• fw: In-situ water fractional flow.
• GOR (SCF/STB): Gas to oil ratio.
• krg/kro: Ratio of gas relative permeability to oil relative permeability in the oil leg.

mbal_forecast_param_oil() arguments

• input_unit: A unit system for parameters, only the character string ‘Field’ is accepted.
• output_unit: A unit system for properties, only the character string ‘Field’ is accepted.
• aquifer_model: Defaulted to NULL, otherwise must be a character string, one of the following eight options: ‘uss_rad_edge’, ‘uss_rad_bottom’, ‘uss_lin_edge’, ‘uss_lin_bottom’, ‘pss_rad_edge’, ‘pss_lin_edge’, ‘pss_lin_bottom’, ‘pot’. For further information about each model, please see ‘Raquifer’ package reference manual (https://CRAN.R-project.org/package=Raquifer).
• N: Original oil in place, STB.
• m: Ratio of original gas cap volume to original oil leg volume, a numeric fraction.
• phi: Reservoir porosity, a numeric fraction.
• swi: Initial water saturation in the reservoir, a numeric fraction.
• Gi: Cumulative gas injection, SCF.
• pb: Bubble point pressure, a numeric value, psi.
• p: Reservoir pressure, a numeric vector, psi.
• pvt: A data frame of PVT properties including pressure ‘p’ in ‘psi’, oil formation volume factor ‘Bo’ in ‘bbl/stb’, solution gas-oil ratio ‘Rs’ in ‘scf/stb’, oil viscosity ‘muo’ in ‘cp’, volatilized oil-gas ratio ‘Rv’ in ‘stb/scf’, gas formation volume factor ‘Bg’ in ‘bbl/scf’, gas viscosity ‘mug’ in ‘cp’, water formation volume factor ‘Bw’ in ‘bbl/stb’, and water viscosity ‘muw’ in ‘cp’.
• cf: Formation compressibility, a numeric value or vector, 1/psi.
• wf: Weight factor, a numeric vector of zeros and ones. A zero value excludes the entire row of reservoir history data at a particular time from the material balance analysis.
• sorg: Residual oil saturation in gas invaded zone (gas cap expansion or gas injection), a numeric fraction.
• rel_perm: A data frame with four columns: gas saturation ‘Sg’, liquid saturation ‘Sl’, gas relative permeability ‘Krg’, and oil relative permeability ‘Krog’.

mbal_forecast_oil() arguments

• forecast_lst: A list object of class ‘forecast_oil’.
• time_lst: A list object of class ‘time/date’.

mbal_forecast_oil() outputs

It returns a data frame with the following columns:

• P (psia): Average reservoir pressure.
• SOo: Average oil saturation in the oil leg.
• SGo: Average gas saturation in the oil leg.
• SWo: Average water saturation in the oil leg.
• SOT: Average oil saturation in the tank.
• SGT: Average gas saturation in the tank.
• SWT: Average water saturation in the tank.
• GOR (SCF/STB): Gas to oil ratio.
• RF_oil: Oil recovery factor.
• RF_gas: Gas recovery factor.
• Liq_dropout: Liquid dropout.
• Igd: Gas-cap-drive index.
• Isd: Solution-gas-drive index.
• Inwd: Natural-water-drive index.
• Ifwd: Compaction-connate_water-drive index.
• Iawd: Artificial-water-drive index.
• Itot: Total-drive index.

mbal_time() arguments

• x: A vector or sequence of times/dates.
• unit: A unit system for input vector x.

mbal_optim_param_gas() arguments

• input_unit: A unit system for parameters, only the character string ‘Field’ is accepted.
• output_unit: A unit system for properties, only the character string ‘Field’ is accepted.
• unknown_param: A character string showing the unknown parameter(s). One of the following options: ‘G’, ‘We’, ‘M’, or ‘G_M’.
• aquifer_model: Defaulted to NULL, otherwise must be a character string, one of the following eight options: ‘uss_rad_edge’, ‘uss_rad_bottom’, ‘uss_lin_edge’, ‘uss_lin_bottom’, ‘pss_rad_edge’, ‘pss_lin_edge’, ‘pss_lin_bottom’, ‘pot’. For further information about each model, please see ‘Raquifer’ package reference manual (https://CRAN.R-project.org/package=Raquifer).
• G: Original gas in place, SCF. If unknown, a NULL value must be assigned.
• phi: Reservoir porosity, a numeric fraction.
• swi: Initial water saturation in the reservoir, a numeric fraction.
• Np: Cumulative oil production, STB.
• Gp: Cumulative gas production, SCF.
• Wp: Cumulative water production, STB.
• Wi: Cumulative water injection, STB.
• We: Cumulative aquifer water influx, BBL. If unknown, a NULL value must be assigned.
• pd: Dew point pressure, a numeric value, psi.
• p: Reservoir pressure, a numeric vector, psi.
• pvt: A data frame of PVT properties including pressure ‘p’ in ‘psi’, oil formation volume factor ‘Bo’ in ‘bbl/stb’, solution gas-oil ratio ‘Rs’ in ‘scf/stb’, oil viscosity ‘muo’ in ‘cp’, volatilized oil-gas ratio ‘Rv’ in ‘stb/scf’, gas formation volume factor ‘Bg’ in ‘bbl/scf’, gas viscosity ‘mug’ in ‘cp’, water formation volume factor ‘Bw’ in ‘bbl/stb’, and water viscosity ‘muw’ in ‘cp’.
• cf: Formation compressibility, a numeric value or vector, 1/psi.
• M: Ratio of non-net-pay pore volume to the reservoir (net-pay) volume, a numeric fraction. If unknown, a NULL value must be assigned.
• phi_a: Aquifer porosity, a numeric fraction.
• perm_h_a: Aquifer horizontal permeability, md. Used in ‘uss_rad_edge’, ‘uss_rad_bottom’, ‘uss_lin_edge’, ‘pss_rad_edge’, ‘pss_lin_edge’ and ‘pot’ aquifer models.
• perm_v_a: Aquifer vertical permeability, md. Used in ‘uss_rad_bottom’, ‘uss_lin_bottom’, ‘pss_rad_bottom’, and ‘pss_lin_bottom’ aquifer models.
• h_a: Aquifer height, ft.
• r_a: Aquifer radius, ft. Used in ‘uss_rad_edge’, ‘uss_rad_bottom’, ‘pss_rad_edge’, and ‘pot’ aquifer models.
• r_R: Reservoir radius, ft. Used in ‘uss_rad_edge’, ‘uss_rad_bottom’, ‘pss_rad_edge’, and ‘pot’ aquifer models.
• w_a: Aquifer width, ft. Used in ‘uss_lin_edge’, ‘uss_lin_bottom’, ‘pss_lin_edge’, and ‘pss_lin_bottom’ aquifer models.
• l_a: Aquifer length, ft. Used in ‘uss_lin_edge’, ‘uss_lin_bottom’, ‘pss_lin_edge’, and ‘pss_lin_bottom’ aquifer models.
• tetha: Fraction of reservoir encircled by the aquifer, degrees. Used in ‘uss_rad_edge’, ‘pss_rad_edge’, and ‘pot’ aquifer models.
• muw_a: Aquifer water viscosity, cp.
• cw_a: Aquifer water compressibility, a numeric value, 1/psi.
• cf_a: Aquifer formation compressibility, a numeric value, 1/psi.
• wf: Weight factor, a numeric vector of zeros and ones. A zero value excludes the entire row of reservoir history data at a particular time from the material balance analysis.
• sgrw: Residual gas saturation in water invaded zone (aquifer encroachment or water injection), a numeric fraction.
• mult_len: A numeric vector of initial estimates for the ‘aquifer_model’ parameters. A vector of length one for the ‘pot’ aquifer model. It applies as a multiplier to the radius of the aquifer. A vector of length two for the ‘uss_rad_edge’, and ‘pss_rad_edge’ aquifer models. The first parameter is applied as a multiplier to the aquifer radius, and the second parameter is applied as a multiplier to the aquifer horizontal permeability. A vector of length two for the ‘uss_lin_edge’, and ‘pss_lin_edge’ aquifer models. The first parameter is applied as a multiplier to the aquifer length, and the second parameter is applied as a multiplier to the aquifer horizontal permeability. A vector of length two for the ‘uss_lin_bottom’, and ‘pss_lin_bottom’ aquifer models. The first parameter is applied as a multiplier to the aquifer height, and the second parameter is applied as a multiplier to the aquifer vertical permeability. A vector of length three for the ‘uss_rad_bottom’ aquifer model. The first parameter is applied as a multiplier to the aquifer radius, the second parameter is applied as a multiplier to the aquifer horizontal permeability, and the third parameter is applied as a multiplier to the aquifer vertical permeability.
• lower: An optional numeric vector of lower bounds for the ‘aquifer_model’ parameters. See ‘minpack.lm’ package for details.
• upper: An optional numeric vector of upper bounds for the ‘aquifer_model’ parameters. See ‘minpack.lm’ package for details.
• control: An optional list of control settings. See ‘minpack.lm’ package for details.

mbal_optim_gas() arguments

• optim_lst: A list object of class ‘optimization_gas’.
• time_lst: A list object of class ‘time/date’.

mbal_optim_gas() outputs

It returns a list object with the following elements and a class according to the ‘optim_lst’ inputs:

• input_unit: A unit system for parameters.
• output_unit: A unit system for properties.
• G: Original gas in place, SCF.
• phi: Reservoir porosity.
• swi: Initial water saturation in the reservoir.
• pd: Dew point pressure.
• p: Reservoir pressure vector.
• cf: Formation compressibility.
• M: Ratio of non-net-pay pore volume to the reservoir (net-pay) volume.
• pvt: A data frame of PVT properties including pressure ‘p’ in ‘psi’, oil formation volume factor ‘Bo’ in ‘bbl/stb’, solution gas-oil ratio ‘Rs’ in ‘scf/stb’, oil viscosity ‘muo’ in ‘cp’, volatilized oil-gas ratio ‘Rv’ in ‘stb/scf’, gas formation volume factor ‘Bg’ in ‘bbl/scf’, gas viscosity ‘mug’ in ‘cp’, water formation volume factor ‘Bw’ in ‘bbl/stb’, and water viscosity ‘muw’ in ‘cp’.
• prod: A data frame of production data, Np, Rp, and Wp.
• inj: A data frame of injection data, Gi, and Wi.
• We: A vector of aquifer encroached water into the reservoir.
• aquifer: A list of aquifer parameters and its class.
• wf: Weight factor.
• sgrw: Residual gas saturation in water invaded zone (aquifer encroachment or water injection).
• p_est: Estimated pressures from the material balance analysis.

mbal_perform_param_gas() arguments

• input_unit: A unit system for parameters, only the character string ‘Field’ is accepted.
• output_unit: A unit system for properties, only the character string ‘Field’ is accepted.
• aquifer_model: Defaulted to NULL, otherwise must be a character string, one of the following eight options: ‘uss_rad_edge’, ‘uss_rad_bottom’, ‘uss_lin_edge’, ‘uss_lin_bottom’, ‘pss_rad_edge’, ‘pss_lin_edge’, ‘pss_lin_bottom’, ‘pot’. For further information about each model, please see ‘Raquifer’ package reference manual.
• G: Original gas in place, SCF.
• phi: Reservoir porosity, a numeric fraction.
• swi: Initial water saturation in the reservoir, a numeric fraction.
• Np: Cumulative oil production, STB.
• Gp: Cumulative gas production, SCF.
• Wp: Cumulative water production, STB.
• Wi: Cumulative water injection, STB.
• We: Cumulative aquifer water influx, BBL. If unknown, a NULL value must be assigned.
• pd: Dew point pressure, a numeric value, psi.
• p: Reservoir pressure, a numeric vector, psi.
• pvt: A data frame of PVT properties including pressure ‘p’ in ‘psi’, oil formation volume factor ‘Bo’ in ‘bbl/stb’, solution gas-oil ratio ‘Rs’ in ‘scf/stb’, oil viscosity ‘muo’ in ‘cp’, volatilized oil-gas ratio ‘Rv’ in ‘stb/scf’, gas formation volume factor ‘Bg’ in ‘bbl/scf’, gas viscosity ‘mug’ in ‘cp’, water formation volume factor ‘Bw’ in ‘bbl/stb’, and water viscosity ‘muw’ in ‘cp’.
• cf: Formation compressibility, a numeric value or vector, 1/psi.
• M: Ratio of non-net-pay pore volume to the reservoir (net-pay) volume, a numeric fraction.
• phi_a: Aquifer porosity, a numeric fraction.
• perm_h_a: Aquifer horizontal permeability, md. Used in ‘uss_rad_edge’, ‘uss_rad_bottom’, ‘uss_lin_edge’, ‘pss_rad_edge’, ‘pss_lin_edge’ and ‘pot’ aquifer models.
• perm_v_a: Aquifer vertical permeability, md. Used in ‘uss_rad_bottom’, ‘uss_lin_bottom’, ‘pss_rad_bottom’, and ‘pss_lin_bottom’ aquifer models.
• h_a: Aquifer height, ft.
• r_a: Aquifer radius, ft. Used in ‘uss_rad_edge’, ‘uss_rad_bottom’, ‘pss_rad_edge’, and ‘pot’ aquifer models.
• r_R: Reservoir radius, ft. Used in ‘uss_rad_edge’, ‘uss_rad_bottom’, ‘pss_rad_edge’, and ‘pot’ aquifer models.
• w_a: Aquifer width, ft. Used in ‘uss_lin_edge’, ‘uss_lin_bottom’, ‘pss_lin_edge’, and ‘pss_lin_bottom’ aquifer models.
• l_a: Aquifer length, ft. Used in ‘uss_lin_edge’, ‘uss_lin_bottom’, ‘pss_lin_edge’, and ‘pss_lin_bottom’ aquifer models.
• tetha: Fraction of reservoir encircled by the aquifer, degrees. Used in ‘uss_rad_edge’, ‘pss_rad_edge’, and ‘pot’ aquifer models.
• muw_a: Aquifer water viscosity, cp.
• cw_a: Aquifer water compressibility, a numeric value, 1/psi.
• cf_a: Aquifer formation compressibility, a numeric value, 1/psi.
• wf: Weight factor, a numeric vector of zeros and ones. A zero value excludes the entire row of reservoir history data at a particular time from the material balance analysis.
• sgrw: Residual gas saturation in water invaded zone (aquifer encroachment or water injection), a numeric fraction.

mbal_perform_gas() arguments

• mbal_lst: A list object of class ‘mbal_gas’.
• time_lst: A list object of class ‘time/date’.

mbal_perform_gas() outputs

It returns a data frame with the following columns:

• P (psia): Average reservoir pressure.
• Eo (bbl/STB): Oil expansivity.
• Eg (bbl/SCF): Gas expansivity.
• Ew (bbl/STB): Water expansivity.
• Ef (bbl/bbl): Rock expansivity.
• Egwf (bbl/SCF): Composite expansivity.
• Et (bbl): Total reservoir expansion.
• F (bbl): Net fluid withdrawal.
• We: Aquifer encroached water.
• Igd: Gas-expansion-drive index.
• Inwd: Natural-water-drive index.
• Ifwd: Compaction-connate_water-drive index.
• Iawd: Artificial-water-drive index.
• Itot: Total-drive index.
• RF_oil: Oil(condensate) recovery factor.
• RF_gas: Gas recovery factor.
• SOg: Average oil(condensate) saturation in gas leg.
• SGg: Average gas saturation in the gas leg.
• SWg: Average water saturation in the gas leg.
• SOT: Average oil(condensate) saturation in the tank.
• SGT: Average gas saturation in the tank.
• SWT: Average water saturation in the tank.
• qo (STB/day): Average oil(condensate) rate within the period.
• qg (SCF/day): Average gas rate within the period.
• qw (STB/day): Average water rate within the period.
• fo: In-situ free-oil(condensate) fractional flow.
• fw: In-situ water fractional flow.
• GOR (SCF/STB): Gas to oil ratio.
• kro/krg: Ratio of oil(condensate) relative permeability to gas relative permeability in the gas leg.

mbal_forecast_param_gas() arguments

• input_unit: A unit system for parameters, only the character string ‘Field’ is accepted.
• output_unit: A unit system for properties, only the character string ‘Field’ is accepted.
• aquifer_model: Defaulted to NULL, otherwise must be a character string, one of the following eight options: ‘uss_rad_edge’, ‘uss_rad_bottom’, ‘uss_lin_edge’, ‘uss_lin_bottom’, ‘pss_rad_edge’, ‘pss_lin_edge’, ‘pss_lin_bottom’, ‘pot’. For further information about each model, please see ‘Raquifer’ package reference manual.
• G: Original gas in place, SCF.
• phi: Reservoir porosity, a numeric fraction.
• swi: Initial water saturation in the reservoir, a numeric fraction.
• Np: Cumulative oil production, STB.
• Gp: Cumulative gas production, SCF.
• pd: Dew point pressure, a numeric value, psi.
• p: Reservoir pressure, a numeric vector, psi.
• pvt: A data frame of PVT properties including pressure ‘p’ in ‘psi’, oil formation volume factor ‘Bo’ in ‘bbl/stb’, solution gas-oil ratio ‘Rs’ in ‘scf/stb’, oil viscosity ‘muo’ in ‘cp’, volatilized oil-gas ratio ‘Rv’ in ‘stb/scf’, gas formation volume factor ‘Bg’ in ‘bbl/scf’, gas viscosity ‘mug’ in ‘cp’, water formation volume factor ‘Bw’ in ‘bbl/stb’, and water viscosity ‘muw’ in ‘cp’.
• cf: Formation compressibility, a numeric value or vector, 1/psi.
• M: Ratio of non-net-pay pore volume to the reservoir (net-pay) volume, a numeric fraction.
• wf: Weight factor, a numeric vector of zeros and ones. A zero value excludes the entire row of reservoir history data at a particular time from the material balance analysis.
• sgrw: Residual gas saturation in water invaded zone (aquifer encroachment or water injection), a numeric fraction.
• rel_perm: A data frame with four columns: gas saturation ‘Sg’, liquid saturation ‘Sl’, gas relative permeability ‘Krg’, and oil relative permeability ‘Krog’.

mbal_forecast_gas() arguments

• forecast_lst: A list object of class ‘forecast_gas’.
• time_lst: A list object of class ‘time/date’.

mbal_forecast_gas() outputs

It returns a data frame with the following columns:

• P (psia): Average reservoir pressure.
• SOg: Average oil saturation in the gas leg.
• SGg: Average gas saturation in the gas leg.
• SWg: Average water saturation in the gas leg.
• SOT: Average oil saturation in the tank.
• SGT: Average gas saturation in the tank.
• SWT: Average water saturation in the tank.
• GOR (SCF/STB): Gas to oil ratio.
• RF_oil: Oil recovery factor.
• RF_gas: Gas recovery factor.
• Liq_dropout: Liquid dropout.
• Igd: Gas-expansion-drive index.
• Inwd: Natural-water-drive index.
• Ifwd: Compaction-connate_water-drive index.
• Iawd: Artificial-water-drive index.
• Itot: Total-drive index.