WetGasPvt.hpp

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// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
// vi: set et ts=4 sw=4 sts=4:
/*
  This file is part of the Open Porous Media project (OPM).
 
  OPM is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 2 of the License, or
  (at your option) any later version.
 
  OPM is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.
 
  You should have received a copy of the GNU General Public License
  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
 
  Consult the COPYING file in the top-level source directory of this
  module for the precise wording of the license and the list of
  copyright holders.
*/
#ifndef OPM_WET_GAS_PVT_HPP
#define OPM_WET_GAS_PVT_HPP
 
#include <opm/material/common/MathToolbox.hpp>
#include <opm/material/common/UniformXTabulated2DFunction.hpp>
#include <opm/material/common/Tabulated1DFunction.hpp>
 
#if HAVE_ECL_INPUT
#include <opm/input/eclipse/EclipseState/EclipseState.hpp>
#include <opm/input/eclipse/EclipseState/Tables/TableManager.hpp>
#include <opm/input/eclipse/Schedule/OilVaporizationProperties.hpp>
#endif
 
#if HAVE_OPM_COMMON
#include <opm/common/OpmLog/OpmLog.hpp>
#endif
 
namespace Opm {
 
template <class Scalar>
class WetGasPvt
{
    using SamplingPoints = std::vector<std::pair<Scalar, Scalar>>;
 
public:
    using TabulatedTwoDFunction = UniformXTabulated2DFunction<Scalar>;
    using TabulatedOneDFunction = Tabulated1DFunction<Scalar>;
 
    WetGasPvt()
    {
        vapPar1_ = 0.0;
    }
 
    WetGasPvt(const std::vector<Scalar>& gasReferenceDensity,
              const std::vector<Scalar>& oilReferenceDensity,
              const std::vector<TabulatedTwoDFunction>& inverseGasB,
              const std::vector<TabulatedOneDFunction>& inverseSaturatedGasB,
              const std::vector<TabulatedTwoDFunction>& gasMu,
              const std::vector<TabulatedTwoDFunction>& inverseGasBMu,
              const std::vector<TabulatedOneDFunction>& inverseSaturatedGasBMu,
              const std::vector<TabulatedOneDFunction>& saturatedOilVaporizationFactorTable,
              const std::vector<TabulatedOneDFunction>& saturationPressure,
              Scalar vapPar1)
        : gasReferenceDensity_(gasReferenceDensity)
        , oilReferenceDensity_(oilReferenceDensity)
        , inverseGasB_(inverseGasB)
        , inverseSaturatedGasB_(inverseSaturatedGasB)
        , gasMu_(gasMu)
        , inverseGasBMu_(inverseGasBMu)
        , inverseSaturatedGasBMu_(inverseSaturatedGasBMu)
        , saturatedOilVaporizationFactorTable_(saturatedOilVaporizationFactorTable)
        , saturationPressure_(saturationPressure)
        , vapPar1_(vapPar1)
    {
    }
 
 
#if HAVE_ECL_INPUT
    void initFromState(const EclipseState& eclState, const Schedule& schedule)
    {
        const auto& pvtgTables = eclState.getTableManager().getPvtgTables();
        const auto& densityTable = eclState.getTableManager().getDensityTable();
 
        assert(pvtgTables.size() == densityTable.size());
 
        size_t numRegions = pvtgTables.size();
        setNumRegions(numRegions);
 
        for (unsigned regionIdx = 0; regionIdx < numRegions; ++ regionIdx) {
            Scalar rhoRefO = densityTable[regionIdx].oil;
            Scalar rhoRefG = densityTable[regionIdx].gas;
            Scalar rhoRefW = densityTable[regionIdx].water;
 
            setReferenceDensities(regionIdx, rhoRefO, rhoRefG, rhoRefW);
        }
 
        for (unsigned regionIdx = 0; regionIdx < numRegions; ++ regionIdx) {
            const auto& pvtgTable = pvtgTables[regionIdx];
 
            const auto& saturatedTable = pvtgTable.getSaturatedTable();
            assert(saturatedTable.numRows() > 1);
 
            auto& gasMu = gasMu_[regionIdx];
            auto& invGasB = inverseGasB_[regionIdx];
            auto& invSatGasB = inverseSaturatedGasB_[regionIdx];
            auto& invSatGasBMu = inverseSaturatedGasBMu_[regionIdx];
            auto& oilVaporizationFac = saturatedOilVaporizationFactorTable_[regionIdx];
 
            oilVaporizationFac.setXYArrays(saturatedTable.numRows(),
                                           saturatedTable.getColumn("PG"),
                                           saturatedTable.getColumn("RV"));
 
            std::vector<Scalar> invSatGasBArray;
            std::vector<Scalar> invSatGasBMuArray;
 
            // extract the table for the gas dissolution and the oil formation volume factors
            for (unsigned outerIdx = 0; outerIdx < saturatedTable.numRows(); ++ outerIdx) {
                Scalar pg = saturatedTable.get("PG" , outerIdx);
                Scalar B = saturatedTable.get("BG" , outerIdx);
                Scalar mu = saturatedTable.get("MUG" , outerIdx);
 
                invGasB.appendXPos(pg);
                gasMu.appendXPos(pg);
 
                invSatGasBArray.push_back(1.0/B);
                invSatGasBMuArray.push_back(1.0/(mu*B));
 
                assert(invGasB.numX() == outerIdx + 1);
                assert(gasMu.numX() == outerIdx + 1);
 
                const auto& underSaturatedTable = pvtgTable.getUnderSaturatedTable(outerIdx);
                size_t numRows = underSaturatedTable.numRows();
                for (size_t innerIdx = 0; innerIdx < numRows; ++ innerIdx) {
                    Scalar Rv = underSaturatedTable.get("RV" , innerIdx);
                    Scalar Bg = underSaturatedTable.get("BG" , innerIdx);
                    Scalar mug = underSaturatedTable.get("MUG" , innerIdx);
 
                    invGasB.appendSamplePoint(outerIdx, Rv, 1.0/Bg);
                    gasMu.appendSamplePoint(outerIdx, Rv, mug);
                }
            }
 
            {
                std::vector<double> tmpPressure =  saturatedTable.getColumn("PG").vectorCopy( );
 
                invSatGasB.setXYContainers(tmpPressure, invSatGasBArray);
                invSatGasBMu.setXYContainers(tmpPressure, invSatGasBMuArray);
            }
 
            // make sure to have at least two sample points per gas pressure value
            for (unsigned xIdx = 0; xIdx < invGasB.numX(); ++xIdx) {
               // a single sample point is definitely needed
                assert(invGasB.numY(xIdx) > 0);
 
                // everything is fine if the current table has two or more sampling points
                // for a given mole fraction
                if (invGasB.numY(xIdx) > 1)
                    continue;
 
                // find the master table which will be used as a template to extend the
                // current line. We define master table as the first table which has values
                // for undersaturated gas...
                size_t masterTableIdx = xIdx + 1;
                for (; masterTableIdx < saturatedTable.numRows(); ++masterTableIdx)
                {
                    if (pvtgTable.getUnderSaturatedTable(masterTableIdx).numRows() > 1)
                        break;
                }
 
                if (masterTableIdx >= saturatedTable.numRows())
                    throw std::runtime_error("PVTG tables are invalid: The last table must exhibit at least one "
                              "entry for undersaturated gas!");
 
 
                // extend the current table using the master table.
                extendPvtgTable_(regionIdx,
                                 xIdx,
                                 pvtgTable.getUnderSaturatedTable(xIdx),
                                 pvtgTable.getUnderSaturatedTable(masterTableIdx));
            }
        }
 
        vapPar1_ = 0.0;
        const auto& oilVap = schedule[0].oilvap();
        if (oilVap.getType() == OilVaporizationProperties::OilVaporization::VAPPARS) {
            vapPar1_ = oilVap.vap1();
        }
 
        initEnd();
    }
 
private:
    void extendPvtgTable_(unsigned regionIdx,
                          unsigned xIdx,
                          const SimpleTable& curTable,
                          const SimpleTable& masterTable)
    {
        std::vector<double> RvArray = curTable.getColumn("RV").vectorCopy();
        std::vector<double> gasBArray = curTable.getColumn("BG").vectorCopy();
        std::vector<double> gasMuArray = curTable.getColumn("MUG").vectorCopy();
 
        auto& invGasB = inverseGasB_[regionIdx];
        auto& gasMu = gasMu_[regionIdx];
 
        for (size_t newRowIdx = 1; newRowIdx < masterTable.numRows(); ++ newRowIdx) {
            const auto& RVColumn = masterTable.getColumn("RV");
            const auto& BGColumn = masterTable.getColumn("BG");
            const auto& viscosityColumn = masterTable.getColumn("MUG");
 
            // compute the gas pressure for the new entry
            Scalar diffRv = RVColumn[newRowIdx] - RVColumn[newRowIdx - 1];
            Scalar newRv = RvArray.back() + diffRv;
 
            // calculate the compressibility of the master table
            Scalar B1 = BGColumn[newRowIdx];
            Scalar B2 = BGColumn[newRowIdx - 1];
            Scalar x = (B1 - B2)/( (B1 + B2)/2.0 );
 
            // calculate the gas formation volume factor which exhibits the same
            // "compressibility" for the new value of Rv
            Scalar newBg = gasBArray.back()*(1.0 + x/2.0)/(1.0 - x/2.0);
 
            // calculate the "viscosibility" of the master table
            Scalar mu1 = viscosityColumn[newRowIdx];
            Scalar mu2 = viscosityColumn[newRowIdx - 1];
            Scalar xMu = (mu1 - mu2)/( (mu1 + mu2)/2.0 );
 
            // calculate the gas formation volume factor which exhibits the same
            // compressibility for the new pressure
            Scalar newMug = gasMuArray.back()*(1.0 + xMu/2)/(1.0 - xMu/2.0);
 
            // append the new values to the arrays which we use to compute the additional
            // values ...
            RvArray.push_back(newRv);
            gasBArray.push_back(newBg);
            gasMuArray.push_back(newMug);
 
            // ... and register them with the internal table objects
            invGasB.appendSamplePoint(xIdx, newRv, 1.0/newBg);
            gasMu.appendSamplePoint(xIdx, newRv, newMug);
        }
    }
 
public:
#endif // HAVE_ECL_INPUT
 
    void setNumRegions(size_t numRegions)
    {
        oilReferenceDensity_.resize(numRegions);
        gasReferenceDensity_.resize(numRegions);
        inverseGasB_.resize(numRegions, TabulatedTwoDFunction{TabulatedTwoDFunction::InterpolationPolicy::RightExtreme});
        inverseGasBMu_.resize(numRegions, TabulatedTwoDFunction{TabulatedTwoDFunction::InterpolationPolicy::RightExtreme});
        inverseSaturatedGasB_.resize(numRegions);
        inverseSaturatedGasBMu_.resize(numRegions);
        gasMu_.resize(numRegions, TabulatedTwoDFunction{TabulatedTwoDFunction::InterpolationPolicy::RightExtreme});
        saturatedOilVaporizationFactorTable_.resize(numRegions);
        saturationPressure_.resize(numRegions);
    }
 
    void setReferenceDensities(unsigned regionIdx,
                               Scalar rhoRefOil,
                               Scalar rhoRefGas,
                               Scalar /*rhoRefWater*/)
    {
        oilReferenceDensity_[regionIdx] = rhoRefOil;
        gasReferenceDensity_[regionIdx] = rhoRefGas;
    }
 
    void setSaturatedGasOilVaporizationFactor(unsigned regionIdx, const SamplingPoints& samplePoints)
    { saturatedOilVaporizationFactorTable_[regionIdx].setContainerOfTuples(samplePoints); }
 
    void setSaturatedGasFormationVolumeFactor(unsigned regionIdx, const SamplingPoints& samplePoints)
    {
        auto& invGasB = inverseGasB_[regionIdx];
 
        const auto& RvTable = saturatedOilVaporizationFactorTable_[regionIdx];
 
        constexpr const Scalar T = 273.15 + 15.56; // [K]
 
        constexpr const Scalar RvMin = 0.0;
        Scalar RvMax = RvTable.eval(saturatedOilVaporizationFactorTable_[regionIdx].xMax(), /*extrapolate=*/true);
 
        Scalar poMin = samplePoints.front().first;
        Scalar poMax = samplePoints.back().first;
 
        constexpr const size_t nRv = 20;
        size_t nP = samplePoints.size()*2;
 
        Scalar rhooRef = oilReferenceDensity_[regionIdx];
 
        TabulatedOneDFunction gasFormationVolumeFactor;
        gasFormationVolumeFactor.setContainerOfTuples(samplePoints);
 
        updateSaturationPressure_(regionIdx);
 
        // calculate a table of estimated densities depending on pressure and gas mass
        // fraction. note that this assumes oil of constant compressibility. (having said
        // that, if only the saturated gas densities are available, there's not much
        // choice.)
        for (size_t RvIdx = 0; RvIdx < nRv; ++RvIdx) {
            Scalar Rv = RvMin + (RvMax - RvMin)*RvIdx/nRv;
 
            invGasB.appendXPos(Rv);
 
            for (size_t pIdx = 0; pIdx < nP; ++pIdx) {
                Scalar pg = poMin + (poMax - poMin)*pIdx/nP;
 
                Scalar poSat = saturationPressure(regionIdx, T, Rv);
                Scalar BgSat = gasFormationVolumeFactor.eval(poSat, /*extrapolate=*/true);
                Scalar drhoo_dp = (1.1200 - 1.1189)/((5000 - 4000)*6894.76);
                Scalar rhoo = rhooRef/BgSat*(1 + drhoo_dp*(pg - poSat));
 
                Scalar Bg = rhooRef/rhoo;
 
                invGasB.appendSamplePoint(RvIdx, pg, 1.0/Bg);
            }
        }
    }
 
    void setInverseGasFormationVolumeFactor(unsigned regionIdx, const TabulatedTwoDFunction& invBg)
    { inverseGasB_[regionIdx] = invBg; }
 
    void setGasViscosity(unsigned regionIdx, const TabulatedTwoDFunction& mug)
    { gasMu_[regionIdx] = mug; }
 
    void setSaturatedGasViscosity(unsigned regionIdx, const SamplingPoints& samplePoints  )
    {
        auto& oilVaporizationFac = saturatedOilVaporizationFactorTable_[regionIdx];
 
        constexpr const Scalar RvMin = 0.0;
        Scalar RvMax = oilVaporizationFac.eval(saturatedOilVaporizationFactorTable_[regionIdx].xMax(), /*extrapolate=*/true);
 
        Scalar poMin = samplePoints.front().first;
        Scalar poMax = samplePoints.back().first;
 
        constexpr const size_t nRv = 20;
        size_t nP = samplePoints.size()*2;
 
        TabulatedOneDFunction mugTable;
        mugTable.setContainerOfTuples(samplePoints);
 
        // calculate a table of estimated densities depending on pressure and gas mass
        // fraction
        for (size_t RvIdx = 0; RvIdx < nRv; ++RvIdx) {
            Scalar Rv = RvMin + (RvMax - RvMin)*RvIdx/nRv;
 
            gasMu_[regionIdx].appendXPos(Rv);
 
            for (size_t pIdx = 0; pIdx < nP; ++pIdx) {
                Scalar pg = poMin + (poMax - poMin)*pIdx/nP;
                Scalar mug = mugTable.eval(pg, /*extrapolate=*/true);
 
                gasMu_[regionIdx].appendSamplePoint(RvIdx, pg, mug);
            }
        }
    }
 
    void initEnd()
    {
        // calculate the final 2D functions which are used for interpolation.
        size_t numRegions = gasMu_.size();
        for (unsigned regionIdx = 0; regionIdx < numRegions; ++ regionIdx) {
            // calculate the table which stores the inverse of the product of the gas
            // formation volume factor and the gas viscosity
            const auto& gasMu = gasMu_[regionIdx];
            const auto& invGasB = inverseGasB_[regionIdx];
            assert(gasMu.numX() == invGasB.numX());
 
            auto& invGasBMu = inverseGasBMu_[regionIdx];
            auto& invSatGasB = inverseSaturatedGasB_[regionIdx];
            auto& invSatGasBMu = inverseSaturatedGasBMu_[regionIdx];
 
            std::vector<Scalar> satPressuresArray;
            std::vector<Scalar> invSatGasBArray;
            std::vector<Scalar> invSatGasBMuArray;
            for (size_t pIdx = 0; pIdx < gasMu.numX(); ++pIdx) {
                invGasBMu.appendXPos(gasMu.xAt(pIdx));
 
                assert(gasMu.numY(pIdx) == invGasB.numY(pIdx));
 
                size_t numRv = gasMu.numY(pIdx);
                for (size_t rvIdx = 0; rvIdx < numRv; ++rvIdx)
                    invGasBMu.appendSamplePoint(pIdx,
                                                gasMu.yAt(pIdx, rvIdx),
                                                invGasB.valueAt(pIdx, rvIdx)
                                                / gasMu.valueAt(pIdx, rvIdx));
 
                // the sampling points in UniformXTabulated2DFunction are always sorted
                // in ascending order. Thus, the value for saturated gas is the last one
                // (i.e., the one with the largest Rv value)
                satPressuresArray.push_back(gasMu.xAt(pIdx));
                invSatGasBArray.push_back(invGasB.valueAt(pIdx, numRv - 1));
                invSatGasBMuArray.push_back(invGasBMu.valueAt(pIdx, numRv - 1));
            }
 
            invSatGasB.setXYContainers(satPressuresArray, invSatGasBArray);
            invSatGasBMu.setXYContainers(satPressuresArray, invSatGasBMuArray);
 
            updateSaturationPressure_(regionIdx);
        }
    }
 
    unsigned numRegions() const
    { return gasReferenceDensity_.size(); }
 
    template <class Evaluation>
    Evaluation internalEnergy(unsigned,
                        const Evaluation&,
                        const Evaluation&,
                        const Evaluation&) const
    {
        throw std::runtime_error("Requested the enthalpy of gas but the thermal option is not enabled");
    }
 
    template <class Evaluation>
    Evaluation viscosity(unsigned regionIdx,
                         const Evaluation& /*temperature*/,
                         const Evaluation& pressure,
                         const Evaluation& Rv,
                         const Evaluation& /*Rvw*/) const
    {
        const Evaluation& invBg = inverseGasB_[regionIdx].eval(pressure, Rv, /*extrapolate=*/true);
        const Evaluation& invMugBg = inverseGasBMu_[regionIdx].eval(pressure, Rv, /*extrapolate=*/true);
 
        return invBg/invMugBg;
    }
 
    template <class Evaluation>
    Evaluation saturatedViscosity(unsigned regionIdx,
                                  const Evaluation& /*temperature*/,
                                  const Evaluation& pressure) const
    {
        const Evaluation& invBg = inverseSaturatedGasB_[regionIdx].eval(pressure, /*extrapolate=*/true);
        const Evaluation& invMugBg = inverseSaturatedGasBMu_[regionIdx].eval(pressure, /*extrapolate=*/true);
 
        return invBg/invMugBg;
    }
 
    template <class Evaluation>
    Evaluation inverseFormationVolumeFactor(unsigned regionIdx,
                                            const Evaluation& /*temperature*/,
                                            const Evaluation& pressure,
                                            const Evaluation& Rv,
                                            const Evaluation& /*Rvw*/) const
    { return inverseGasB_[regionIdx].eval(pressure, Rv, /*extrapolate=*/true); }
 
    template <class Evaluation>
    Evaluation saturatedInverseFormationVolumeFactor(unsigned regionIdx,
                                                     const Evaluation& /*temperature*/,
                                                     const Evaluation& pressure) const
    { return inverseSaturatedGasB_[regionIdx].eval(pressure, /*extrapolate=*/true); }
 
    template <class Evaluation>
    Evaluation saturatedWaterVaporizationFactor(unsigned /*regionIdx*/,
                                              const Evaluation& /*temperature*/,
                                              const Evaluation& /*pressure*/) const
    { return 0.0; /* this is non-humid gas! */ }
 
    template <class Evaluation = Scalar>
    Evaluation saturatedWaterVaporizationFactor(unsigned /*regionIdx*/,
                                              const Evaluation& /*temperature*/,
                                              const Evaluation& /*pressure*/, 
                                              const Evaluation& /*saltConcentration*/) const
    { return 0.0; }
 
    template <class Evaluation>
    Evaluation saturatedOilVaporizationFactor(unsigned regionIdx,
                                              const Evaluation& /*temperature*/,
                                              const Evaluation& pressure) const
    {
        return saturatedOilVaporizationFactorTable_[regionIdx].eval(pressure, /*extrapolate=*/true);
    }
 
    template <class Evaluation>
    Evaluation saturatedOilVaporizationFactor(unsigned regionIdx,
                                              const Evaluation& /*temperature*/,
                                              const Evaluation& pressure,
                                              const Evaluation& oilSaturation,
                                              Evaluation maxOilSaturation) const
    {
        Evaluation tmp =
            saturatedOilVaporizationFactorTable_[regionIdx].eval(pressure, /*extrapolate=*/true);
 
        // apply the vaporization parameters for the gas phase (cf. the Eclipse VAPPARS
        // keyword)
        maxOilSaturation = min(maxOilSaturation, Scalar(1.0));
        if (vapPar1_ > 0.0 && maxOilSaturation > 0.01 && oilSaturation < maxOilSaturation) {
            constexpr const Scalar eps = 0.001;
            const Evaluation& So = max(oilSaturation, eps);
            tmp *= max(1e-3, pow(So/maxOilSaturation, vapPar1_));
        }
 
        return tmp;
    }
 
    template <class Evaluation>
    Evaluation saturationPressure(unsigned regionIdx,
                                  const Evaluation&,
                                  const Evaluation& Rv) const
    {
        typedef MathToolbox<Evaluation> Toolbox;
 
        const auto& RvTable = saturatedOilVaporizationFactorTable_[regionIdx];
        constexpr const Scalar eps = std::numeric_limits<typename Toolbox::Scalar>::epsilon()*1e6;
 
        // use the tabulated saturation pressure function to get a pretty good initial value
        Evaluation pSat = saturationPressure_[regionIdx].eval(Rv, /*extrapolate=*/true);
 
        // Newton method to do the remaining work. If the initial
        // value is good, this should only take two to three
        // iterations...
        bool onProbation = false;
        for (unsigned i = 0; i < 20; ++i) {
            const Evaluation& f = RvTable.eval(pSat, /*extrapolate=*/true) - Rv;
            const Evaluation& fPrime = RvTable.evalDerivative(pSat, /*extrapolate=*/true);
 
            // If the derivative is "zero" Newton will not converge,
            // so simply return our initial guess.
            if (std::abs(scalarValue(fPrime)) < 1.0e-30) {
                return pSat;
            }
 
            const Evaluation& delta = f/fPrime;
 
            pSat -= delta;
 
            if (pSat < 0.0) {
                // if the pressure is lower than 0 Pascals, we set it back to 0. if this
                // happens twice, we give up and just return 0 Pa...
                if (onProbation)
                    return 0.0;
 
                onProbation = true;
                pSat = 0.0;
            }
 
            if (std::abs(scalarValue(delta)) < std::abs(scalarValue(pSat))*eps)
                return pSat;
        }
 
        std::stringstream errlog;
        errlog << "Finding saturation pressure did not converge:"
               << " pSat = " << pSat
               << ", Rv = " << Rv;
#if HAVE_OPM_COMMON
        OpmLog::debug("Wet gas saturation pressure", errlog.str());
#endif
        throw NumericalIssue(errlog.str());
    }
 
    template <class Evaluation>
    Evaluation diffusionCoefficient(const Evaluation& /*temperature*/,
                                    const Evaluation& /*pressure*/,
                                    unsigned /*compIdx*/) const
    {
        throw std::runtime_error("Not implemented: The PVT model does not provide a diffusionCoefficient()");
    }
 
    const Scalar gasReferenceDensity(unsigned regionIdx) const
    { return gasReferenceDensity_[regionIdx]; }
 
    const Scalar oilReferenceDensity(unsigned regionIdx) const
    { return oilReferenceDensity_[regionIdx]; }
 
    const std::vector<TabulatedTwoDFunction>& inverseGasB() const {
        return inverseGasB_;
    }
 
    const std::vector<TabulatedOneDFunction>& inverseSaturatedGasB() const {
        return inverseSaturatedGasB_;
    }
 
    const std::vector<TabulatedTwoDFunction>& gasMu() const {
        return gasMu_;
    }
 
    const std::vector<TabulatedTwoDFunction>& inverseGasBMu() const {
        return inverseGasBMu_;
    }
 
    const std::vector<TabulatedOneDFunction>& inverseSaturatedGasBMu() const {
        return inverseSaturatedGasBMu_;
    }
 
    const std::vector<TabulatedOneDFunction>& saturatedOilVaporizationFactorTable() const {
        return saturatedOilVaporizationFactorTable_;
    }
 
    const std::vector<TabulatedOneDFunction>& saturationPressure() const {
        return saturationPressure_;
    }
 
    Scalar vapPar1() const {
        return vapPar1_;
    }
 
    bool operator==(const WetGasPvt<Scalar>& data) const
    {
        return this->gasReferenceDensity_ == data.gasReferenceDensity_ &&
               this->oilReferenceDensity_ == data.oilReferenceDensity_ &&
               this->inverseGasB() == data.inverseGasB() &&
               this->inverseSaturatedGasB() == data.inverseSaturatedGasB() &&
               this->gasMu() == data.gasMu() &&
               this->inverseGasBMu() == data.inverseGasBMu() &&
               this->inverseSaturatedGasBMu() == data.inverseSaturatedGasBMu() &&
               this->saturatedOilVaporizationFactorTable() == data.saturatedOilVaporizationFactorTable() &&
               this->saturationPressure() == data.saturationPressure() &&
               this->vapPar1() == data.vapPar1();
    }
 
private:
    void updateSaturationPressure_(unsigned regionIdx)
    {
        const auto& oilVaporizationFac = saturatedOilVaporizationFactorTable_[regionIdx];
 
        // create the taublated function representing saturation pressure depending of
        // Rv
        size_t n = oilVaporizationFac.numSamples();
        Scalar delta = (oilVaporizationFac.xMax() - oilVaporizationFac.xMin())/Scalar(n + 1);
 
        SamplingPoints pSatSamplePoints;
        Scalar Rv = 0;
        for (size_t i = 0; i <= n; ++ i) {
            Scalar pSat = oilVaporizationFac.xMin() + Scalar(i)*delta;
            Rv = saturatedOilVaporizationFactor(regionIdx, /*temperature=*/Scalar(1e30), pSat);
 
            pSatSamplePoints.emplace_back(Rv, pSat);
        }
 
        //Prune duplicate Rv values (can occur, and will cause problems in further interpolation)
        auto x_coord_comparator = [](const auto& a, const auto& b) { return a.first == b.first; };
        auto last = std::unique(pSatSamplePoints.begin(), pSatSamplePoints.end(), x_coord_comparator);
        if (std::distance(pSatSamplePoints.begin(), last) > 1) // only remove them if there are more than two points
            pSatSamplePoints.erase(last, pSatSamplePoints.end());
 
        saturationPressure_[regionIdx].setContainerOfTuples(pSatSamplePoints);
    }
 
    std::vector<Scalar> gasReferenceDensity_;
    std::vector<Scalar> oilReferenceDensity_;
    std::vector<TabulatedTwoDFunction> inverseGasB_;
    std::vector<TabulatedOneDFunction> inverseSaturatedGasB_;
    std::vector<TabulatedTwoDFunction> gasMu_;
    std::vector<TabulatedTwoDFunction> inverseGasBMu_;
    std::vector<TabulatedOneDFunction> inverseSaturatedGasBMu_;
    std::vector<TabulatedOneDFunction> saturatedOilVaporizationFactorTable_;
    std::vector<TabulatedOneDFunction> saturationPressure_;
 
    Scalar vapPar1_;
};
 
} // namespace Opm
 
#endif