BlackoilWellModel.hpp

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/*
  Copyright 2016 SINTEF ICT, Applied Mathematics.
  Copyright 2016 - 2017 Statoil ASA.
  Copyright 2017 Dr. Blatt - HPC-Simulation-Software & Services
  Copyright 2016 - 2018 IRIS AS
 
  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 3 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/>.
*/
 
#ifndef OPM_BLACKOILWELLMODEL_HEADER_INCLUDED
#define OPM_BLACKOILWELLMODEL_HEADER_INCLUDED
 
#include <dune/common/fmatrix.hh>
 
#include <dune/istl/bcrsmatrix.hh>
#include <dune/istl/matrixmatrix.hh>
 
#include <opm/common/OpmLog/OpmLog.hpp>
 
#include <opm/input/eclipse/Schedule/Group/Group.hpp>
#include <opm/input/eclipse/Schedule/Group/GuideRate.hpp>
#include <opm/input/eclipse/Schedule/Schedule.hpp>
#include <opm/input/eclipse/Schedule/Well/WellTestState.hpp>
 
#include <opm/material/densead/Math.hpp>
 
#include <opm/simulators/flow/countGlobalCells.hpp>
#include <opm/simulators/flow/FlowBaseVanguard.hpp>
 
#include <opm/simulators/linalg/matrixblock.hh>
 
#include <opm/simulators/timestepping/SimulatorReport.hpp>
#include <opm/simulators/timestepping/gatherConvergenceReport.hpp>
 
#include <opm/simulators/utils/DeferredLogger.hpp>
 
#include <opm/simulators/wells/BlackoilWellModelGasLift.hpp>
#include <opm/simulators/wells/BlackoilWellModelGeneric.hpp>
#include <opm/simulators/wells/BlackoilWellModelGuideRates.hpp>
#include <opm/simulators/wells/BlackoilWellModelNetwork.hpp>
#include <opm/simulators/wells/BlackoilWellModelRescoup.hpp>
#include <opm/simulators/wells/GasLiftGroupInfo.hpp>
#include <opm/simulators/wells/GasLiftSingleWell.hpp>
#include <opm/simulators/wells/GasLiftSingleWellGeneric.hpp>
#include <opm/simulators/wells/GasLiftWellState.hpp>
#include <opm/simulators/wells/GroupStateHelper.hpp>
#include <opm/simulators/wells/GuideRateHandler.hpp>
#include <opm/simulators/wells/MultisegmentWell.hpp>
#include <opm/simulators/wells/ParallelWBPCalculation.hpp>
#include <opm/simulators/wells/ParallelWellInfo.hpp>
#include <opm/simulators/wells/PerforationData.hpp>
#include <opm/simulators/wells/RateConverter.hpp>
#include <opm/simulators/wells/RegionAverageCalculator.hpp>
#include <opm/simulators/wells/StandardWell.hpp>
#include <opm/simulators/wells/VFPInjProperties.hpp>
#include <opm/simulators/wells/VFPProdProperties.hpp>
#include <opm/simulators/wells/WGState.hpp>
#include <opm/simulators/wells/WellConnectionAuxiliaryModule.hpp>
#include <opm/simulators/wells/WellInterface.hpp>
#include <opm/simulators/wells/WellProdIndexCalculator.hpp>
#include <opm/simulators/wells/WellState.hpp>
#include <opm/simulators/wells/rescoup/RescoupProxy.hpp>
 
#include <cstddef>
#include <map>
#include <memory>
#include <optional>
#include <string>
#include <tuple>
#include <vector>
 
namespace Opm {
 
template<class Scalar> class BlackoilWellModelNldd;
template<class T, template <typename, typename...> class Storage> class SparseTable;
 
#if COMPILE_GPU_BRIDGE
template<class Scalar> class WellContributions;
#endif
 
        template<typename TypeTag>
        class BlackoilWellModel : public WellConnectionAuxiliaryModule<TypeTag, BlackoilWellModel<TypeTag>>
                                , public BlackoilWellModelGeneric<GetPropType<TypeTag, Properties::Scalar>,
                                                                  typename GetPropType<TypeTag, Properties::FluidSystem>::IndexTraitsType>
        {
        public:
            // ---------      Types      ---------
            using Grid = GetPropType<TypeTag, Properties::Grid>;
            using EquilGrid = GetPropType<TypeTag, Properties::EquilGrid>;
            using FluidSystem = GetPropType<TypeTag, Properties::FluidSystem>;
            using ElementContext = GetPropType<TypeTag, Properties::ElementContext>;
            using Indices = GetPropType<TypeTag, Properties::Indices>;
            using Simulator = GetPropType<TypeTag, Properties::Simulator>;
            using Scalar = GetPropType<TypeTag, Properties::Scalar>;
            using RateVector = GetPropType<TypeTag, Properties::RateVector>;
            using GlobalEqVector = GetPropType<TypeTag, Properties::GlobalEqVector>;
            using SparseMatrixAdapter = GetPropType<TypeTag, Properties::SparseMatrixAdapter>;
            using ModelParameters = BlackoilModelParameters<Scalar>;
 
            using WellConnectionModule = WellConnectionAuxiliaryModule<TypeTag, BlackoilWellModel<TypeTag>>;
            using IndexTraits = typename FluidSystem::IndexTraitsType;
            using GroupStateHelperType = GroupStateHelper<Scalar, IndexTraits>;
 
            constexpr static std::size_t pressureVarIndex = GetPropType<TypeTag, Properties::Indices>::pressureSwitchIdx;
 
            static const int numEq = Indices::numEq;
            static const int solventSaturationIdx = Indices::solventSaturationIdx;
            static constexpr bool has_solvent_ = getPropValue<TypeTag, Properties::EnableSolvent>();
            static constexpr bool has_polymer_ = getPropValue<TypeTag, Properties::EnablePolymer>();
            static constexpr EnergyModules energyModuleType_ = getPropValue<TypeTag, Properties::EnergyModuleType>();
            static constexpr bool has_energy_ = (energyModuleType_ == EnergyModules::FullyImplicitThermal);
            static constexpr bool has_micp_ = Indices::enableMICP;
            static constexpr bool has_geochem_ = getPropValue<TypeTag, Properties::EnableGeochemistry>();
            static constexpr bool has_bioeffects_ = getPropValue<TypeTag, Properties::EnableBioeffects>();
 
            // TODO: where we should put these types, WellInterface or Well Model?
            // or there is some other strategy, like TypeTag
            using VectorBlockType = Dune::FieldVector<Scalar, numEq>;
            using BVector = Dune::BlockVector<VectorBlockType>;
 
            using PolymerModule = BlackOilPolymerModule<TypeTag, has_polymer_>;
            using BioeffectsModule = BlackOilBioeffectsModule<TypeTag, has_bioeffects_>;
 
            // For the conversion between the surface volume rate and reservoir voidage rate
            using RateConverterType = RateConverter::
                SurfaceToReservoirVoidage<FluidSystem, std::vector<int> >;
 
            // For computing average pressured used by gpmaint
            using AverageRegionalPressureType = RegionAverageCalculator::
                AverageRegionalPressure<FluidSystem, std::vector<int> >;
 
            BlackoilWellModel(Simulator& simulator, const NewtonIterationContext& iter_ctx);
 
            void init();
            void initWellContainer(const int reportStepIdx) override;
 
            void beginEpisode()
            {
                OPM_TIMEBLOCK(beginEpsiode);
                beginReportStep(simulator_.episodeIndex());
            }
 
            void beginTimeStep();
 
            void beginIteration()
            {
                OPM_TIMEBLOCK(beginIteration);
                assemble(simulator_.timeStepSize());
            }
 
            void endIteration()
            { }
 
            void endTimeStep()
            {
                OPM_TIMEBLOCK(endTimeStep);
                timeStepSucceeded(simulator_.time(), simulator_.timeStepSize());
            }
 
            void endEpisode()
            {
                endReportStep();
            }
 
            void computeTotalRatesForDof(RateVector& rate,
                                         unsigned globalIdx) const;
 
            template <class Context>
            void computeTotalRatesForDof(RateVector& rate,
                                         const Context& context,
                                         unsigned spaceIdx,
                                         unsigned timeIdx) const;
 
 
            using WellInterfacePtr = std::unique_ptr<WellInterface<TypeTag>>;
 
            using BlackoilWellModelGeneric<Scalar, IndexTraits>::initFromRestartFile;
            void initFromRestartFile(const RestartValue& restartValues)
            {
                initFromRestartFile(restartValues,
                                    this->simulator_.vanguard().transferWTestState(),
                                    grid().size(0),
                                    this->simulator_.vanguard().enableDistributedWells());
            }
 
            using BlackoilWellModelGeneric<Scalar, IndexTraits>::prepareDeserialize;
            void prepareDeserialize(const int report_step)
            {
                prepareDeserialize(report_step, grid().size(0),
                                   this->simulator_.vanguard().enableDistributedWells());
            }
 
            data::Wells wellData() const
            {
                auto wsrpt = this->wellState()
                    .report(this->simulator_.vanguard().globalCell().data(),
                            [this](const int well_index)
                            { return this->wasDynamicallyShutThisTimeStep(well_index); },
                            this->rsConstInfo());
 
                BlackoilWellModelGuideRates(*this)
                    .assignWellGuideRates(wsrpt, this->reportStepIndex());
 
                this->assignWellTracerRates_(wsrpt);
 
                if constexpr (has_geochem_) {
                    this->assignWellSpeciesRates_(wsrpt);
                }
 
                if (const auto& rspec = eclState().runspec();
                    rspec.co2Storage() || rspec.h2Storage())
                {
                    // The gas reference density (surface condition) is the
                    // same for all PVT regions in CO2STORE/H2STORE runs so,
                    // for simplicity, we use region zero (0) here.
 
                    this->assignMassGasRate(wsrpt, FluidSystem::referenceDensity(FluidSystem::gasPhaseIdx, 0));
                }
 
                this->assignWellTargets(wsrpt);
 
                this->assignDynamicWellStatus(wsrpt);
 
                // Assigning (a subset of the) property values in shut
                // connections should be the last step of wellData().
                this->assignShutConnections(wsrpt, this->reportStepIndex());
 
                return wsrpt;
            }
 
            data::WellBlockAveragePressures wellBlockAveragePressures() const
            {
                return this->wbp_.computeWellBlockAveragePressures(this->gravity_);
            }
 
#if COMPILE_GPU_BRIDGE
            // accumulate the contributions of all Wells in the WellContributions object
            void getWellContributions(WellContributions<Scalar>& x) const;
#endif
 
            // Check if well equations is converged.
            ConvergenceReport getWellConvergence(const std::vector<Scalar>& B_avg, const bool checkWellGroupControlsAndNetwork = false) const;
 
            const SimulatorReportSingle& lastReport() const;
 
            void addWellContributions(SparseMatrixAdapter& jacobian) const;
 
            // add source from wells to the reservoir matrix
            void addReservoirSourceTerms(GlobalEqVector& residual,
                                         const std::vector<typename SparseMatrixAdapter::MatrixBlock*>& diagMatAddress) const;
 
            // called at the beginning of a report step
            void beginReportStep(const int time_step);
 
            void calculateExplicitQuantities() const;
 
            void prepareTimeStep(DeferredLogger& deferred_logger);
 
            bool
            updateWellControls(DeferredLogger& deferred_logger);
 
            void updateAndCommunicate(const int reportStepIdx);
 
            bool updateGroupControls(const Group& group,
                                    DeferredLogger& deferred_logger,
                                    const int reportStepIdx);
 
            const WellInterface<TypeTag>& getWell(const std::string& well_name) const;
 
            using PressureMatrix = Dune::BCRSMatrix<Opm::MatrixBlock<Scalar, 1, 1>>;
 
            void addWellPressureEquations(PressureMatrix& jacobian,
                                          const BVector& weights,
                                          const bool use_well_weights) const;
            void addWellPressureEquationsStruct(PressureMatrix& jacobian) const;
            void addWellPressureEquationsDomain(PressureMatrix& jacobian,
                                                const BVector& weights,
                                                const bool use_well_weights,
                                                const int domainIndex) const
            {
                if (!nldd_) {
                    OPM_THROW(std::logic_error, "Attempt to access NLDD data without a NLDD solver");
                }
                return nldd_->addWellPressureEquations(jacobian,
                                                       weights,
                                                       use_well_weights,
                                                       domainIndex);
            }
 
            const std::vector<WellInterfacePtr>& localNonshutWells() const
            {
                return well_container_;
            }
 
            const SparseTable<int>& well_local_cells() const
            {
                if (!nldd_) {
                    OPM_THROW(std::logic_error, "Attempt to access NLDD data without a NLDD solver");
                }
                return nldd_->well_local_cells();
            }
 
            const std::map<std::string, int>& well_domain() const
            {
                if (!nldd_) {
                    OPM_THROW(std::logic_error, "Attempt to access NLDD data without a NLDD solver");
                }
 
                return nldd_->well_domain();
            }
 
            auto begin() const { return well_container_.begin(); }
            auto end() const { return well_container_.end(); }
            bool empty() const { return well_container_.empty(); }
 
            bool addMatrixContributions() const
            { return param_.matrix_add_well_contributions_; }
 
            int numStrictIterations() const
            { return param_.strict_outer_iter_wells_; }
 
            int compressedIndexForInterior(int cartesian_cell_idx) const override
            {
                return simulator_.vanguard().compressedIndexForInterior(cartesian_cell_idx);
            }
 
            int compressedIndexForInteriorLGR(const std::string& lgr_tag, const Connection& conn) const override
            {
                return simulator_.vanguard().compressedIndexForInteriorLGR(lgr_tag, conn);
            }
 
            // using the solution x to recover the solution xw for wells and applying
            // xw to update Well State
            void recoverWellSolutionAndUpdateWellState(const BVector& x);
 
            // using the solution x to recover the solution xw for wells and applying
            // xw to update Well State
            void recoverWellSolutionAndUpdateWellStateDomain(const BVector& x,
                                                             const int domainIdx);
            // Update cellRates_ with contributions from all wells
            void updateCellRates();
 
            // Update cellRates_ with contributions from wells in a specific domain
            void updateCellRatesForDomain(int domainIndex,
                                          const std::map<std::string, int>& well_domain_map);
 
            const Grid& grid() const
            { return simulator_.vanguard().grid(); }
 
            const Simulator& simulator() const
            { return simulator_; }
            Simulator& simulator()
            { return simulator_; }
 
            BlackoilWellModelNetwork<TypeTag>& network() { return network_; }
            const BlackoilWellModelNetwork<TypeTag>& network() const { return network_; }
 
            std::vector<WellInterfacePtr>& wellContainer() { return well_container_; }
            const std::vector<WellInterfacePtr>& wellContainer() const { return well_container_; }
 
            void setNlddAdapter(BlackoilWellModelNldd<TypeTag>* mod)
            { nldd_ = mod; }
 
            GuideRateHandler<Scalar, IndexTraits>& guideRateHandler()
            { return guide_rate_handler_; }
 
            const GuideRateHandler<Scalar, IndexTraits>& guideRateHandler() const
            { return guide_rate_handler_; }
 
            // === Reservoir Coupling ===
 
            ReservoirCoupling::Proxy<Scalar>& rescoup() { return rescoup_; }
            const ReservoirCoupling::Proxy<Scalar>& rescoup() const { return rescoup_; }
 
            void updateGuideRates(const int report_step_idx,
                                  const double sim_time)
            {
                this->guide_rate_handler_.updateGuideRates(
                    report_step_idx, sim_time, this->wellState(), this->groupState()
                );
            }
 
            bool isReservoirCouplingMaster() const { return rescoup_.isMaster(); }
 
            bool isReservoirCouplingSlave() const { return rescoup_.isSlave(); }
 
            bool isReservoirCouplingMasterGroup(const std::string& group_name) const {
                return rescoup_.isMasterGroup(group_name);
            }
 
            ReservoirCouplingMaster<Scalar>& reservoirCouplingMaster() {
                return rescoup_.master();
            }
            const ReservoirCouplingMaster<Scalar>& reservoirCouplingMaster() const {
                return rescoup_.master();
            }
 
            ReservoirCouplingSlave<Scalar>& reservoirCouplingSlave() {
                return rescoup_.slave();
            }
            const ReservoirCouplingSlave<Scalar>& reservoirCouplingSlave() const {
                return rescoup_.slave();
            }
 
#ifdef RESERVOIR_COUPLING_ENABLED
            void setReservoirCouplingMaster(ReservoirCouplingMaster<Scalar>* master)
            {
                rescoup_.setMaster(master);
                this->guide_rate_handler_.setReservoirCouplingMaster(master);
                this->groupStateHelper().setReservoirCouplingMaster(master);
            }
            void setReservoirCouplingSlave(ReservoirCouplingSlave<Scalar>* slave)
            {
                rescoup_.setSlave(slave);
                this->guide_rate_handler_.setReservoirCouplingSlave(slave);
                this->groupStateHelper().setReservoirCouplingSlave(slave);
            }
#endif
 
            bool updateWellControlsAndNetwork(const bool mandatory_network_balance,
                                              const double dt,
                                              DeferredLogger& local_deferredLogger);
 
            // TODO: finding a better naming
            void assembleWellEqWithoutIteration(const double dt);
 
            const std::vector<Scalar>& B_avg() const
            { return B_avg_; }
 
            const ModelParameters& param() const
            { return param_; }
 
            bool useTightRcNetworkCoupling() const
            { return !param_.rc_network_loose_coupling_; }
 
#ifdef RESERVOIR_COUPLING_ENABLED
            BlackoilWellModelRescoup<TypeTag>& rescoupHelper() { return rescoupHelper_; }
#endif
 
 
            template<class FluidState, class SingleWellState>
            static Scalar computeTemperatureWeightFactor(const int perf_index, const int np, const FluidState& fs, const SingleWellState& ws)
            {
                const auto& perf_phase_rate = ws.perf_data.phase_rates;
                // we only have one temperature pr cell any phaseIdx will do
                Scalar cellTemperatures = fs.temperature(/*phaseIdx*/0).value();
                Scalar weight_factor = 0.0;
                for (unsigned phaseIdx = 0; phaseIdx < FluidSystem::numPhases; ++phaseIdx) {
                    if (!FluidSystem::phaseIsActive(phaseIdx)) {
                        continue;
                    }
                    Scalar cellInternalEnergy = fs.enthalpy(phaseIdx).value() -
                                            fs.pressure(phaseIdx).value() / fs.density(phaseIdx).value();
                    Scalar cellBinv = fs.invB(phaseIdx).value();
                    Scalar cellDensity = fs.density(phaseIdx).value();
                    Scalar perfPhaseRate = perf_phase_rate[perf_index*np + phaseIdx];
                    weight_factor += cellDensity * (perfPhaseRate / cellBinv) * (cellInternalEnergy / cellTemperatures);
                }
                return (std::abs(weight_factor) + 1e-13);
            }
 
        protected:
            Simulator& simulator_;
 
            // a vector of all the wells.
            std::vector<WellInterfacePtr> well_container_{};
 
            std::vector<bool> is_cell_perforated_{};
 
            void initializeWellState(const int timeStepIdx);
 
            // create the well container
            void createWellContainer(const int report_step) override;
 
            WellInterfacePtr
            createWellPointer(const int wellID,
                              const int report_step) const;
 
            template <typename WellType>
            std::unique_ptr<WellType>
            createTypedWellPointer(const int wellID,
                                   const int time_step) const;
 
            WellInterfacePtr createWellForWellTest(const std::string& well_name,
                                                   const int report_step,
                                                   DeferredLogger& deferred_logger) const;
 
            const ModelParameters param_;
            std::size_t global_num_cells_{};
            // the number of the cells in the local grid
            std::size_t local_num_cells_{};
            Scalar gravity_{};
            std::vector<Scalar> depth_{};
            bool alternative_well_rate_init_{};
            std::unique_ptr<RateConverterType> rateConverter_{};
            std::map<std::string, std::unique_ptr<AverageRegionalPressureType>> regionalAveragePressureCalculator_{};
 
            SimulatorReportSingle last_report_{};
            GuideRateHandler<Scalar, IndexTraits> guide_rate_handler_{};
            ReservoirCoupling::Proxy<Scalar> rescoup_{};
 
            // A flag to tell the convergence report whether we need to take another newton step
            bool network_needs_more_balancing_force_another_newton_iteration_{false};
 
            std::vector<Scalar> B_avg_{};
 
            const EquilGrid& equilGrid() const
            { return simulator_.vanguard().equilGrid(); }
 
            const EclipseState& eclState() const
            { return simulator_.vanguard().eclState(); }
 
            // compute the well fluxes and assemble them in to the reservoir equations as source terms
            // and in the well equations.
            void assemble(const double dt);
 
            // well controls and network pressures affect each other and are solved in an iterative manner.
            // the function handles one iteration of updating well controls and network pressures.
            // it is possible to decouple the update of well controls and network pressures further.
            // the returned two booleans are {continue_due_to_network, well_group_control_changed}, respectively
            std::tuple<bool, bool, Scalar> updateWellControlsAndNetworkIteration(const bool mandatory_network_balance,
                                                                        const bool relax_network_tolerance,
                                                                        const bool optimize_gas_lift,
                                                                        const double dt,
                                                                        DeferredLogger& local_deferredLogger);
 
            void initializeLocalWellStructure(const int  reportStepIdx,
                                              const bool enableWellPIScaling);
 
            void initializeGroupStructure(const int reportStepIdx);
 
            // called at the end of a time step
            void timeStepSucceeded(const double simulationTime, const double dt);
 
            // called at the end of a report step
            void endReportStep();
 
            // setting the well_solutions_ based on well_state.
            void updatePrimaryVariables();
 
            void updateAverageFormationFactor();
 
            void computePotentials(const std::size_t widx,
                                   const WellState<Scalar, IndexTraits>& well_state_copy,
                                   std::string& exc_msg,
                                   ExceptionType::ExcEnum& exc_type) override;
 
            const std::vector<Scalar>& wellPerfEfficiencyFactors() const;
 
            void calculateProductivityIndexValuesShutWells(const int reportStepIdx, DeferredLogger& deferred_logger) override;
            void calculateProductivityIndexValues(DeferredLogger& deferred_logger) override;
            void calculateProductivityIndexValues(const WellInterface<TypeTag>* wellPtr,
                                                  DeferredLogger& deferred_logger);
 
            // The number of conservation quantities.
            int numConservationQuantities() const;
 
            int reportStepIndex() const;
 
            void assembleWellEq(const double dt);
 
            void prepareWellsBeforeAssembling(const double dt);
 
            void extractLegacyCellPvtRegionIndex_();
 
            void extractLegacyDepth_();
 
            void updateWellTestState(const double simulationTime, WellTestState& wellTestState);
 
            void wellTesting(const int timeStepIdx, const double simulationTime, DeferredLogger& deferred_logger);
 
            void calcResvCoeff(const int fipnum,
                               const int pvtreg,
                               const std::vector<Scalar>& production_rates,
                               std::vector<Scalar>& resv_coeff) const override;
 
            void calcInjResvCoeff(const int fipnum,
                                  const int pvtreg,
                                  std::vector<Scalar>& resv_coeff) const override;
 
            void computeWellTemperature();
 
        private:
            // Private helper methods (alphabetical order)
            // --------------------------------------------
 
            void assignWellSpeciesRates_(data::Wells& wsrpt) const;
            void assignWellTracerRates_(data::Wells& wsrpt) const;
 
            bool isRescoupCoupledNetworkParticipant_() const;
 
            bool isRescoupMasterCoupledNetworkIteration_() const;
 
            bool isRescoupSlaveCoupledNetworkIteration_() const;
 
            bool isRescoupSlaveOnSyncStepFirstSubstep_() const;
 
            bool isRescoupSlaveConnectedToMasterNetwork_() const;
 
            bool maybeSendSlaveGroupFlowToMaster_(const int reportStepIdx);
 
            void sendSlaveNetworkLoopTerminationSignal_();
 
            bool shouldDoPreStepNetworkRebalance_(const int episodeIdx) const;
 
            void updateNetworkActiveState_();
 
            BlackoilWellModelGasLift<TypeTag> gaslift_;
            BlackoilWellModelNetwork<TypeTag> network_;
#ifdef RESERVOIR_COUPLING_ENABLED
            BlackoilWellModelRescoup<TypeTag> rescoupHelper_;
#endif
            BlackoilWellModelNldd<TypeTag>* nldd_ = nullptr; 
 
            // These members are used to avoid reallocation in specific functions
            // instead of using local variables.
            // Their state is not relevant between function calls, so they can
            // (and must) be mutable, as the functions using them are const.
            mutable BVector x_local_;
 
            // Store cell rates after assembling to avoid iterating all wells and connections for every element
            std::map<int, RateVector> cellRates_;
 
            [[nodiscard]] auto rsConstInfo() const
                -> typename WellState<Scalar,IndexTraits>::RsConstInfo;
        };
 
} // namespace Opm
 
#include "BlackoilWellModel_impl.hpp"
 
#endif // OPM_BLACKOILWELLMODEL_HEADER_INCLUDED