/*
Copyright 2020 Equinor ASA.
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/>.
*/
#include <opm/input/eclipse/Schedule/GasLiftOpt.hpp>
#include <fmt/format.h>
namespace Opm {
template<typename TypeTag>
GasLiftSingleWell<TypeTag>::
GasLiftSingleWell(const WellInterface<TypeTag> &well,
const Simulator &ebos_simulator,
const SummaryState &summary_state,
DeferredLogger &deferred_logger,
WellState &well_state,
const GroupState &group_state,
GasLiftGroupInfo &group_info,
GLiftSyncGroups &sync_groups,
const Parallel::Communication& comm,
bool glift_debug
)
// The parent class GasLiftSingleWellGeneric contains all stuff
// that is not dependent on TypeTag
: GasLiftSingleWellGeneric(
deferred_logger,
well_state,
group_state,
well.wellEcl(),
summary_state,
group_info,
well.phaseUsage(),
ebos_simulator.vanguard().schedule(),
ebos_simulator.episodeIndex(),
sync_groups,
comm,
glift_debug
)
, ebos_simulator_{ebos_simulator}
, well_{well}
{
const auto& gl_well = *gl_well_;
if(useFixedAlq_(gl_well)) {
updateWellStateAlqFixedValue_(gl_well);
this->optimize_ = false; // lift gas supply is fixed
}
else {
setAlqMaxRate_(gl_well);
this->optimize_ = true;
}
setupPhaseVariables_();
// get the alq value used for this well for the previous iteration (a
// nonlinear iteration in assemble() in BlackoilWellModel).
// If gas lift optimization has not been applied to this well yet, the
// default value is used.
this->orig_alq_ = this->well_state_.getALQ(this->well_name_);
if(this->optimize_) {
setAlqMinRate_(gl_well);
// NOTE: According to item 4 in WLIFTOPT, this value does not
// have to be positive.
// TODO: Does it make sense to have a negative value?
this->alpha_w_ = gl_well.weight_factor();
if (this->alpha_w_ <= 0 ) {
displayWarning_("Nonpositive value for alpha_w ignored");
this->alpha_w_ = 1.0;
}
// NOTE: According to item 6 in WLIFTOPT:
// "If this value is greater than zero, the incremental gas rate will influence
// the calculation of the incremental gradient and may be used
// to discourage the allocation of lift gas to wells which produce more gas."
// TODO: Does this mean that we should ignore this value if it
// is negative?
this->alpha_g_ = gl_well.inc_weight_factor();
// TODO: adhoc value.. Should we keep max_iterations_ as a safety measure
// or does it not make sense to have it?
this->max_iterations_ = 1000;
}
}
/****************************************
* Private methods in alphabetical order
****************************************/
template<typename TypeTag>
GasLiftSingleWellGeneric::BasicRates
GasLiftSingleWell<TypeTag>::
computeWellRates_( double bhp, bool bhp_is_limited, bool debug_output ) const
{
std::vector<double> potentials(NUM_PHASES, 0.0);
this->well_.computeWellRatesWithBhp(
this->ebos_simulator_, bhp, potentials, this->deferred_logger_);
if (debug_output) {
const std::string msg = fmt::format("computed well potentials given bhp {}, "
"oil: {}, gas: {}, water: {}", bhp,
-potentials[this->oil_pos_], -potentials[this->gas_pos_],
-potentials[this->water_pos_]);
displayDebugMessage_(msg);
}
for (auto& potential : potentials) {
potential = std::min(0.0, potential);
}
return {-potentials[this->oil_pos_],
-potentials[this->gas_pos_],
-potentials[this->water_pos_],
bhp_is_limited
};
}
template<typename TypeTag>
std::optional<double>
GasLiftSingleWell<TypeTag>::
computeBhpAtThpLimit_(double alq) const
{
auto bhp_at_thp_limit = this->well_.computeBhpAtThpLimitProdWithAlq(
this->ebos_simulator_,
this->summary_state_,
alq,
this->deferred_logger_);
if (bhp_at_thp_limit) {
if (*bhp_at_thp_limit < this->controls_.bhp_limit) {
const std::string msg = fmt::format(
"Computed bhp ({}) from thp limit is below bhp limit ({}), (ALQ = {})."
" Using bhp limit instead",
*bhp_at_thp_limit, this->controls_.bhp_limit, alq);
displayDebugMessage_(msg);
bhp_at_thp_limit = this->controls_.bhp_limit;
}
//bhp_at_thp_limit = std::max(*bhp_at_thp_limit, this->controls_.bhp_limit);
}
else {
const std::string msg = fmt::format(
"Failed in getting converged bhp potential from thp limit (ALQ = {})", alq);
displayDebugMessage_(msg);
}
return bhp_at_thp_limit;
}
template<typename TypeTag>
void
GasLiftSingleWell<TypeTag>::
setupPhaseVariables_()
{
const auto& pu = this->phase_usage_;
bool num_phases_ok = (pu.num_phases == 3);
if (pu.num_phases == 2) {
// NOTE: We support two-phase oil-water flow, by setting the gas flow rate
// to zero. This is done by initializing the potential vector to zero:
//
// std::vector<double> potentials(NUM_PHASES, 0.0);
//
// see e.g. runOptimizeLoop_() in GasLiftSingleWellGeneric.cpp
// In addition the VFP calculations, e.g. to calculate BHP from THP
// has been adapted to the two-phase oil-water case, see the comment
// in WellInterfaceGeneric.cpp for the method adaptRatesForVFP() for
// more information.
if ( pu.phase_used[BlackoilPhases::Aqua] == 1
&& pu.phase_used[BlackoilPhases::Liquid] == 1
&& pu.phase_used[BlackoilPhases::Vapour] == 0)
{
num_phases_ok = true; // two-phase oil-water is also supported
}
else {
throw std::logic_error("Two-phase gas lift optimization only supported"
" for oil and water");
}
}
assert(num_phases_ok);
this->oil_pos_ = pu.phase_pos[Oil];
this->gas_pos_ = pu.phase_pos[Gas];
this->water_pos_ = pu.phase_pos[Water];
}
template<typename TypeTag>
void
GasLiftSingleWell<TypeTag>::
setAlqMaxRate_(const GasLiftWell &well)
{
auto& max_alq_optional = well.max_rate();
if (max_alq_optional) {
// NOTE: To prevent extrapolation of the VFP tables, any value
// entered here must not exceed the largest ALQ value in the well's VFP table.
this->max_alq_ = *max_alq_optional;
}
else { // i.e. WLIFTOPT, item 3 has been defaulted
// According to the manual for WLIFTOPT, item 3:
// The default value should be set to the largest ALQ
// value in the well's VFP table
const auto& table = well_.vfpProperties()->getProd()->getTable(
this->controls_.vfp_table_number);
const auto& alq_values = table.getALQAxis();
// Assume the alq_values are sorted in ascending order, so
// the last item should be the largest value:
this->max_alq_ = alq_values.back();
}
}
template<typename TypeTag>
bool
GasLiftSingleWell<TypeTag>::
checkThpControl_() const
{
const int well_index = this->well_state_.index(this->well_name_).value();
const Well::ProducerCMode& control_mode =
this->well_state_.well(well_index).production_cmode;
bool thp_control = control_mode == Well::ProducerCMode::THP;
const WellInterfaceGeneric &well = getWell();
thp_control = thp_control || well.thpLimitViolatedButNotSwitched();
if (this->debug) {
if (!thp_control) {
displayDebugMessage_("Well is not under THP control, skipping iteration..");
}
}
return thp_control;
}
}