OilfieldToolsNet/opm-simulators
4
0
Fork 0
mirror of https://github.com/OPM/opm-simulators.git synced 2025-02-25 18:55:30 -06:00
Code Issues Packages Projects Releases Wiki Activity

Well testing of gas lift wells

Browse Source 
Assign a maximum ALQ value to each GLIFT producer when doing well testing
in beginTimeStep(). This allows the well to be considered open. Then,
later in the timestep, when assemble() is called, the full gas lift
optimization procedure can adjust the ALQ to its correct value.

It is also observed that in some cases when gas lift is switched off by
setting ALQ to zero, and later in the schedule is switched back on again,
it might not be possible to determine bhp from thp for low small ALQ values.
Instead of aborting the gas lift optimization, we should try increasing
ALQ until we get convergence or until the maximum ALQ for the well is
reached.
This commit is contained in:
Håkon Hægland
2022-03-27 07:57:31 +02:00
parent ec9be88736
commit 11907495c1
4 changed files with 88 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files

47
opm/simulators/wells/GasLiftSingleWellGeneric.cpp
View File

@@ -294,19 +294,38 @@ checkThpControl_() const
return thp_control;
}
std::pair<std::optional<double>,double>
GasLiftSingleWellGeneric::
computeConvergedBhpAtThpLimitByMaybeIncreasingALQ_() const
{
auto alq = this->orig_alq_;
double new_alq = alq;
std::optional<double> bhp;
while (alq <= (this->max_alq_ + this->increment_)) {
if (bhp = computeBhpAtThpLimit_(alq); bhp) {
new_alq = alq;
break;
}
alq += this->increment_;
}
return {bhp, new_alq};
}
std::optional<GasLiftSingleWellGeneric::BasicRates>
std::pair<std::optional<GasLiftSingleWellGeneric::BasicRates>,double>
GasLiftSingleWellGeneric::
computeInitialWellRates_() const
{
std::optional<BasicRates> rates;
if (auto bhp = computeBhpAtThpLimit_(this->orig_alq_); bhp) {
double initial_alq = this->orig_alq_;
//auto alq = initial_alq;
//if (auto bhp = computeBhpAtThpLimit_(this->orig_alq_); bhp) {
if (auto [bhp, alq] = computeConvergedBhpAtThpLimitByMaybeIncreasingALQ_(); bhp) {
{
const std::string msg = fmt::format(
"computed initial bhp {} given thp limit and given alq {}",
*bhp, this->orig_alq_);
"computed initial bhp {} given thp limit and given alq {}", *bhp, alq);
displayDebugMessage_(msg);
}
initial_alq = alq;
auto [new_bhp, bhp_is_limited] = getBhpWithLimit_(*bhp);
rates = computeWellRates_(new_bhp, bhp_is_limited);
if (rates) {
@@ -320,7 +339,7 @@ computeInitialWellRates_() const
else {
displayDebugMessage_("Aborting optimization.");
}
return rates;
return {rates, initial_alq};
}
std::optional<GasLiftSingleWellGeneric::LimitedRates>
@@ -819,12 +838,13 @@ getRateWithGroupLimit_(
}
std::optional<GasLiftSingleWellGeneric::LimitedRates>
std::pair<std::optional<GasLiftSingleWellGeneric::LimitedRates>, double>
GasLiftSingleWellGeneric::
getInitialRatesWithLimit_() const
{
std::optional<LimitedRates> limited_rates;
if (auto rates = computeInitialWellRates_(); rates) {
double initial_alq = this->orig_alq_;
if (auto [rates, alq] = computeInitialWellRates_(); rates) {
if (this->debug) {
displayDebugMessage_(
"Maybe limiting initial rates before optimize loop..");
@@ -832,8 +852,9 @@ getInitialRatesWithLimit_() const
auto temp_rates = getLimitedRatesFromRates_(*rates);
BasicRates old_rates = getWellStateRates_();
limited_rates = updateRatesToGroupLimits_(old_rates, temp_rates);
initial_alq = alq;
}
return limited_rates;
return {limited_rates, initial_alq};
}
GasLiftSingleWellGeneric::LimitedRates
@@ -1166,18 +1187,17 @@ runOptimizeLoop_(bool increase)
{
if (this->debug) debugShowProducerControlMode();
std::unique_ptr<GasLiftWellState> ret_value; // nullptr initially
auto rates = getInitialRatesWithLimit_();
auto [rates, cur_alq] = getInitialRatesWithLimit_();
if (!rates) return ret_value;
// if (this->debug) debugShowBhpAlqTable_();
if (this->debug) debugShowAlqIncreaseDecreaseCounts_();
if (this->debug) debugShowTargets_();
bool success = false; // did we succeed to increase alq?
bool alq_is_limited = false;
auto cur_alq = this->orig_alq_;
LimitedRates new_rates = *rates;
auto [temp_rates2, new_alq] = maybeAdjustALQbeforeOptimizeLoop_(
*rates, cur_alq, increase);
if (checkInitialALQmodified_(new_alq, cur_alq)) {
if (checkInitialALQmodified_(new_alq, this->orig_alq_)) {
auto delta_alq = new_alq - cur_alq;
new_rates = temp_rates2;
cur_alq = new_alq;
@@ -1591,7 +1611,10 @@ checkAlqOutsideLimits(double alq, [[maybe_unused]] double oil_rate)
// NOTE: checking for an upper limit should not be necessary
// when decreasing alq.. so this is just to catch an
// illegal state at an early point.
if (alq >= this->parent.max_alq_) {
if (this->parent.checkALQequal_(alq, this->parent.max_alq_)) {
return false;
}
else if (alq > this->parent.max_alq_) {
warn_( "unexpected: alq above upper limit when trying to "
"decrease lift gas. aborting iteration.");
result = true;