std::vector<double>
Opm::WellDensitySegmented::computeConnectionDensities(const Wells& wells,
const WellStateFullyImplicitBlackoil& wstate,
const PhaseUsage& phase_usage,
const std::vector<double>& b_perf,
const std::vector<double>& rsmax_perf,
const std::vector<double>& rvmax_perf,
const std::vector<double>& surf_dens_perf)
{
// Verify that we have consistent input.
const int np = wells.number_of_phases;
const int nw = wells.number_of_wells;
const int nperf = wells.well_connpos[nw];
if (wells.number_of_phases != phase_usage.num_phases) {
OPM_THROW(std::logic_error, "Inconsistent input: wells vs. phase_usage.");
}
if (nperf*np != int(surf_dens_perf.size())) {
OPM_THROW(std::logic_error, "Inconsistent input: wells vs. surf_dens.");
}
if (nperf*np != int(wstate.perfPhaseRates().size())) {
OPM_THROW(std::logic_error, "Inconsistent input: wells vs. wstate.");
}
if (nperf*np != int(b_perf.size())) {
OPM_THROW(std::logic_error, "Inconsistent input: wells vs. b_perf.");
}
if ((!rsmax_perf.empty()) || (!rvmax_perf.empty())) {
// Need both oil and gas phases.
if (!phase_usage.phase_used[BlackoilPhases::Liquid]) {
OPM_THROW(std::logic_error, "Oil phase inactive, but non-empty rsmax_perf or rvmax_perf.");
}
if (!phase_usage.phase_used[BlackoilPhases::Vapour]) {
OPM_THROW(std::logic_error, "Gas phase inactive, but non-empty rsmax_perf or rvmax_perf.");
}
}
// 1. Compute the flow (in surface volume units for each
// component) exiting up the wellbore from each perforation,
// taking into account flow from lower in the well, and
// in/out-flow at each perforation.
std::vector<double> q_out_perf(nperf*np);
for (int w = 0; w < nw; ++w) {
// Iterate over well perforations from bottom to top.
for (int perf = wells.well_connpos[w+1] - 1; perf >= wells.well_connpos[w]; --perf) {
for (int phase = 0; phase < np; ++phase) {
if (perf == wells.well_connpos[w+1] - 1) {
// This is the bottom perforation. No flow from below.
q_out_perf[perf*np + phase] = 0.0;
} else {
// Set equal to flow from below.
q_out_perf[perf*np + phase] = q_out_perf[(perf+1)*np + phase];
}
// Subtract outflow through perforation.
q_out_perf[perf*np + phase] -= wstate.perfPhaseRates()[perf*np + phase];
}
}
}
// 2. Compute the component mix at each perforation as the
// absolute values of the surface rates divided by their sum.
// Then compute volume ratios (formation factors) for each perforation.
// Finally compute densities for the segments associated with each perforation.
const int gaspos = phase_usage.phase_pos[BlackoilPhases::Vapour];
const int oilpos = phase_usage.phase_pos[BlackoilPhases::Liquid];
std::vector<double> mix(np);
std::vector<double> x(np);
std::vector<double> surf_dens(np);
std::vector<double> dens(nperf);
for (int w = 0; w < nw; ++w) {
for (int perf = wells.well_connpos[w]; perf < wells.well_connpos[w+1]; ++perf) {
// Find component mix.
const double tot_surf_rate = std::accumulate(q_out_perf.begin() + np*perf,
q_out_perf.begin() + np*(perf+1), 0.0);
if (tot_surf_rate != 0.0) {
for (int phase = 0; phase < np; ++phase) {
mix[phase] = std::fabs(q_out_perf[perf*np + phase]/tot_surf_rate);
}
} else {
// No flow => use well specified fractions for mix.
std::copy(wells.comp_frac + w*np, wells.comp_frac + (w+1)*np, mix.begin());
}
// Compute volume ratio.
x = mix;
double rs = 0.0;
double rv = 0.0;
if (!rsmax_perf.empty() && mix[oilpos] > 0.0) {
rs = std::min(mix[gaspos]/mix[oilpos], rsmax_perf[perf]);
}
if (!rvmax_perf.empty() && mix[gaspos] > 0.0) {
rv = std::min(mix[oilpos]/mix[gaspos], rvmax_perf[perf]);
}
if (rs != 0.0) {
// Subtract gas in oil from gas mixture
x[gaspos] = (mix[gaspos] - mix[oilpos]*rs)/(1.0 - rs*rv);
}
if (rv != 0.0) {
// Subtract oil in gas from oil mixture
x[oilpos] = (mix[oilpos] - mix[gaspos]*rv)/(1.0 - rs*rv);;
}
double volrat = 0.0;
for (int phase = 0; phase < np; ++phase) {
volrat += x[phase] / b_perf[perf*np + phase];
}
for (int phase = 0; phase < np; ++phase) {
surf_dens[phase] = surf_dens_perf[perf*np + phase];
}
// Compute segment density.
dens[perf] = std::inner_product(surf_dens.begin(), surf_dens.end(), mix.begin(), 0.0) / volrat;
}
}
return dens;
}
std::vector<double>
Opm::WellDensitySegmented::computeConnectionPressureDelta(const Wells& wells,
const WellStateFullyImplicitBlackoil& wstate,
const PhaseUsage& phase_usage,
const std::vector<double>& b_perf,
const std::vector<double>& rsmax_perf,
const std::vector<double>& rvmax_perf,
const std::vector<double>& z_perf,
const std::vector<double>& surf_dens,
const double gravity)
{
// Verify that we have consistent input.
const int np = wells.number_of_phases;
const int nw = wells.number_of_wells;
const int nperf = wells.well_connpos[nw];
if (wells.number_of_phases != phase_usage.num_phases) {
OPM_THROW(std::logic_error, "Inconsistent input: wells vs. phase_usage.");
}
if (surf_dens.size() != size_t(wells.number_of_phases)) {
OPM_THROW(std::logic_error, "Inconsistent input: surf_dens vs. phase_usage.");
}
if (nperf*np != int(wstate.perfPhaseRates().size())) {
OPM_THROW(std::logic_error, "Inconsistent input: wells vs. wstate.");
}
if (nperf*np != int(b_perf.size())) {
OPM_THROW(std::logic_error, "Inconsistent input: wells vs. b_perf.");
}
if (nperf != int(z_perf.size())) {
OPM_THROW(std::logic_error, "Inconsistent input: wells vs. z_perf.");
}
if ((!rsmax_perf.empty()) || (!rvmax_perf.empty())) {
// Need both oil and gas phases.
if (!phase_usage.phase_used[BlackoilPhases::Liquid]) {
OPM_THROW(std::logic_error, "Oil phase inactive, but non-empty rsmax_perf or rvmax_perf.");
}
if (!phase_usage.phase_used[BlackoilPhases::Vapour]) {
OPM_THROW(std::logic_error, "Gas phase inactive, but non-empty rsmax_perf or rvmax_perf.");
}
}
// Algorithm:
// We'll assume the perforations are given in order from top to
// bottom for each well. By top and bottom we do not necessarily
// mean in a geometric sense (depth), but in a topological sense:
// the 'top' perforation is nearest to the surface topologically.
// Our goal is to compute a pressure delta for each perforation.
// 1. Compute the flow (in surface volume units for each
// component) exiting up the wellbore from each perforation,
// taking into account flow from lower in the well, and
// in/out-flow at each perforation.
std::vector<double> q_out_perf(nperf*np);
for (int w = 0; w < nw; ++w) {
// Iterate over well perforations from bottom to top.
for (int perf = wells.well_connpos[w+1] - 1; perf >= wells.well_connpos[w]; --perf) {
for (int phase = 0; phase < np; ++phase) {
if (perf == wells.well_connpos[w+1] - 1) {
// This is the bottom perforation. No flow from below.
q_out_perf[perf*np + phase] = 0.0;
} else {
// Set equal to flow from below.
q_out_perf[perf*np + phase] = q_out_perf[(perf+1)*np + phase];
}
// Subtract outflow through perforation.
q_out_perf[perf*np + phase] -= wstate.perfPhaseRates()[perf*np + phase];
}
}
}
// 2. Compute the component mix at each perforation as the
// absolute values of the surface rates divided by their sum.
// Then compute volume ratios (formation factors) for each perforation.
// Finally compute densities for the segments associated with each perforation.
const int gaspos = phase_usage.phase_pos[BlackoilPhases::Vapour];
const int oilpos = phase_usage.phase_pos[BlackoilPhases::Liquid];
std::vector<double> mix(np);
std::vector<double> x(np);
std::vector<double> dens(nperf);
for (int w = 0; w < nw; ++w) {
for (int perf = wells.well_connpos[w]; perf < wells.well_connpos[w+1]; ++perf) {
// Find component mix.
const double tot_surf_rate = std::accumulate(q_out_perf.begin() + np*perf,
q_out_perf.begin() + np*(perf+1), 0.0);
if (tot_surf_rate != 0.0) {
for (int phase = 0; phase < np; ++phase) {
mix[phase] = std::fabs(q_out_perf[perf*np + phase]/tot_surf_rate);
}
} else {
// No flow => use well specified fractions for mix.
std::copy(wells.comp_frac + w*np, wells.comp_frac + (w+1)*np, mix.begin());
}
// Compute volume ratio.
x = mix;
double rs = 0.0;
double rv = 0.0;
if (!rsmax_perf.empty() && mix[oilpos] > 0.0) {
rs = std::min(mix[gaspos]/mix[oilpos], rsmax_perf[perf]);
}
if (!rvmax_perf.empty() && mix[gaspos] > 0.0) {
rv = std::min(mix[oilpos]/mix[gaspos], rvmax_perf[perf]);
}
if (rs != 0.0) {
// Subtract gas in oil from gas mixture
x[gaspos] = (mix[gaspos] - mix[oilpos]*rs)/(1.0 - rs*rv);
}
if (rv != 0.0) {
// Subtract oil in gas from oil mixture
x[oilpos] = (mix[oilpos] - mix[gaspos]*rv)/(1.0 - rs*rv);;
}
double volrat = 0.0;
for (int phase = 0; phase < np; ++phase) {
volrat += x[phase] / b_perf[perf*np + phase];
}
// Compute segment density.
dens[perf] = std::inner_product(surf_dens.begin(), surf_dens.end(), mix.begin(), 0.0) / volrat;
}
}
// 3. Compute pressure differences between perforations.
// dp_perf will contain the pressure difference between a
// perforation and the one above it, except for the first
// perforation for each well, for which it will be the
// difference to the reference (bhp) depth.
std::vector<double> dp_perf(nperf);
for (int w = 0; w < nw; ++w) {
for (int perf = wells.well_connpos[w]; perf < wells.well_connpos[w+1]; ++perf) {
const double z_above = perf == wells.well_connpos[w] ? wells.depth_ref[w] : z_perf[perf - 1];
const double dz = z_perf[perf] - z_above;
dp_perf[perf] = dz * dens[perf] * gravity;
}
}
// 4. Compute pressure differences to the reference point (bhp) by
// accumulating the already computed adjacent pressure
// differences, storing the result in dp_perf.
// This accumulation must be done per well.
for (int w = 0; w < nw; ++w) {
const auto beg = dp_perf.begin() + wells.well_connpos[w];
const auto end = dp_perf.begin() + wells.well_connpos[w + 1];
std::partial_sum(beg, end, beg);
}
return dp_perf;
}