From 0756e2d1c1b80f9ab9d4b42a212effd30a4f1218 Mon Sep 17 00:00:00 2001
From: Stein Krogstad <stein.krogstad@sintef.no>
Date: Thu, 26 Oct 2023 13:50:42 +0200
Subject: [PATCH] Initialize rates/previous rates before well-test

---
 opm/simulators/wells/BlackoilWellModel_impl.hpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/opm/simulators/wells/BlackoilWellModel_impl.hpp b/opm/simulators/wells/BlackoilWellModel_impl.hpp
index 1ce2daf58..1e0a61d05 100644
--- a/opm/simulators/wells/BlackoilWellModel_impl.hpp
+++ b/opm/simulators/wells/BlackoilWellModel_impl.hpp
@@ -544,6 +544,14 @@ namespace Opm {
             well->setVFPProperties(vfp_properties_.get());
             well->setGuideRate(&guideRate_);
 
+            // initialize rates/previous rates to prevent zero fractions in vfp-interpolation
+            if (well->isProducer()) {
+                well->updateWellStateRates(ebosSimulator_, this->wellState(), deferred_logger);
+            }
+            if (well->isVFPActive(deferred_logger)) {
+                well->setPrevSurfaceRates(this->wellState(), this->prevWellState());
+            }
+
             well->wellTesting(ebosSimulator_, simulationTime, this->wellState(), this->groupState(), wellTestState(), deferred_logger);
         }
     }