diff --git a/opm/autodiff/BlackoilModelBase_impl.hpp b/opm/autodiff/BlackoilModelBase_impl.hpp
index 99ecd8a29..b447d985c 100644
--- a/opm/autodiff/BlackoilModelBase_impl.hpp
+++ b/opm/autodiff/BlackoilModelBase_impl.hpp
@@ -223,7 +223,7 @@ namespace detail {
 
         // TODO: put this for now to avoid modify the following code.
         // TODO: this code can be fragile.
-        const Wells* wells_arg = &(asImpl().well_model_.wells());
+        const Wells* wells_arg = asImpl().well_model_.wellsPointer();
 
 #if HAVE_MPI
         if ( linsolver_.parallelInformation().type() == typeid(ParallelISTLInformation) )
diff --git a/opm/autodiff/MultisegmentWells.cpp b/opm/autodiff/MultisegmentWells.cpp
index 5a98b201e..7cb88b49b 100644
--- a/opm/autodiff/MultisegmentWells.cpp
+++ b/opm/autodiff/MultisegmentWells.cpp
@@ -294,6 +294,12 @@ namespace Opm {
     }
 
 
+    const Wells*
+    MultisegmentWells::wellsPointer() const
+    {
+        return wells_;
+    }
+
 
 
 
diff --git a/opm/autodiff/MultisegmentWells.hpp b/opm/autodiff/MultisegmentWells.hpp
index e1e9976ba..0d8e5aece 100644
--- a/opm/autodiff/MultisegmentWells.hpp
+++ b/opm/autodiff/MultisegmentWells.hpp
@@ -102,6 +102,8 @@ namespace Opm {
 
             const Wells& wells() const;
 
+            const Wells* wellsPointer() const;
+
             int numPhases() const { return num_phases_; };
 
             int numWells() const { return wells_multisegment_.size(); }
diff --git a/opm/autodiff/StandardWells.hpp b/opm/autodiff/StandardWells.hpp
index 5a1cfe10f..7b367f43a 100644
--- a/opm/autodiff/StandardWells.hpp
+++ b/opm/autodiff/StandardWells.hpp
@@ -70,10 +70,12 @@ namespace Opm {
 
             const WellOps& wellOps() const;
 
-            int numPhases() const { return num_phases_; };
+            int numPhases() const { return wells().number_of_phases; };
 
             const Wells& wells() const;
 
+            const Wells* wellsPointer() const;
+
             /// return true if wells are available in the reservoir
             bool wellsActive() const;
             void setWellsActive(const bool wells_active);
@@ -172,7 +174,6 @@ namespace Opm {
             bool wells_active_;
             const Wells*   wells_;
             const WellOps  wops_;
-            const int num_phases_;
 
             const BlackoilPropsAdInterface* fluid_;
             const std::vector<bool>*  active_;
diff --git a/opm/autodiff/StandardWells_impl.hpp b/opm/autodiff/StandardWells_impl.hpp
index 056290388..ccbea3c42 100644
--- a/opm/autodiff/StandardWells_impl.hpp
+++ b/opm/autodiff/StandardWells_impl.hpp
@@ -72,9 +72,9 @@ namespace Opm
 
 
     StandardWells::StandardWells(const Wells* wells_arg)
-      : wells_(wells_arg)
+      : wells_active_(wells_arg!=nullptr)
+      , wells_(wells_arg)
       , wops_(wells_arg)
-      , num_phases_(wells_arg->number_of_phases)
       , fluid_(nullptr)
       , active_(nullptr)
       , phase_condition_(nullptr)
@@ -116,6 +116,10 @@ namespace Opm
     }
 
 
+    const Wells* StandardWells::wellsPointer() const
+    {
+        return wells_;
+    }
 
 
 
@@ -149,8 +153,13 @@ namespace Opm
     int
     StandardWells::numWellVars() const
     {
+        if ( !localWellsActive() )
+        {
+            return 0;
+        }
+
         // For each well, we have a bhp variable, and one flux per phase.
-        const int nw = localWellsActive() ? wells().number_of_wells : 0;
+        const int nw = wells().number_of_wells;
         return (numPhases() + 1) * nw;
     }
 
@@ -365,9 +374,10 @@ namespace Opm
             return;
         } else {
             const std::vector<int>& well_cells = wellOps().well_cells;
-            mob_perfcells.resize(num_phases_, ADB::null());
-            b_perfcells.resize(num_phases_, ADB::null());
-            for (int phase = 0; phase < num_phases_; ++phase) {
+            const int num_phases = wells().number_of_phases;
+            mob_perfcells.resize(num_phases, ADB::null());
+            b_perfcells.resize(num_phases, ADB::null());
+            for (int phase = 0; phase < num_phases; ++phase) {
                 mob_perfcells[phase] = subset(rq[phase].mob, well_cells);
                 b_perfcells[phase] = subset(rq[phase].b, well_cells);
             }
@@ -390,7 +400,7 @@ namespace Opm
     {
         if( ! localWellsActive() ) return ;
 
-        const int np = num_phases_;
+        const int np = wells().number_of_phases;
         const int nw = wells().number_of_wells;
         const int nperf = wells().well_connpos[nw];
         Vector Tw = Eigen::Map<const Vector>(wells().WI, nperf);
@@ -603,7 +613,7 @@ namespace Opm
     {
         if( localWellsActive() )
         {
-            const int np = num_phases_;
+            const int np = wells().number_of_phases;
             const int nw = wells().number_of_wells;
 
             // Extract parts of dwells corresponding to each part.