diff --git a/opm/autodiff/MultisegmentWell_impl.hpp b/opm/autodiff/MultisegmentWell_impl.hpp
index af6eb1179..7536b598a 100644
--- a/opm/autodiff/MultisegmentWell_impl.hpp
+++ b/opm/autodiff/MultisegmentWell_impl.hpp
@@ -33,7 +33,7 @@ namespace Opm
     , segment_inlets_(numberOfSegments())
     , perforation_cell_pressure_diffs_(number_of_perforations_, 0.0)
     , segment_perforation_depth_diffs_(number_of_perforations_)
-    , segment_comp_initial_(numberOfSegments(), std::vector<double>(numWellEq, 0.0))
+    , segment_comp_initial_(numberOfSegments(), std::vector<double>(numComponents(), 0.0))
     , segment_densities_(numberOfSegments(), 0.0)
     , segment_depth_diffs_(numberOfSegments(), 0.0)
     {
@@ -762,8 +762,10 @@ namespace Opm
     computeInitialComposition()
     {
         for (int seg = 0; seg < numberOfSegments(); ++seg) {
-            for (int eq_idx = 0; eq_idx < numWellEq; ++eq_idx) {
-                segment_comp_initial_[seg][eq_idx] = surfaceVolumeFraction(seg, eq_idx).value();
+            // TODO: probably it should be numWellEq -1 more accurately,
+            // while by meaning it should be num_comp
+            for (int comp_idx = 0; comp_idx < numComponents(); ++comp_idx) {
+                segment_comp_initial_[seg][comp_idx] = surfaceVolumeFraction(seg, comp_idx).value();
             }
         }
     }
diff --git a/opm/autodiff/StandardWell_impl.hpp b/opm/autodiff/StandardWell_impl.hpp
index e420ea967..f42159cc4 100644
--- a/opm/autodiff/StandardWell_impl.hpp
+++ b/opm/autodiff/StandardWell_impl.hpp
@@ -316,7 +316,7 @@ namespace Opm
     StandardWell<TypeTag>::
     wellVolumeFraction(const int compIdx) const
     {
-        const auto pu = phaseUsage();
+        const auto& pu = phaseUsage();
         if (active()[Water] && compIdx == pu.phase_pos[Water]) {
             return primary_variables_evaluation_[WFrac];
         }
@@ -1525,6 +1525,8 @@ namespace Opm
     StandardWell<TypeTag>::
     computeAccumWell()
     {
+        // TODO: it should be num_comp, while it also bring problem for
+        // the polymer case.
         for (int eq_idx = 0; eq_idx < numWellEq; ++eq_idx) {
             F0_[eq_idx] = wellSurfaceVolumeFraction(eq_idx).value();
         }