diff --git a/lib/ecl/well_segment_collection.cpp b/lib/ecl/well_segment_collection.cpp
index 8da80cca75..102ab5f41b 100644
--- a/lib/ecl/well_segment_collection.cpp
+++ b/lib/ecl/well_segment_collection.cpp
@@ -18,6 +18,8 @@
 
 #include <stdbool.h>
 
+#include <vector>
+
 #include <ert/util/util.h>
 #include <ert/util/vector.hpp>
 
@@ -33,58 +35,61 @@
 
 
 struct well_segment_collection_struct {
-  int_vector_type * segment_index_map;
-  vector_type * __segment_storage;
+  std::vector<int> segment_index_map;
+  std::vector<well_segment_type*> __segment_storage;
 };
 
 
 
 well_segment_collection_type * well_segment_collection_alloc(void) {
-  well_segment_collection_type * segment_collection = (well_segment_collection_type*)util_malloc( sizeof * segment_collection );
-
-  segment_collection->__segment_storage = vector_alloc_new();
-  segment_collection->segment_index_map = int_vector_alloc( 0 , -1 );
+  well_segment_collection_type * segment_collection = new well_segment_collection_type();
   return segment_collection;
 }
 
 
 
 void well_segment_collection_free(well_segment_collection_type * segment_collection ) {
-  vector_free( segment_collection->__segment_storage );
-  int_vector_free( segment_collection->segment_index_map );
-  free( segment_collection );
+  for (int i = 0; i < static_cast<int>(segment_collection->__segment_storage.size()); i++)
+    well_segment_free( segment_collection->__segment_storage[i] );
+  delete segment_collection;
 }
 
 
 
 int well_segment_collection_get_size( const well_segment_collection_type * segment_collection ) {
-  return vector_get_size( segment_collection->__segment_storage );
+  return segment_collection->__segment_storage.size();
 }
 
 
 void well_segment_collection_add( well_segment_collection_type * segment_collection , well_segment_type * segment) {
   int segment_id = well_segment_get_id( segment );
-  int current_index = int_vector_safe_iget( segment_collection->segment_index_map , segment_id );
-  if (current_index >= 0)
-    vector_iset_owned_ref( segment_collection->__segment_storage , current_index , segment , well_segment_free__);
+  int current_index = -1;
+  if (segment_id < static_cast<int>(segment_collection->segment_index_map.size()))
+    current_index = segment_collection->segment_index_map[segment_id];
+  if (current_index >= 0) {
+    well_segment_free( segment_collection->__segment_storage[current_index] );
+    segment_collection->__segment_storage[current_index] = segment;
+  }
   else {
-    int new_index = vector_get_size(segment_collection->__segment_storage);
-    vector_append_owned_ref( segment_collection->__segment_storage , segment , well_segment_free__);
-    if (segment_id >= int_vector_size(segment_collection->segment_index_map))
-      int_vector_resize(segment_collection->segment_index_map, segment_id+1, -1);
-    int_vector_iset( segment_collection->segment_index_map , segment_id , new_index);
+    int new_index = segment_collection->__segment_storage.size();
+    segment_collection->__segment_storage.push_back( segment );
+    if ( segment_id >= static_cast<int>(segment_collection->segment_index_map.size()) )
+      segment_collection->segment_index_map.resize(segment_id+1, -1);
+    segment_collection->segment_index_map[segment_id] = new_index;
   }
 }
 
 
 
 well_segment_type * well_segment_collection_iget( const well_segment_collection_type * segment_collection , int index) {
-  return (well_segment_type*)vector_iget( segment_collection->__segment_storage , index );
+  return segment_collection->__segment_storage[ index ];
 }
 
 
 well_segment_type * well_segment_collection_get( const well_segment_collection_type * segment_collection , int segment_id) {
-  int internal_index = int_vector_safe_iget( segment_collection->segment_index_map , segment_id );
+  int internal_index = -1;
+  if (segment_id < static_cast<int>(segment_collection->segment_index_map.size()))
+    internal_index = segment_collection->segment_index_map[segment_id];
   if (internal_index >= 0)
     return well_segment_collection_iget( segment_collection , internal_index );
   else
@@ -93,7 +98,9 @@ well_segment_type * well_segment_collection_get( const well_segment_collection_t
 
 
 bool  well_segment_collection_has_segment( const well_segment_collection_type * segment_collection , int segment_id) {
-  int internal_index = int_vector_safe_iget( segment_collection->segment_index_map , segment_id );
+  int internal_index = -1;
+  if (segment_id < static_cast<int>(segment_collection->segment_index_map.size()))
+    internal_index = segment_collection->segment_index_map[segment_id];
   if (internal_index >= 0)
     return true;
   else
@@ -135,8 +142,8 @@ int well_segment_collection_load_from_kw( well_segment_collection_type * segment
 
 
 void well_segment_collection_link(const  well_segment_collection_type * segment_collection) {
-  int index;
-  for (index = 0; index < vector_get_size( segment_collection->__segment_storage); index++) {
+  size_t index;
+  for (index = 0; index < segment_collection->__segment_storage.size(); index++) {
     well_segment_type * segment = well_segment_collection_iget( segment_collection , index );
     int outlet_segment_id = well_segment_get_outlet_id( segment );
     if (!well_segment_nearest_wellhead(segment)) {