diff --git a/opm/parser/eclipse/EclipseState/Schedule/Well/WellTestState.hpp b/opm/parser/eclipse/EclipseState/Schedule/Well/WellTestState.hpp
index ac4820080..dd0b8e114 100644
--- a/opm/parser/eclipse/EclipseState/Schedule/Well/WellTestState.hpp
+++ b/opm/parser/eclipse/EclipseState/Schedule/Well/WellTestState.hpp
@@ -195,7 +195,7 @@ public:
 
 
     std::vector<std::string> test_wells(const WellTestConfig& config, double sim_time);
-
+    void filter_wells(const std::vector<std::string>& existing_wells);
     /*
       The purpose of this container is to manage explicitly *closed wells*,
       since the class has no relation to the set of of wells defined in the
diff --git a/src/opm/parser/eclipse/EclipseState/Schedule/Well/WellTestState.cpp b/src/opm/parser/eclipse/EclipseState/Schedule/Well/WellTestState.cpp
index c3307f6ed..8a9d1b558 100644
--- a/src/opm/parser/eclipse/EclipseState/Schedule/Well/WellTestState.cpp
+++ b/src/opm/parser/eclipse/EclipseState/Schedule/Well/WellTestState.cpp
@@ -110,6 +110,14 @@ namespace Opm {
     }
 
 
+    void WellTestState::filter_wells(const std::vector<std::string>& existing_wells) {
+        std::unordered_set<std::string> well_set{ existing_wells.begin(), existing_wells.end() };
+        for (auto& [wname, test_well] : this->wells) {
+            if (well_set.count(wname) == 0)
+                test_well.closed = false;
+        }
+    }
+
 
     size_t WellTestState::num_closed_wells() const {
         return std::count_if(this->wells.begin(), this->wells.end(), [](const auto& well_pair) { return well_pair.second.closed; });
diff --git a/tests/BASE.UNRST b/tests/BASE.UNRST
new file mode 100644
index 000000000..7bdf08bdf
Binary files /dev/null and b/tests/BASE.UNRST differ
diff --git a/tests/parser/WTEST.cpp b/tests/parser/WTEST.cpp
index eb82f29e7..4753dc5a5 100644
--- a/tests/parser/WTEST.cpp
+++ b/tests/parser/WTEST.cpp
@@ -90,6 +90,14 @@ BOOST_AUTO_TEST_CASE(WTEST_STATE) {
     st.close_well("WELLX", WellTestConfig::Reason::PHYSICAL, 100. * day);
     BOOST_CHECK_EQUAL(st.num_closed_wells(), 2U);
 
+    {
+        auto st2 = st;
+        st2.filter_wells(std::vector<std::string>{"WELLX"});
+
+        BOOST_CHECK(!st2.well_is_closed("WELL_NAME"));  // This well has been opened/removed by the filter_wells() call
+        BOOST_CHECK( st2.well_is_closed("WELLX"));
+    }
+
     const UnitSystem us{};
 
     WellTestConfig wc;