#14960 Sim Events: Use first segment MD as user defined reference MD

When a SEGMENT event is applied (SIMEVENTS mapping or timeline
set_timestamp), set the segment collection Reference MD Type to User
Defined and the reference MD to the start MD of the first segment
interval, so WELSEGS TOP_LENGTH matches the first segment.

ApplicationLibCode/ProjectDataModel/WellEvents/RimWellEventTimeline.cpp

@@ -53,6 +53,7 @@
 
 #include <algorithm>
 #include <cmath>
+#include <limits>
 #include <set>
 
 CAF_PDM_SOURCE_INIT( RimWellEventTimeline, "WellEventTimeline" );
@@ -577,6 +578,15 @@ bool RimWellEventTimeline::applySegmentEvent( const RimWellEventSegment& event,
         interval->setMaxSegmentLength( event.maxSegmentLength() );
         interval->setFixedSegmentLength( event.fixedSegmentLength() );
 
+        // WELSEGS TOP_LENGTH is the reference MD, which must be the start of the first segment
+        double firstSegmentMD = std::numeric_limits<double>::infinity();
+        for ( auto* existingInterval : segmentCollection->intervals() )
+        {
+            firstSegmentMD = std::min( firstSegmentMD, existingInterval->startMD() );
+        }
+        segmentCollection->setReferenceMDType( RimSegmentCollection::ReferenceMDType::MANUAL_REFERENCE_MD );
+        segmentCollection->setManualReferenceMD( firstSegmentMD );
+
         segmentCollection->updateConnectedEditors();
         return true;
     }

GrpcInterface/Python/rips/simulator_events.py

@@ -2643,7 +2643,8 @@ def _apply_segment(
         return
 
     timeline_event = timeline.add_segment_event(**kwargs, **lengths)
-    interval = well_path.segment_collection().add_segment_interval(
+    segment_collection = well_path.segment_collection()
+    interval = segment_collection.add_segment_interval(
         start_md=start_md,
         end_md=end_md,
         diameter=kwargs.get("inner_diameter", 0.152),
@@ -2655,6 +2656,12 @@ def _apply_segment(
         interval.set_max_segment_length(length=lengths["max_segment_length"])
     if "fixed_segment_length" in lengths:
         interval.set_fixed_segment_length(length=lengths["fixed_segment_length"])
+    # WELSEGS TOP_LENGTH is the reference MD: use the start of the first segment.
+    segment_collection.reference_md_type = "UserDefined"
+    segment_collection.user_defined_reference_md = min(
+        i.start_md for i in segment_collection.intervals()
+    )
+    segment_collection.update()
     _apply_event_comment(event, timeline_event)
     report.events_applied += 1
 

GrpcInterface/Python/rips/tests/test_simulator_events.py

@@ -71,7 +71,8 @@ class FakeCompletionSettings:
 
 
 class FakeSegmentInterval:
-    def __init__(self):
+    def __init__(self, start_md=0.0):
+        self.start_md = start_md
         self.segment_length_calls = []
 
     def set_fixed_segment_length(self, length):
@@ -90,15 +91,20 @@ class FakeSegmentInterval:
 class FakeSegmentCollection:
     def __init__(self):
         self.segment_interval_calls = []
-        self.intervals = []
+        self._intervals = []
         self.update_calls = 0
+        self.reference_md_type = "GridEntryPoint"
+        self.user_defined_reference_md = 0.0
 
     def add_segment_interval(self, **kwargs):
         self.segment_interval_calls.append(kwargs)
-        interval = FakeSegmentInterval()
-        self.intervals.append(interval)
+        interval = FakeSegmentInterval(kwargs["start_md"])
+        self._intervals.append(interval)
         return interval
 
+    def intervals(self):
+        return self._intervals
+
     def update(self):
         self.update_calls += 1
 
@@ -2029,6 +2035,18 @@ class TestApplying:
             }
         ]
 
+    def test_segment_mapping_sets_reference_md_to_first_segment(self):
+        text = (
+            'SIMEVENTS 1.2\nWELL "55_33-A-1"\n'
+            "  2024-01-01 SEGMENT MDSTART=1500 MDEND=2500\n"
+            "  2024-01-01 SEGMENT MDSTART=1200 MDEND=1500\n"
+        )
+        timeline, report = self._apply(text)
+        assert report.errors == []
+        segment_collection = timeline.segment_calls[0]["well_path"].segment_collection()
+        assert segment_collection.reference_md_type == "UserDefined"
+        assert segment_collection.user_defined_reference_md == 1200.0
+
     def test_segment_min_max_lengths_are_mapped(self):
         text = (
             'SIMEVENTS 1.2\nWELL "55_33-A-1"\n'
@@ -2043,7 +2061,7 @@ class TestApplying:
         assert call["max_segment_length"] == 50.0
         assert "fixed_segment_length" not in call
 
-        interval = call["well_path"].segment_collection().intervals[0]
+        interval = call["well_path"].segment_collection().intervals()[0]
         assert interval.segment_length_calls == [("min", 5.0), ("max", 50.0)]
 
     def test_segment_fixed_length_is_mapped(self):
@@ -2058,7 +2076,7 @@ class TestApplying:
         assert "min_segment_length" not in call
         assert "max_segment_length" not in call
 
-        interval = call["well_path"].segment_collection().intervals[0]
+        interval = call["well_path"].segment_collection().intervals()[0]
         assert interval.segment_length_calls == [("fixed", 12.0)]
 
     def test_segment_rejects_pressure_components(self):
@@ -3247,6 +3265,44 @@ class TestSimulatorEventsIntegration:
         assert "'HFA'" in headers[0]
         assert "'H--'" in headers[1]
 
+    def test_segment_events_set_user_defined_reference_md(
+        self, project_with_case_and_wells
+    ):
+        project, case, timeline = project_with_case_and_wells
+        well = next(wp for wp in project.well_paths() if "A" in wp.name)
+        document = parse_simulator_events(
+            "SIMEVENTS 1.2\n"
+            f'WELL "{well.name}"\n'
+            "  2024-01-01 SEGMENT      MDSTART=1500  MDEND=2500\n"
+            "  2024-01-01 SEGMENT      MDSTART=1200  MDEND=1500\n"
+            "  2024-01-01 PERFORATION  MDSTART=2000  MDEND=2200\n"
+        )
+        report = apply_simulator_events_document(document, timeline, project)
+        assert report.errors == []
+
+        segment_collection = well.segment_collection()
+        assert segment_collection.reference_md_type == "UserDefined"
+        assert segment_collection.user_defined_reference_md == 1200.0
+
+        schedule = timeline.generate_schedule_text(
+            eclipse_case=case, export_msw_for_wells=[well]
+        )
+        header = schedule.split("WELSEGS\n", 1)[1].split("/", 1)[0]
+        header_values = [
+            line.split()
+            for line in header.splitlines()
+            if line.strip() and not line.strip().startswith("--")
+        ][0]
+        top_length = float(header_values[2])
+        assert top_length == pytest.approx(1200.0)
+
+        segment_collection.reference_md_type = "GridEntryPoint"
+        segment_collection.update()
+        timeline.set_timestamp(timestamp="2024-12-24")
+        segment_collection = well.segment_collection()
+        assert segment_collection.reference_md_type == "UserDefined"
+        assert segment_collection.user_defined_reference_md == 1200.0
+
     def test_apply_unknown_well_warns_and_applies_nothing(
         self, project_with_case_and_wells
     ):

docs/simulatorEvents.md

@@ -226,6 +226,8 @@ Each event adds the underlying segment timeline event and a corresponding **Segm
 
 The segment lengths control the MSW segmentation of the interval. Lengths must be positive. `FIXED_SEGMENT_LENGTH` cannot be combined with `MIN_SEGMENT_LENGTH` or `MAX_SEGMENT_LENGTH`, and `MIN_SEGMENT_LENGTH` cannot exceed `MAX_SEGMENT_LENGTH`. Violations are reported as parse errors.
 
+Applying a SEGMENT event also sets the well's segment *Reference MD Type* to *User Defined*, with *User Defined Reference MD* set to the start MD of the first (shallowest) segment interval. This value is written as `TOP_LENGTH` in `WELSEGS`.
+
 **VALVE** → `add_valve_event` (requires an existing perforation at the MD)
 
 | Attribute | Required | Maps to |