diff --git a/AsbCloudInfrastructure/Services/Subsystems/SubsystemOperationTimeService.cs b/AsbCloudInfrastructure/Services/Subsystems/SubsystemOperationTimeService.cs
index 64c5022e..1faa769f 100644
--- a/AsbCloudInfrastructure/Services/Subsystems/SubsystemOperationTimeService.cs
+++ b/AsbCloudInfrastructure/Services/Subsystems/SubsystemOperationTimeService.cs
@@ -76,7 +76,7 @@ namespace AsbCloudInfrastructure.Services.Subsystems
             {                
                 var begin = request.GtDate?.ToUtcDateTimeOffset(well.Timezone.Hours);
                 var end = request.LtDate?.ToUtcDateTimeOffset(well.Timezone.Hours);
-                data = Trim(data, begin, end);      
+                data = TrimOperation(data, begin, end);      
             }
 
             var dtos = data.Select(o => Convert(o, well.Timezone.Hours));
@@ -109,21 +109,35 @@ namespace AsbCloudInfrastructure.Services.Subsystems
             return statList;
         }
 
-        private static IEnumerable<SubsystemOperationTime> Trim(IEnumerable<SubsystemOperationTime> data, DateTimeOffset? gtDate, DateTimeOffset? ltDate)
+        private static IEnumerable<SubsystemOperationTime> TrimOperation(IEnumerable<SubsystemOperationTime> data, DateTimeOffset? gtDate, DateTimeOffset? ltDate)
         {
-            var items = data.Select((item) =>
+            if (!ltDate.HasValue && !gtDate.HasValue) 
+                return data.Select(d => d.Adapt<SubsystemOperationTime>());
+
+            var items = data.Select((item) => 
             {
+                var operationTime = item.Adapt<SubsystemOperationTime>();
+                if (!(item.DepthStart.HasValue && item.DepthEnd.HasValue))
+                    return operationTime;
+
+                var dateDiff = (item.DateEnd - item.DateStart).TotalSeconds;
+                var depthDiff = item.DepthEnd.Value - item.DepthStart.Value;
+                var a = depthDiff / dateDiff;               
+                var b = item.DepthStart.Value;
+
                 if (gtDate.HasValue && item.DateStart < gtDate.Value)
                 {
-                    item.DateStart = gtDate.Value;
-                    item.DepthStart = null;
+                    operationTime.DateStart = gtDate.Value;
+                    var x = (gtDate.Value - item.DateStart).TotalSeconds;
+                    operationTime.DepthStart = (float)(a * x + b);
                 }
                 if (ltDate.HasValue && item.DateEnd > ltDate.Value)
                 {
-                    item.DateEnd = ltDate.Value;
-                    item.DepthEnd = null;
+                    operationTime.DateEnd = ltDate.Value;
+                    var x = (ltDate.Value - item.DateStart).TotalSeconds;
+                    operationTime.DepthEnd = (float)(a * x + b);
                 }
-                return item;
+                return operationTime;
             });
 
             return items;