diff --git a/AsbCloudInfrastructure/Services/DataSaubStatDrillingQualityService.cs b/AsbCloudInfrastructure/Services/DataSaubStatDrillingQualityService.cs
index f83932db..b8b11639 100644
--- a/AsbCloudInfrastructure/Services/DataSaubStatDrillingQualityService.cs
+++ b/AsbCloudInfrastructure/Services/DataSaubStatDrillingQualityService.cs
@@ -126,20 +126,20 @@ public class DataSaubStatDrillingQualityService : IDataSaubStatDrillingQualitySe
 
         while (indexEnd < dataSaub.Count() - 1)
         {
-            indexStart = Array.FindIndex(dataSaub, indexEnd, t => t.IdFeedRegulator == idFeedRegulator);
-            if (indexStart < 0)
-                break;
+                indexStart = Array.FindIndex(dataSaub, indexEnd, t => t.IdFeedRegulator == idFeedRegulator);
+                if (indexStart < 0 || indexStart == dataSaub.Count() - 1)
+                    break;
 
-            indexEnd = FindIndexEnd(indexStart, idFeedRegulator, dataSaub);
+                indexEnd = FindIndexEnd(indexStart, idFeedRegulator, dataSaub);
 
-            var length = indexEnd - indexStart + 1;
-            var subset = dataSaub.AsSpan(indexStart, length);
+                var length = indexEnd - indexStart + 1;
+                var subset = dataSaub.AsSpan(indexStart, length);
 
-            if ((subset[^1].WellDepth - subset[0].WellDepth) < 0.15)
-                continue; // мелкие выборки не учитываем.
+                if ((subset[^1].WellDepth - subset[0].WellDepth) < 0.15)
+                    continue; // мелкие выборки не учитываем.
 
-            var stats = CalcStatsDrillingQuality(idFeedRegulator, subset, checkQuality);
-            result.Add(stats);
+                var stats = CalcStatsDrillingQuality(idFeedRegulator, subset, checkQuality);
+                result.Add(stats);
 
         }
         return result;