diff --git a/AsbCloudInfrastructure/Services/WellService.cs b/AsbCloudInfrastructure/Services/WellService.cs
index 01f9cb32..d55bd2a5 100644
--- a/AsbCloudInfrastructure/Services/WellService.cs
+++ b/AsbCloudInfrastructure/Services/WellService.cs
@@ -128,7 +128,7 @@ namespace AsbCloudInfrastructure.Services
 
         public override async Task<int> InsertAsync(WellDto dto, CancellationToken token)
         {
-            if (await IsExistingTelemetryAsync(dto.IdTelemetry, token))
+            if (IsTelemetryAssignedToDifferentWell(dto))
                 throw new ArgumentInvalidException("Телеметрия уже была привязана к другой скважине.", nameof(dto));
             
             if (dto.IdWellType is < 1 or > 2)
@@ -160,10 +160,10 @@ namespace AsbCloudInfrastructure.Services
             throw new NotImplementedException();
         }
 
-        public override async Task<int> UpdateAsync(WellDto dto,
+        public override async Task<int> UpdateAsync(WellDto dto, 
             CancellationToken token)
         {
-            if (await IsExistingTelemetryAsync(dto.IdTelemetry, token))
+            if (IsTelemetryAssignedToDifferentWell(dto))
                 throw new ArgumentInvalidException("Телеметрия уже была привязана к другой скважине.", nameof(dto));
             
             if (dto.IdWellType is < 1 or > 2)
@@ -341,13 +341,18 @@ namespace AsbCloudInfrastructure.Services
             throw new Exception($"Can't find timezone for well {wellDto.Caption} id: {wellDto.Id}");
         }
 
-        private Task<bool> IsExistingTelemetryAsync(int? idTelemetry, CancellationToken cancellationToken)
+        private bool IsTelemetryAssignedToDifferentWell(WellDto wellDto)
         {
-            if (!idTelemetry.HasValue)
-                return Task.FromResult(false);
+            if (!wellDto.IdTelemetry.HasValue)
+                return false;
+
+            var existingWellWithAssignedTelemetry = GetCache()
+                .FirstOrDefault(x => x.IdTelemetry == wellDto.IdTelemetry);
+
+            if (existingWellWithAssignedTelemetry is null)
+                return false;
             
-            return dbSet.AnyAsync(x => x.IdTelemetry == 
-                                       idTelemetry.Value, cancellationToken);
+            return existingWellWithAssignedTelemetry.Id != wellDto.Id;
         }
 
         private static AsbCloudDb.Model.IMapPoint GetCoordinates(Well well)