diff --git a/AsbCloudApp/Repositories/IGtrRepository.cs b/AsbCloudApp/Repositories/IGtrRepository.cs
index 706b6be2..39fbef07 100644
--- a/AsbCloudApp/Repositories/IGtrRepository.cs
+++ b/AsbCloudApp/Repositories/IGtrRepository.cs
@@ -4,6 +4,7 @@ using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
 using AsbCloudApp.Requests;
+using AsbCloudApp.Data;
 
 namespace AsbCloudApp.Repositories
 {
@@ -60,5 +61,15 @@ namespace AsbCloudApp.Repositories
         /// <returns></returns>
         [Obsolete]
         IEnumerable<WitsItemRecordDto> GetLastData(int idWell);
+
+        /// <summary>
+        /// Доступные даты по скважине
+        /// </summary>
+        /// <param name="idWell"></param>
+        /// <param name="geDate"></param>
+        /// <param name="leDate"></param>
+        /// <param name="token"></param>
+        /// <returns></returns>
+        Task<DatesRangeDto?> GetRangeAsync(int idWell, DateTimeOffset? geDate, DateTimeOffset? leDate, CancellationToken token);
     }
 }
diff --git a/AsbCloudApp/Requests/GtrRequest.cs b/AsbCloudApp/Requests/GtrRequest.cs
index 43de25c4..89d281a3 100644
--- a/AsbCloudApp/Requests/GtrRequest.cs
+++ b/AsbCloudApp/Requests/GtrRequest.cs
@@ -10,7 +10,7 @@ public class GtrRequest
 	/// <summary>
 	/// Дата начала выборки.По умолчанию: текущее время - IntervalSec
 	/// </summary>
-	public DateTime? Begin { get; set; }
+	public DateTimeOffset? Begin { get; set; }
 
 	/// <summary>
 	/// Интервал времени даты начала выборки, секунды
diff --git a/AsbCloudInfrastructure/Repository/GtrWitsRepository.cs b/AsbCloudInfrastructure/Repository/GtrWitsRepository.cs
index cbf87456..3f8333c9 100644
--- a/AsbCloudInfrastructure/Repository/GtrWitsRepository.cs
+++ b/AsbCloudInfrastructure/Repository/GtrWitsRepository.cs
@@ -15,6 +15,8 @@ using System.Threading.Tasks;
 using AsbCloudApp.Exceptions;
 using AsbCloudApp.Requests;
 using Mapster;
+using AsbCloudApp.Data;
+using System.ComponentModel.DataAnnotations;
 
 namespace AsbCloudInfrastructure.Repository
 {
@@ -82,6 +84,42 @@ namespace AsbCloudInfrastructure.Repository
         public async Task<IEnumerable<GtrWitsDto>> GetAsync(int idWell, GtrRequest request, CancellationToken token) =>
             await GetAsync<WitsItemFloat, float>(idWell, request, token);
 
+        public async Task<DatesRangeDto?> GetRangeAsync(int idWell, DateTimeOffset? geDate, DateTimeOffset? leDate, CancellationToken token)
+        {
+            var telemetry = telemetryService.GetOrDefaultTelemetryByIdWell(idWell);
+            
+            if (telemetry is null)
+                return null;
+
+            var rangeQuery = db
+                .Set<WitsItemFloat>()
+                .Where(e => e.IdTelemetry == telemetry.Id);
+
+            if (geDate is not null)
+                rangeQuery = rangeQuery.Where(e => e.DateTime >= geDate);
+
+            if (leDate is not null)
+                rangeQuery = rangeQuery.Where(e => e.DateTime <= leDate);
+
+            var groupedQuery = rangeQuery.GroupBy(e => e.IdTelemetry)
+                .Select(group => new
+                {
+                    Min = group.Min(e => e.DateTime),
+                    Max = group.Max(e => e.DateTime)
+                });
+            var range = await groupedQuery.FirstOrDefaultAsync(token);
+
+            if (range is null) 
+                return null;
+
+            var result = new DatesRangeDto
+            {
+                From = range.Min.ToOffset(telemetry.TimeZone!.Offset),
+                To = range.Max.ToOffset(telemetry.TimeZone!.Offset),
+            };
+            return result;
+        }
+
         private async Task<IEnumerable<GtrWitsDto>> GetAsync<TEntity, TType>(int idWell, GtrRequest request, CancellationToken token)
             where TEntity : WitsItemBase<TType> 
             where TType : notnull
@@ -116,8 +154,8 @@ namespace AsbCloudInfrastructure.Repository
                 {
                     var items = groupByInterval.Select(e => e);
                     var values = items.GroupBy(e => (e.IdRecord, e.IdItem))
-                        .Where(parameter => parameter.Any())
-                        .ToDictionary(parameter => WitsParameters[parameter.Key], g => g.Last().Value.ToString());
+                        .Where(group => WitsParameters.ContainsKey(group.Key))
+                        .ToDictionary(group => WitsParameters[group.Key], g => (object)g.Last().Value);
 
                     var dto = values.Adapt<GtrWitsDto>();
                     dto.DateTime = items.Last().DateTime.ToOffset(timezoneOffset);
@@ -142,6 +180,19 @@ namespace AsbCloudInfrastructure.Repository
                     .Where(e => e.DateTime >= dateBegin)
                     .Where(e => e.DateTime <= dateEnd);
             }
+            else
+            {
+                var lastDate = query
+                    .OrderBy(e=>e.DateTime)
+                    .LastOrDefault()
+                    ?.DateTime 
+                    ?? DateTimeOffset.UtcNow;
+                var dateBegin = lastDate.AddSeconds(-request.IntervalSec);
+                var dateEnd = lastDate;
+                query = query
+                    .Where(e => e.DateTime >= dateBegin)
+                    .Where(e => e.DateTime <= dateEnd);
+            }
 
             return query;
         }
diff --git a/AsbCloudWebApi/Controllers/SAUB/GtrWitsController.cs b/AsbCloudWebApi/Controllers/SAUB/GtrWitsController.cs
index a339f1b8..f234d33c 100644
--- a/AsbCloudWebApi/Controllers/SAUB/GtrWitsController.cs
+++ b/AsbCloudWebApi/Controllers/SAUB/GtrWitsController.cs
@@ -11,6 +11,9 @@ using System.Threading.Tasks;
 using AsbCloudApp.Exceptions;
 using AsbCloudApp.Requests;
 using Microsoft.AspNetCore.Http;
+using AsbCloudApp.Data;
+using System;
+using Org.BouncyCastle.Asn1.Ocsp;
 
 namespace AsbCloudWebApi.Controllers.SAUB
 {
@@ -58,6 +61,31 @@ namespace AsbCloudWebApi.Controllers.SAUB
             return Ok(dtos);
         }
 
+        /// <summary>
+        /// Возвращает диапазон дат за которые есть телеметрия за период времени
+        /// </summary>
+        /// <param name="idWell"></param>
+        /// <param name="geDate"></param>
+        /// <param name="leDate"></param>
+        /// <param name="token"></param>
+        /// <returns></returns>
+        [HttpGet("{idWell}/dateRange")]
+        [ProducesResponseType(typeof(DatesRangeDto), (int)System.Net.HttpStatusCode.OK)]
+        [ProducesResponseType((int)System.Net.HttpStatusCode.NotFound)]
+        [ProducesResponseType((int)System.Net.HttpStatusCode.NoContent)]
+        public virtual async Task<ActionResult<DatesRangeDto?>> GetRangeAsync(
+            [FromRoute] int idWell,
+            DateTimeOffset? geDate,
+            DateTimeOffset? leDate,
+            CancellationToken token)
+        {
+            await AssertUserHasAccessToWellAsync(idWell, token);
+
+            var range = await gtrRepository.GetRangeAsync(idWell, geDate, leDate, token);
+
+            return Ok(range);
+        }
+
         /// <summary>
         /// Получить загруженные данные ГТИ по скважине
         /// </summary>
@@ -81,7 +109,7 @@ namespace AsbCloudWebApi.Controllers.SAUB
             if (!isCompanyOwnsWell)
                 return Forbid();
 
-            var content = await gtrRepository.GetAsync(idWell, request.Begin,
+            var content = await gtrRepository.GetAsync(idWell, request.Begin?.DateTime,
               request.IntervalSec, request.ApproxPointsCount, token).ConfigureAwait(false);
 
             return Ok(content);