Our company renders services on core drilling. Experience and qualification of our specialists and also used modern equipment ensures average core recovery over 90%. Highly-skilled specialists manage core drilling direction. Work experience:Our specialists, who previously worked for other companies, recovered approximately 4000 meters of drill sample daily and have a broad experience in core drilling in complex geological conditions in different regions of Russia and Ukraine. Republic of Tatarstan, Bashkortostan, Orenburg region, Samara region, West and East Siberia, Polar Regions, Kaliningrad, shelf of Black sear etc. Average core recovery is more than 90%. In 2014 "Gasinvestproject" extracted core for "Poltava Drilling Company" LLC in well No.2 Vodyanskaya field. 38.4 meters of core were extracted with its average recovery of 90%. Intervals of core drilling: 4321.5 – 4331.5 m; 4369.0 – 4377.4 m; 4421.0 – 4431.0 m; 4851,5 – 4861.5 m.Core drilling services include the following:
- Works on core drilling in vertical, inclined and horizontal oil and gas wells with use of one- and two-section core extractors;
- Study of geological conditions and selection of the most efficient technique and core extraction technology;
- Designing and ordering of different structures of core extractors ;
- Provision of PDC drilling heads of different types and modifications;
- Development and ordering of special bottom hole assembly for core extraction;
- Technological and methodological support of core drilling process by highly-skilled specialists directly at wells;
- Packing of core in boxes and transfer to Customer against transfer/acceptance certificate.
Core drilling technology:Our company uses core extractors UKR-172/100 of one- and two-section design with diameter of extracted core of 100 mm upon core drilling of wells. Outer diameter of the frame along main length is 175.0 mm. To minimize vibration during drilling all core extractors are completed with centralizers 212.0 mm in diameter. We use drilling heads 215.9 mm in diameter, reinforced with double row of diamond destruction cutters, as rock destruction tool. Their housing has special wear-resistant coating. Bit gauge surface is reinforced diamond-bearing inserts.
Drilling method: rotary method and use of downhole drilling motor. Length of one travel is up to 14 meters, depending on geological conditions. Core is packed in wooden boxes on the surface or plastic containers on Customer's demand. Unique core drilling methods and operations, developed by our employees in the course of their activity, are also part of the technology of our company. This equipment can be used upon core drilling in well bore 215.9-295.3 mm in diameter.
Technical characteristics of core extractors UKR-172/100:Outer diameter of casing along main length, mm............................................................175Centralizer diameter, mm.................................................................................................212Tool length ( one/two sections), mm..................................................................8815/15900designed length of core extractor ( one/two sections), mm................................7195/14315Connecting thread:- Upper (coupling)..........................................................................З-133 GOST R50864-96- Lower (nipple).............................................................................З-161 GOST R 50864-96Weight of device assembly ( one/two sections), kg................................................850/1405Acceptable pump feed, l/sec..............................................................................................25Acceptable axial load, tons............................................................................................1 – 8Rotation frequency of drilling head, min-1 (rev/min)............................................. 60 – 120Makeup torque of connecting thread, kN m...............................................................13 – 15
NOTE: acceptable tolerance of weight : В± 3 % and acceptable length tolerance: В± 2.