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Main types of executed works

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Welding-assembling works


PetroGas FZE executes all complex of welding-assembling works on welding and installation of pipelines of all diameters and metal structures at construction sites, including on pipelines transporting crude hydrocarbons with increased concentration of sulphur.

Types of welding:

- manual electric arc-welding by welding electrodes,

- automatic roll submerged arc welding of pipes at pipe welding station,

- gas tungsten arc welding (GTAW) by electrode with filler metal wire ER 70S6 type and other.

Welding works are executed by “Fronius”, “Lincoln K2406-1”, “Miller”, C-100, АS-81, АDD-4 and other types of welding machines.

Welding-assembling works in unfavorable conditions (atmospheric precipitations, wind over 10 m/s) are executed in shelters.

Welding materials are dried and burned directly before welding in accordance with established regulations.

Assembling of pipe joints is executed using internal and external line-up clamps.


Thermal treatment of welding joints


Welding joints on pipelines designed for transportation of sulfurous gas are thermally treated after welding.

Thermal treatment is executed as negative hardening of metal, which is intended for:

- Decreasing of residual welding stresses in welding joints;

- Decreasing of metal hardness level of welding joints and adjacent area

- Improvement of metal structure;

- optimization of mechanical and corrosion properties of welding joint metal

Main operations during thermal treatment of welding joints:

- modes of thermal treatment are chosen depending on steel grade, pipe wall thickness and technological option of welding;

- types and quantity of heating devices and schemes of their reasonable placement and switching on are chosen;

- transducers, heating device and heat insulation are installed on welded joint;

- equipment is switched on and then preheating, curing and cooling of welding joint;

- heat insulation, heating device and transducers are dismantled;

- quality control of welding joints by measuring of hardness;

- preparation of technical documentation on thermal treatment.

Thermal treatment is executed on six- and twelve channel equipment «Standard Europe» 82-12 (82-6).




The main earthworks include:

- planning works,

- trenching and ditching,

- embankment,

- subfoundation soil compaction,

- backfilling of trenches and ditches

- recultivation.

Trenching and ditching in sandy soil is done by dozers and single bucket excavators.

Bucket wheel excavators are used for trenching in compact, stabilized and wet soil.

Integrated earthwork is used for deep trenching, when surface soil up to 1-1.2m is excavated by dozers and the other parts till design reference mark in loose soil – by single bucket excavator (dragline type) or by single bucket backhoe excavator and bucket capacity not less than 1m3.

Trenching and ditching is rocky soil is executed by KOMATSU D-355А or КАТ- D9Н heavy dozer with preparatory soil by mechanical hoeing.

Backfilling of trenches and ditches is done by dozers and single bucket backhoe excavators.

Embankments are installed by dozers out of mineral local and imported soils.

Soil compaction is executed by BOMAG, BW 212D,  DU-85, rollers or multiple passes of dozer or caterpillar tractors, as well as by pneumatic compaction with the following measuring of soil density.

Earthworks in close vicinity on both sides of operational communication in places of their crossing or passing along should be manually only.


Insulation-laying works


Insulation work technique in field conditions includes:

- Preparation of insulation materials;

- Drying and preheating of insulated surface;

- Cleaning of outside surface of pipeline (when using pre-insulated pipes), or areas of welding joints (when using pre-insulated pipes) from dirt, rust and slag;

- Primer applying (primer, adhesive layer) on cleaned surface of pipeline or its certain areas;

- Application of insulation and protective coating on primed areas of pipeline;

- Installation of heat shrink sleeves on welding joints.

Insulation of welding joints with heat shrink sleeves is performed on trench edge followed by these operations:

- Quality control of applied insulation;

- Laying (lowering) of pipeline into design position.

Insulation work technique on joints of connecting elements of pipeline includes the following major operations:

- Cleaning of surface to be insulated

- Drying or pre-heating of joint or pipe-bend;

- Primer application;

- Coating application;

- Quality Control of Coating.


Insulation-laying works in field condition are executed by string of side booms:

- Simultaneously - works on cleaning, insulation and laying of pipeline are done in a single process flow of non-insulated pipes;

- Separately - works on cleaning, insulation of welding joints (of insulated pipes) should be done in advance relatively to laying of pipeline.

Continuity check of insulation coating of pipelines is checked by cathode polarization.


Concrete Weight coating


Concrete Weight Coating

- Concrete Weight Coating;

- PG CWC plant located 300 m from to the Aladja jetty;

- CWC process operation released by impingement, on CRC-evans equipment;

- Operation capacity 0,47 m3/min up to 48 inches pipes;

- Company has all necessary cranes for loading and unloading pipes in the Aladja port and trucks for transportation through Turkmenistan territory;

- Stock piling area 500x500 m.

Operation and quality control process submit requirements ASTM, BV and DNV standards:

- Pipe isolation controlled by Holiday detection up to 25Kv voltage;

- All destructive and non-destructive tests are made by certify laboratory on the site;

- Cores and cubes crush tests released by Baz Macina 001-OT;

- Final production weight accuracy +-1%;

- Batching plant accuracy +-1%.


Survey works


Survey works executed include:

- Topographic survey;

- Processing of survey results;

- Well drilling and soil sampling;

- Measuring of electrical resistivity of soils;


Engineering surveys are executed by surveying party of geodetic engineers, geological engineer, hydrologist, electrical engineer, drilling foreman, drilling foreman assistant, drivers, and auxiliary personnel.

Barges, special pontoons and tug boats are used for well drilling on water barriers.  

GPS Trimble EPOCH 25 and Trimble М3 electronic tacheometer are used for topographic survey.

Processing of results of field measurements and drawing of surveyor’s plans is executed by: Trimble geomatic, Credo, Autocad.

Probe well drilling for soil sampling is done by boring machine PBU-2 with continous-flight augers and core method Ø 120-160mm

Measuring of specific electrical resistency of soils is done by M-146 four-probe system.

Laboratory tests of soil and water are performed in Central Laboratory of Ministry of Geology of Turkmenistan.


Civil works


- earthwork;

- subfoundation soil compactio;

- concrete, reinforced concrete works and installation of piles and foundations;

- brick laying and installation of concrete wall and other structures;

- finishing works;

- installation of heat-gas water supply systems, sewerage, air conditioning, ventilation systems;

- improvement of territory, fencing and road construction.



Installation of instrumentation, fire alarm and communication systems


- Installation works on mounting of cable racks, channels, blocks and structures for laying of cables in different environmental conditions (hazardous areas, offshore platforms, compressor  and oil treatment stations);

- Installation works on mounting of cable racks, channels, blocks in sea invironmet conditions (offshore platforms), explosive and fire-hazardous areas;

- Installation works on preparation and installation of different clamping, supports and racks for installation of instrumentation gages and other instrumentation process equipment;

- Works on installation, calibration and adjustment of pressure gauges and differential pressure transmitter, temperature, level and flow meters, vibration gage as well as other digital and visual gauges;

- Calibration and setting of equipment with up-to-date devices, such as FLUKE-726 calibrator, HART communicator 375 programming device, Tektronix P6015A up-to-date oscillograph, etc;

- Installation, hook up and adjustment of telecommunication networks, public address systems, Ethernet communications, fiber-optic cable;

- Installation, hook up and adjustment of fire-alarm system and public address systems;

- Installation, hook up and adjustment of gas detecting systems;

- Installation, hook up and adjustment of technical process management system (control cabinets, controllers, operator stations, reserve server stations, etc.);

- Works with installation of software and backing up;

- Installation, hook up and adjustment of backup supply (UPS systems, accumulator station);

- Installation, hook up and adjustment of systems of fiscal measuring of process product;

- Installation and adjustment of process systems, ESDV drives, electrical drives of different types;

- Setting of logic of technical process work.


Electrical installation works


- Construction of 0.4-35kV overhead electric power lines (installation and assembling of poles and cables/lines, connections);

- Installation and assembling of close distribution units (KTP-6/0.4kV ,КRU-6kV, КRU-35kV);

- Electrical installation of 6-35kV open distribution devices (installation and connection of portals, buses, breakers, arresters and transformers);

- Cable laying,  0.4-35kV (in trenches, on racks);

- Installation of 6-70kV junction boxes(on cables of XLPE cross-linked polyethylene;

- Electrical cable termination 0.4-35kV;

- Electrical installation of internal lighting system (electrical wiring of building and structures);

- Electrical installation of external lighting system (installation and electrical mounting of lighting poles and masts);

- Installation of cable racks (installation and assembling of cable trays and operation platforms and ladders);

- Electrical mounting of grounding devices and grounding loops;

- Installation of 0.4-35kV transformers (installation, assembling, bus arrangement, connection);

- Installation of 0.4-35kV electric motors (installation, connection);

- Setting of electrical equipment (check, setting, installation of relay protection and automatics);

- High voltage tests of electrical equipment;

- Installation of cathode, anode and galvanic protecting systems for process equipment.