The oil-and-gas industry


Oil production mastering initiated by Russian oil industrial companies on marine shelf is a well-known fact, which is currently supported with Caspian shelf projects and intensification of work for "Sakhalin - 1", "Sakhalin-4,5" projects. It is worth mentioning about construction, in particular, re-equipment of floating boring station for "Prirazlomnaya" deposits.

The complex of engineering structures for the development of offshore oil and gas deposits includes isolated stationary or floating units (platforms) with the weight of up to 300 thousand tons, downhole equipment, sea-floor equipment with the weight of up to 1500-2000 tons, cable systems for hole remote control, flexible pipe lines with suspension and counterbalancing systems, large-section transport underwater pipelines, ships for pipe laying, oil tankers, coastal equipment and other types of equipment.

There is every prerequisite for the successful application of titanium alloys in the following systems and equipment for oil and gas offshore deposits development: deep-water drilling risers; casing tubes; producing risers; pumps and systems of sea water, drinking water, drilling water and associated water; tubings for process solutions circulation systems; liquid separators, heat exchanging equipment of various designations; high-pressure vessels; high-strength flexible braces for platform fastening.

Operating conditions of oil-field equipment are basically similar to operating conditions of ship-building articles, hence, the following significant differences can be specified: higher salt load of brine water; presence of hydrogen sulphide and carbon-dioxide gas in the operating media; presence of aerobic and anaerobic (in particular, sulphide generating components) components in the extracted products and in the environment; elevated temperatures of operating media; low atmosphere temperatures up to - 40-50С; possible salt and wax deposits on the surfaces; high pressure of operating media; presence of abrasive components in the transported products.

The most extensive experience in titanium alloys application in the offshore industry has been gained by Norway and Great Britain. Alloyed stainless steels have been used in the offshore industry in the North Sea for more than 30 years (Norwegian and British Sector). Nevertheless, corrosion damages were revealed for high-alloy steels, for e.g. intergranular corrosion is typical for steel with nickel content of 5,5% in a number of process media and corrosion cracking is typical in the chloride medium at the temperature of 100 °С; crevice corrosion is typical for steel with nickel content of 25% causing seal failure of flanges after two years' service (Oseberg A and Gullfaks A platforms). At the same time titanium being used for different applications exhibited its unique resistance to the most or if not to all types of corrosion from which it had to be suffered during the development of sea oil deposits.

The first well-known application of titanium alloy for the basic equipment designated for oil production on the marine shelf is the application of titanium in load-bearing joints of producing riser by Placid Oil Company on Green Canyon platform in the Gulf of Mexican (Manufacturer - Cameron Iron Works Inc).

Loterios Company supplied 4 caissons (distributing main line) for the fire system. The inside diameter of the caisson is 900 mm, 20/40 mm wall thickness, total length - 34 meters, weight - 10 t. Heat exchangers of titanium alloys produced in Japan are used on Steel Head platform (Alaska shelf).

The first experience of titanium alloys application for Norwegian Units Floating Drilling Units dates back to the year 1986 when Mobil Exploration Norway Inc. decided to use titanium instead of steel for the ballast water system of Statfjord A platform (Norway). Service life was 5 years and 6 months. During subsequent years similar substitution was conducted for Statfjord B and Statfjord C platform after 3-4 years' operation of steel structures.

300 and 400 tons, of titanium, respectively, are used for Heidran and Troll platforms having been commissioned in 1994-1995. Estimated service life of Troll platform is 70 years and this choice shows that at last reasonable relations between the service life of platforms (deposit) and the service life of the equipment for these platforms can be established.

As deeper-water systems of sea oil production are being built the need for titanium alloys application for subsea equipment fabrication have drastically increased. So, the majority of companies predict that the depths level of up to 2.5 km will have been reached by 2010. At that the significance of titanium application will be enhanced on account of the three major reasons:
- For a number of subsea equipment components application of alloys with high specific strength and low modulus of elasticity is required;
- Saving in weight is required for the equipment used on the platform. Based on the data given by Shell Oil Company, weight reduction of the subsea equipment by 1 ton allows reducing the weight of the support equipment by 3 tons that is equal to saving of approximately 150 thousand dollars. Each excess pound of the equipment on the platform deck or on the producing ship comes to $6.5;
- Titanium and its alloys possess reliability, including high corrosion resistance in seawater and operating media in the course of oil production.

According to the leading companies titanium and its alloys shall become one of the basic structural materials for deepwater oil production. JSC VSMPO, possessing a unique complex for production and processing of titanium alloys, can manufacture high-performance equipment for oil producing complex.

Currently, JSC VSMPO delivers piping elements (tube of 150 to 1000 in nominal dia. with the wall thickness - 4 mm up to 12 mm, branches, flanges, T-joints, adapting pipes) from titanium alloys designated for systems of sea, ballast and brine water for Floating Drilling Unit "Prirazlomnaya". The products are manufactured to specifications developed by the Company's specialists for this project and approved by the Federal Environmental, Process and Nuclear Surveillance Agency as well as FGUP RUBIN and FGUP SEVMASH.

Joint work on designing and manufacturing formation fluid heater with the trial pressure of 23,0 МPа is being carried out with JSC TаtNIIneftemash for stationary drilling unit, which will be put into operation at Obninsk bay.

Морская платформа

ea platform

Aluminium in oil-and-gas industry

Development of new deposits and increase of well depth impose certain requirements on materials used in manufacture of parts and assemblies for oil and gas field equipment as well as for oil refining equipment.
High strength-to-weight ratio of aluminium alloys allows to reduce weight of drilling equipment, facilitate its transportability and provide driving deep wells. Corrosion-resistant aluminium alloys enable to improve maintainability of drill, lifting and oil-and-gas pipes. The enhanced corrosion cracking strength allows to use aluminium alloys in manufacture of storage containers for oil and its products. The main structural material used for manufacture of drill pipes from aluminium alloys is D16 alloy. AMg2, AMg3, AMg5 and AMg6 have shown high resistance to crude oil and some kinds of gasoline. Among the aluminium-magnesium alloys mentioned above, AMg2 is the most common alloy used for manufacture of equipment, particularly for manufacture of condenser and refrigerators at oil refineries. In the USA equipment for oil industry is produced from aluminium alloys of Зххх, 5ххх and 6ххх series. 6063 alloy tubes are used in drilling equipment structures.

Offshore platforms are assembled from tubes from 6061 and 6063 alloys as well as high-strength 2014 and 7075 alloys. AD00, AD0 and AD1 aluminium is used for manufacture of containers, towers, condensers, etc. for acetic acid production, sulphurization of fatty alcohols, production of potassium chlorate, sodium and ammonium nitrate, hydrocyanic acid, etc.
AMc, AMg2, AMgЗ and AMg5 aluminium alloys are recommended by chemical industry for manufacture of vessels operating under pressure at temperatures ranging from -196 to +150 ?С.

In the USA alloys of 1ххх, Зххх and 5ххх series are used depending on service conditions of chemical industry equipment. In particular cases, 2ххх and 7ххх low corrosion resistant alloys hardened by heat treatment are used to provide higher strength.

Chemicals storage containers are manufactured from highly corrosion resistant alloys - 1100 or 3003 alloys; high-pressure vessels - from 5052 or 6063 alloys; containers, tanks and other equipment for storage of acetic acid, high-molecular fatty acids and alcohols and other chemicals - from 3003, 6061, 6063, 5052 alloys; tanks for ozone-containing fertilizers solutions - from 3004; 5052 and 5454 alloys; storage containers for ammonium nitrate solutions - from 1100, 3003, 3004, 5050, 5454, 6061 and 6062 alloys.