The Metallurgy Options for Tubing

The Metallurgy Options for Tubing The metallurgy of tubing is a significant factor while picking tubing for a specific situation. By and large the tubing is comprised of carbon or low combination prepares, martensitic hardened steel, Duplex treated steel or other erosion safe composites like Nickel-base compound and so on. METALLURGY FOR TUBING: Carbon steel is an amalgam of carbon and iron containing up to 2% carbon and up to 1.65% manganese and lingering amounts of different elements.Steels with a complete alloying component substance of not exactly about 5% however more than indicated for carbon steel are assigned as low combination steel.Carbon steel is the most well-known composite utilized in oil industry as a result of its moderately ease. In spite of the fact that erosion obstruction of these prepares is constrained still they have been utilized in oil industry since long acceptably. They are reasonable for somewhat destructive situations like low fractional weight of CO2 low halfway weight of H2S. A material chose for a specific situation may not stay appropriate for the situation the ecological conditions change.CO2 can cause outrageous weight reduction consumption confined erosion, H2S can cause sulfide stress breaking and erosion. Chlorides at high temperature can cause pressure erosion splitting and pitting of metals, while low pH when all is said in done expands consumption rate. For instance the accompanying material are viewed as impervious to sulfide stress splitting : Low and medium composite carbon, containing under 1% nickel. AISI 300 arrangement treated steels (Austenitic) that is completely strengthened and liberated from cold work. The accompanying materials have been found to have practically no protection from sulfide stress breaking: AISI Grades 420 and 13% Cr martensitic hardened steel. All virus completed prepares including low and medium amalgam prepares, numerous assortment of treated steel. The constraints of Carbon steel, 9-Cr-1 Mo, 13-Cr, Duplex tempered steel are experienced in different situations and downhole tasks. METALLURGY OPTIONS FOR TUBING: The different metallurgical alternatives inspected for tubing and other downhole gear are Carbon Low Alloy Steels, 9 Cr-1Mo steel, 13% Cr hardened steel, Duplex Stainless steel and nickel based combinations. A brief of the reasonableness and impediments of these materials in different conditions experienced in oil and gas wells: 9Cr-1Mo steel. This steel is resistant to stretch erosion splitting within the sight of chlorides like other nickel free low compound prepares. Consumption opposition of this steel within the sight of H2S is poor. Subsequently it isn't utilized in tubing metallurgy regularly. 13Cr Stainless steel. This steel can be utilized upto 100 atms CO2 fractional weight and upto 150 degree Celsius temperature with chloride upto 50 gms/L. This martensitic grade is known to be powerless to sulfide stress splitting in sharp environment.This material is commonly utilized for sweet wells where least souring is normal. Duplex Stainless Steel. Duplex SS has superb consumption opposition in CO2 condition. The restriction of their utilization is their powerlessness to stretch consumption splitting at high temperature and constrained protection from sulfide stress breaking, when H2S is available in the delivered liquid. Nickel Based Alloys. Nickel based compounds are required to be utilized in amazingly destructive conditions including exceptionally high halfway weight of H2S and CO2 alongside nearness of free sulfur or oxygen. Choice OF TUBING METALLURGY: From the different metallurgical alternatives I have broke down, it tends to be presumed that low composite carbon steel isn't reasonable for the wells where high consumption chance included, especially in seaward. In the event that low permit materials were to be utilized, an escalated erosion inhibitor treatment program is fundamental. Notwithstanding, even with the best of projects, the answer for the issue would be experimentation. Albeit 9Cr-1 Mo prepares are impervious to CO2 assault, they ought not be considered for this application since their application in chloride condition is constrained up to 10 gms/l (1%).With the high centralizations of chlorides combined with the high all around bore temperature; this material isn't appropriate for downhole use in these wells. Duplex hardened steel is powerless to chloride stress splitting and ought not be utilized with the CaCl2 packer liquid. Additionally, the cost for Duplex material is three to multiple times the expense of 13 Cr SS material, which would make it monetarily inadmissible. Thus, disregarding the extra direct expense for tubing , it is suggested that dependent on the caliper overview results , high consumption chance wells of field ought to be re-finished with 13% Cr SS L-80 tubing material. Issues OBSERVED: The event of metal misfortune consumption in pipeline is brought about by the nearness of corrodents in the delivered water. Inward consumption in pipeline can be brought about by the nearness of plant scale, slag incorporations, inappropriate warmth treatment, ill-advised welding, excessively high or too low speed and so on. The disintegration/erosion impact can be brought about by too high liquid speed. Water and slop manufacture create with too low liquid speed that may cause pitting and microscopic organisms invasions. At low liquid speed, water will in general isolate to the base of the pipeline. When the pipeline is water wetted, the consumption starts. At the point when consumption isn't controlled, time to first disappointment because of erosion will be regularly from three to twelve years relying upon the divider thickness and working conditions. Erosion of most material is unavoidable and would seldom be able to be totally wiped out. Be that as it may, it very well may be constrained via cautiously choosing material and assurance techniques at the plan stage. For instance, as carbon steel is less protection from erosion stipend is given notwithstanding the plan thickness when they are relied upon to deal with tolerably destructive liquid. Essentially, outside surface of the pipeline are shielded from destructive soils by giving defensive coatings. All things considered, there is constantly startling disappointment which results from at least one of the accompanying reasons : Poor decision of material. Inadequate creation. Inappropriate plan. Deficient security/upkeep. Inadequate material. End: Consumption because of quality of CO2 gas alongside horrible water science is the reason for the channeling disappointments. It is suggested that tubing metallurgy will be of L-80 13 Cr hardened steel with premium joints. The downhole metallurgy will be 13 Cr SS. These elastomeric materials include: Nitrile: An elastic compound with base material as Butadiene Acrylonitrile. Viton: A fluoroelastomer made by Dupont. Fluorel: A fluoroelastomer made by 3M organization. Ryton: A polyphenylene sulfide made by Philips Petroleum Company. REFERENCES: Impact of microstructure Cr content in steel on CO2 corrsion. By Masakatsu Veda, Aki Ikeda, Japan. Expectation of the dangers of CO2 consumption in oil and gas wells. By Jl Crolet, Mr Bonis. CO2 consumption in oil wells. By Gunalton , Zadko.