Surface protection technology for oil casing tube

Oil pipeline is the main components of the oil wells, the cost of accounting for oil well development and production costs 20% to 30%, while oil casing usually accounts for 73% to 76% of the entire oil pipe consumption. In the process of exploitation of oil (gas), great corrosion hazards, how to solve the oil casing corrosion is very critical. The casing is a permanent part of the wells, and the life of the sleeve directly determines the life of the wells.

Oil (gas) oil well casing corrosion has three salient features.
(1) corrosive media for gas, water, hydrocarbons, solid phase coexistence of multiphase flow, white and promote each other, the corrosion can sometimes be much stronger than the single-phase medium.
(2) high temperature and / or high-pressure environment, especially the deep and ultra-deep wells, downhole temperature of more than 120 to 140, more than 100 MPa pressure in such an environment will promote corrosion and accelerate the corrosion rate.
(3) H2S, CO2, O2, Cl-and water main oil and gas fields corrosive media. H2S, CO2 is generally from the formation of oil and gas, CO2 can also be injected from the secondary oil recovery gas lift gas, O2 is generally injected into the liquid from the ground such as mud, injection water. In the same content.
Case, the O2 corrosive than CO2 and H2 S; Cl-itself does not cause corrosion, but its high mobility, promote local acidification can contribute significantly to corrosion; water is the carrier of the electrochemical corrosion.
Oil casing complex service environment, poor corrosion, the common factors and the interaction is more likely to lead to even aggravate the corrosion of the casing and tubing. Mechanics and service environment conditions the basic requirements of the oil casing oil casing corrosion characteristics and type of discussion and analysis, the Tube in the service process should also meet the dual demands of mechanics and service environmental conditions, in addition to have excellent resistance to to corrosion and wear resistance, but also has high anti-collapse strength, the high joint sealing off and tensile strength, resistance to perforation cracking resistance to creep relaxation, the yield strength of the steam injection temperature is reduced and less performance.
Oil casing steel surface protection technology
In the process of exploitation of oil (gas), pipe serving in the extremely harsh and complex environments, bear the brunt of the surface of the material, the use of appropriate surface protection technology, a whole new layer chemical composition or structure of the protective layer formed on the surface to improve its hardness and wear resistance, corrosion resistance, extending its life, the partial substitution of expensive corrosion resistant alloy pipe, meets the conditions of service requirements, but also to control the cost of the oil casing in a more economical range. Casing has been applied surface protection technology: surface coating process, the laser surface hardening process and surface alloying.