Heavy Loaded Parts of Petrochemical Equipment Destruction Cause Investigation

The problem of using specialized passivating metals and alloys lies in a rather narrow range of the protecting film performance. With a slight change in operating conditions, the film is destroyed and an avalanche-like process of local corrosion begins at the place of film breakdown. A sequence has been developed for determining parts destruction causes, including a sequential analysis of operating conditions; nature of the part destruction; corrosion products composition; phase inversion in the alloy during overheating or mechanical stress in the part.

Results of Bench Tests of Tube Steels of the Production Tubing with a Chromium Content of 1%, 3% and 5% on a Unit Simulating the Operating Conditions of Producing Wells

Currently, most of the fields of RUE Production Association Belorusneft are at a late stage of development, which is characterized by a high water cut of well production. One of the main tasks in such conditions is the search for engineering solutions aimed at preventing corrosion of well equipment during oil production. Under the operating conditions of producing wells of the fields of RUE Production Association Belorusneft, well equipment is subject to electrochemical carbon dioxide corrosion [1]; mainly the inner surface of the tubing is subject to corrosion attack. The average rate of local corrosion in the corrosive environments of the oil fields of Belarus is 2–3 mm/a. The first cases of corrosion damage to production tubing were identified in 2010. Taking into account the high cost of stainless tubing, since 2011, the technology of inhibitory corrosion protection has been successfully implemented in the fields of Belarus by the method of constant dosing of the reagent into the annulus of production wells. The use of inhibitors made it possible to eliminate well failures due to tubing leakage, extend their service life by at least 4 times and reduce the local corrosion rate to 0.1 mm/a. However, an increase in the number of production wells damaged by corrosion caused by water encroachment of the wells, as well as an increase in the cost of reagents for oilfield chemicals require the use of new technological approaches, the search for alternative, economically more profitable solutions.

Corrosion behavior of X80 pipeline steel local defect pits under static liquid film

In this work, the corrosion electrochemical information under different thicknesses of liquid film was tested. The local corrosion development process of X80 steel under different thicknesses of liquid film was studied by combining the detection and analysis of scale and the matrix corrosion morphology. The corrosion was studied by EIS. The composition and microstructures of corrosion scale at different locations were detected by EDS and SEM, and the metal matrix was detected by 3D topography technology to analyze the local corrosion. The results show that a liquid film with a thickness greater than or equal to 1 mm has no effect on the mechanism of the corrosion process, but has a control effect on the corrosion rate and the time of each stage in corrosion. The corrosion process can be divided into two stages: in the early stage, the concentration of ions inside and outside ADP is the same, so the corrosion is uniform; in the later stage, due to the influence of CO2 dissolution and mass transfer distance, the cathodic reaction is mainly outside ADP and the anodic reaction is mainly inside ADP. In addition, corrosion acidification occurs in ADP, which enhances the corrosion process in ADP.

Reasons Analysis on Corrosion Perforation of L245 Pipeline from Interior Wall

The leakage accident of corrosion perforation occurred in the L245 oil pipeline. After pipe replacement,the defects were analyzed by means of macro analysis, corrosion product analysis, medium composition analysis, chemical composition analysis, mechanical property test and SEM. The results showed that the corrosion perforation was caused by local corrosion, and the synergistic effect of HCO3- and Cl- in transportation medium was the main cause of local corrosion.

Analysis of regulatory requirements for the assessment of carbon dioxide corrosion at gas production facilities

Aim.In many fields, the produced gas contains corrosive CO2, which, in combination with moisture and other factors, stimulates the intensive development of corrosion processes, including local ones, which requires careful attention to the assessment of the corrosiveness of operating fluids in order to select effective anti-corrosion protection. Ensuring reliable and safe operation of equipment and pipelines prevents not only man-made risks, but also no less important environmental risks, which are especially dangerous for marine underwater facilities for Arctic coastal facilities.Methods.The analysis of normative and technical documentation in the field of assessment of corrosion risks, aggressive factors of internal corrosion and operating conditions of gas and gas condensate fields has been carried out.Results.One of the criteria for assessing the corrosion hazard is the corrosion rate of steel under operating conditions. However, the normative documents predominantly regulate the general corrosion rate, which evaluates the uniform thinning of the metal. But the rate of local corrosion is in no way taken into account, which is most relevant precisely for the conditions of carbon dioxide corrosion of steel. Another tool for identifying risks can be a corrosion allowance to the pipe wall thickness, which should be selected at the design stage and which is provided to compensate for corrosion losses during the operation of gas pipelines. It is shown that the minimum corrosion allowance (3 mm) specified in the main regulatory documents is insufficient, especially for offshore facilities.Conclusion.The experience of operating gas production facilities confirms that the rate of local corrosion can reach several mm/year. To limit this, effective anti-corrosion measures should be chosen, for example, the use of corrosion inhibitors, and a reasonable level of corrosion allowance should be provided that would take into account the corresponding level of corrosion risks at the gas production facility.