Advances in Abandonment and Disposal Technology of Aging Oil and Gas Pipelines

When the operation benefit of an oil and gas pipeline is not enough to cover its operation cost, and the pipeline is no alternative use, seriously damaged, aged or the operation risk exceeds the acceptable range, it is bound to cause serious safety and environmental hazards along the pipeline, especially for the over age pipeline in service, therefore its scientific abandonment and reasonable disposal is particularly important and urgent. Focused on the methods for judging abandonment, retirement modes, cleaning and environmental management of oil and gas pipelines, the characteristics of existing methods for predicting the remaining life of the pipelines and their application in abandonment and disposal are compared and analyzed, and the basis and adaptability of oil and gas pipelines retirement are illuminated. According to the actual situation and environment of the discarded pipelines, the selection basis and applicable conditions of the pipeline and facility disposal methods such as demolition, in-situ shelving and their combination are expounded. It is found that North America has rich experience and mature technology in oil and gas pipeline abandonment and disposal, but many countries, including China, seriously lack scientific and systematic evaluation standards, practical experience, related theoretical and technical investigations. This study has important reference and practical significance for promoting the development of abandonment and disposal technology of an aging oil and gas pipeline, and ensuring the personal safety and ecological environmental protection along the abandoned pipeline. This paper presents the status quo of over age service and abandonment decision-making of oil and gas pipelines in the world, draws lessons from the experience of safety and environmental protection disposal of the global abandoned pipelines, and puts forward the principle and method of abandonment judgment and scientific disposal of the aging pipelines based on residual life evaluation. This method has sufficient basis, strong adaptability and wide application.

Design of inductors for the installation of induction soldering of pipeline joints in the oil and gas industry

The article discusses the use of induction brazing for connecting oil and gas pipelines. The rationale for the choice of induction brazing in the oil and gas industry is considered. The work calculates the main parameters of the inductor. On the basis of calculations, using a mathematical apparatus, a schematic diagram of an inductor with a diameter of 90 mm is created for installing induction soldering. It is proposed to use and develop inductors of various diameters (60, 90 and 135 mm) to create an induction unit that allows connecting pipelines of oil and gas equipment in order to increase the reliability of equipment and the efficiency of oil and gas production and processing.

A review of crack growth models for near-neutral pH stress corrosion cracking on oil and gas pipelines

This paper presents a review of four existing growth models for near-neutral pH stress corrosion cracking (NNpHSCC) defects on buried oil and gas pipelines: Chen et al.’s model, two models developed at the Southwest Research Institute (SwRI) and Xing et al.’s model. All four models consider corrosion fatigue enhanced by hydrogen embrittlement as the main growth mechanism for NNpHSCC. The predictive accuracy of these growth models is investigated based on 39 crack growth rates obtained from full-scale tests conducted at the CanmetMATERIALS of Natural Resources Canada of pipe specimens that are in contact with NNpH soils and subjected to cyclic internal pressures. The comparison of the observed and predicted crack growth rates indicates that the hydrogen-enhanced decohesion (HEDE) component of Xing et al.’s model leads to on average reasonably accurate predictions with the corresponding mean and coefficient of variation (COV) of the observed-to-predicted ratios being 1.06 and 61.2%, respectively. The predictive accuracy of the other three models are markedly poorer. The analysis results suggest that further research is needed to improve existing growth models or develop new growth models to facilitate the pipeline integrity management practice with respect to NNpHSCC.

SMOOTH AND REDUCED OIL AND GAS PIPES WITH INCREASED CORROSION RESISTANCE

Formulation of the problem. Corrosion of pipes used in the oil and gas industry leads to significant economic losses, therefore, increasing their corrosion resistance and durability is an urgent task. Purpose: generalization of results of developments of technologies of manufacturing and research of qualitative characteristics of oil and gas pipelines (smooth) and pump-compressor (threaded) pipes of the increased and high corrosion resistance and giving recommendations on their application in oil and gas industry in environments of various corrosion aggressiveness. Methodology. The microstructure of tubular steels and protective coatings was studied by light metallography and electron microscopy. Complex corrosion studies included laboratory tests of samples in model chloride and hydrogen sulfide-containing media, the resistance to sulfide corrosion cracking under stress (SCCS) and hydrogen cracking (НС) according to the methods of NACE TM 0177 and NACE TM 0284 as well as operational tests at the oil fields of Ukraine. Mechanical properties for stretching and impact bending of samples by standard methods. Results. The results of the development of production technologies and the study of the qualitative characteristics of oil and gas pipelines and tubing with increased and high corrosion resistance in aggressive oil and gas production environments are summarized. The influence of the chemical composition of steels and protective coatings, as well as pipe manufacturing technologies on their microstructure, corrosion resistance in various media, and mechanical properties is shown. Scientific novelty. For the first time, the presence of special low-energy boundaries in the ferrite of low-alloy ferrite-pearlite and high-alloy ferritic-austenitic steels was established, their number and energy level were estimated. The high operational reliability of threaded pipes with a protective coating is substantiated. Practical value. The results of the work and recommendations for the rational use of oil and gas pipes with increased corrosion resistance can be used to increase the economic efficiency of production in the oil and gas industry.