Pipeline Infrastructure Research Articles

Convergence study for composite gas flow in pipes

AbstractUtilizing hydrogen in energy sources plays a crucial step towards a complete transition to renewable energies since production at‐scale is possible. The study works towards developing monitoring and control strategies of proportionally induced hydrogen in existing pipeline infrastructure. With this aim, a scalable model is utilized to compute the flow of composite gas along a pipe. The transient model is solved using finite element discretization and error convergence is studied for a test case. Coupling of species transport to track mixture composition along the pipe is also studied for a test case and error behaviors are investigated. Finally, simulations performed for a practical testcase are compared with a recently available open‐source tool for studying flow dynamics. The study highlights the deployment and usage of state‐of‐the‐art simulation tools against existing industrial necessities while providing invaluable insights into dynamics of gas mixtures.

The Tie that Binds: The Trials of US–Canada Energy Infrastructure

The subject of International Energy does not get any bigger than the bilateral energy trade between the United States and Canada. Our two countries share a singular geopolitical endowment: the world's longest and highest value trading border—bounded by two oceans—where not a shot has been fired in anger since the War of 1812. We share unusual natural resources and common institutions: (1) a continent with multiple productive hydrocarbon basins and renewable energy resources, including hydroelectric, solar, and wind; (2) English common law with strong Constitutional and judicial protections for private property; (3) federal governmental systems; and (4) highly competitive energy production and transport infrastructure industries. With such institutional foundations, our two nations exhibit by far the world's oldest and most extensive pipeline infrastructure systems and dozens of international power transmission links. The long‐time lack of military conflict, stability of institutions of governance, and highly competitive business infrastructure generally has always been the source of great industrial productivity in providing low‐cost energy for consumers and businesses in North America.

Kazakhstan to supply crude oil to Germany

Kazakhstan has secured approval from Moscow to use its pipeline infrastructure in order to transport 300,000 tons of oil to Germany in the first quarter of 2023, a state-run company (Kaztransoil) announced on January 13, 2023. Deliveries in January, 2023 amounted to 20,000 tons. Kazakhstan plans to export up to 1.5 million tons to Germany via Russia in 2023, but in the future, the volume could be increased to 7 million tons. As for now, oil transportation through Russia seems more beneficial to Kazakhstan, whereas the so-called Middle Corridor transportation route, which involves shipping oil tankers that would cross the Caspian Sea before unloading crude onto freight transport traveling through Azerbaijan, Georgia and Turkey is still limited in capacity and far costlier than using Russian infrastructure. Besides, the ongoing and frozen conflicts in Caucasus could in future endanger the security of Kazakhstan’s oil supply to the EU countries via South Caucasus. Keywords: Kazakhstan, Russia, Germany, Oil, Pipeline, Ukraine, Middle Corridor, Energy Security, Energy.

Predicting Natural Gas Pipeline Failures Caused by Natural Forces: An Artificial Intelligence Classification Approach

Pipeline networks are a crucial component of energy infrastructure, and natural force damage is an inevitable and unpredictable cause of pipeline failures. Such incidents can result in catastrophic losses, including harm to operators, communities, and the environment. Understanding the causes and impact of these failures is critical to preventing future incidents. This study investigates artificial intelligence (AI) algorithms to predict natural gas pipeline failures caused by natural forces, using climate change data that are incorporated into pipeline incident data. The AI algorithms were applied to the publicly available Pipeline and Hazardous Material Safety Administration (PHMSA) dataset from 2010 to 2022 for predicting future patterns. After data pre-processing and feature selection, the proposed model achieved a high prediction accuracy of 92.3% for natural gas pipeline damage caused by natural forces. The AI models can help identify high-risk pipelines and prioritize inspection and maintenance activities, leading to cost savings and improved safety. The predictive capabilities of the models can be leveraged by transportation agencies responsible for pipeline management to prevent pipeline damage, reduce environmental damage, and effectively allocate resources. This study highlights the potential of machine learning techniques in predicting pipeline damage caused by natural forces and underscores the need for further research to enhance our understanding of the complex interactions between climate change and pipeline infrastructure monitoring and maintenance.

How do coalitions stop pipelines? Conditions that affect strategic action mobilizations and their outcomes

The study develops a strategic action perspective on public opposition to energy infrastructure by examining the conditions that lead to mobilization and conditions and actions that lead to a decision not to build a pipeline. Based on clearly defined inclusion criteria, fifty cases of proposed natural gas pipeline infrastructure in the U.S. were selected. Location within just one state is associated with a lower level of mobilization against a pipeline. In cases with higher opposition, the no-build outcome is associated with location in at least one state that leans toward the Democratic Party (more progressive), a higher level of tactics and more diverse coalitions, and pipeline opposition from state government officials. A processual model of the mobilization process, decision points, and outcomes is developed. Even with federal government approval, court decisions and state-government certification can create legal and regulatory hurdles that are associated with a no-build outcome. Given limited mobilization resources, opposition coalitions may benefit from strategic action focused on institutional targets of action such as the decisions of uncaptured regulatory agencies and the courts. The study also identifies incremental rule changes in these targets of action and the potential for improved democratic governance.

Steel pipeline for the hydrogen storage and delivery: metallurgical viewpoint for Finnish ecosystem

For more than a century, hydrogen has been used as an industrial chemical to produce ammonia for fertilizers and to process intermediate products in oil refineries. However, hydrogen has recently received renewed interest due to its ability to reduce carbon emissions to the atmosphere, particularly in the steel-making industries. Thus, hydrogen has the potential to play a critical role in combating climate change and achieving Finland's national goal of carbon neutrality by 2035. In this regard, national and global demand for hydrogen is rapidly increasing, and it is now three times more than what it was in 1975. The production and supply of hydrogen for industrial consumption would be a massive business that is expected to expand even faster than before. According to the IEA, the total demand for hydrogen in pure and mixed gas was approximately 115-120 million tones in 2018. (Gaseous) hydrogen can be efficiently transported by pipeline networks at a pressure of typically <100 bar. Pipelines provide an economical means of transporting hydrogen in large quantities over long/short distances, and hence they are often found serving end users who take hydrogen from a local central source of production. Nevertheless, the correct pipe material for hydrogen distribution must be designed and used, and the current natural gas pipeline infrastructure must be upgraded significantly if it is to be used for the delivery of pure hydrogen at high pressure. Hence, new research is needed to focus mainly on the possibility of use/modification of available natural gas pipeline network for hydrogen delivery as well as the study on the new economical pipeline material, exclusively for hydrogen transportation and storage.

Influence of Hydrogen on Vintage Polyethylene Pipes: Slow Crack Growth Performance and Material Properties

The distribution of hydrogen and how this can be widely achieved plays a significant role in the transition from fossil fuels to clean fuel. Using the existing natural gas pipeline network can be a suitable option for countries with extensive pipeline infrastructure. This study is aimed at investigating the compatibility of the existing polyethylene (PE) distribution pipe network with hydrogen. This paper utilises the cyclic pennsylvania edge notch test (CPENT) method together with material property measurements including melting point, crystallinity, and oxidative induction time (OIT) to understand the impact of exposing two different PE pipe resins to hydrogen at different exposure times. It was found that exposure to hydrogen has a noticeable impact time to failure, while the bulk crystallinity, OIT, and melting point showed little change. A change in crystal orientation was observed, and this likely accounts for the difference in time to failure when exposed to hydrogen.

Comments: Energy Transition and Labor Transition

Canada is ramping up its commitment to energy transition with its “just” transition bill. And with it comes concern about employment in the oil and gas sector. The proposed bill will be introduced early this year with the intent to help workers in the oil and gas sector move into clean energy jobs by defining principles to guide decisions and creating jobs. Natural Resources Minister Jonathan Wilkinson has described the bill as an action plan for “sustainable jobs.” “I said it many times publicly that I do not believe that the challenge we are going to face is that there are workers who are displaced that will not find other good-paying jobs. I am actually quite worried that there are so many opportunities … we will not have enough workers to fill the jobs,” Wilkinson recently told CBC News. Gil McGowan, president of the Alberta Federation of Labor, told CBC News, “This shouldn’t be a political issue, this is an issue about what’s really happening in the global economy.” He added that if done right, the bill could incentivize technologies like carbon capture and hydrogen. But when it comes to workers’ compensation in oil and gas vs. clean energy, how does it compare? The answer depends on the roles of workers and their locations, qualifications, experience, and training. An ex-coal miner who now runs a government-funded Just Transition center supporting former Canadian coal workers summed it up: “It’s 100% not that simple ... to go from making C$100,000 to C$40,000 plays a big part in the decision making that comes with the idea of losing your livelihood.” Adam Legge, president of the Business Council of Alberta, wrote in November 2020 in CBC Calgary that more worker transition programs are needed. He highlighted the interest in the Calgary Economic Development EDGE UP program which retrains people displaced from oil and gas into high-growth digital technology opportunities. The program saw 1,300 applicants for 100 available slots. Another program, AltaML Applied AI Lab, had 500-plus applications for its first cohort of eight participants for a 16-week course. On a global level, in the International Energy Agency’s (IEA) inaugural World Energy Employment report published in September 2022, Dr. Fatih Birol, executive director of IEA, highlighted the acceleration of clean energy transitions and securing of energy supply chains prompted by Russia’s invasion of Ukraine. He wrote, “Its success will depend a great deal on the actions governments, industry, labor representatives, and educators take to prepare the energy workforce of tomorrow. Above all, it will depend on the capable workers responsible for designing, building, operating, and overseeing the new energy economy.” The energy sector requires more highly skilled workers than others, with 45% of the workforce requiring some degree of tertiary education, from university degrees to vocational certifications. On average, the sector also sees higher wages. The report found oil supply has the highest employment among fossil fuels, at almost 8 million workers in 2019. Five million work in extraction and production, and around 1.4 million each in transport and refineries. Nearly 20% of the jobs are in the Middle East; 15% each in North America and Africa. Refining accounts for 1.4 million, concentrated in the Asia Pacific region. Skills of oil and gas workers are in demand by other energy sectors because of the applicability of their higher-level expertise. For example, petroleum and gas engineering skills in seismic interpretation, drilling and completions, reservoir, and flow assurance are applicable to geothermal. Chemical engineers in refineries can apply their expertise to green fuels and hydrogen. The report added, “Skilled workers can transfer to deepwater offshore wind, carbon capture and storage, or midstream hydrogen pipeline infrastructure, among many other job disciplines.” Emerging clean energy industries such as hydrogen and CCUS today constitute small portions of the energy workforce but are important areas of growth and demand highly skilled workers to establish and expand these industries. About 35,000 people work in hydrogen production today, according to the IEA report. The sector is expected to see high growth and requires skills that are compatible with those of oil and gas workers, with the addition of specialized safety training. The worlds’ first engineering courses in hydrogen safety have been developed by the European HySafe consortium. For those workers who must or wish to seek alternative opportunities, will their outcomes match or surpass their current roles? There are no guarantees or promises. The determining factors are many. Even with all things being equal such as the freedom and opportunity to choose, education, training, etc.—the individual will make the final call.

INFRASTRUCTURE FINANCING IN INDIA: A STUDY OF RECENT INITIATIVES

This article elaborates on the changes that have taken place in the realm of infrastructure investment in India and its mode of financing. In India in the initial stages of development, the Government played a dominant role in infrastructure financing. Today, India gives top priority to the Private-Public Participation mode of financing infrastructure. Considering the importance of infrastructure, new schemes like PM Gati Shakti, the National Infrastructure Pipeline, and National Monetization Pipeline have been introduced by the government to give a fillip to the infrastructure sector in India. All these programs will enrich the ‘Amrit-Kaal’ to take India to the galaxy of developed countries in the world.

Natural Gas Flaring Management System: A Novel Tool for Sustainable Gas Flaring Reduction in Nigeria

The use of hydrocarbon fuels increases with population growth and rising standards of living, and so does natural gas flaring. Natural gas flaring is both a waste of natural resources and a violation of Nigeria’s energy policy for sustainable development through natural gas conservation. However, it remains the most cost-efficient and effective associated natural gas (ANG) management option in developing countries such as Nigeria. The World Bank’s initiative to eliminate routine gas flaring by 2030 has increased the need to limit or eliminate routine gas flaring. Often, studies on natural gas utilisation techniques fail to consider the lack of practical tools that integrate economic, technical, and regulatory factors into a gas flaring management framework, and the intricacies of existing tools, which often come at the expense of simplicity to achieve real-time information output. This paper aims to establish a framework and ANG management tool to reduce regular gas flaring in Nigeria. This research established a management framework (using a flowchart decision tree) and models to provide a user-friendly ANG flaring tool (using a MATLAB graphical front end user interface with back-end ASPEN HYSYS thermodynamic models). This was combined with techno-economic models for liquefied natural gas, gas-to-methanol, and gas-to-wire ANG utilisation options. The tool was then tested with data obtained from Fields Y and X in the Niger Delta region of Nigeria. The results, considering both economic and technical factors, showed that the choice of liquefied natural gas for Field Y was best due to its proximity to the pipeline infrastructure and its cost-effectiveness, and the availability of a high-demand LNG market for that area. For Field X, gas-to-wire was best due to its proximity to the electrical grid and high electricity requirements for that area. Additional geographical profiles in West Africa and ANG utilisation alternatives were recommended for further investigation. This paper developed and validated a one-of-a-kind ANG flaring management tool that incorporates techno-economic analysis of selected ANG utilisation options to assist operators and investors in making more profitable investment decisions.

Process design, exergy, and economic assessment of a conceptual mobile autothermal methane pyrolysis unit for onsite hydrogen production

The present study proposes a conceptual mobile autothermal methane pyrolysis unit for onsite hydrogen production. Considering the shortage of hydrogen pipeline infrastructure between production plants and fuelling stations in most places where hydrogen is required, it is imperative to create alternative hydrogen production means. The design combines a catalytic plasma methane pyrolysis unit with a steam char gasification setup, combustion, and biomethanation unit for hydrogen production. The reactor design includes Ni - Br in a bubble column acting as a catalyst. Energy and exergy calculations followed by a comprehensive economic analysis were appraised to evaluate the efficiency and performance of the integrated process. The levelized cost of hydrogen (LCOH) from the conceptual design ranged from 1.3 to 1.47 U.S.$/kg, while the proposed design's net present value (NPV) was in the range of 3.76 – 4.35 M.U.S.$. Factors such as equipment purchase cost (EPC) and feedstock cost significantly influenced the NPV and LCOH. In addition, a positive NPV and lower LCOH outline the proposed design's profitability. Finally, an optimized methane conversion of 76.8 % was obtained from the study.

The effect of soil type on the behaviour of a tolerably mobile subsea foundation

Tolerably mobile subsea foundations may be used to replace conventional fixed mudmat foundations for pipeline infrastructure and are designed to slide on the seabed along with the connected pipeline, in order to accommodate thermally induced horizontal forces. This allows the size of the foundation and the resulting fabrication and installation costs to be substantially reduced. The performance of mobile foundations is explored in this paper through four centrifuge model tests on a normally consolidated or lightly over-consolidated reconstituted calcareous silt obtained from the Northwest Shelf of Western Australia. The results are compared to three existing tests performed on a kaolin clay. The results show that under typical periodic surface sliding and intervening rests, sliding resistance evolves within a cycle with resistance peaks evident at either end of the sliding footprint due to the formation of berms, and the residual resistance increasing with sliding cycles towards a drained state. Shear and consolidation-induced settlements accumulate with sliding cycles although at a reducing rate. The tests in the calcareous silt show higher normalised initial peak sliding resistance, a more dramatic loss and slower recovery of sliding resistance with cycles, and slower rate of decrease of incremental settlement compared with the response in kaolin clay.

Blockchain Secured Dynamic Machine Learning Pipeline for Manufacturing

ML-based applications already play an important role in factories in areas such as visual quality inspection, process optimization, and maintenance prediction and will become even more important in the future. For ML to be used in an industrial setting in a safe and effective way, the different steps needed to use ML must be put together in an ML pipeline. The development of ML pipelines is usually conducted by several and changing external stakeholders because they are very complex constructs, and confidence in their work is not always clear. Thus, end-to-end trust in the ML pipeline is not granted automatically. This is because the components and processes in ML pipelines are not transparent. This can also cause problems with certification in areas where safety is very important, such as the medical field, where procedures and their results must be recorded in detail. In addition, there are security challenges, such as attacks on the model and the ML pipeline, that are difficult to detect. This paper provides an overview of ML security challenges that can arise in production environments and presents a framework on how to address data security and transparency in ML pipelines. The framework is presented using visual quality inspection as an example. The presented framework provides: (a) a tamper-proof data history, which achieves accountability and supports quality audits; (b) an increase in trust by protocol for the used ML pipeline, by rating the experts and entities involved in the ML pipeline and certifying legitimacy for participation; and (c) certification of the pipeline infrastructure, the ML model, data collection, and labelling. After describing the details of the new approach, the mitigation of the previously described security attacks will be demonstrated, and a conclusion will be drawn.

Pipeline Infrastructure Required to Meet the Requirements on AI

The theme of this issue is infrastructure as code (IaC). This concept typically refers to the application of software engineering practices in managing deployment infrastructure. Moving from physical hardware to virtual machines using configuration files that are way more flexible—and they can be version controlled and distributed. As such, IaC paves the way for automation and DevOps. This column touches upon similar topics: pipeline infrastructure to meet regulatory requirements on trustworthy AI solutions.

Использование космических изображений для калибровки системы линейных координат при геопространственном моделировании трубопроводов

The technique of geospatial modeling of pipeline systems, which is discussed in the article, is designed to use satellite survey data for calibration of a linear referencing system (LRS). It is proposed to use satellite images to determine the planned position of pipeline objects, which can act as calibration points. The article considers the features of using space images to determine the planned position of pipeline objects that can act as calibration points are considered. The technique of geospatial modeling of pipeline systems based on the use of LRS is based on the data of in-line inspections (ILI) in the formation and updating of geospatial models of pipeline systems. The use of such a technique makes it possible to independently detect pipeline defects by means of ILI and perform their localization in the geoinformation space with the help of LRS. The use of space-based images to increase the calibration points of the LRS makes it possible to significantly increase the accuracy of the position of defects in space. The novelty of the work lies in the refinement of the geopositioning of pipeline infrastructure objects by using linear coordinate systems in conjunction with space images, which was not proposed in previously published papers on this topic.

Prospects of using public and private partnership for the reconstruction of Ukraine in the post-war period

Problem statement. Because of the military aggression of the Russian Federation, the Ukrainian people and the authorities face demanding challenges regarding the reconstruction of the country. One of the main priorities during the recovery in the post- war period is to find new, alternative sources of financing, in particular, using the advantages of public and private partnership (PPP). Analysis of recent research and publications. The proposals of Ukrainian and foreign researchers and practitioners regarding the PPP mechanism application for implementing the reconstruction of public and industrial buildings, construction and management of new highways, and other projects may be valuable for post-war reconstruction of Ukraine. Additional research on the PPP specifics in martial law and the post-war period is necessary to improve the regulatory and institutional support of public and private partnership and investment activities. Highlighting the previously unsolved parts of the general problem. Identification of opportunities for increasing the transparency of relevant measures, improving legislation related to the PPP, including in the field of concession instruments, development of proper institutional support for the PPP are significant areas of research related to the further development of public and private partnership in Ukraine, in particular, in the conditions of martial law and the post-war period. Presentation of the main material. Restoring the functioning of critical infrastructure facilities as soon as possible and gradual reconstruction of other objects which are necessary for the full life of the country are the essential tasks of Ukraine. It is not possible to put the financial burden only on the state and local budgets in a short period. Private investments should be attracted through the PPP mechanism, which, according to the experience of other countries, is one of the most effective ways to attract funds for developing the infrastructure and providing services to consumers in many fields. The experience of countries that have rebuilt their national economies after military conflicts in recent decades is helpful. The legislation of the Republic of Serbia uses the term "Public contract" and the concept of public and private partnership, which enables central and local authorities to meet infrastructure needs. The use of PPP in this country allows attracting private capital for construction and operation of roads, schools, water supply, landfills, and other projects in a lack of budgetary funds. The experience of other countries in promoting PPP development shows the effectiveness of the functioning of specialized institutions. For example, the Kosovo PPP Committee promotes and supports the implementation of PPP in many sectors of the economy to provide more efficient infrastructure and public services at a lower cost. According to the analysis of international experience, the most common reconstruction projects using PPP in the world are those implemented in the road and transport infrastructure, port, railway, and aviation activities, pipeline infrastructure development, stadiums, etc. The historical example of the aid of the United States of America to European countries after the Second World War is valuable. Accordingly, it is institutionally appropriate to provide help to Ukraine through a specialized agency with the participation of donor countries and in agreement with the International Monetary Fund and the World Bank. Similarly to the "Marshall Plan", it would be appropriate for aid recipients to provide detailed plans and reports on investment projects and the progress of their implementation to the created agency that would establish and regulate the relevant criteria and requirements. Creating the national coordinating body in Ukraine, developing a strategy and determining priorities for the country’s recovery, and forming the central and regional project management teams are necessary steps for combining public finance and private investment. It is essential, in particular, in conditions of concession, which provide for the transfer of the state or municipal property to a private investor for temporary use. Moreover, there should be provided the availability of information and transparency of the activities of relevant institutions and equal opportunities for potential private investors to participate in PPP projects for restoring Ukrainian facilities. Conclusions and prospects for further research. The public and private partnership mechanism aims at increasing the efficiency and quality of the implementation of reconstruction projects and commissioning the new facilities within the post-war reconstruction of Ukraine. The transparency of investment activities based on the PPP mechanism and the rational distribution of powers in cooperation with interested parties should play an important role. The experience of European countries that carried out reconstruction after military conflicts indicates the feasibility of developing institutional support for the PPP mechanism and transparency of information and activities of the relevant institutions. It is advisable to conduct further research on the problems of reconstruction of Ukraine involving the public and private partnership mechanism by improving the institutional support of investment processes in Ukraine.

Satellite Imaging Techniques for Ground Movement Monitoring of a Deep Pipeline Trench Backfilled with Recycled Materials

The damage to pipeline infrastructures caused by reactive soils has been a critical challenge for asset owners. Sustainable backfilling materials have recently gained interest to stabilize highly reactive zones as a pre-emptive approach towards sustainability. In this study, two adjacent sections of a sewer pipeline trench in Melbourne, Australia were backfilled with two blends of 100% recycled aggregates. The sites were monitored for ground deformations during October 2020–February 2022 (17 months) using surveying techniques. Interferometric synthetic aperture radar (InSAR) techniques and algorithms were also employed to estimate the ground movements of the sites and surrounding regions. The cross-validation of deformation results achieved from both techniques enabled an in-depth analysis of the effectiveness of the recycled aggregates to address reactive soil issues in urban developments. Observational deformation data and their spatiotemporal variation in the field were satisfactorily captured by the InSAR techniques: differential InSAR (DInSAR), persistent scatterer interferometry (PSI), and small baseline subset (SBAS). The SBAS estimations were found to be the closest to field measurements, primarily due to the analysis of zones without well-defined geometries. This study’s contribution to existing knowledge defines the spatiotemporal influence of sustainable backfill in areas with reactive soil through field data and satellite imaging. The relationship between InSAR techniques and actual field behavior of sustainable backfill can be a baseline for the growing construction that may be challenging to perform field monitoring due to resource constraints.

Comparison and Clarification of China and US CCUS Technology Development

The content of the China-US CCUS technology development roadmap is summarized based on the roadmap update in 2019. Qualitative analysis and evaluation were conducted from the perspectives of running CCUS demonstrations or industrial projects, CO2 pipeline infrastructure, established regulatory frameworks, policy support, research and development capabilities, and geological storage resources. A simple analysis of the development status of carbon capture, storage, and utilization technology through relevant patent data is provided. Future planning by China and the United States in terms of planning volume, investment funds, related industries, transportation methods, geological storage, geological utilization, other utilization methods, and incentive policies is compared. Overall, US CCUS technology development is in the leading position in the world; it has entered the stage of small-scale commercial promotion, while the overall development level of China’s CCUS technology is still behind the international advanced level in a small-scale experimental demonstration period, and is still in the catch-up stage. However, as the Chinese government has put forward the strategy of “carbon peaking and carbon neutralization”, CCUS has ushered in a golden opportunity for development in China, and some large-scale industrial demonstration projects have been carried out. This study analyzes China’s advantages and challenges in developing CCUS and gives some suggestions on the direction that China’s CCUS development should take in the future.

Onshore Buried Steel Fuel Pipelines at Fault Crossings: A Review of Critical Analysis and Design Aspects

Onshore buried steel pipeline infrastructure is a critical component of the fuel supply system. Pipeline failure due to seismic actions is socially, environmentally, and economically unacceptable and thus the design of pipelines in geohazard areas, such as fault crossings, remains a hot topic for the pipeline community. There is an intense research effort on the evaluation of the pipeline mechanical behavior and the strength verification at fault crossings. Still, some aspects need in-depth consideration concerning practical applications. A state-of-the-art review is presented on three critical analysis and design aspects, namely, the calculation of the design fault displacement via deterministic and probabilistic methods, the effect of numerical modeling parameters such as soil spring properties, and the alternative pipe protection measures in terms of availability, efficiency, and selection process. The critical review offers a thorough insight into what is available and how to employ it in design, assisting engineers and pipe operators in improving pipe safety.

Experimental evaluation of enhanced oil recovery in unconventional reservoirs using cyclic hydrocarbon gas injection

The significant amount of gas produced from unconventional reservoirs in the US in recent years has reduced market prices for hydrocarbon gas and created an opportunity for using low-cost gas in enhanced oil recovery (EOR) projects. In addition to its availability in large quantities and at low cost, injecting produced gas back into the reservoir prevents flaring the gas, reducing environmental concerns associated with greenhouse gas emissions to the atmosphere. Furthermore, while CO2 has shown tremendous success as an EOR injectant in huff-and-puff operations in tight liquid-rich shales, the lack of sufficient pipeline infrastructure supplying low-cost CO2 as well as operational issues (e.g., corrosion) has forced field operators to consider other gas options, such as produced gas, to substitute for or mix with CO2.While limited, experimental and numerical studies conducted on produced gas huff-and-puff in unconventional resources have shown promising results and highlighted the great potential of this technique for enhanced oil recovery from ultra-tight shale resources. The objective of the current work is to investigate the feasibility of produced gas huff-and-puff operations in one of the major oil-producing shale formations in North America further by performing several flow experiments using various mixtures of hydrocarbon gases. Three reservoir-condition core-flooding experiments are carefully designed and executed on shale core plugs in the absence and presence of proppant-filled fractures. After establishing initial two-phase brine-oil conditions in the core samples, hydrocarbon gas is injected into the medium through a huff-and-puff approach. The cycle of injection-soaking-production is repeated multiple times in each experiment. The results show that the use of hydrocarbon gas in huff-and-puff operations has great potential similar to CO2 for enhanced oil recovery from tight shale rocks and can lead to remarkable oil recovery. The hydrocarbon gas mixture in the fracture penetrates the matrix due to pressure and concentration gradients during the injection and soaking periods and forces the oil to leave the matrix during the depressurization process. It is observed that the rate of oil production is high in the first cycle and decreases in subsequent cycles as the rate of mass transfer and the amount of oil remaining in the matrix decrease. The average oil production due to the cyclic gas injection process in an intact and fractured composite rock sample was more than 48 and 21%, respectively. The results show that even though the ultratight formations could be heavily fractured, a proper cyclic gas injection EOR scheme could potentially improve oil recovery from the shale oil reservoirs, significantly.