Offshore Pipeline Construction Research Articles

A mathematical programming approach to export pathway planning of distributed hydrogen production in offshore wind farm

Hydrogen production is a vital development trend to improve the economics and penetration rate of offshore wind farms (OWFs), and distributed hydrogen production (DHP) is a preferred solution for deep and far sea OWFs without expensive submarine cables and offshore substations. The export pathway of OWF-DHP consists of collection pipelines, transmission pipelines, and offshore compressor stations. In this paper, mathematical programming is introduced to explore the export pathway planning problem of OWF-DHP. Firstly, the area of OWF is discretized into multiple grids with the center of the grids being the candidate locations of the offshore compressor station. Then, a binary integer quadratic programming problem is established to optimize both the offshore compressor station location and pipeline construction with different topologies. Further, the mathematical model is solved by the branch and cut algorithm integrated with the proposed dimension reduction methods. Finally, the effectiveness of the proposed export pathway planning approach is verified by the actual data of Baltic Eagle OWF in Germany, which would support the construction of the OWF-DHP project.

Underwater image denoising based on curved wave filtering and two-dimensional variational mode decomposition

Underwater image denoising technology is of great significance in underwater operation. Underwater operations (such as offshore oil drilling, undersea tunnels, pipeline construction, underwater archaeology, biological research, and lifesaving) require stable and clear underwater images to aid analysis. Due to the scattering and absorption of light by water bodies, obtaining high-quality underwater images is a challenging task. Underwater images are prone to low contrast, low resolution and edge distortion. Therefore, it is difficult to accurately separate the effective signal when removing the underwater image noise, which leads to the image contrast reduction. Also the edge contour is not clear, and the detail loss is serious. Therefore, we propose a novel underwater image denoising method based on curved wave filter and two-dimensional variational mode decomposition. Firstly, the noisy image is decomposed by two-dimensional variational mode decomposition, and a series of modal components with different center frequencies are obtained. The effective modal components are selected by correlation coefficient and structural similarity. And the effective modal components are processed by the curve-wave filter. Finally, the filtered modal components are reconstructed to remove the noise in the image. The experimental results show that, compared with other state-of-the-art methods, the proposed method has clearer denoising results, less mean square error, and better denoising effect.

Numerical study of Articulated Concrete Mattresses (ACMs) for offshore pipeline protection

In offshore pipeline projects, inevitably long sections of the transportation pipeline network require protection from natural hazards. Under such environmental conditions, concrete mattresses are recognized as a well-proven technology to surpass challenges in offshore pipeline construction, umbilical deployment and seabed protection/stabilization. To have a better understanding of the physical process of Fluid–Structure–Seabed-Interactions (FSSI) with a ACMs–Pipe–Seabed system, a workable numerical model is proposed to simulate wave–current induced soil responses around the system. Based on the proposed model, this paper discusses the momentary seabed liquefaction near the offshore pipeline and the stability of ACMs. Numerical examples show that ACMs have a significant positive effect on preventing seabed liquefaction around the pipeline by pushing the liquefaction zone to both sides of the shaft. Compared with unprotected conditions, the instability of the protective layer is mainly concentrated in its edge area, and the liquefaction depth can be reduced by around half of the pipe diameter. For the double ACMs–Pipe-System, it is found that the stability of the nearby seabed foundation is related to the mattress spacing and interaction angle.

A review of onshore and offshore pipeline construction and decommissioning cost in the USA - part 2. Offshore and deepwater decommissioning cost algorithms

In the second part of this two-part review on the cost to construct and decommission oil and gas pipelines in the USA, summary data of offshore pipeline construction and decommissioning cost are described, along with hypothetical pipeline decommissioning cost algorithms for the deepwater Gulf of Mexico. Similarities and differences between design and construction trade-offs are described to better understand the cost differences that arise between projects. Over long periods of time, significant temporal impacts enter cost statistics due to inflation, market conditions, regulatory and technology changes, and spatial impacts are always present due to differences in geologic conditions, infrastructure, and terrain. Most factors are unobservable and not available for evaluation, but there are many similarities in processes and infrastructure that allow normalised cost to serve as a useful first-order benchmark. [Received: May 26, 2020; Accepted: June 3, 2020]

A review of onshore and offshore pipeline construction and decommissioning cost in the USA - part 2. Offshore and deepwater decommissioning cost algorithms

A review of onshore and offshore pipeline construction and decommissioning cost in the USA - part 2. Offshore and deepwater decommissioning cost algorithms

A review of onshore and offshore pipeline construction and decommissioning cost in the USA - part 1: specifications, cost estimation and onshore construction

The cost to construct and decommission oil and gas pipelines varies widely between onshore and offshore regions as well as within each area, depending on numerous factors. The purpose of this review is to evaluate publicly available data sources for onshore and offshore pipeline installation and decommissioning activities in the USA. The activities and processes involved, factors that impact cost, cost statistics and limitations of analysis are presented for onshore and offshore pipeline installation and decommissioning. Similarities and differences between construction and decommissioning processes and the tradeoffs involved in design are described to better understand the cost differences that arise between projects. In the first part of a two-part review, an overview of pipeline manufacturing and API 5L specifications introduce relevant terminology and basic pipeline requirements, and a description of cost estimation procedures, normalisation, and data sources provides the evaluation framework. A description of onshore pipeline construction cost data and analysis concludes the paper. [Received: May 4, 2020; Accepted: June 3, 2020]

A review of onshore and offshore pipeline construction and decommissioning cost in the USA - part 1: specifications, cost estimation and onshore construction

The cost to construct and decommission oil and gas pipelines varies widely between onshore and offshore regions as well as within each area, depending on numerous factors. The purpose of this review is to evaluate publicly available data sources for onshore and offshore pipeline installation and decommissioning activities in the USA. The activities and processes involved, factors that impact cost, cost statistics and limitations of analysis are presented for onshore and offshore pipeline installation and decommissioning. Similarities and differences between construction and decommissioning processes and the tradeoffs involved in design are described to better understand the cost differences that arise between projects. In the first part of a two-part review, an overview of pipeline manufacturing and API 5L specifications introduce relevant terminology and basic pipeline requirements, and a description of cost estimation procedures, normalisation, and data sources provides the evaluation framework. A description of onshore pipeline construction cost data and analysis concludes the paper. [Received: May 4, 2020; Accepted: June 3, 2020]

Offshore pipeline construction cost in the U.S. Gulf of Mexico

The oil and gas pipeline network in the U.S. Gulf of Mexico is the largest offshore pipeline network in the world, but construction cost statistics are not a frequent topic of investigation. Using data sources from the Federal Energy Regulatory Commission, industry publications and press releases, pipeline construction cost in the U.S. Gulf of Mexico from 1980 to 2014 are examined. The average inflation-adjusted cost to install FERC pipelines from 1995 to 2014 was $3.3 million/mi ($2.1 million/km), and industry publication pipeline cost average $3.1 million/mi ($1.9 million/km). Data sources vary in their scope and quality and need to be interpreted with an understanding of their limitations. A description of each data source and its limitations are provided.