This paper presents the design and development of a conceptual prototype of an autonomous self-driven inline inspection robot, called Smart-Spider. The primary objective is to use this type of robot for offshore oil and gas pipeline inspection, especially for those pipelines where the conventional intelligent pigging systems could not or be difficult to be deployed. The Smart-Spider, which is real-time controlled by its own on-board MCU core and power supplied by a hugged-up battery, is expected to execute pipeline inspection in an autonomous manner. A flexible mechanism structure is applied to realize the spider's flexibility to adapt to different diameters of pipelines as well as to handle some irregular situations, such as to pass through an obstructed areas or to maneuver at a corner or junction. This adaptation is automatically controlled by the MCU controller based on pressure sensors' feedback. The equipped devices, such as the selected motors and battery package, as well as the human-and-machine interface are also discussed in detail. Some preliminary laboratory testing results illustrated the feasibility and cost-effectiveness of this design and development in a very promising manner.
Injection of water into wells is a common practice in offshore oil and gas installations, and here as in many other industries the water has to be deaerated before it is sent through miles of pipelines to reduce the risk of corrosion in those pipelines and other downstream equipment. It requires extremely low concentrations of dissolved oxygen for the corrosion of metals to begin, and removing the dissolved oxygen is currently done in large vacuum deaeration towers, a highly energy demanding process, along with additional injection of chemical oxygen scavengers. In many instances these processes are controlled in a feed-forward manner, where the operators rely on infrequent sampling and corresponding measurements to control the process. The possibilities for optimization in this field are thus numerous. The main challenges are online measurements of dissolved oxygen and their use in feedback control. This article gives a brief review of the state-of-the-art and investigates the potential of using dissolved oxygen as a reliable feedback parameter, taking inspiration from onshore waste water industries which have been dealing with dissolved oxygen feedback control since the 1970's.
Modern ports face not only a paradox of combining efficiency and effectiveness, but also a paradox of balancing activities characterized by different time horizons and stakeholder expectations. The structural changes underlying these paradoxes are the co-existence of downward pressures on market premiums and the increasing demands on the relational capabilities of port authorities. The increasing demand on relational capabilities is caused by the fact that modern ports are hubs for industrial activities that span the organizational boundaries of firms, integrating port systems and the hinterland. Thus, port authorities must simultaneously focus on cost efficiency and systemic coordination within complex port systems. As indicated by recent research on port governance and competitiveness, this implies that port authorities must assume and combine different organizational roles. The present paper takes this discussion further by classifying the organizational roles of port authorities in terms of role complexity, relational capital, and systemic functions within the port system. Based on a case study, the paper shows that the use of systemic functions implies the development of new business models, and that the adoption of the roles by port authorities depends on how emerging relational capabilities are embedded in structures of value co-creation and value co-capture.
This paper investigates the optimal control solution using MPC for a typical offshore topside de-oiling process. By considering the combination of the upstream three-phase gravity separator and the downstream de-oiling hydrocyclone set-up as one integrated plant, the plant-wide control problem is formulated and handled using MPC technology. The de-oiling dynamics of the hydrocyclone are estimated via system identification while the key dynamics of the considered gravity separator are modeled based on mass balance and experimental parameter estimation. The developed MPC solution is simulated and experimentally validated via a lab-scaled pilot plant. The comparison of performances of the MPC controlled system with those of a PID controlled system, which emulates the commonly deployed control solution in most current installations, shows the promising results in optimally balancing the gravity separator's (level) control and hydrocyclone's (PDR) control.
This paper contributes to the understanding of competition and industry evolution by analyzing how submarket dynamics and agency influence the development of the emerging industrial field of Danish offshore wind energy. We argue that industry evolution is sensitive to the balance between integration, overlap and disintegration across submarkets. This balance depends on how strategic intent and behavior influence submarket dynamics, leading to the conclusion that effects of agency and managerial intent should play a more prominent role in studies of industry evolution.
The upstream offshore multi-phase well-pipeline-riser installations are facing huge challenges related to slugging flow: An unstable flow regime where the flow rates, pressures and temperatures oscillate in the multi-phase pipelines. One typical severe slug is induced by vertical wells or risers causing the pressure to build up and hence originates the oscillating pressure and flow. There exist many negative consequences related to the severe slugging flow and thus lots of investments and effort have been put into reducing or completely eliminating the severe slug. This paper reviews in detail the state-of-the-art related to analysis, detection, dynamical modeling and elimination of the slug within the offshore oil & gas Exploration and Production (E&P) processes. Modeling of slugging flow has been used to investigate the slug characteristics and for design of anti-slug control as well, however most models require specific facility and operating data which, unfortunately, often is not available from most offshore installations. Anti-slug control has been investigated for several decades in the oil & gas industry, but many of these existing methods suffer the consequent risk of simultaneously reducing the oil & gas production. This paper concludes that slug is a well defined phenomenon, but even though it has been investigated for several decades the current anti-slug control methods still have problems related to robustness. It is predicted that slug-induced challenges will be even more severe as a consequence of the longer vertical risers caused by deep-water E&P in the future.
Offshore de-oiling installations are facing an increasing challenge with regards to removing oil residuals from produced water prior to discharge into the ocean. The de-oiling of produced water is initially achieved in the primary separation processes using gravity-based multi-phase separators, which can effectively handle large amounts of oil-well fluids but may struggle with the efficient separation of small dispersed oil particles. Thereby hydrocyclone systems are commonly employed in the downstream Produced Water Treatment (PWT) process for further reducing the oil concentration in the produced water before it can be discharged into the ocean. The popularity of hydrocyclone technology in the offshore oil and gas industry is mainly due to its rugged design and low maintenance requirements. However, to operate and control this type of system in an efficient way is far less simple, and alternatively this task imposes a number of key control challenges. Specifically, there is much research to be performed in the direction of dynamic modeling and control of de-oiling hydrocyclone systems. The current solutions rely heavily on empirical trial-and-error approaches. This paper gives a brief review of current hydrocyclone control solutions and the remaining challenges and includes some of our recent work in this topic and ends with a motivation for future work.
Manufacturing in high-income countries is on the decline and Denmark is no exception. Manufacturing employment and the number of firms have been shrinking as a share of the total and in absolute levels. This paper uses a rich linked employer-employee dataset to examine this decline from 1994 to 2007. We propose a different approach to analyze deindustrialization and generate a series of novel stylized facts about the evolution. While most of the decline can be attributed to firm exit and reduced employment at surviving manufacturers, we document that a non-negligible portion is due to firms switching industries, from manufacturing to services. We focus on this last group of firms before, during, and after their sector switch. Overall this is a group of small, highly productive, import intensive firms that grow rapidly in terms of value-added and sales after they switch. By 2007, employment at these former manufacturers equals 8.7 percent of manufacturing employment, accounting for half the decline in manufacturing employment. We focus on the composition of the workforce as firms make their transition. In addition, we identify two types of switchers: one group resembles traditional wholesalers and another group that retains and expands their R&D and technical capabilities. Our findings emphasize that the focus on employment at manufacturing firms overstates the loss in manufacturing-related capabilities that are actually retained in many firms that switch industries.
This book explores the transformation of Danish shipbuilding from 1975-2015. Specifically it expores the closure of B&W Shipyard in 1980, Nakskov Shipyard in 1986, Aalborg Shipyard in 1987-88, Burmeister and Wain Shipyard in 1996 and Danyard Frederikshavn in 1999. The author identifies 27 firms that were spun out during the closure of five Danish shipyards and finds that several of these firms were able to apply the inherent resources in new activities with more value added. The book also finds that the competencies of the redundant workers from the four shipyards were useful in other parts of the Danish labor market. The book sheds new light how internal and external factors influence the transformation of mature industries.
We present an arbitrary-order spectral element method for general-purpose simulation of non-overturning water waves, described by fully nonlinear potential theory. The method can be viewed as a high-order extension of the classical finite element method proposed by Cai et al. (1998)[5], although the numerical implementation differs greatly. Features of the proposed spectral element method include: nodal Lagrange basis functions, a general quadrature-free approach and gradient recovery using global L2projections. The quartic nonlinear terms present in the Zakharov form of the free surface conditions can cause severe aliasing problems and consequently numerical instability for marginally resolved or very steep waves. We show how the scheme can be stabilised through a combination of over-integration of the Galerkin projections and a mild spectral filtering on a per element basis. This effectively removes any aliasing driven instabilities while retaining the high-order accuracy of the numerical scheme. The additional computational cost of the over-integration is found insignificant compared to the cost of solving the Laplace problem. The model is applied to several benchmark cases in two dimensions. The results confirm the high order accuracy of the model (exponential convergence), and demonstrate the potential for accuracy and speedup. The results of numerical experiments are in excellent agreement with both analytical and experimental results for strongly nonlinear and irregular dispersive wave propagation. The benefit of using a high-order – possibly adapted – spatial discretisation for accurate water wave propagation over long times and distances is particularly attractive for marine hydrodynamics applications.