Guidelines on Designing Marine Hoses for Oil/Gas Applications

The work conducted gives guidelines on designing Marine Hoses for Oil/Gas applications. It was presented at the International symposium of recent research progress on multi-hazard resilient onshore and offshore structures. Organised by: Tsinghua University, Deep-Sea Technology Division, Chinese Society for Oceanography Ocean Engineering Division, China Association of Marine Affairs; Chairs: Facheng Wang, Cheng Fang

Numerical Modeling of Oil/Gas Flow in Pipes in Deep Sea

The poster is on numerical model, and an introductory work on using the Fluid-Structure Interaction Model Of Abaqus To Analyse The Flow Of Oil/Gas In The Pipes In Deep Se

Novel Composite Riser Development for Offshore Deep Water Applications

Due to the increasing energy demand, there is need for a more sustainable conduit for producing and transporting fluids in the oil and gas industry. This is also in response to the increase in exploration activities in offshore deep water, from shallow waters to deep waters. Thus, more length of marine risers and subsea pipelines are required, which increases the weight of the offshore structure. The properties of composites will be harnessed to help reduce the weight of the marine risers. This necessitated the need for the development of composite risers, the studies of the mechanics and hydrodynamics of composite risers. The study shows that composite risers can be applied on offshore structures however, it works most successfully when used as a hybrid composite riser system, and when used as a top tension composite riser system

Modeling and Characterization of Novel Deepwater Marine Risers

Offshore explorations has moved from shallow waters to deep waters. This requires longer risers, resulting in significant weight increase. To improve riser technology, composite materials can be used. They offer advantages that can be harnessed. These include high corrosion resistance, fatigue resistance, high strength characteristics and weight savings since they are lightweight with low bending stiffness. Currently, there are approximately 3,400 deep water wells in the Gulf of Mexico (GoM) having depths greater than 150 meters, and a worldwide undiscovered deep water reserves estimated to exceed 200 billion barrels and 25% of the total US reserves (BOEM, 2016), while others are in regions such as Angola, Brazil, Canada, Egypt, India, Morocco and the UK. The application of composite risers in offshore engineering for ultra-deep applications has been facing a lot of challenges, such as in West Africa and Gulf of Mexico. Presently, the steel catenary risers are used for deep water applications requiring large diameter pipes, and both the flexible and top-tensioned risers are used for shallow water applications. Current trend in the industry is the application of composite riser technology used mostly for deep waters, which have over 1000m depth. The first time composite risers were successfully deployed offshore was on Heidrun Platform in 1995 as a composite joint. This started the success in the historical trend of composite riser development. This research involves hydrodynamic loading using ANSYS AQWA. The main research focus on the characterization and the behaviour as regards the fatigue of composite risers. ANSYS APDL & ANSYS ACP are used to model the composite materials, create the composite layers for the materials like AS4/PEEK. This was done considering the mechanical properties of the composite material. Some coupling analysis on a floating platform using the risers and mooring is also being investigated

Numerical design of Novel Composite risers for deep water applications

Due to recent challenges in oil exploration, there has been an increase in oil exploration from shallow waters to deep waters. This requires more length of the risers and thus an increase in the weight of the risers on the offshore structure. Risers are conduits which are used to transport fluid from the oil well to the offshore platform of transport vessel. The application of composites in riser design is to harness the properties of composites. This includes the reduction in the weight of the structure, and to improve the material behaviour. Submarine hoses are also a type of risers that are connected to buoys and other offshore structures but have short service periods. The design for some load cases on the composite riser is presented

Mechanics, hydrodynamics and novel design of composite risers with application on offshore hoses

Currently, there are approximately 3,400 deepwater wells in the Gulf of Mexico (GoM) having depths greater than 150 meters, and a worldwide undiscovered deepwater reserves estimated to exceed 200 billion barrels and 25% of the total US reserves (BOEM, 2016), while others are in regions such as Angola, Brazil, Canada, Egypt, India, Morocco and the UK. The application of composite risers in offshore engineering for ultra-deep applications has been facing a lot of challenges, such as in West Africa and Gulf of Mexico. Presently, the steel catenary risers are used for deepwater applications requiring large diameter pipes, while the flexible while top-tensioned risers are used for shallow water applications, but composite riser technology used mostly for deepwaters, as this is an exciting frontier in the offshore industry as it provides a potential solution for future riser design challenges. This research involves hydrodynamic loading using ANSYS AQWA and modelling composite riser using Orcaflex to investigate the Riser Installation behaviour. The behaviour of composite risers is compared against the behaviour of top-tensioned steel risers with the main research focus on the motion characterization and the behaviour as regards the fatigue of composite materials, considering that composite materials are lightweight , combustible but not corrosive. ANSYS APDL and ANSYS ACP are used to model the composite materials and AS4/PEEK was first used considering the mechanical properties make it a good composite material for composite material. Some comparison is made with some research done on composite materials, and further studies is done on the fatigue analysis of the composite risers which is ongoing and specific attention is given on the applicability, and to present the design the local and global analysis, in other to reduce installation and maintenance costs. Recommendations from this will enable other industry specifications like ABS, DNV, API, EN and ISO on composite risers as currently they are limited codes and specifications on composite risers

An Investigation on the Vortex Effect of a CALM Buoy under Water Waves Using Computational Fluid Dynamics (CFD)

Floating offshore structures (FOS) must be designed to be stable, to float, and to be able to support other structures for which they were designed. These FOS are needed for different transfer operations in oil terminals. However, water waves affect the motion response of floating buoys. Under normal sea states, the free-floating buoy presents stable periodic responses. However, when moored, they are kept in position. Mooring configurations used to moor buoys in single point mooring (SPM) terminals could require systems such as Catenary Anchor Leg Moorings (CALM) and Single Anchor Leg Moorings (SALM). The CALM buoys are one of the most commonly-utilised type of offshore loading terminal. Due to the wider application of CALM buoy systems, it is necessary to investigate the fluid structure interaction (FSI) and vortex effect on the buoy. In this study, a numerical investigation is presented on a CALM buoy model conducted using Computational Fluid Dynamics (CFD) in ANSYS Fluent version R2 2020. Some hydrodynamic definitions and governing equations were presented to introduce the model. The results presented visualize and evaluate specific motion characteristics of the CALM buoy with emphasis on the vortex effect. The results of the CFD study present a better understanding of the hydrodynamic parameters, reaction characteristics and fluid-structure interaction under random waves

Modelling and Characterization of Novel Deepwater Composite Risers

Currently, there are approximately 3,400 deepwater wells in the Gulf of Mexico (GoM) having depths greater than 150 meters, and a worldwide undiscovered deepwater reserves estimated to exceed 200 billion barrels and 25% of the total US reserves (BOEM, 2016), while others are in regions such as Angola, Brazil, Canada, Egypt, India, Morocco and the UK. The application of composite risers in offshore engineering for ultra-deep applications has been facing a lot of challenges, such as in West Africa and Gulf of Mexico. Presently, the steel catenary risers are used for deepwater applications requiring large diameter pipes, while the flexible while top-tensioned risers are used for shallow water applications, but composite riser technology used mostly for deepwaters, as this is an exciting frontier in the offshore industry as it provides a potential solution for future riser design challenges. This research involves hydrodynamic loading using ANSYS AQUA and modelling composite riser using Orcaflex to investigate the Riser Installation behaviour. The behaviour of composite risers is compared against the behaviour of top-tensioned steel risers with the main research focus on the motion characterization and the behaviour as regards the fatigue of composite materials, considering that composite materials are light-weight, combustible but not corrosive. ANSYS APDL is used to model the composite materials and AS4/PEEK was first used considering the mechanical properties make it a good composite material for composite material. Some comparison is made with some research done on composite materials, and further studies is done on the fatigue analysis of the composite risers which is ongoing and specific attention is given on the applicability, and to present the design the local and global analysis, in other to reduce installation and maintenance costs. Recommendations from this will enable other industry specifications like ABS, DNV, API, EN and ISO on composite risers as currently they are limited codes and specifications on composite risers

Numerical Investigation of Winglet Aerodynamics and Dimple Effect of NACA 0017 Airfoil for a Freight Aircraft

Drag reduction is an ever-present challenge within the aeronautical engineering industry. This paper presents two substantial wing modifications: the addition of a winglet of a freighter aircraft and a dimpled wing on the NACA 0017 aerofoils. Studies on nine (9) different geometries of dimpled aerofoils were performed against a control model of an aerofoil without any dimple. Computational fluid dynamics (CFD) analysis was performed using two (2) commercial CFD platforms. This paper also explored two novel solutions of aircraft optimisation to mitigate the effects of drag and leading-edge pressure, while increasing the effect of lift. The optimised performance model of a freighter aircraft increased its aerodynamic efficiency. The study found that at take-off velocity of 82 m/s, winglets decreased pressure on the wing by 16.31%, through flow redirection and better flow integration into aerofoils wake. The study also analysed the separation layer and its effect through the appropriate use of the dimple effect. Increased lift effects were observed on a NACA 0017 aerofoil. Despite the low increase in drag of 6% from the modifications, the resultant L/D ratio was highly increased. This study also faced some challenges with validating the model. Hence some validation approaches were taken, and some other approaches suggested for future studies