It goes on to detail the mechanisms, applications, and challenges of the various sand control options in both vertical and horizontal applications. It mainly focuses on a practical project requiring the participants to apply what they have learned by selecting, designing and presenting the most appropriate sand control completion for several case study wells for both cold primary and thermal application.
Expanding on existing methodologies for the design optimization of mooring systems for offshore renewable energy devices, this paper explores the optimization of the axial stiffness of a mooring system, a key property that governs the motion of the moored renewable energy device. The optimization using a covariance matrix adaptation evolutionary strategy is executed with respect to both the motion response of the moored device, and the cumulative fatigue damage in the mooring lines. Previous mooring system optimization work has focused on geometry optimization of the system considering known material properties, whilst this paper explores the optimization of the axial stiffness properties of the mooring system identifying ways in which the response of the system can be optimized through changes in the material properties. Considering the case of a moored heaving buoy similar to an offshore renewable energy device, the present case study optimizes the mooring system simultaneously minimizing the cumulative fatigue damage in the mooring lines while also maximizing the heave response which is responsible for the energy generated by the device.
As society moves to reduce the greenhouse gas emissions associated with electricity generation, renewable energy and in particular offshore renewable energy devices are seen as playing an increasing role in achieving the global emissions targets. Though offshore renewable energy continues to be deployed at increasing rates, it still remains a relatively nascent field which requires innovative engineering solutions in order to be cost competitive with more traditional energy sources. With this aim in mind, optimization techniques are increasingly being applied to the design and operation of offshore renewable energy devices in order to maximize the relative efficiency of these developments and identify novel solutions to the unique challenges faced by this sector (Baños et al., 2011, Iqbal et al., 2014).
In recent years as the number of offshore wind farms developed has rapidly increased, the closer to shore shallow water sites are approaching capacity. As a result of this, floating offshore wind turbines, which can operate further from shore and in deeper waters have become a major research focus. A vital component of these floating offshore renewable energy devices are the mooring systems which at the same time keep the device on station for the desired operational life while at the same time allowing the required motion from which energy can be generated. The mooring system therefore represents a key component which must be carefully designed to suit both the device and the site at which the device is being deployed (Harris et al., 2004, Johanning et al., 2006b).
The O&G industry and renewables industry are integrating more and more through the use of energy conversion systems to cut costs. This paper describes the testing and applications of a renewable generated power source. EC-OG has developed a novel autonomous Subsea Power Hub which utilizes ocean currents to generate electricity.
ABSTRACT: Large-scale CO2 injection in saline aquifers will cause pressure build-up in brine far beyond the extent of CO2 plume. In this paper, we evaluate the geomechanical responses of large-scale CO2 storage in the multilayer aquifer of the Kra Al-Maru Trend in Kuwait. The site was selected after screening the whole territory of Kuwait, identifying and ranking of candidate sites for geological CO2 storage. We simulated the CO2 injection and geomechanical responses during 40 years of injection with an injection rate of 11 million tonnes/year. Results of numerical simulations show that after 40 years of injection the extent of CO2 plume is within the radial range of 4 km from the injectors, while the pressure build-up is felt up to 55 km. The largest pressure build-up of 2.3 MPa and the associated poro-elastic stress changes in the reservoir-seal pair are located within the radial range of about 5 km from the injectors. CO2 injection can induce a maximum uplift at the ground surface of 11 cm. The present-day noncritical state of stress and the magnitudes of induced stress changes suggest a low risk for containment integrity. Future studies will be required with a dedicated well to obtain core and perform detailed site characterization.
This paper considers the geomechanical aspects associated with large-scale CO2 injection and geological storage in the multilayer aquifer of the Kra Al-Maru Trend in Kuwait. The potential multilayer aquifer CO2 storage site was selected based on the results of a site selection study performed for the whole territory of Kuwait. Geomechanical characterization and assessment of the selected storage site were performed with existing data provided by the Kuwait Oil Company (KOC). No additional experimental or site investigations were performed in this study.
Assessment of geomechanical response to large-scale CO2 injection in saline aquifers is reported in the literature for different storage sites. Large-scale impact of CO2 storage is due to the large area of elevated pressures in the storage formation, which extends several tens to hundreds of kilometers from the injection zone. Examples are for instance the potential CO2 storage in the Illinois Basin (Birkholzer and Zhou, 2009), the Shenhua CCS project in China (Zhu et al., 2015) and the South West Hub Project in Australia (Zhang et al., 2015). Although the footprint of elevated pressures is large, the mechanical impact on overlying sealing formations can be low, posing a negligible threat to the integrity of containment (e.g. the Sleipner CO2 injection project in Norway; Rutqvist, 2012).
Floating Facilities are widely spread by the time, and production from those Units is becoming more and more relevant in the oil & gas market. Since the start up of "Agip Milano" in 1978, Eni has put continuous effort to grow in this contest, claiming today a fleet of an important variety of typologies and peculiarity of characteristics. Experience has been matured, following the change in context and background conditions, supporting the transformation of Floating Facilities from Units conceived to exploit marginal, near to shore fields with low complexity, in Units fit to exploit large and complex fields. Progress in deep water exploration and drilling over the past ten-plus years has also yielded a large number of new discoveries, definitely to be developed through Floating Units. Current projects entail increasing complexity of production environment and highly sophisticated and technologically advanced production systems, and, now more than ever, a solid and efficient O&M management philosophy is perceived as a fundamental need. For this reason, an incisive, efficient and correct approach to "Readiness for Operations" helps to improve overall safety and to reduce operating costs. Eni consolidated process of "Operations Readiness and Assurance", as applied to Floating Facilities, with full involvement of O&M Contractor, will be described in this paper taking advantage of several examples.
Zu, Yan (Oil & Gas Technology Centre, DNV GL) | Chiu, Chunyiu (Corresponding Author) | Cho, Chungun (Oil & Gas Technology Centre, DNV GL) | Wang, Andy (Oil & Gas Technology Centre, DNV GL) | Ruskin, Alex (Oil & Gas Technology Centre, DNV GL) | Qiu, Xiaohong (Noble Denton Marine Services, DNV GL)
The Kebabangan (KBB) Central Processing Platform was installed offshore Malaysia in June 2014 and set the record as the heaviest platform installed by the Dynamic Positioning (DP) float-over method. The deck installation vessel was upgraded with DP capability by adding two portable azimuth thrusters to allow a safe and efficient installation of the platform. This novel upgrade was performed for the sole purpose of achieving overall cost and time efficiencies during the installation phase of this project, and was the first conversion of its type in the oil and gas and marine industries.
This paper describes the ad-hoc conversion of the heavy-lift vessel Xiang Rui Kou (XRK) to DP-2 class, with comprehensive focus on the impetus for conversion and the technical and practical challenges addressed by the solution developed, such as thruster selection, feasibility assessment, DP capacity study, state-of-art engineering analyses, relevant tests and the actual installation operation.
KBB Northern Hub Project is located offshore Sabah, Malaysia in the South China Sea, approximately 92km northwest of Kota Kinabalu.
The KBB topsides with a NTE weight of 20,500MT was originally planned to be installed by COSCO’s 50,000 MT deadweight X-class vessel using the moored float-over method. The installation location had a water depth of 142m and a seabed slope near the platform, meaning a traditional 8-point mooring system would be expensive to purchase and operationally challenging to install. These challenges necessitated an investigation into using alternative station-keeping methodology for the installation operation.A DP-assisted float-over operation can reduce the weather windows required to perform the actual float-over (Beerendonk et al, 2008). Without the need to connect mooring lines and perform significant onsite preparations, the float-over operation itself can be performed within a much shorter timeframe, typically reducing the operational reference period (shown in Fig. 1) from several days down to several hours. There are clear benefits to cost due to involvement of less marine spread and higher operability, and also to operational safety due to a shorter exposure period. The DP-assisted float-over method thus offers clear advantages over the traditional, mooring-assisted approach.
Technip Umbilicals and Angoflex have been awarded a contract by Eni to supply umbilicals to its East Hub development project in Block 15/06, offshore Angola. The contract covers project management and manufacture of approximately 15 km of dynamic and static steel tube umbilicals for the field, which is located 350 km north of Luanda in water depths of 450 m to 600 m. The manufacturing of the umbilicals is set to be completed in the second half of next year.
Zhang, Y. (CSIRO Minerals) | Schaubs, P. M. (CSIRO Minerals) | Langhi, L. (CSIRO Energy) | Delle Piane, C. (CSIRO Energy) | Dewhurst, D. N. (CSIRO Energy) | Stalker, L. (CSIRO Energy) | Michael, K. (CSIRO Energy)
An area in the Southern Perth Basin has been identified as a potentially suitable site for CO2injection, due to its proximity to major CO2emission sources and the presence of potentially suitable geology. The project for testing and proving up of the storage area is known as the South West Hub Project or SW Hub. Recently acquired 2D seismic and well data have allowed a detailed description of facies, measurement of rock properties and development of a 3D structural model for the area. This 3D model has been used as the basis for a preliminary fault seal analysis and also for the development of simplified geomechanical models for the SW Hub using FLAC3D. The geomechanical modelling used in situ stress (magnitude, orientation) and pore pressure conditions as a starting point and then simulated CO2injection from a single well at rates of 1 to 5 million tons per year for 20 years. No matter whether weak or strong faults were used, no faults were reactivated nor the top seal breached under any of the simulated injection rates. Average uplift in the weak fault scenario was modelled at between 0.4 and 1.8 cm for injection rates of 1 to 5 million tons per year. The strong fault model showed slightly smaller uplifts. The majority of uplift was noted in the first 5 years of injection and flattened off rapidly after this point in time. This is consistent with geomechanical models from other CO2storage sites and from actual field measurements.
Suitable geology and proximity to large sources of carbon dioxide led to the Southern Perth Basin being investigated as a potential geological storage site . The specific area selected is in the region of the Harvey- 1 well (Figure 1) around 150 km south of Perth in Western Australia. This has become known as the South West Hub project and this area is currently undergoing extensive site assessment in terms of reservoir quality, containment potential, structural geology, facies analysis, rock properties and the like.
Focused waves are commonly used to represent extreme wave events. This study examines the numerical modelling of unidirectional focused wave groups using different tools. The focusing of the wave groups is achieved through an iterative correction of the amplitudes and the phases of the wave components that form the energy spectrum of the group. The scope of the paper is to compare the accuracy and the efficiency of the numerical models employed and to investigate if an integrated numerical modelling approach is applicable. Experimental results are used as a benchmark to assess the accuracy of the replication of the physical processes of the problem by the numerical models.