The effects of simulator training on ice management performance are studied and used to propose an evidence-based method for training ship operators to a target performance level. In a previous study we found that, on average, experienced seafarers performed better in an ice management simulator than inexperienced seafaring cadets (Veitch et al. 2019). In our current research, a curriculum developed based on the results of Veitch et al. (2019) and the requirements of the Polar Code (International Maritime Organization 2017), was used to train a group of seafaring cadets on an individual basis in either one or two training sessions. After training, each seafaring cadet completed one of the same scenarios used by Veitch et al. (2019) and this was used as a basis of performance evaluation. In all performance metrics, the average performance of the inexperienced cadets improved after training. In most performance metrics, the performance of the inexperienced cadets improved with each subsequent training session. A trend created from the relationship between amount of training and ice management performance represents a method for estimating the amount of training required to reach a specified performance target. This method can be used to inform future ice management training requirements and can be applied to other types of operator training in order to predict the amount of training needed to reach a performance target.
Elhaj, Murtada (Memorial University of Newfoundland) | Abdullatif, Osman (King Fahd University of Petroleum and Minerals) | Abdulraheem, Abdulazeez (King Fahd University of Petroleum and Minerals) | Hassan, Amjed (King Fahd University of Petroleum and Minerals) | Sultan, Abdullah (King Fahd University of Petroleum and Minerals)
The science of Acoustics deals with the propagation of mechanical waves in the three phases of materials, solids, liquids, and gases. In exploration and reservoir engineering, acoustic wave velocities play an essential role in reservoir description. The primary challenge in the initial evaluation and characterization of reservoirs is related to the understanding of its geology, petrophysics, and geomechanics. Therefore, an accurate estimation of acoustic wave velocities and rock porosity is essential for better reservoir description and performance as well as a better forecast of seismic properties. In this reseach, the primary objective is to analyze the texture, mineralogy, porosity and permeability data of outcrop carbonate rock samples to study the impact of confining pressure on wave velocities. Furthermore, an empirical correlation is proposed for relating porosity with acoustic properties.
Ninety outcrops samples are collected from Dam Formation in Al-Lidam area in Eastern Province, Saudi Arabia to develop a correlation. The carbonate samples varies from mudstone to grainstone facies. The samples are collected, prepared, and tested for this experimental study based on API standards. Compressional and shear wave velocities of carbonate rocks are measured under dry and fully brine-saturated conditions for 5 to 25 MPa effective confining pressures at room temperature. Moreover, porosity and permeability are measured using three different techniques, viz., AP-608 Automated Porosimeter-Permeameter, Helium Porosimeter, and thin section technique. Finally, the results are compared with those from other studies related to the same area.
A state-of-the-art review is presented on seismic properties, relationship with porosity and acoustics in addition to the current trend and the future challenges in the area. The laboratory investigations for this study reveals that Al-Lidam area has different types of facies. The results also show that both compressional and shear wave velocities increase as the confining pressure on the dry samples increase. However, the compressional wave velocities increased and the shear wave velocities decreased with confining pressure under fully saturated conditions. A new correlation is presented for carbonate rocks to predict porosity from acoustic wave velocities.
This study will help in improving the exploration efforts as well as give a better explanation for reservoir characterization, facies recognition, geophysical interpretation, and engineering calculations. This attempt will open a new research area for engineers and scientists to study the effect of variation in different properties on wave velocities.
Ice-structure interaction (ISI) is a complex process, which requires a thorough understanding of the underlying physics to ensure safe operations in the ice-covered regions. Application of discrete element method (DEM) to compute ice loads on structures is a widely accepted approach, where the equations of rigid body motions are solved for all ice pieces in the computational domain. In most ISI simulations, the ice zone is assumed to be resting on a static water foundation omitting the hydrodynamic effects (added mass, water drag, wave damping) of the interacting bodies. This assumption can introduce erroneous results to simulations of the floating ice floes behavior, which in turn will incur uncertainties in planning ice management activities.
In this paper, a smooth particle hydrodynamics (SPH) based computational fluid dynamics (CFD) code is coupled with a three-dimensional DEM model to take the hydrodynamic effects of the interacting bodies including the ice pieces into account. The ice zone is modeled as discrete elements, which allows computing interaction forces by considering contact laws. The water foundation is modeled using smooth particles, which are modelled with the Naiver-Stokes equations.
Several applications of ship and offshore structures interacting with level ice and pack ice are simulated. A scenario of an offshore supply vessel operating in the marginal ice zone (MIZ) that is subject to wave forces is also simulated to show how this approach can be used for modelling complex real-world problems. This scenario is unique in a sense that it yields a multi-physics solution, where ice-structure-wave are all included in a single CFD simulation as a fully coupled analysis. The cost of the simulation is significantly reduced by running the computations on a Graphics Processing Unit (GPU) instead of a typical CPU workstation. Some of the initial results of ice-structure interactions are presented in this paper and a reasonable agreement with reduced scale model test results are found.
Ice management is an important consideration for any offshore petroleum operation conducted in an area that could encounter sea ice. Ice management could be performed for a number of reasons: to reduce global ice loads on the installation, to avoid ice interaction with underwater components such as risers or turrets, or to allow for close proximity operations such as loading / offloading, manning / de-manning, or evacuation in the case of an emergency event. The purpose of this project is to provide baseline information relating to ice clearing operations conducted in pack ice conditions. This information includes outcomes of different ice clearing operations in terms of loads on a GBS structure and ice concentration upstream of the GBS structure. It also includes loads measured on the support vessel that is conducting the ice clearing operations for a subset of the clearing techniques considered.
To investigate this problem, model testing experiments were conducted in NRC-OCRE's ice tank located in St. John's NL, Canada. These experiments involved systematic testing involving various pack ice conditions representative of the Grand Banks area and two models: a support vessel and a GBS structure. The environmental conditions included: two ice concentrations, two ice piece sizes, and two ice piece drift speeds. Four ice clearing techniques were tested in each condition. The ice clearing techniques included two fixed position tests; where the support vessel was held in place upstream of the GBS using flexible mooring lines and two free running tests; where the support vessel was remotely controlled and maneuvered upstream of the GBS.
Results are provided in terms of loads measured on the GBS model with clearing support, loads measured on the support vessel during the fixed ice clearing operations, ice free zones created upstream of the GBS and aft of the support vessel during ice clearing tests, reductions in GBS loads due to ice clearing operations, reductions in ice concentration upstream of the GBS due to ice clearing operations, and a summary of ice events that led to large pack ice loads. The significant factors that influenced each result were also identified.
These results complement existing literature relating to physical ice clearing operations by providing the outcomes of systematic testing in different ice conditions which is available in public domain. These results could be used as benchmark values for design or numerical model validation. In addition, they could provide insight to operators, regulators and academia to support informed decision making regarding the level of ice management support required in different operating environments. All dimensions and test results in this paper are provided at full scale value.
Asadi, Mohammad Bagher (Memorial University of Newfoundland) | Ameri, Mohammad Javad (Amirkabir University of Technology) | Amini, Shahram (Dana Energy Corp) | Zendehboudi, Sohrab (Memorial University of Newfoundland)
Multiple-fracture-horizontal-well (MFHW) technology plays a crucial role in production from less economically attractive reservoirs, through enhancing the well productivity. The formation around the fracture might be damaged considerably during fracturing processes because of the fracture-fluid leakoff into the reservoir. Different attempts have been made to achieve an optimal design for MFHWs; however, the effect of fracture-fluid leakoff has been neglected in most of these research investigations, leading to unrealistic and inaccurate results. This study aims to fill this knowledge gap. A new mathematical approach is introduced to evaluate the effect of the fracture-fluid-leakoff phenomenon on the fracture characteristics during hydraulic fracturing. The unified-fracture-design (UFD) concept is used in this research work to optimize the productivity of MFHWs where the direct boundary-element method (DBEM) is applied. The distributed-volumetric-sources (DVS) method, which offers a semianalytical response of a reservoir to closed outer boundaries with respect to a source, is also extended, and the results obtained from these two different techniques are compared. Then, the proposed methodology is applied to a synthetic case study to evaluate the influence of fracture-fluid leakoff on the productivity index (PI) and to obtain the fracture dimensions that result in the optimal productivity. It is concluded that leakoff leads to influx-pattern variation. Also, it is found that the optimal fracture for the leakoff case is shorter and wider at a constant proppant number, in contrast to the case without a leakoff event. This study proposes an accurate and reliable approach for productivity determination of MFHWs that can assist the petroleum industry to optimize hydraulic-fracturing operations.
Khan, Faisal (Memorial University of Newfoundland) | Taylor, Rocky (Memorial University of Newfoundland) | Veitch, Brian (Memorial University of Newfoundland) | Veitch, Erik (Memorial University of Newfoundland) | Smith, Doug (Memorial University of Newfoundland)
In this paper, a method is presented for visualizing and understanding the operational dynamics of a shipping operation. The method uses system performance measurement and functional signatures. System performance measurement allows assessors to understand the level of performance that is being achieved by the operation. The functional signatures then provides insight into the functional dynamics that occur for each level of performance. By combining system performance measurement with functional signatures, there is a framework to help understand what levels of performance are being achieved and why certain levels of performance are being achieved. The insight gained from this approach can be helpful in managing shipping operations. Data from an ice management ship simulator is used to demonstrate this method and compare different operational approaches.
Time lapse seismic monitoring usually involves looking for small changes in localized regions. Quantifying the uncertainty related to these changes is important because it affects exploration and production decisions. Traditional methods that use pixel by pixel quantification with large models are computationally infeasible. We use a local acoustic solver in the area of interest, which allows for fast computation of the wavefield solves. This allows us to use a Metropolis Hastings algorithm in a Bayesian inversion to address the uncertainty that is present in the estimation of 4D velocity changes.
Presentation Date: Tuesday, October 16, 2018
Start Time: 8:30:00 AM
Location: 204C (Anaheim Convention Center)
Presentation Type: Oral
We explore the feasibility of using ultrasound to image through bone. The strong velocity and acoustic impedance contrast between bone and soft tissue like that between salt and sediments, significantly reduces the amount of energy transmitted and generates strong internal multiples. In this paper we present a novel framework for imaging the interior of long bones by using a group sparse hyperbolic radon transform to both denoise and despeckle the resulting image and suppress the internal multiples. Using this technique we demonstrate that it is possible to image the interior of bones despite large velocity contrasts and strong multiples on synthetic and in-vivo data.
Presentation Date: Tuesday, October 16, 2018
Start Time: 8:30:00 AM
Location: 211A (Anaheim Convention Center)
Presentation Type: Oral
Huang, Xin (Jilin University) | Farquharson, Colin G. (Memorial University of Newfoundland) | Yin, Changchun (Jilin University.) | Cao, Xiaoyue (Jilin University.) | Zhang, Bo (Jilin University.) | Liu, Yunhe (Jilin University.) | Cai, Jing (Jilin University.)
Spectral-element (SE) and meshfree approaches are two kinds of numerical algorithms based on the Galerkin method, neither of which requires a particularly refined subdivision of the mesh to obtain accurate results. The main difference between SE and meshfree methods is that a tessellated physical mesh linked to the physical model should be applied for the SE method but not the meshfree method. In order to overcome the limitations imposed by the link between mesh and model for the SE method, and adopting ideas from the meshfree method, we propose a transformation of the conventional SE method in which the conductivity is no longer assumed constant within a cell and dealt with via numerical integration. In this paper, we first present the basic theory for the new approach, then use this method to model airborne electromagnetic responses for 1D and 3D earth models in order to verify the efficiency and accuracy of the new approach.
Presentation Date: Wednesday, October 17, 2018
Start Time: 1:50:00 PM
Location: Poster Station 4
Presentation Type: Poster
Uranium deposits in the Athabasca Basin are normally related to graphitic faults which typically behave like thin conductors. Slingram-style time-domain electromagnetic (TDEM) methods are commonly used in the exploration of the uranium deposits in the Athabasca Basin. A finite-volume time-domain (FVTD) method that is designed to model the Slingram-style electromagnetic (EM) surveys in parallel is presented. Numerical experiments show that this method can reproduce results that were previously presented in the literature. Results are also shown for a real data-set from the Athabasca Basin.
Presentation Date: Thursday, October 18, 2018
Start Time: 8:30:00 AM
Location: 213B (Anaheim Convention Center)
Presentation Type: Oral