Clukey, Edward Charles (BP Exploration) | Tognarelli, Michael (BP America ) | Li, George (SBM Offshore) | Ghosh, Rupak (ExxonMobil Corp) | Phillips, Ryan Douglas (C-Core) | Zakeri, Arash (C-Core) | Elliott, Brad (Memorial University of Newfoundland and Labrador) | Bhattacharyya, Anirban (BP America ) | Sun, Qunli (Technip Engineering)
Pipeline/soil interaction involves complex interplay of soil type and strength, burial depth, pipeline displacement path, contact mechanics, soil strain localization, and pipe feed-in among other parameters. Further complexity is introduced in fully coupled models to simulate ice keel/seabed/pipeline interaction events for example, where ice keel/seabed interface contact, keel bearing pressures and subgouge soil deformations are important. In order to establish confidence in more complex models, sub-interaction scenarios can be extracted and simplified. This study focuses on pipeline/soil interaction in plane strain form to examine the effects that burial depth and pipe direction of travel have on soil failure mechanisms. The coupled eulerian lagrangian (CEL) method, used in this study, is shown to provide consistent results with past work. The implications of this work in the context of modelling ice keel/seabed/pipeline interaction and model verification are discussed.
This paper presents the results of a series of physical experiments to quantify the drag force on a submarine pipeline caused by a glide block or an out-runner block impact normal to the pipe axis. The experiments were carried out in a geotechnical centrifuge at C-CORE under submerged conditions at a centrifugal force of 30 times the Earth's gravity (i.e. N = 30) and simulated steady and uniform impact velocities ranging between 0.1 and 1.3 m/s with the soil blocks being approximately 5 m in height in prototype scale. The soil blocks were made of kaolin clay consolidated to have undrained shear strengths ranging between about 4 and 6 kPa. The diameter of the model pipes were 6.35 and 9.5 mm corresponding to about 0.19 and 0.29 m in prototype terms. The shear strain rates, defined as the ratio of impact velocity to pipe diameter, in the centrifuge model are N times higher than that in the prototype. The shear rates simulated ranged from about 10 to 136 reciprocal seconds. The paper presents a method for estimating block impact drag force on submarine pipelines based on the results of the centrifuge experiments.
A submarine pipeline is a system of connected sections of pipe that usually transports crude oil or refined hydrocarbons. The pipe is laid on or buried in the seafloor. It typically ranges from 0.1 m to 1.0 m in diameter. The total length of a pipeline is dictated by the distances between the production platform(s) and the onshore or offshore destination(s) and by the route which poses the least risk in terms of offshore geohazards. Submarine landslides and the associated mass movement can potentially have devastating consequences on seafloor installations such as pipelines, flow lines, well systems, cables, etc. Submarine landslides occur frequently on both passive and active continental margins and slopes, releasing sediment volumes that may travel distances as long as hundreds of kilometres on gentle slopes (0.5 to 3°) over the course of less than an hour to several days . The movement of landslide and the released sediment volumes in general terms are so called ‘density flows'. From the initiation to deposition, density flows undergo complex processes that depend on many factors such as the composition, strength characteristics and properties, terrain topography, etc.
Geohazards in an offshore oil and gas perspective can be due to local and/or regional site and soil conditions having the potential to develop into failure events causing loss of life and damage to the environment or field installations. Triggering of these events can be caused by natural geological processes or by man's activities, as outlined in a recent state of-the-art review . Research on understanding the mechanisms behind and the risks posed by submarine slides has intensified in the past decade [e.g. 3, 4-10], mainly because of the increasing number of deep-water petroleum fields that have been discovered and in some cases developed. Production from offshore fields in areas with earlier sliding activity is ongoing in the Norwegian margin, Gulf of Mexico, offshore Brazil, the Caspian Sea and West Africa .
Estimating magnitude of the drag forces on pipelines caused by density flow impact is an important design consideration in offshore engineering. For buried pipelines in cohesive soils in slowly moving unstable slopes, the available methods seem to provide more or less similar estimates for the drag force normal to the pipe axis. However, this is not the case for estimates of the drag force parallel to the pipe axis . In cohesive soils, the magnitude of the drag force is a function of the rate at which the soil is sheared during interaction with the pipe. Recent works by Zakeri et al. [1, 12-14] provide a method for estimating drag forces caused by clay-rich debris flow (fully remoulded and fluidized density flow) impacting a pipeline normal to its axis. Later, the work was extended to cover all angles of impact .
Produced water accounts for the largest volume in the production stage of offshore oil and gas operations. There are very few studies dedicated to investigating impacts of produced water discharge in Arctic/cold regions. As exploration expands into these regions, the effects of the cold temperatures, high motion, ice, and extended periods of sunlight on fate and toxicity of constituents will need to be more fully understood due to environmental concerns and production costs. The fate of discharged produced water is determined by dilution and mixing, volatilization/dissolution/sedimentation, and biochemical/chemical reactions. These transport/transformation mechanisms are not well characterized in cold environments. Low temperature and motion may affect efficiency of separation equipment and reduce natural biodegradation and evaporation. As a result, the type of constituents targeted in warmer climates may not be a concern in cold regions and
may be replaced by other constituents. The first part of this paper will identify chemicals of concern in produced water for cold regions and model their fate in the environment. Due to the low temperatures, many of the contaminant transformations will be governed by equilibrium. Identification of the chemicals of concern leads into the second theme of this paper. Oil and grease is monitored for regulatory purposes however, what is defined as "oil and grease?? depends on analytical/sampling methods which vary between regions. For instance, some methods measure both the dispersed and the dissolved hydrocarbons, so measurements of dispersed oil tend to be "overestimated?? when compared against limits. Comparison of analytical data between platforms or building of annual trends is also complicated. Discrete sampling, when the sample analysis is done onshore, delays mitigation or corrective actions with respect to process control and does not give an accurate temporal trend in oil in water discharge. Using the information from the "identification and fate?? section of this work we have been developing molecularly imprinted polymers (MIPs) for highly selective isolation, detection and measurement of key constituents (e.g. alkylphenols) and are working toward devices to house the MIPs for online analysis. The development of these systems will allow the non-specialist to quickly identify constituents in the field and enable extensive data collection in real time and hence the knowledge to make informed and timely decisions.
In this paper, the significance of boundary conditions (L/D ratio), initial geometric imperfections, anisotropic material properties, and material constitutive model on the local buckling response of plain and girth welded pipes was evaluated using continuum finite element modelling procedures. A numerical model was developed, using the finite-element simulator ABAQUS/Standard, to predict the local buckling and post-buckling response of high strength pipelines subject to combined state of loading. The numerical procedures were calibrated using test data from large-scale experiments examining the local buckling of high strength linepipe. The moment and strain response estimates, predicted by the numerical simulation tool, was consistent with the experimental data well into the post-yield range. As the models with high L/D ratio exhibit global Euler-type response, a numerical algorithm was developed to calculate the local section moment response based on FE predictions.
With the majority of estimated Arctic oil and gas reserves being held offshore, ice gouging will likely be a major consideration in the design of transport pipelines in these regions. The implications of the effects of ice gouging on buried pipelines are well understood. The ability to model this phenomenon using advanced numerical simulation tools has been proven in recent years, and is demonstrated in this paper. The uncertainty that revolves around these tools, due to limitations in the available physical dataset that can be utilized to validate the results, is discussed.
In this paper, a limited parametric study on the influence of ice keel attack angle and interface strength on the free-field subgouge displacement field, and subsequent effects on a buried pipeline is presented. The Coupled Eulerian Lagrangian finite element formulation available in ABAQUS/Explicit and the Arbitrary Lagrangian Eulerian formulation in LS-DYNA are used to conduct the numerical experiment. The results are shown and the observations are discussed in detail. Finally, an assessment in terms of the challenges of implementing the numerical tools in an engineering application is provided.
A primary challenge of Arctic and harsh environment offshore field development is the protection of subsea pipelines and flowlines on the seabed. Damage from ice either through direct contact or through soil movements/pressures acting on the pipeline from ice gouging is a serious risk. Trenching and burial of pipelines in Arctic and harsh environments such as the Beaufort Sea, Chukchi Sea and the Grand Banks are considered to be the primary means of preventing damage from ice. Trenching can provide adequate protection for pipelines in Arctic areas. This paper presents the challenges associated with trenching and burial of pipelines and flowlines in Arctic and harsh environments, and discusses the state-of-the-art trenching and dredging technologies. Future equipment developments required to meet functional specifications for working in Arctic and harsh environments is then presented. Furthermore, key areas surrounding the operability of trenching and associated equipment are also discussed. This paper shows that there are a number of challenges facing trenching pipelines in arctic regions, and there are limitations of current trenching and dredging equipments. A continued effort is required by the industry to overcome a number of key issues and challenges and promote productions in Arctic and harsh environment frontiers.
Thomas, Brandon George (Husky Energy) | Iliyas, Abduljelil (Memorial University of Newfoundland and Labrador) | Johansen, Thormod Ekely (Memorial University of Newfoundland and Labrador) | Hawboldt, Kelly (Memorial University of Newfoundland and Labrador) | Khan, Faisal (Memorial University of Newfoundland and Labrador)
A consortium of university-industry researchers are developing sustainable and environmentally friendly enhanced oil recovery (EOR) technology for oil fields off the east coast of Newfoundland, Canada. This paper is foundational work on potential implementation of air and flue gas injection techniques. The paper discusses reservoir and facility considerations of air and flue gas injection and provides recommendations for project evaluation. The paper presents screening level results for Husky Energy's White Rose Field as a case study.
Newfoundland offshore fields contain light oil (30-37 oAPI, 0.5-0.8 cP) making the fields potential targets for gas based EOR. However, with the oil fields located 310-350 km off the coast, availability of injection gas and logistical problems present barriers to EOR. Air injection has the advantages of an unlimited supply of injectant, success in laboratory and field applications, years of safe operation, and potential for an estimated 10% incremental oil recovery in waterflooded reservoirs. The challenges toward implementation of both techniques considering field characteristics and infrastructure are discussed along with practical solutions to aid implementation.
The evaluation of sustainable and environmentally friendly EOR technologies is inline with long-term regulatory requirement and is timely as oil production from existing fields is beginning to decline. Moreover, with only 3 of over 20 discovered fields off the coast of Newfoundland currently developed, the conclusions and recommendations may also be valuable in the near future for evaluation of EOR techniques for the remote fields offshore Newfoundland.
Description of the Proposed Paper:
The value of wellness paper is a comprehensive research review that proposes a conceptual model of the costs associated with high and low risk employees on an annual and career model. This model accurately addresses the variables specific to the oil and gas industry including the internal and external factors which must be addressed by the organization prior to engaging in wellness activities. This paper accurately portrays the specific costs by division as well as highlights the effect of wellness on safety as it relates to health as well as regulatory burden and license to operate.
This conceptual model provides the audience with the accurate costs, factors and concerns associated with wellness initiatives in remote environments. Several factors such as senior managements role, medical costs, replacement workers and re-training are relayed to the audience encompassing the full scope of wellness risk as it exists in the offshore.
Results, Observations, and Conclusions:
The value of wellness paper quantifies that a high risk employee can cost a company $125,000 per year if encompassing all high risk factors and up to 2.65 million dollars over the course of a career. This paper concludes that by adopting a wellness culture and controlling for wellness risk the organization can avoid serious costs and gain intangible advantages in regulatory burden, license to operate and brand equity and company loyalty.
Significance of Subject Matter:
Wellness may be a substantial contributer to both HSE and value to an organization. Companies controlling for wellness risk with a comprehensive wellness program will control costs, operational issues such as safety and license to operate as well as retain and maintain employees in a competitive aging job market.
Finn, David William (Memorial University of Newfoundland and Labrador)
Atlantic Canada has seen the successful development of four major offshore projects in a technically-challenging frontier environment with high discovery and development costs. The response to the challenges of ice and a harsh operating environment have contributed to the growth of a significant R&D and engineering consulting capacity that is now being applied to projects in arctic, sub-arctic and other ice-covered regions. Although significant investment is being applied globally towards petroleum resource development in these environments, considerable technical challenges remain. A concerted R&D effort will be required to enable economic development of these resources. With the scarcity of arctic engineering and related capacity in the global R&D/engineering community, collaboration can minimize redundant research effort and share technology development risks and costs. This paper will present a review of some of the "arctic?? R&D capabilities and activities in Atlantic Canada, including ongoing and recently completed projects.
The International Energy Agency's World Energy Outlook 2008 reference scenario projects a 45% increase in global energy demand by 2030, with hydrocarbons accounting for 80% of supply (International Energy Agency, 2008)—the world still faces a "fossil energy future??. This demand will be largely met in three ways: improved recovery from currently producing reservoirs; the development of known but previously uneconomic or low quality reserves such as shale gas and oil sands; and the discovery and exploitation of new resources in remote regions, including deep water and/or harsh environments such as the arctic.
The recently-released US Geological Survey assessment of circum-arctic resources estimates that the area north of the Arctic Circle contains 1669 trillion cubic feet of natural gas, 90 billion barrels of oil and 44 billion barrels of natural gas liquids (US Geological Survey, 2008), equivalent to twice the reserves of Canada's oil sands. It is further estimated that 84% of these resources lie in offshore basins. The resources of sub-arctic regions with arctic-like engineering challenges like the Caspian Sea, Sakhalin Island, and the Labrador Shelf are not included in this assessment. The cost of exploration, drilling and transportation in these areas will make economic development challenging, and the development of new technologies and engineering solutions is central to reducing costs and enabling the safe and environmentally-sound development of these resources.
Many of the challenges facing northern offshore development are already found on Canada's eastern frontier: sea ice and icebergs, cold temperatures, and severe winds and waves. The threat of iceberg scouring to the integrity of any pipeline built on the Grand Banks of Newfoundland, for example, has made the development of the 4.5 trillion cubic feet (tcf ) of proven gas reserves there problematic, and perhaps uneconomic with current technology. Research and technology development that delivers new ideas, improved technology and improved economics in this environment will in some cases be directly applicable to arctic and sub-arctic regions.