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Results
ABSTRACT For the last years several oil and gas fields were discovered on the North-Eastern Sakhalin offshore. Their construction is planned for the nearest future. From November till July water area of this region is covered by thick ice. Characteristics of such ice cover will determine design on selection of platform types and configurations. The results of the multi-year studies focused on fast and drift ice physico-mechanical properties are presented in this paper. The authors have worked out an ice sampling procedure, which help to avoid errors in determination of strength design values. Due to availability of the multi-year data for both cold and mild winters and due to the procedure mentioned above the design values for physicomechanical properties of sea ice in the region under discussion were obtained. INTRODUCTION The presence of a dynamic ice cover complicates development of facilities for the Arctic seas offshore construction. High cost and ecological responsibility of ice-resistant oil and gas producing structures result to strict safety requirements, which depend on reliability of design parameters. A large number of various approaches and methods for obtaining ice load design values account for complexity and insufficient investigation of the ice failure physical process during ice-structure interaction, peculiarities of structure design, unstable and conditional strength characteristics, variability of ice cover properties in various regions, relativelyinsufficient number of experiments, associated with in situ measurements of ice loads on offshore structures. In the case of same initial data the estimation results may vary greatly and complicate practical usage of investigation data (Vershinin, 1988). Multi-year experimental studies of the Sakhalin offshore ice regime were undertaken in order to meet requirements of design works on oil and gas field constructions (Fig.1).
- North America (0.70)
- Asia > Russia > Far Eastern Federal District > Sakhalin Oblast (0.55)
- Research Report > New Finding (0.34)
- Research Report > Experimental Study (0.34)
- Well Drilling > Wellbore Design > Wellbore integrity (0.61)
- Reservoir Description and Dynamics > Reservoir Characterization (0.61)
ABSTRACT The primary goals of NAD (Nansen Arctic Drilling Program) are to understand:the climatic and paleoceanographic evolution of the Arctic region and its effects on global climate, the biosphere and the dynamics of the world ocean and atmosphere; the nature and evolution of the major structural features of the Arctic Ocean Basin and circum-Arctic continental margins. These scientific questions and considerations of present knowledge and available technologies suggest the following strategy and criteria. First, comprehensive regional and detailed site surveys must be completed. Second, coring must be of high quality and should ultimately meet the following specifications: penetration to several hundreds of meters below the seafloor, including approximately 100 meters of rock; continuous hydraulic piston coring; high-resolution well logging; drilling in water depths ranging from 10 meters to 4,000 meters; and environmental protection must be ensured. The primary target areas in a first phase of drilling in the Arctic Ocean are the Yermak Plateau and Chukchi Rise. It is anticipated drilling will commence in 1996 or sooner. INTRODUCTlON There is growing evidence that the polar regions play a key role in the physical processes responsible for global climatic fluctuations; in some circumstances they may be a prime mover of such oscillations. Ice and snow conditions in the Arctic are highly sensitive to climatic variations and significantly impact the climate. Changes in sea-ice extent and thickness profoundly alter the transfer of heat between the ocean and atmosphere. In addition there is widening appreciation of the polar regions as a natural repository of information about past climatic fluctuations and past environmental events causally related to climatic fluctuations. Understanding the causes and consequences of past climate and environmental change in the polar regions is critical to predicting future climates modified by man.
- North America > United States (1.00)
- Europe (1.00)
- North America > Canada > Yukon > Old Crow Basin (0.99)
- North America > Canada > Quebec > Arctic Platform (0.96)
- North America > Canada > Nunavut > Arctic Platform (0.96)
- North America > United States > Alaska > Arctic Ocean (0.89)
- Reservoir Description and Dynamics > Reservoir Characterization (1.00)
- Well Drilling > Well Planning (0.86)
- Health, Safety, Environment & Sustainability > Environment > Climate change (0.69)
ABSTRACT In this paper the potential for progressive failure of a Gravity Base Structure (GBS) founded on a hypothetical soil profile is evaluated. A provision in the Commentary to the Canadian Code for the Design, Construction and Installation of Fixed Offshore Structures advises the undertaking of such an analysis under certain foundation and loading conditions. The ability to study and model the behaviour of a strain softening material is a prerequisite for any progressive failure study. With this objective, a finite element program that has been developed at the University of Alberta, was used to study the overall response of a foundation subjected to GBS loading. The influence of the strength and stiffness parameters of various layers and the depth of embedment of a hypothetical weak layer on the potential for progressive failure were evaluated. The results of this study illustrate the types of analysis required to meet the requirements of the Canadian Code. They also illustrate the importance of a comprehensive site investigation and the need to identify weak and brittle layers embedded in otherwise competent material. INTRODUCTION Gravity Base Structures (GBS), used as production platforms and/or storage tanks at sea, are built at a deep water coastal site and then towed to the immersion point. The stability of these structures is achieved primarily by self-weight as a result of the dimensions and the weight of the reinforced concrete base. Therefore they do not require any anchoring to the sea bottom (I.e Tirant, 1979). The advantage of such an installation procedure is that the installation time is reduced to a minimum (1 or 2 days), compared to fixed platforms on piles. This is very beneficial in hostile environments such as that often encountered off the NE Atlantic Canadian coast.
- Reservoir Description and Dynamics > Reservoir Characterization (0.69)
- Facilities Design, Construction and Operation > Offshore Facilities and Subsea Systems (0.54)
- Well Drilling > Wellhead Design > Wellhead integrity (0.41)
- Health, Safety, Environment & Sustainability > HSSE & Social Responsibility Management > Contingency planning and emergency response (0.41)
ABSTRACT The effects of municipal (sewage) sludge and crude oil on physical and mechanical properties of laboratory prepared marine clays were investigated. Contaminants appeared to influence the development of clay microstructure and thus some of the physical and mechanical properties of sedimented marine clay. A mixture of illite, Ca-montmorlllonite. kaolinite and chlorite minerals constituted the laboratory prepared "marine clay". Among the physical and mechanical properties measured or observed are physico-chemical properties, index properties, microstructure, shear strength, stiffness, permeability and compressibility. The influence of crude oil and sludge on these physical and mechanical properties and the microstructure was evaluated based on criteria such as flocculation. dispersion. agglomeraition and Coulombic forces between the particles and the contaminants. INTRODUCTION The impact of progressive pollution of the world oceans has become an important problem for the researchers to solve. The dumping of pollutants into ocean waters adversely affects the marine environment and the biological environment. Contaminants may influence the development of clay microstructure and subsequently the physical and mechanical properties of the marine sediments. Engineers and Scientists, however know little about such influences·. Most industrial wastes contain varying amounts of petroleum hydrocarbons and heavy metals. These products alter sediment-water equilibrium and influence the depositional process and also the natural physical and chemical changes the sediments undergo after deposition. Petroleum hydrocarbon contamination of ocean sediments may occur through tanker accidents. spills from coastal facilities. offshore petroleum production and natural seepage (Geyer. 1980). Oil components are carried to the bottom by sedimentation. Oil can then penetrate deep into the sediment and remain there for many years after a spill. Municipal or sewage sludge has been one of the heavily ocean disposed wastes. Sewage sludge outfalls into the marine environment can discharge large quantities of heavy metals in both dissolved and particulate forms.
- Geology > Sedimentary Geology > Depositional Environment (1.00)
- Geology > Mineral > Silicate > Phyllosilicate (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Lifecycle > Treatment (0.49)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid selection and formulation (chemistry, properties) (0.50)
- Well Drilling > Drilling Fluids and Materials > Drilling fluid management & disposal (0.50)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics > Flow in porous media (0.35)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (0.35)