Layer | Fill | Outline |
---|
Map layers
Theme | Visible | Selectable | Appearance | Zoom Range (now: 0) |
---|
Fill | Stroke |
---|---|
Collaborating Authors
Reservoir Characterization
Unexpected Natures of CO2 Hydrate Membrane In Saturated Water: An Explanation By the Free Water Molecule Model
Aya, L. (Maritime Research Institute) | gamane, K. (Maritime Research Institute) | Kojima, R. (Maritime Research Institute) | Yamamoto, T. (University of Tsukuba) | Nariai, H. (University of Tsukuba)
ABSTRACT Basing on the "free water molecules" to be defined by the water .~. molecules that can dissolve more guest molecules (solute), it is well explained that the deformation of hydrate membrane observed in sub-saturated conditions when stressed is not the usual elastic or plastic deformation but should be the rebuild of hydrate. This model can also explain why the hydrate membrane in saturated water with CO2, where no free water molecules exist, behaves so brittle that it does not deform until the stress reaches its strength and the membrane breaks abruptly. INTRODUCTION Because liquid CO2 forms hydrate deeper than 500 m (north Pacific) or 900 m depth (north Atlantic), various kinds of properties related to the CO2 hydrate to evaluate the CO2 ocean sequestration methods as the ways to mitigate the global warming have been measured in the last decade. Among those properties, several phenomena are difficult to be explained from the bases of conventional knowledge. For example, the membrane strength has a sharp peak just below the dissociation temperature (Yamane et al, 1998). Another abnormal phenomenon found recently is that the hydrate membrane in saturated water with CO2 shows not only high peak of strength but also no deformation until the stress reaches its strength, although it shows a large deformation in sub-saturated water when stressed and rather weak strength. In order to explain quantitatively the latter abnormality, the authors proposed a "free water molecule model" in which free water molecules are defined by water molecules i that can dissolve the guest molecules more (Yamane et al., 2000). This paper deals with the explanation on the brittle nature of CO2 hydrate in saturated water and a new data to support the free water molecule model.
- Well Completion > Completion Installation and Operations (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management (1.00)
- Facilities Design, Construction and Operation > Flow Assurance > Hydrates (0.90)
ABSTRACT Obtaining very high resolution seismic images of sediments near the sea floor in deep water is fraught with problems. The conventional approach has been to tow a subbottom profiler near the bottom but, if the water depth is a kilometre or more, vessel speed and manoeuverability are so restricted that it becomes more economical to mount the profiler on an autonomous underwater vehicle. Either way, the survey would be expensive. Moreover, in depths of a kilometre or more, source energy levels are so restricted that the depth of subbottom penetration is limited to a few tens of metres. A research program at the University of Mississippi has been investigating ways of improving seismic resolution while achieving significant penetration and has obtained some remarkable results in the Gulf of Mexico. Deploying a commercial watergun just below the surface of the water and towing a single-channel hydrophone array at a few hundred metres depth, the program has demonstrated that, in a thousand metres of water, sea-floor resolutions of tens of centimetres and penetration of hundreds of metres can be achieved. Vessel speeds were typically 2โ4 knots but it is likely that higher speeds are possible. The demonstrated results were achieved by combining rapid digitization with state-of-the-art signal processing. Processing was done on a desktop computer and easily could have been done on board ship. The method is discussed and illustrated by examples of both raw and processed data. INTRODUCTION Reflection seismic profiling has been used throughout most of the 20 th century to map deep geologic formations. The method was revolutionized in the late 1950s and early 1960s when digital technology was applied to petroleum exploration. Three decades later digital seismic profiling was being used to image shallow formations for engineering and environmental purposes.
- North America > United States > Louisiana (0.30)
- North America > United States > Mississippi (0.26)
- Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)
- Data Science & Engineering Analytics (1.00)
ABSTRACT The possibility of designing and developing a remote, multi sensor, monitoring station for long term investigation and research of the near-sea-floor hydrocarbon system within the hydrate stability zone of the northern Gulf of Mexico has been discussed for some years. A program was initiated in 1999 to design and assemble a station which will monitor physical and chemical parameters of the sea water and sea-floor sediments on a more-orless continuous basis over an extended period of time. It is planned that an operational station will be installed in at least a thousand meters of water by 2004. The heart of the station will be a net of vertical arrays of sensors. Each array will occupy the lower portion of the water column and a hole bored into the sea floor. Sensors will include hydrophones to record compression waves, thermistors to measure temperature within the water and the sediment, and optic fibers connected to an optical spectrometer to identify and quantify hydrocarbon gases. The lowermost sensor of each array will be a three-component accelerometer pushed into the sediments at the bottom of the hole to record compression and shear waves. Peripheral sensors will include a sea-floor positioning system and an acoustic doppler current profiler. Also, if sufficient electrical power is available, several video systems with pan and tilt capability will be installed. The video images would be posted on a web site in near-to-real time and made available for educational and public outreach purposes. The most likely scenario is that, at first, the data will be recorded on the sea floor and periodically downloaded by an underwater vehicle. Eventually, the station will be connected via optic fiber to a surface structure, such as an oil platform, and the data transmitted in near-to-real time to a shore facility at the Stennis Space Center.
- North America > United States > Mississippi (0.49)
- North America > United States > Texas (0.47)
- Geology > Structural Geology > Tectonics (1.00)
- Geology > Geological Subdiscipline (0.94)
- Government > Regional Government > North America Government > United States Government (1.00)
- Energy > Oil & Gas > Upstream (1.00)
- North America > United States > Gulf of Mexico > Central GOM > West Gulf Coast Tertiary Basin > Green Canyon > Block 52 > Marquette Field (0.93)
- North America > Canada > Alberta > Joliet Field > Bonavista Joliet 10-31-25-7 Well (0.93)
ABSTRACT The paper deals with design criteria which enable to adopt rational solutions when designing oil-and-gas field platforms meant to be operated under action of ice, wave and wind loads in regions with high seismic activity. It presents an approach for designing such facilities and designs of offshore ice-resistant platforms for oil-and-gas production. INTRODUCTION At present Russia actively explores and develops its offshore oiland- gas fields. A specific feature of Russian shelf is severe naturaland- climatic conditions and complex hydrological nature of seas in areas of hydrocarbon deposits. Most important are wave, ice and seismic conditions that requires a special approach and architectural-and-structural solutions when designing facilities for the above regions. DESIGN PROBLEMS OF OFFSHORE PLATFORMS FOR REGIONS WITH HIGH SEISMIC ACTMTY A lot of offshore facilities installed on seabed are known (Mirzoev 1992: Dowson 1986; API RP 2T 1997) such as gravity type- held on soil by ballast, pilled- on pile foundation, and pileand- gravity type. Continuous structures (steel or reinforced concrete) constructed of floors, which form a tight contour, positively withstand action of ice fields transferring their forces to soil. However, if sea depth is more than 60โ80 m, platforms of such type become bulky and metal-consuming, and their cost increases as a function of depth in the third power. In addition, a larger amount of ballast is required to provide the stability of gravity platforms in seismic regions, that along with increase in pressure caused by ice loads can result in an unacceptable collapse pressure on soil. It is also obvious that platforms with supports on seabed are not reliable under conditions of high seismicity. Much less sensitive to seismic action are platforms on floating base with tension links anchored by gravity anchors or pile anchors.
- Europe > Russia (0.49)
- North America > United States > Colorado > Cheyenne County (0.25)
- Reservoir Description and Dynamics > Reservoir Characterization (0.75)
- Facilities Design, Construction and Operation > Offshore Facilities and Subsea Systems (0.52)
- Well Drilling (0.49)
Summary of Five Years' Field Test On Mechanical Properties
Ushikoshi, Juntaro (Mitsui Engineering & Shipbuilding Co., Ltd.) | Kamio, Zenji (Mitsui Engineering & Shipbuilding Co., Ltd.) | Matsushita, Hisao (Nippon Kaiji Kyokai) | Sakai, Masafumi (Taisei Corporation) | Takeuchi, Takahiro (Hachinohe Institute of Technology) | Terashima, Takashi (Pacific Consultants Co., Ltd.) | Akagawa, Satoshi (Hokkaido University) | Nakazawa, Naoko (Forest Works Inc.) | Saeki, Hiroshi (Hokkaido University)
ABSTRACT In Notoro Lagoon (Lat. 44.05 N, Long. 144.10 E), Hokkaido, Japan, Japan Ocean Industries Association,(JOIA) conducted indentation tests using a vertical model structure to acquire basic data for determination of scale effect on ice loads. The test program was conducted in January and February, from 1996 to 2000. During this field test, mechanical strength and physical properties of the first-year sea ice were also measured. Especially, mean values and standard deviation of compressive strength were obtained for each of the five years. This report attempts to correlate the compressive strength at a temperature of around -30(2 with the physical properties of the ice. The maximum compressive strength expected under probability distribution of 99.7% was estimated to be or below 4 MPa. The compressive strength was found to be affected by the crystal structure and the strength of crystal structure itself was recognized as; snow ice < columnar ice < granular ice. 1. Introduction JOIA conducted an indentation test program using a vertical model structure in order to acquire data for determination of scale effect on ice loads. This was implemented in January and February for the five years from 1996 to 2000 in Notoro Lagoon (Lat. 44.05 N, Long. 144.10 E), Hokkaido. While the test was taking place, the mechanical properties (compressive strength, bending strength) and physical properties (density, salinity) of the first-year sea ice sheet were measured. The compression tests were conducted with an ice temperature around-3ยฐC, similar to that of the ice sheet during the indentation tests. There are many experimental data conducted below an ice temperature of-5ยฐC, including the research by Saeki et a1.(1985) but experimental data around-30(2; are scarce. The range of deviations of compressive strength of sea ice in Notoro Lagoon roughly agrees with that of sea ice in Lake Saroma measured by Saeki et al (1985).
- Well Drilling > Wellbore Design > Wellbore integrity (0.71)
- Reservoir Description and Dynamics > Reservoir Characterization (0.71)
ABSTRACT A numerical scheme was developed to solve the unsteady, twodimensional Navier-Stokes equations and the exact free surface boundary conditions for simulating the propagation of a solitary wave over rigid sand ripples. A piston-type wavemaker was incorporated in the computational domain to generate periodic and solitary waves as the incident waves. A boundary-fitted coordinate system was used in this model. One of our main results showed that as a solitary wave passes over rigid sand ripples, the fluid particles near the bed are lifted up by the primary vortices induced at the lee side of the sand ripple crest and are transported to the opposite direction of the wave. This is different from what occurs in the case of periodic waves, where the fluid particles are transported in the direction of the waves. INTRODUCTION The flow field on the sand ripples has frequently been studied in an oscillatory flow field. Earlier, Horikawa and Watanabe (1968) used the hydrogen bubble technique to measure the velocity distributions in oscillatory boundary layer over artificial ripples. Du Toit and Sleath (1981) employed laser Doppler velocimetry to measure the flow fields near the crest and trough sections of a wavy wall and showed that a significant increase in the turbulent intensity was induced by the vortices. Sato et al. (1984) described the overall velocity vectors near a wave boundary using a hot-film velocimeter. Sato et al. (1987) further performed these experiments using a laser Doppler velocimeter and obtained the spatial distributions of the Reynolds stress, the eddy viscosity, and the characteristics of the turbulent energy production and dissipation rate in the boundary layer. Similar measurements were also performed by Ikeda et al. (1991) and found that the generation of the Reynolds stress is limited within the vortices and the associated eddy viscosity showed a sinusoidal variation.
- Reservoir Description and Dynamics > Reservoir Characterization (0.48)
- Data Science & Engineering Analytics > Information Management and Systems (0.46)
ABSTRACT This study is to investigate, experimentally and numerically, wave=induced flow inside and around a porous structure. Laboratory experiments were conducted to visualize the wave-induced flow field. Numerical simulations were also performed for investigation of the flow and its governing physical quantities. The calculated wave height distribution is confirmed in good agreement with experimental results. Flow passing through the permeable structure is also confirmed in both experiments and computations. Moreover, it is found that the flow near the corner can play an important role on overall flow field inside and around the structure. Introduction It is well known that the microorganisms live on the surface of rubbles of rubble mound breakwater and form biofilm. This biofilm is also understood to contribute in natural purification of water by biological processes. Recently, the field experiments have been conducted to confirm the water purification function of the biofitm formed on the surface of rubbles of breakwater (Tsuji, 1994; Fujii, 1995; Miyaoka, 1995). Based on the results obtained from a series of field experiment, the water quality was improved when the number of microorganisms in the biofilm increases. Thus, the porous structure is expected to have water purification function due to microorganisms living there. The sea area inside the basin of a port is usually a semi-closed area and water exchange between inside and outside of the basin is not active. Moreover, it is common that there is a river or a canal in the port that transfer the wastewater into the basin. That's why the water quality is not good in port. Considering the facts mentioned above, the structure like a perforated caisson breakwater filled with rubbles should be a suitable structure having both wave controlling function and water purification function.
- Health, Safety, Environment & Sustainability > Environment (0.74)
- Reservoir Description and Dynamics > Reservoir Characterization (0.62)
ABSTRACT A study was undertaken to determine if oblique incidence ultrasonic C-scans could predict changes in the tensile properties of carbon-epoxy laminates that had been subjected to low level impacts. Angle-ply laminates were manufactured to provide roughly a 3:1 ratio of longitudinal-to-transverse extensional stiffness. The specimens were divided into two groups for impacting, a delamination group and a rigid group. After impacting, each specimen underwent a normal incidence C-scan and an oblique incidence C-scan using a focusing transducer to reduce beam spread. The normal incidence scan was used to map the damage area and the oblique incidence scan was used to quantify the changes in extensional stiffness. Tensile tests were performed on each specimen and strength, extensional stiffness, and Poisson's ratios were determined. A comparison of the ultrasonic data with the tensile test data reveals that the variations in mechanical properties were too small and unmeasurable for the damage levels and types used in this study. INTRODUCTION Composite materials, especially laminated composites, have generated much interest in recent years and for good reason. These composites have high strength-to-weight and high stiffness-to-weight ratios, thus lending themselves to applications where weight is a premium, such as automobiles, mass transit, and aerospace. In addition laminated composites can be specifically designed beforehand for the intended loads and/or deflections that will be seen in service. This last characteristic provides the engineer the rare opportunity of optimizing the design provided he or she knows what the design constraints are. One aspect of composite use that has always initiated debate is with damage assessment and evaluation. The indentation could be from a tool drop, or a hail strike, or from flying debris, but the impact was not sufficient to visually break up the surface.
- Materials (0.86)
- Energy > Oil & Gas > Upstream (0.83)
- Transportation (0.74)
Damages Due to the Eastern Marmara Earthquake (EME) At Port Structures
Yuksel, Y. (Yildiz Technical University) | รevik, E. (Yildiz Technical University) | รelikoglu, Y. (Yildiz Technical University) | Bostan, T. (Yildiz Technical University) | รzmen, H.I. (Ports and Airports Construction) | รzgรผiven, O. (Ports and Airports Construction)
ABSTRACT Lzmit Bay is located at the eastern part of Marmara Sea. It is approximately 50 km length. On the 17th of August (EME), an earthquake of 7.4 magnitudes with the epicenter at the southeastern corner of the Izmit Bay caused heavy damages to the port structures. This paper summarizes type of damages recorded at different type of infrastructures such as wharfs. Especially, Derince Port is given as an example in this paper. The port includes 500m of block type quay wall at 5m to 10m water depths, 900m long piled and sheet piled quays. The port area (80.000m 2) behind the quay structures generally composed of fill, experienced a settlement of 70 cm due to liquefaction. Derince Port receives about 600 ships/year loading about two million tons/year of general cargoes. Containers are handled by general-purpose shore crane of 35 tons capacity. One of the wharfs is used for Ro-Ro operations. Another example is a fishery port. The breakwater that is 230m length also suffered due to settlement in the port. However, the second earthquake is experienced in Marmara Sea near |stanbul. There is an important port, which is called Haydarpasa. Hence a scenario will be given in this paper for Haydarpasa Port, if the next segment to rupture to the west of |zmit near |stanbul because Marmara Sea stress increased up to 5 bars. INTRODUCTION Turkey has had a long history of large earthquakes that often occur in progressive adjacent earthquakes. The North Anatolian Fault Zone (NAFZ) is a major fracture that marks the boundary between the Anatolian plate and the larger Eurasian continental block. Northward movement of Arabian Plate causes stress accumulation along the NAFZ, and this compression regime forces Anatolian Plate to escape westward at a rate of-24 mm per year (Stein et al., 1997).
Study On the Seismic Response of a Semi-Submerged Bridge Including the Hydrodynamic Force
Ueda, Shigeru (Tottori University) | Kihara, Kazuyoshi (Mitsubishi Heavy Industries Ltd.) | Inoue, Koichi (Mitsubishi Heavy Industries Ltd.) | Hirai, Jun (Mitsubishi Heavy Industries Ltd.) | Ikesue, Shunichi (Mitsubishi Heavy Industries Ltd.)
ABSTRACT Authors have proposed a semi-submerged bridge for the access to a man-made land. In this study, for the purpose of investigating characteristics of the fluid force on this bridge, two kinds of underwater vibration test and analysis were carried out. The estimating method of fluid forces has been established by using the result of tests. And the measured result of seimic response showed that the seismic response analysis method with estimated fluid forces could estimate the seismic response of this bridge properly. Introduction Recently in Japan, much effort is concentrated to reclamation of offshore region for construction of artificial islands and accordingly a bridge is required as the means of connection between the island and proper land or between the islands each. In the case of normal bridge construction in such a reclaimed ground, dead load for the ground is so huge that the ground has to be strengthened and it costs too much. In order to reduce the load of bridge's weight to the ground, authors have suggested the application of the "Semi-Submerged-type Bridge" instead of the conventional ones. Fignre.1 shows the imaging perspective of the settlement of semi-submerged-type bridge. The proportion of this bridge is just like the normal arch bridge but designed up side down, so that some portion of the structure goes under water completely, and then the buoyancy for the submerged portion supports a part of the weight of whole structure so that not only the load for the ground but also the section of members itself placed under water is able to be reduced economically. As for the usual floating bridge, since whole the weight is cancelled by buoyancy of water and not supported rigidly at all, it sometimes shows the critical motion for the tide or wave of water.