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ABSTRACT The stability and lives extension of marine pipes are important in coastal engineering and the factors that influence the pipelines are corresponding to the coastal environment. To stabilize the pipes, blocks are a good solution and they are widely utilized in the engineering field. In this study, marine pipes are sited 0.5 meters higher than the sea bed and attached with blocks. With 1 m/s currents and sea bed which size of sand is 0.2 mm, we calculate the force load on marine pipes to analyze the relation among currents, change of sea bed and the structure including a marine pipe with blocks. A three-dimensional computational fluid dynamics code, FLOW-3D, solves Navier-Stokes type equations embedded with turbulence closure models is used. RNG model is utilized to solve turbulence calculation. Velocity, force load, and turbulent characteristics which are inconvenient to measure in the field are simulated and investigated and the drag coefficients under various situations are computed. Moreover, the interactions among current, sediment flushing and marine pipes with blocks are also discussed. The influences on the marine pipes caused by the distance between blocks are concluded and regressed for appropriate design. With proper prediction of impact on marine pipes and sediment flushing at sea bed, the stability and lives extension of sea pipes are expected to be improved in the future. INTRODUCTION Pipelines are commonly used in the marine engineering, like taking cooling water from the sea to cool down the facilities and then discharging the effluent back to the environment. Since the pipelines play such an important role, they have become one of the significant concerns in application of engineering field, like Zhao et al. (2016) study the influences of pore pressure accumulations around the buried pipeline in the seabed and protected in trench layer with partial back fills. Chiew et al. (1990) and Sumer et al. (2002) also studied the souring situation around the pipeline. Tom et al. (2018) concluded that sediment transportation is related to the ratio of oscillation amplitude to cylinder diameter which is less than 12.
- North America > United States (0.68)
- Asia (0.68)
- Europe (0.47)
Abstract The objective of this paper is to derive representative vertical extreme current profiles for a location offshore Borneo continental shelf using statistical methods. Firstly, 95th percentile was used on one-year through the water column current measurements in 140 m of water to identify extreme current profiles. Principal Component Analysis (PCA) was then applied to the extremes to retain fundamental modes of the current dataset. The statistical approach was followed by K-means clustering analysis to objectively group the extreme current profiles. Lastly, actual weather and sea state conditions are examined to validate and explain each extreme current profile. Extreme currents are typically observed during the Northeast monsoon in South China Sea (boreal winter). From the statistical analysis, there are two prominent ocean current profiles observed at the location, (1) sheared profile with strong surface currents and (2) mid-depth current maxima. Type 1 profile is typically observed during strong winds, which lead to the formation of a wind-driven sheared profile with maxima at the surface. In contrast, Type 2 current profile has relatively weak near sea surface currents, while strong currents are observed at 60-100 m water depth. This profile is accompanied by a formation of mixing layer within a thermocline region and might be associated with the formation of basin-wide Kelvin wave in response to north-easterly monsoon.
Target-oriented time-lapse waveform inversion using redatumed data: Feasibility and robustness
Li, Yuanyuan (King Abdullah University of Science and Technology (KAUST)) | Guo, Qiang (King Abdullah University of Science and Technology (KAUST)) | Alkhalifah, Tariq (King Abdullah University of Science and Technology (KAUST)) | Kazei, Vladimir (King Abdullah University of Science and Technology (KAUST))
Seismic monitoring of the changes in the subsurface induced by various types of injections into reservoirs is important, yet challenging. Time-lapse waveform inversion can retrieve quantitative estimates of subsurface property changes. Considering that property changes usually occur in a limited region rather than the whole subsurface, we present a target-oriented time-lapse waveform inversion method, which allows for dynamic monitoring of the target of interest. We employ a redatuming technique to produce virtual data at a desired datum level for the target-oriented inversion. Given the redatumed time-lapse data, the property changes can be quantitatively estimated from the data difference for the virtual survey using a double-difference waveform inversion (DDWI). In the numerical examples, the dependence of the inversion performance on the quality of overburden model and its robustness to nonrepeatable acquisition survey and random noise is investigated. The numerical results demonstrate that the inversion method is capable of recovering the time-lapse changes reasonably well under some challenging circumstances. We will show field data examples at the conference. Presentation Date: Wednesday, October 14, 2020 Session Start Time: 9:20 AM Presentation Time: 11:25 AM Location: Poster Station 2 Presentation Type: Poster
ABSTRACT The process of water intake in power engineering is discussed in this study. Preventing objects inserted into the intakes from destroying the mechanism and organisms drawn into the pipes from injuring themselves and less head loss generated in water intake are both important issues to make sure water intake work smoothly. Intake heads in this study are in different geometry with those in the past and they are attached with pipes. There are six present intake pipes set on the intake pipe at its upstream and a pump is set at the downstream of the pipe. There are full holes in the intake pipes which are surrounded by screens and the water flows into the pipe through the screens and holes. With all these designs, water flowing into the pipe is able to be perceived. A three-dimensional computational fluid dynamics software, FLOW-3D, solves Navier-Stokes type equations embedded with various turbulence closure models and the mesh convergence is utilized in the paper. RANS equations are solved with the standard ฮบ-ฮต turbulence model and the volume of fluid method is applied to track the water surface elevation. Most water flowing into the pipes from the intake pipe which is the nearest one to the pump station is observed in the modeling results at six intake pipes. Amount of flow through the intake pipes gradually decreases from the one nearest to the pump to the one farthest to the pump. The velocity field shows the flows are not nearly horizontally flow into porous head. Actually the intake head is like a single point source and the flow concentrated to the intake head. In this study we also try to establish a formula by simulate many different size and number of intake. The relation between head loss coefficient and numbers and sizes of intake pipes are investigated and concluded as regression analysis for further application in engineering field. INTRODUCTION Lots of sea water is needed for the power plants to cool down the facilities. The sea water is flowing into the intake heads, through the pipes and entering the power plant. Intake heads used in the past are set with foundations and unable to be portable with pipes. Intake heads in this study are in different geometry with those in the past. They are set on the pipes and movable with pipes which is really convenient for engineering application.
- Asia (0.47)
- North America > United States (0.29)
How Organic Carbon Content and Thermal Maturity Affect Acoustic Properties (and Ultimately Seismic Response) in a Shale Gas/Oil Formation: Woodford Shale, Permian Basin
Harris, Nicholas B. (University of Alberta) | Moghadam, Al (Northern Alberta Institute of Technology) | Dong, Tian (China University of Geosciences Wuhan)
Abstract Organic carbon content and thermal maturity are critical to the evaluation of shale gas and shale oil plays, determining the productivity of the formation and type of hydrocarbons that are produced. In this analysis, we demonstrate that these parameters also affect acoustic properties; thus, well logs and potentially seismic data can be inverted to estimate organic richness and maturity. Our study is based on data from two cored wells in the Woodford Formation, Permian Basin, west Texas, that had been previously studied to develop sedimentological and geochemical models for black shale deposition. The KCC 503 well is relatively shallow, and the Woodford Shale here has a maturity of 0.71% Ro, just entering the oil window. The RTC 1 well is relatively deep, and the Woodford in this well has a maturity of 1.48% Ro, in the wet gas window. In our analysis, we link rock composition, including total organic carbon (TOC) content and thermal maturity to data on p-wave (VP) and s-wave (VS) velocities and density and derivative properties including Vp/Vs ratios, impedance, geomechanical parameters including Poisson's Ratio and Young's Modulus and Lamรฉ parameters mu and lambda. We then test whether stratigraphic intervals within the Woodford can be geophysically distinguished and potentially mapped with seismic data. TOC content is reflected in two well logs: gamma ray, which responds to uranium and is in turn linked to organic carbon content; and neutron porosity log, which responds to hydrogen content. Neutron porosity values are higher than core porosities because of the organic carbon content, much higher in the lower maturity KCC 503 well because of the development of a bitumen phase that is no longer present in the higher maturity RTC 1 well due to cracking to hydrocarbons. Gamma ray and neutron porosity are both inversely related to Vp and Vs. In the KCC 503 well, neutron porosity correlates more strongly to these parameters due to the presence of bitumen; in the RTC 1 well, both gamma ray and neutron porosity provide comparably strong correlations. Correlations to impedance are similar. Both gamma ray and neutron porosity predict Young's Modulus but not Poisson's Ratio. Vp, Vs, and impedance increase as a function of thermal maturity. Vp/Vs decreases as a function of thermal maturity, due to the greater increase in Vs compared to Vp, but is not sensitive to TOC in an individual well. Stratigraphic intervals of the Woodford Shale have distinctive acoustic parameters. Vp/Vs ratios distinguish the three main subdivisions: the organic-rich Middle Woodford is characterized by low Vp/Vs ratios in comparison to the Upper (intermediate values) and Lower (high values). Poisson's Ratio values follow similar trends. This suggests that internal units within the Woodford Shale can be mapped with seismic data.
- North America > United States > Oklahoma (1.00)
- North America > United States > Texas > Dawson County (0.24)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (1.00)
- Geology > Petroleum Play Type > Unconventional Play (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Geological Subdiscipline > Geochemistry (1.00)
- Geophysics > Seismic Surveying (1.00)
- Geophysics > Borehole Geophysics (1.00)
- North America > United States > Texas > Permian Basin > Yeso Formation (0.99)
- North America > United States > Texas > Permian Basin > Yates Formation (0.99)
- North America > United States > Texas > Permian Basin > Wolfcamp Formation (0.99)
- (22 more...)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)
- Reservoir Description and Dynamics > Fluid Characterization > Geochemical characterization (1.00)
Continuous Observation of Turbulent Flow near the Hydrothermal Venting Area in the Okinawa Trough, Japan
Furushima, Yasuo (Research and Development Center for Submarine Resources Japan Agency for Marine-Earth Science and Technology) | Higashi, Hironori (Center for Regional Environmental Research National Institute for Environmental Studies) | Fukuhara, Tatsuo (Japan Marine Surveys Association, KANSO Co., Ltd.) | Matsuda, Takeya (Japan Marine Surveys Association, Kokusai Kogyo Co., Ltd.) | Furuichi, Naoki (National Research Institute of Fisheries Engineering / Japan Fisheries Research and Education Agency) | Yamamoto, Hiroyuki (Research and Development Center for Submarine Resources Japan Agency for Marine-Earth Science and Technology) | Fukushima, Tomohiko (Research and Development Center for Submarine Resources Japan Agency for Marine-Earth Science and Technology)
ABSTRACT The aim of this study was to reveal continuous fluctuations in deep-sea turbulent intensity (ฮต: the turbulent energy-dissipation rate) by using expendable vertical microstructure profiler and correlate them with in situ environmental data obtained from the monitoring station installed on the sea floor. The turbulent intensity (ฮต) near the sea bottom changed from 10 to 10 (W kg) and the maximum ฮต value was observed from a flood tide between ebb tides. Moreover, the ฮต was relatively strong around the bottom, and water temperature increased to 0.1โ0.2 ยฐC. INTRODUCTION Recently, developments in submarine-based mining have actively increased throughout the world. Submarine-based mining may negatively affect the surrounding ecosystem and environments as it results in seafloor disturbance, subsequent suspension, diffusion of sediment particles, and redeposition (Furuuchi et al., 2016). Therefore, understanding the basics of fluid structure, such as the current velocity in the bottom mixed layer (BML) and the intensity of vertical mixing (turbulent flow intensity), is important for assessing the effects of such mining on the environment. In particular, the development of the BML near the sea floor is one of the most important environmental factors to consider. Studies have carried out current measurements of the deep-sea flow around the sea floor near hydrothermal fields in the Okinawa Trough (Furushima et al., 2015, 2016, 2018). Furushima et al. (2015, 2018) successfully recovered deep-sea current data of the layers between the seafloor and 40โ60 m above the seafloor for each observation point by using the acoustic Doppler current profiler (ADCP). These results almost corresponded with the thickness of the BML obtained from a large-eddy simulation (LES) model (Furuichi et al., 2014, 2016). Furthermore, the measurement results obtained at the Hatoma Knoll and Iheya North fields showed a remarkably interesting fluctuation, and during a period of approximately 3 h, the range for the depths at which the currents were successfully recorded increased in a pulse form up to the upper layer at โผ120 m, allowing measurements in almost all of the layers (Furushima and Yamamoto, 2015; Furushima et al., 2016, 2018). Furushima et al. (2016, 2018) indicted that the period of this pulse corresponded to the shift from an ebb tide to a high tide and the measurement results of the flow that appeared in the pulse form may indicate the fluctuation of the blowout of hydrothermal water.
- Asia > Japan (1.00)
- Asia > Middle East > Qatar > Arabian Gulf (0.25)
- Asia > Middle East > Qatar > Arabian Gulf > Rub' al Khali Basin > North Field > Laffan Formation (0.99)
- Asia > Japan > Okinawa Field (0.97)
ABSTRACT Japan Deep-sea Impact Experiment (JET) is an in situ experiment aimed at evaluating environmental impacts and monitoring the recovery process arising from manganese nodule mining. The experiment has been done in 1994, and monitoring surveys have continued to 1996. However, due to short monitoring period, understandings of recovery process was insufficient. While 17โ18 years after, the Deep Ocean Resources Development Co., Ltd revisited the site and surveyed the environmental condition. As a result, the environmental impacts, which was recognized immediately after and one year after the benthic disturbance were not recognized after 17โ18 years. The present authors show the result and discuss the significance of long term monitoring survey. INTRODUCTION With metal resources being run short, there has been increased attention given to the development of seabed mineral resources. At the same time, environmental impact assessments (EIA) have come to be required to be more rigorous than ever before (Fukushima and Nishijima, 2017). However, since there is no actual development being carried out, it's not easy to correctly assess the environmental impact. In 1972, the Lamont Doherty Geological Survey undertook a desk study in regard to the environmental impact of deep-sea mining (Ozturgut et al., 1997). Then the National Oceanic and Atmospheric Administration (NOAA) conducted a large-scale baseline study (DOMES: 1976โ1980) (Ozturgut et al, 1978; Ozturgut, 1981); the results of that survey were used to list the factors that were thought to be potentially adverse impact to an environment in Programmatic Environmental Impact Statement (PEIS) (NOAA, 1980). The following year, NOAA narrowed the list down to two possibilities that were thought to be particularly serious (Marine Environmental Research Plan 1981โ85) (NRC, 1984). The first possibility was that miner or collector could impact benthic organism directly (physically) while the other was that the resuspension and resettlement of marine sediment accompanying the operation of those machines could indirectly impact on benthic organisms in surrounding areas. Since then, NOAA has been tackling verification experiments such as the Acute Mortality Experiment (1987) (Smith et al., 1988) and QUAGMIRE Expedition II (1990) (Wilson, 1990), which are specific to the sediment's resuspension and resettlement (hereinafter, benthic disturbance). Then, in 1992, a new device aiming to create benthic disturbances (hereinafter, the disturber) was developed and the creation of benthic disturbance in the Clarion-Clipperton Fracture Zone (CCZ) was successful (Trueblood, 1993). This is known as the Benthic Impact Experiment (BIE) (1992). Subsequently, the same device was used to carry out the Japan Deep-sea Impact Experiment (JET) (1994) and IOM'BIE (1995) in the CCZ as well as the Indian Deep-sea Environment Experiment (INDEX) (1997) in the Indian Ocean (hereinafter, referred to as the BIE-type experiment) (Fukushima, 1994; Kotlinski, 1995; Sharma et al, 2000). As just described, until now, there has been a step-by-step consideration including desk studies, background surveys, a listing of potential effects, and the narrowing down of the same, followed by a verification experiment. Through four BIE-type experiments, it was revealed that benthic disturbance adverse effect on benthic organism, at least temporarily. However, the monitoring was discontinued one year later for BIE, two years later for JET, and five years later for IOMBIE, and three years later for INDEX (44 months). Therefore, the duration of the impact remained unknown.
- North America > United States (1.00)
- Asia > Japan > Tลhoku > Fukushima Prefecture > Fukushima (0.48)
- Asia > Japan > Kantล (0.29)
- Research Report > Experimental Study (1.00)
- Research Report > New Finding (0.94)
Abstract Wave breaking is an important phenomenon in coastal protection due to the dissipated energy. Such phenomenon is also responsible for the nearshore sediment transport caused by the generated turbulence and currents. The aim of this work is to apply two different CFD numerical codes to simulate accurately spilling and plunging wave breaking. Numerically simulated free surface elevations and velocities were compared with experimental data and also with numerical results published elsewhere. In spite of the differences that were found between the performances of the numerical models, they reproduced well the experimental data. Introduction Depth induced wave breaking is a rather complex process usually associated with energy dissipation, splash, air entrainment and an enhancement of turbulence. The type of wave breaking is of the utmost importance, especially because it determines the level of energy dissipation. On the other hand, the location of the wave breaking and the air entrained are crucial for, amongst other effects, the associated sediment transport and for the stability of maritime structures. The wave breaking dynamics have been the subject of a number of studies. Svendsen (1987) analyzed the turbulence in the surf zone and the energy dissipation. Rivero and Arcilla (1995) developed a formulation to evaluate the vertical wave shear stress distribution in the surf zone. Recently, Zou et al. (2006) proposed a new approach to describe the vertical distribution of the wave shear stress in a variable water depth with breaking and non-breaking wave conditions. The theoretical predictions were compared with field measurements provided by Wilson et al. (2014).
Summary We present a study on the lithofacies characterization of the Marcellus shale gas formation. The data set consists of nine vertical wells, each with petrophysical logs of composition (quartz, calcite, clay, and total organic carbon) and elastic parameters (density, and compressional and shear velocity) along four geological sections, i.e., the Mahatango Formation, and the Upper Marcellus, the Cherry Valley carbonate formation, and the Lower Marcellus members of the Marcellus Formation. We successfully used a new mathematical technique known as Topological Data Analysis (TDA) to identify lithofacies groups in the vertical profiles that possess well-defined marginal distributions in the velocity-density plane.
- North America > United States > West Virginia (0.69)
- North America > United States > Virginia (0.69)
- North America > United States > Pennsylvania (0.69)
- (3 more...)
- Geology > Mineral > Silicate (0.58)
- Geology > Petroleum Play Type > Unconventional Play > Shale Play > Shale Gas Play (0.49)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock (0.37)
Comparative Study on Role of Schmidt Number in Suspension Modeling
Son, Minwoo (Chungnam National University) | Byun, Ji-sun (Chungnam National University) | Chung, Eun-Sung (Seoul National University of Science & Technology) | Han, Jin-Tae (Korea Institute of Civil Engineering & Building Technology)
Abstract This study aims to investigate the effects of Schmidt number on calculation of sediment suspension. Schmidt number is a constant for turbulent diffusion and turbulence intensity. Two different types of sediment (the cohesive and the non-cohesive) are tested using one dimensional vertical numerical model. Two simulation conditions (oscillatory flow and steady current) are applied to numerical experiments. It is found in this study that Schmidt number has different effects on cohesive and non-cohesive sediments.