The Experts below are selected from a list of 502704 Experts worldwide ranked by ideXlab platform
Satoru Suzuki - One of the best experts on this subject based on the ideXlab platform.
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risk assessment of oxytetracycline in Water Phase to major sediment bacterial community a Water sediment microcosm study
Environmental Toxicology and Pharmacology, 2013Co-Authors: Natsumi Suga, Satoru SuzukiAbstract:Abstract With an increasing need for assessing the risk of aquaculture antibiotics, there has been growing interest in their fate and effect on sedimentary bacteria. Here we show the risk assessment for oxytetracycline (OTC) use in seaWater and its subsequent transfer to sediment, and illustrate that the sediment bacterial community was stable against OTC at dosed concentrations. Water-sediment microcosm experiments were conducted to simulate quiescent aquaculture conditions. The sorption coefficient (Kd) was 12.3–44.2 mL/g, which is lower than the previous reports employing vigorous mixing. In a denaturing gradient gel electrophoresis (DGGE) analysis, the addition of OTC at 50 μg/L into the Water Phase had little effect on the major sediment bacterial community structure. This finding suggests that low concentrations of OTC in the Water Phase – such as those used within many aquaculture operations – do not pose a high risk of causing major changes in environmental sediment bacterial community structures.
Chenhong Hou - One of the best experts on this subject based on the ideXlab platform.
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a fully coupled semi analytical model for effective gas Water Phase permeability during coal bed methane production
Fuel, 2018Co-Authors: Zheng Sun, Juntai Shi, Tao Zhang, Dong Feng, Fengrui Sun, Liang Huang, Chenhong HouAbstract:Abstract Although many breakthrough efforts have been made in recent years, it is still challenging to gain a clear knowledge of the variation regularities of effective gas/Water Phase permeability with the pressure depletion. The reasons behind this phenomenon can be attributed to the coexistence of multiple effects and the transition of the flow behavior at different production stages. To date, the fully-coupled model for effective gas/Water Phase permeability in coal-bed methane (CBM) reservoirs is still lacking and is significantly necessary to be developed. Firstly, the Palmer-Mansoori (PM) model is employed to represent the variation relationship between absolute permeability and pressure. Secondly, after rigorous derivation of the gas–Water two Phase partial differential equations in coal seams, the relationship between pressure and saturation in infinitesimal coal is obtained, which can be solved through an iterative algorithm. Subsequently, combined with the Corey relative permeability model, the relative gas/Water Phase permeability can be described as a function of pressure. Finally, coupling the absolute permeability model and relative permeability model, the effective gas/Water Phase permeability can also be quantified as a function of pressure or saturation. And the reliability and the accuracy of the proposed model is successfully verified through comparisons with experimental data and previous model collected from published literature. Furthermore, on the basis of the proposed semi-analytical model, the effects of critical desorption pressure, gas desorption capacity, stress dependence, and matrix shrinkage on effective permeability are identified. And many implications and direct insights are achieved through the sensitive analysis process. The semi-analytical model, for the first time, incorporates nearly all known mechanisms and can achieve more accurate characterization of effective permeability during the production process. Moreover, due to the concise form and precise feature, the proposed model will serve as a simple, practical and robust tool for the development of CBM reservoirs.
S. M. Hassanizadeh - One of the best experts on this subject based on the ideXlab platform.
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Solute Mass Exchange Between Water Phase and Biofilm for a Single Pore
Transport in Porous Media, 2015Co-Authors: C. Z. Qin, S. M. HassanizadehAbstract:Currently, there are no tractable approaches available for modeling non-equilibrium mass exchange of a solute between Water Phase and biofilm in porous media. The present work contributes to a quantitative description of the mass exchange of a solute over a single pore domain under a wide range of prevailing conditions. First, we developed a semiempirical model for the rate of solute mass exchange between Water Phase and biofilm. Then, extensive microscale simulations in a single pore were conducted. Results were averaged over a single pore domain, in order to determine a tube-scale kinetic rate coefficient as a function of various transport and biofilm properties. We illustrated the dependencies of the coefficient on a number of variables like Péclet number, Damköhler number, and biofilm volume fraction. Based on those results, we developed empirical formulae for the tube-scale mass exchange coefficient as a function of Damköhler number and biofilm volume fraction. Finally, we verified the proposed mass exchange rate against microscale simulations of solute transport in a long capillary tube. Good match was obtained over a wide range of conditions.
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Solute Mass Exchange Between Water Phase and Biofilm for a Single Pore
Transport in Porous Media, 2015Co-Authors: Chaozhong Qin, S. M. HassanizadehAbstract:Currently, there are no tractable approaches available for modeling non-equilibrium mass exchange of a solute between Water Phase and biofilm in porous media. The present work contributes to a quantitative description of the mass exchange of a solute over a single pore domain under a wide range of prevailing conditions. First, we developed a semiempirical model for the rate of solute mass exchange between Water Phase and biofilm. Then, extensive microscale simulations in a single pore were conducted. Results were averaged over a single pore domain, in order to determine a tube-scale kinetic rate coefficient as a function of various transport and biofilm properties. We illustrated the dependencies of the coefficient on a number of variables like Peclet number, Damkohler number, and biofilm volume fraction. Based on those results, we developed empirical formulae for the tube-scale mass exchange coefficient as a function of Damkohler number and biofilm volume fraction. Finally, we verified the proposed mass exchange rate against microscale simulations of solute transport in a long capillary tube. Good match was obtained over a wide range of conditions.
Natsumi Suga - One of the best experts on this subject based on the ideXlab platform.
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risk assessment of oxytetracycline in Water Phase to major sediment bacterial community a Water sediment microcosm study
Environmental Toxicology and Pharmacology, 2013Co-Authors: Natsumi Suga, Satoru SuzukiAbstract:Abstract With an increasing need for assessing the risk of aquaculture antibiotics, there has been growing interest in their fate and effect on sedimentary bacteria. Here we show the risk assessment for oxytetracycline (OTC) use in seaWater and its subsequent transfer to sediment, and illustrate that the sediment bacterial community was stable against OTC at dosed concentrations. Water-sediment microcosm experiments were conducted to simulate quiescent aquaculture conditions. The sorption coefficient (Kd) was 12.3–44.2 mL/g, which is lower than the previous reports employing vigorous mixing. In a denaturing gradient gel electrophoresis (DGGE) analysis, the addition of OTC at 50 μg/L into the Water Phase had little effect on the major sediment bacterial community structure. This finding suggests that low concentrations of OTC in the Water Phase – such as those used within many aquaculture operations – do not pose a high risk of causing major changes in environmental sediment bacterial community structures.
Yili Kang - One of the best experts on this subject based on the ideXlab platform.
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A new method of Water Phase trapping damage evaluation on tight oil reservoirs
Journal of Petroleum Science and Engineering, 2019Co-Authors: Tian Jian, Lijun You, Yili Kang, Pingya Luo, Dujie ZhangAbstract:Abstract Displacement pressure difference and initial Water saturation are two key factors of evaluating Water Phase trapping (WPT) damage under a given reservoir situation. Requiring a high displacement pressure to drive liquid through a tight rock, the conventional method has difficulty in measuring very small liquid flow rates. Besides, it exists a strongly advantageous flow path selectivity phenomenon, causing a situation that the Water existing in those thinner pores cannot be moved effectively. As a result, the irreducible Water saturation is high after oil displacing Water, thus leading to an overestimated oil permeability damage from WPT. This paper would have presented a high back pressure displacement method (HBPD) for the establishment of initial Water saturation and measurement of liquid permeability of core samples from tight oil reservoirs. Then the damage of WPT using this new method was compared with the results obtained by the conventional method. According to the reservoir fluid flow situation, pore pressure and downstream pressure were simulated by the operation of back pressure. Results showed that an average initial Water saturation (Swi) of 46.2% was established by the conventional method. However, the Swi established with the use of this new method was only 29.9%, which was consistent with the results from sealed core data of the reservoir. The oil permeability damage derived from Water Phase trapping was estimated as an average of 37.0% with the conventional method while that of 21.8% by the new method respectively. The conventional method overestimated the damage of Water Phase trapping at 41.4%. Our research appears to have an insight into analyzing oil-Water flow behaviors and investigating the reservoir forming process of tight oil reservoirs.
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Integrated Evaluation of Water Phase Trapping Damage Potential in Tight Gas Reservoirs
All Days, 2009Co-Authors: Lijun You, Yili KangAbstract:Abstract Water Phase trapping is the most vital damage to tight sandstone reservoirs, which is different from Water blocking, and it is a key barrier to improve resource assessment, successful exploration and efficient development operations. It cannot be evaluated by the traditional method evaluating Water blocking. This paper takes example from Daniudi tight gas reservoir in northern Ordos Basin, China. The potential tendency to Water Phase trapping damage is intense by the research on the geology characters such as abnormal low Water saturation, pore structure. The severity of Water trapping in Daniudi gas filed was proved by the experiments of the effects of Water saturation on gas relative permeability, spontaneous imbibition and Phase retention of Water and dill-in fluids. Based on the influence mechanisms of initial Water saturation, reservoir pressure, liquid properties and pore structure on Water Phase trapping, dimensionless Phase trapping coefficient (PTC) was put forward to predict Water Phase trapping damage potential. The saturation and invasion depth of filtrate varying with time around wellbore were simulated, the results show that when there is no filtrate cake on the well wall the Daniudi gas reservoirs, especially P1x2+3 gas reservoir is prone to be damaged by Water trapping to be wrongly evaluated or to be undervalued. In view of the theories and research results, serial measurements to prevent and treat Water Phase trapping are adopted to protect gas reservoirs and P1x2+3 gas reservoirs was detected to become the major pay formation. The practices of gas formation damage control verified the results of evaluation. Introduction The large scale development of tight gas is of profound significance, but the unfavorable geologic status and prone damage greatly limit its development Water Phase trapping is defined as the permeability reduction process of near wellbore reservoirs and fracture faces when Water saturation is from initial Water saturation to irreducible Water saturation and to 100% during the process of well operation (Bennion, 1996). Water Phase trapping induced by drill-in fluids filtration invasion can change the initial reservoir conditions, which hinders evaluation and economic development of reserves (Kang, 2000). Water Phase trapping damage could induce fluid sensitivity damage and aggravate stress sensitivity damage and other damages, which bring tight gas reservoirs one disaster after another (You,2006). Water block neglects the fact that the initial Water saturation of gas reservoir is lower than the irreducible Water saturation in tight gas reservoirs. So Water Phase trapping is difference from Water block, and the evaluation of Water Phase trapping damage cannot use the permeability damage ratio which is often used to evaluate liquid sensitivity and Water block. Bennion (1996) provided the Phase trapping index (APTi), whose basic formulation is based solely upon permeability and initial Water saturation values. This basic formulation is widespread use, but the reservoir pressure, liquid property is not taken into consideration in this basic formulation. The traditional methods such as permeability damage ratio and aqueous Phase trapping index (APTi) have their shortages to precisely predict Water Phase trapping, especially that of low permeable or tight reservoirs. The measurement of permeability damage ratio of tight reservoirs rocks is time consuming, and the measurement error is large. The measurement of permeability damage ratio does not also take consider of the effect of permeability, initial Water saturation, reservoir pressure and rock wettabilty on aqueous trapping. The Phase trapping is a complex process, and is the main damage mechanism to oil and gas reservoirs, especial tight gas reservoirs which have abundant resource and huge development potential and are also a main development objective in these years, so a or serious new evaluation methods is urgent.