Homogeneous methods for ecological applications to the nutrient cycle are analyzed,and the results are presented according to the marine ecology work discussed.To do justice to the explanations,the materials are summa...Homogeneous methods for ecological applications to the nutrient cycle are analyzed,and the results are presented according to the marine ecology work discussed.To do justice to the explanations,the materials are summarized,and the methods are discussed and improved for both interested readers and experts in the field.Both the materials and the methods serve informative and popularizing as well as applicable and interpretive purposes and,in order to achieve the widest possible dissemination,are shared under the strict supervision of the earlier individual publications discussed here.The aeolian syntheses quantify the impact of atmospheric deposition of nutrients in the Western Mediterranean as one-twentieth of the baseline vertical fluxes of organic matter,while estimates for the Eastern Mediterranean reach one-eighth.Possible changes and additions in the global ocean are discussed as well as ecosystem updates and their relevance to the specific orography,hydrology and geochemistry associated with the lower trophodynamic degrees of freedom.Finally,the dynamics of the basins are analyzed,with increasing nutrient inputs leading to a top-down control of net plankton growth in the western basin and to an extremely nutrient-poor state in the eastern basin.展开更多
Source rocks(shales) exhibit different geometric pore types and considerable anisotropy caused by the preferential orientation of the clay and kerogen layers,which is not accounted for in classical rockphysics models....Source rocks(shales) exhibit different geometric pore types and considerable anisotropy caused by the preferential orientation of the clay and kerogen layers,which is not accounted for in classical rockphysics models.Pore geometry can be effectively studied through the aspect ratio,and in this study,we use the aspect ratio to characterize different pore geometries.Then,we consider a pore connectivity index as well as a lamination index associated with these orientations.An inclusion-based theory(differential effective medium and self-consistent approximation) and the Brown-Korringa equations are used in the modeling approach.The results show that the indices as well as the aspect ratio of the connected pores significantly affect the elastic properties.We propose an inversion method to invert these three parameters simultaneously from experimental vertical P-and S-wave velocities using a global optimization algorithm.The method is applied to well log and seismic data from the Longmaxi shale reservoir in southwest China to verify its pre dictive ability.展开更多
In heterogeneous natural gas reservoirs, gas is generally present as small patchlike pockets embedded in the water-saturated host matrix. This type of heterogeneity, also called "patchy saturation", causes s...In heterogeneous natural gas reservoirs, gas is generally present as small patchlike pockets embedded in the water-saturated host matrix. This type of heterogeneity, also called "patchy saturation", causes significant seismic velocity dispersion and attenuation. To establish the relation between seismic response and type of fluids, we designed a rock physics model for carbonates. First, we performed CT scanning and analysis of the fluid distribution in the partially saturated rocks. Then, we predicted the quantitative relation between the wave response at different frequency ranges and the basic lithological properties and pore fluids. A rock physics template was constructed based on thin section analysis of pore structures and seismic inversion. This approach was applied to the limestone gas reservoirs of the right bank block of the Amu Darya River. Based on poststack wave impedance and prestack elastic parameter inversions, the seismic data were used to estimate rock porosity and gas saturation. The model results were in good agreement with the production regime of the wells.展开更多
频域有限差分(finite difference frequency domain,FDFD)方法是地震波场模拟的常用方法,FDFD地震波场模拟的关键之一是构造能有效压制数值频散的FDFD系数。在已有的构造地震波场模拟FDFD系数的方法中,随一个网格内的波长个数变化的自适...频域有限差分(finite difference frequency domain,FDFD)方法是地震波场模拟的常用方法,FDFD地震波场模拟的关键之一是构造能有效压制数值频散的FDFD系数。在已有的构造地震波场模拟FDFD系数的方法中,随一个网格内的波长个数变化的自适应FDFD系数可以最大程度地压制数值频散。目前计算自适应FDFD系数的方法涉及角度积分、共轭梯度优化、顺序初值选取、光滑正则化等问题,不仅较难实现而且计算效率较低。为了简化自适应FDFD系数的计算并提高相应计算效率,本文提出一种新的计算自适应FDFD系数的方法。所提方法首先将不同离散传播角度的平面波解代入FDFD格式,构造相应的最小二乘问题。由于该最小二乘问题较为病态,常规的基于正规方程组的求解方法难以得到光滑的自适应FDFD系数,本文提出通过QR矩阵分解求解相应超定线性方程组来求解该最小二乘问题。相比已有的基于角度积分、共轭梯度优化、顺序初值选取的计算自适应FDFD系数的方法,所提方法在可以得到光滑自适应FDFD系数的基础上,不仅计算过程更简洁,且计算效率明显提高。数值波场模拟结果表明,基于QR矩阵分解的自适应系数FDFD方法可以达到与基于角度积分、共轭梯度优化、顺序初值选取的自适应系数FDFD方法相同的精度,同时所需的计算时间更少。展开更多
We performed ultrasonic experiments in specimens from a tight oil reservoir. The P-wave attenuation of fl uid-saturated specimens was estimated by the spectral ratio method. The results suggest that at ultrasonic freq...We performed ultrasonic experiments in specimens from a tight oil reservoir. The P-wave attenuation of fl uid-saturated specimens was estimated by the spectral ratio method. The results suggest that at ultrasonic frequencies, most specimens have stronger attenuation under gas-saturated conditions than at water- or oil-saturated conditions. The P-wave attenuation positively correlates with permeability. Scanning electron microscopy observations and the triple-porosity structure model were used to simulate the wave propagation. The P-wave velocity dispersion and attenuation are discussed on the basis of the Biot, Biot– Rayleigh double-porosity medium, and the triple-porosity structure models. The results suggest that the Biot and Biot–Rayleigh models cannot explain the attenuation, whereas the triple-porosity structure model is in agreement with the experimental data. Furthermore, we infer that microcracks are common in a porosity of 5%–10%, and the size of microcracks increases in samples with higher porosity. However, the volume ratios of microcracks and clay inclusions remain constant regardless of porosity variations. The size of microcracks is signifi cantly larger than the clay inclusions, and the bulk modulus of microcracks is lower than the bulk modulus of clays.展开更多
Microbial enhanced oil recovery （MEOR） methods apply injection of bacteria to depleted oil reservoirs to produce oil, which had remained unrecovered after the conventional methods of production. The ability ofthermo...Microbial enhanced oil recovery （MEOR） methods apply injection of bacteria to depleted oil reservoirs to produce oil, which had remained unrecovered after the conventional methods of production. The ability ofthermophilic anaerobic bacteria to produce gas as the main mechanism in potential MEOR in high salinities of 70-100 g/L was investigated in this study. Maximum gas production of up to 350 mL per 700 mL of salty solution was produced at a salinity of 90 g/L stably during 2-4 days of experiment. The experimental results were upscaled to the Snorre Oilfield, Norway, and simulated using ECLIPSE software for 27 months. The best scenarios showed that the increase in oil recovery on average was at 21% and 17.8% respectively. This study demonstrated that anaerobic bacteria used in biogas plants could be an attractive candidate for MEOR implementation due to their ability to withstand high temperature and salinity, and produce gas in large volumes.展开更多
The wave-induced local fluid flow mechanism is relevant to the complex heterogeneity of pore structures in rocks.The analysis of the local fluid flow mechanism is useful for accurately describing the wave propagation ...The wave-induced local fluid flow mechanism is relevant to the complex heterogeneity of pore structures in rocks.The analysis of the local fluid flow mechanism is useful for accurately describing the wave propagation characteristics in reservoir rocks.In the exploration and production of hydrocarbon reservoirs,the real stratum may be partially saturated with a multi-phase fluid mixture in general.Therefore,it is of great significance to investigate the wave velocity dispersion and attenuation features in relation to pore structures and fluids.In this work,the characteristics of fabric microstructures are obtained on the basis of pressure dependency of dry rock moduli using the effective medium theory.A novel anelasticity theoretical model for the wave propagation in a partially-saturated medium is presented by combining the extended Gurevich squirt-flow model and White patchysaturation theory.Numerical simulations are used to analyze wave propagation characteristics that depend on water saturation,external patchy diameter,and viscosity.We consider a tight sandstone from the Qingyang area of the Ordos Basin in west China and perform ultrasonic measurements under partial saturation states and different confining pressures,where the basic properties of the rock are obtained at the full gas saturation.The comparison of experimental data and theoretical modeling results shows a fairly good agreement,indicating that the new theory is effective.展开更多
The shale oil reservoir within the Yanchang Formations of Ordos Basin harbors substantial oil and gas resources and has recently emerged as the primary focus of unconventional oil and gas exploration and development.D...The shale oil reservoir within the Yanchang Formations of Ordos Basin harbors substantial oil and gas resources and has recently emerged as the primary focus of unconventional oil and gas exploration and development.Due to its complex pore and throat structure,pronounced heterogeneity,and tight reservoir characteristics,the techniques for conventional oil and gas exploration and production face challenges in comprehensive implementation,also indicating that as a vital parameter for evaluating the physical properties of a reservoir,permeability cannot be effectively estimated.This study selects 21 tight sandstone samples from the Q area within the shale oil formations of Ordos Basin.We systematically conduct the experiments to measure porosity,permeability,ultrasonic wave velocities,and resistivity at varying confining pressures.Results reveal that these measurements exhibit nonlinear changes in response to effective pressure.By using these experimental data and effective medium model,empirical relationships between P-and S-wave velocities,permeability and resistivity and effective pressure are established at logging and seismic scales.Furthermore,relationships between P-wave impedance and permeability,and resistivity and permeability are determined.A comparison between the predicted permeability and logging data demonstrates that the impedance–permeability relationship yields better results in contrast to those of resistivity–permeability relationship.These relationships are further applied to the seismic interpretation of shale oil reservoir in the target layer,enabling the permeability profile predictions based on inverse P-wave impedance.The predicted results are evaluated with actual production data,revealing a better agreement between predicted results and logging data and productivity.展开更多
In recent years,the Yanchang shale-oil formations of the Ordos Basin are rich in reserves with complex lithology and structure characteristics,low porosity and low permeability,and weak anomalies for oil and water dis...In recent years,the Yanchang shale-oil formations of the Ordos Basin are rich in reserves with complex lithology and structure characteristics,low porosity and low permeability,and weak anomalies for oil and water discriminations,have been the key targets of unconventional oil/gas resource exploration and development in the relevant areas.The joint acoustic-electrical(AE)properties can be used to interpret reservoir lithology,mineralogy,pore structure,and fluid saturation.To conduct tests of thin section analysis,X-ray diff raction,and ultrasonic and electrical experiments at diff erent pressures and saturation degrees,cores from the shale-oil formations in the Q area of the basin are collected.The variations in AE properties with respect to clay content,porosity,pressure(microfracture),and saturation are analyzed.The experimental results indicate that the rock physics behaviors of sandstones with diff erent clay contents vary significantly.The AE properties of clean sandstones are basically dependent on the microfractures(pressure),while for muddy sandstones,the clay content is an important factor affecting the responses.The target reservoir consists of interbedded sandstone and shale layers.The AE equivalent medium equations and the Gurevich theory are applied to establish the joint models for the diff erent lithologies and simulate the variations in AE properties with respect to fluid type,pore structure,and mineral components.The three-dimensional joint templates of clean and muddy sandstones,as well as shale,are developed based on the elastic and electrical attributes and then calibrated using the experimental and well-log data.The reservoir properties are estimated with the templates and validated by the log data.The results indicate that the joint templates based on lithology characteristics can eff ectively characterize the properties of interbedded sandstone and shale layers.Furthermore,the combined application of AE data provides more beneficial information for the assessment of rock properties,leading to precise estimates that conform with the actual formation conditions.展开更多
Prevention of mother-to-child transmission(PMTCT)of HIV with highly active antiretroviral therapy(HARRT)allows the HIV^+pregnant mothers to have vaginal delivery and breastfeed.Here we investigated the maternal plasma...Prevention of mother-to-child transmission(PMTCT)of HIV with highly active antiretroviral therapy(HARRT)allows the HIV^+pregnant mothers to have vaginal delivery and breastfeed.Here we investigated the maternal plasma immunoglobulin,cytokine secretion and the outcome of the exposed infants among the HIV^+HAART treated pregnan women in Nigeria.In this study,different plasma immunoglobulins and cytokines were measured in the HIV^+HAART treated pregnant mothers.Pooled culture supernatants of B and T lymphocytes showed lower levels of IFN-γ,IL-10 and IL-4.There were lower IFN-γand IL-10 secretions at 1st trimester;however,IL-10 continued to be lower throughout 2nd and 3rd trimesters.TNF-αsecretion significantly decreased as pregnancy progressed to term.There were high plasma IgG and low IgM in the HIV^+HAART treated pregnant women.Plasma IgG was high during 1st and 3rd trimesters.After one year of follow up,all the exposed children were seronegative for HIV-1 and HIV-2.Vaginal delivery and breastfeeding among HIV^+HAART treated mothers have shown to be safe.The use of HAART by the infected mothers and the use of septrin and niverapin by the exposed infants prevented mother to-child transmission of HIV.展开更多
The strongest documented seismic disaster ever occurred in the Po Plain area (January 3, 1117, M = 6.5) involved significant damage over a large zone. The genetic mechanism of such </span><span style="fo...The strongest documented seismic disaster ever occurred in the Po Plain area (January 3, 1117, M = 6.5) involved significant damage over a large zone. The genetic mechanism of such </span><span style="font-family:Verdana;">an </span><span style="font-family:Verdana;">event, most probably caused by more than one earthquake, is still </span><span style="font-family:Verdana;">an </span><span style="font-family:Verdana;">object of debate. Above all, the sources so far proposed cannot account for significant features of the observed macroseismic field. In this work, we suggest that the damage in the Verona zone was caused by the activation of a fault in the Lessini tectonic district, while damage in the central Po Plain may be related to a thrust fault located beneath the Giudicarie belt. The effects felt in northern Tuscany might derive from the seismic activ</span><span style="font-family:Verdana;">ation</span><span style="font-family:""><span style="font-family:Verdana;"> of the pre</span><span style="font-family:Verdana;">sumed SW-ward buried prolongation of the Giudicarie fault. The presence of such transpressional lithospheric discontinuity in the Adriatic domain since the upper Miocene and its reactivation (Pliocene-Pleistocene</span><span style="font-family:Verdana;">) as a thrust zone is mainly suggested by an accurate analysis of the observed deformation pattern in the central Mediterranean region. The proposed Giudicarie source may also help to explain the damage observed in the central Po Plain on December 25, 1222, which is not compatible with the seismic sources so far proposed.展开更多
Detection of small cancer biomarkers with low molecular weight and a low concentration range has always been challenging yet urgent in many clinical applications such as diagnosing early-stage cancer,monitoring treatm...Detection of small cancer biomarkers with low molecular weight and a low concentration range has always been challenging yet urgent in many clinical applications such as diagnosing early-stage cancer,monitoring treatment and detecting relapse.Here,a highly enhanced plasmonic biosensor that can overcome this challenge is developed using atomically thin two-dimensional phase change nanomaterial.By precisely engineering the configuration with atomically thin materials,the phase singularity has been successfully achieved with a significantly enhanced lateral position shift effect.Based on our knowledge,it is the first experimental demonstration of a lateral position signal change>340μm at a sensing interface from all optical techniques.With this enhanced plasmonic effect,the detection limit has been experimentally demonstrated to be 10^(-15) mol L^(−1) for TNF-α cancer marker,which has been found in various human diseases including inflammatory diseases and different kinds of cancer.The as-reported novel integration of atomically thin Ge_(2)Sb_(2)Te_(5) with plasmonic substrate, which results in a phase singularity and thus a giant lateral position shift, enables the detection of cancer markers with low molecular weight at femtomolar level. These results will definitely hold promising potential in biomedical application and clinical diagnostics.展开更多
文摘Homogeneous methods for ecological applications to the nutrient cycle are analyzed,and the results are presented according to the marine ecology work discussed.To do justice to the explanations,the materials are summarized,and the methods are discussed and improved for both interested readers and experts in the field.Both the materials and the methods serve informative and popularizing as well as applicable and interpretive purposes and,in order to achieve the widest possible dissemination,are shared under the strict supervision of the earlier individual publications discussed here.The aeolian syntheses quantify the impact of atmospheric deposition of nutrients in the Western Mediterranean as one-twentieth of the baseline vertical fluxes of organic matter,while estimates for the Eastern Mediterranean reach one-eighth.Possible changes and additions in the global ocean are discussed as well as ecosystem updates and their relevance to the specific orography,hydrology and geochemistry associated with the lower trophodynamic degrees of freedom.Finally,the dynamics of the basins are analyzed,with increasing nutrient inputs leading to a top-down control of net plankton growth in the western basin and to an extremely nutrient-poor state in the eastern basin.
基金funded by the National Natural Science Foundation of China (No. 42374128)by the Fundamental Research Funds for the Central Universities (No. B240201110)。
文摘Source rocks(shales) exhibit different geometric pore types and considerable anisotropy caused by the preferential orientation of the clay and kerogen layers,which is not accounted for in classical rockphysics models.Pore geometry can be effectively studied through the aspect ratio,and in this study,we use the aspect ratio to characterize different pore geometries.Then,we consider a pore connectivity index as well as a lamination index associated with these orientations.An inclusion-based theory(differential effective medium and self-consistent approximation) and the Brown-Korringa equations are used in the modeling approach.The results show that the indices as well as the aspect ratio of the connected pores significantly affect the elastic properties.We propose an inversion method to invert these three parameters simultaneously from experimental vertical P-and S-wave velocities using a global optimization algorithm.The method is applied to well log and seismic data from the Longmaxi shale reservoir in southwest China to verify its pre dictive ability.
基金sponsored by the NSFC(41104066)973 Program of China(No.2014CB239006)+1 种基金NSTMP of China(Nos.2011ZX05004-003 and 2011ZX05029-003)12th 5-Year Basic Research Program of CNPC(No.2011A-3601)
文摘In heterogeneous natural gas reservoirs, gas is generally present as small patchlike pockets embedded in the water-saturated host matrix. This type of heterogeneity, also called "patchy saturation", causes significant seismic velocity dispersion and attenuation. To establish the relation between seismic response and type of fluids, we designed a rock physics model for carbonates. First, we performed CT scanning and analysis of the fluid distribution in the partially saturated rocks. Then, we predicted the quantitative relation between the wave response at different frequency ranges and the basic lithological properties and pore fluids. A rock physics template was constructed based on thin section analysis of pore structures and seismic inversion. This approach was applied to the limestone gas reservoirs of the right bank block of the Amu Darya River. Based on poststack wave impedance and prestack elastic parameter inversions, the seismic data were used to estimate rock porosity and gas saturation. The model results were in good agreement with the production regime of the wells.
基金supported by the National Natural Science Foundation of China(No.42174161,No.41974123)China Postdoctoral Science Foundation(No.2022M711004)+1 种基金China National Petroleum Corporation Exploration and Development Research Institute Open Fund(No.822102016)the Jiangsu Province Science Fund for Distinguished Young Scholars(No.BK20200021).
文摘频域有限差分(finite difference frequency domain,FDFD)方法是地震波场模拟的常用方法,FDFD地震波场模拟的关键之一是构造能有效压制数值频散的FDFD系数。在已有的构造地震波场模拟FDFD系数的方法中,随一个网格内的波长个数变化的自适应FDFD系数可以最大程度地压制数值频散。目前计算自适应FDFD系数的方法涉及角度积分、共轭梯度优化、顺序初值选取、光滑正则化等问题,不仅较难实现而且计算效率较低。为了简化自适应FDFD系数的计算并提高相应计算效率,本文提出一种新的计算自适应FDFD系数的方法。所提方法首先将不同离散传播角度的平面波解代入FDFD格式,构造相应的最小二乘问题。由于该最小二乘问题较为病态,常规的基于正规方程组的求解方法难以得到光滑的自适应FDFD系数,本文提出通过QR矩阵分解求解相应超定线性方程组来求解该最小二乘问题。相比已有的基于角度积分、共轭梯度优化、顺序初值选取的计算自适应FDFD系数的方法,所提方法在可以得到光滑自适应FDFD系数的基础上,不仅计算过程更简洁,且计算效率明显提高。数值波场模拟结果表明,基于QR矩阵分解的自适应系数FDFD方法可以达到与基于角度积分、共轭梯度优化、顺序初值选取的自适应系数FDFD方法相同的精度,同时所需的计算时间更少。
基金the Specially Appointed Professor Program of Jiangsu Province, China,the National Natural Science Foundation of China (No. 41704109)the Fundamental Research Funds for the Central Universities, China.(No. 2016B13114).
文摘We performed ultrasonic experiments in specimens from a tight oil reservoir. The P-wave attenuation of fl uid-saturated specimens was estimated by the spectral ratio method. The results suggest that at ultrasonic frequencies, most specimens have stronger attenuation under gas-saturated conditions than at water- or oil-saturated conditions. The P-wave attenuation positively correlates with permeability. Scanning electron microscopy observations and the triple-porosity structure model were used to simulate the wave propagation. The P-wave velocity dispersion and attenuation are discussed on the basis of the Biot, Biot– Rayleigh double-porosity medium, and the triple-porosity structure models. The results suggest that the Biot and Biot–Rayleigh models cannot explain the attenuation, whereas the triple-porosity structure model is in agreement with the experimental data. Furthermore, we infer that microcracks are common in a porosity of 5%–10%, and the size of microcracks increases in samples with higher porosity. However, the volume ratios of microcracks and clay inclusions remain constant regardless of porosity variations. The size of microcracks is signifi cantly larger than the clay inclusions, and the bulk modulus of microcracks is lower than the bulk modulus of clays.
文摘Microbial enhanced oil recovery （MEOR） methods apply injection of bacteria to depleted oil reservoirs to produce oil, which had remained unrecovered after the conventional methods of production. The ability ofthermophilic anaerobic bacteria to produce gas as the main mechanism in potential MEOR in high salinities of 70-100 g/L was investigated in this study. Maximum gas production of up to 350 mL per 700 mL of salty solution was produced at a salinity of 90 g/L stably during 2-4 days of experiment. The experimental results were upscaled to the Snorre Oilfield, Norway, and simulated using ECLIPSE software for 27 months. The best scenarios showed that the increase in oil recovery on average was at 21% and 17.8% respectively. This study demonstrated that anaerobic bacteria used in biogas plants could be an attractive candidate for MEOR implementation due to their ability to withstand high temperature and salinity, and produce gas in large volumes.
基金supported by the National Natural Science Foundation of China(Grant no.41704109)the Jiangsu Province Outstanding Youth Fund Project(Grant no.BK20200021).
文摘The wave-induced local fluid flow mechanism is relevant to the complex heterogeneity of pore structures in rocks.The analysis of the local fluid flow mechanism is useful for accurately describing the wave propagation characteristics in reservoir rocks.In the exploration and production of hydrocarbon reservoirs,the real stratum may be partially saturated with a multi-phase fluid mixture in general.Therefore,it is of great significance to investigate the wave velocity dispersion and attenuation features in relation to pore structures and fluids.In this work,the characteristics of fabric microstructures are obtained on the basis of pressure dependency of dry rock moduli using the effective medium theory.A novel anelasticity theoretical model for the wave propagation in a partially-saturated medium is presented by combining the extended Gurevich squirt-flow model and White patchysaturation theory.Numerical simulations are used to analyze wave propagation characteristics that depend on water saturation,external patchy diameter,and viscosity.We consider a tight sandstone from the Qingyang area of the Ordos Basin in west China and perform ultrasonic measurements under partial saturation states and different confining pressures,where the basic properties of the rock are obtained at the full gas saturation.The comparison of experimental data and theoretical modeling results shows a fairly good agreement,indicating that the new theory is effective.
基金supports from the National Natural Science Foundation of China(42104110,41974123,42174161,and 12334019)the Natural Science Foundation of Jiangsu Province(BK20210379,BK20200021)+1 种基金the Postdoctoral Science Foundation of China(2022M720989)the Fundamental Research Funds for the Central Universities(B210201032).
文摘The shale oil reservoir within the Yanchang Formations of Ordos Basin harbors substantial oil and gas resources and has recently emerged as the primary focus of unconventional oil and gas exploration and development.Due to its complex pore and throat structure,pronounced heterogeneity,and tight reservoir characteristics,the techniques for conventional oil and gas exploration and production face challenges in comprehensive implementation,also indicating that as a vital parameter for evaluating the physical properties of a reservoir,permeability cannot be effectively estimated.This study selects 21 tight sandstone samples from the Q area within the shale oil formations of Ordos Basin.We systematically conduct the experiments to measure porosity,permeability,ultrasonic wave velocities,and resistivity at varying confining pressures.Results reveal that these measurements exhibit nonlinear changes in response to effective pressure.By using these experimental data and effective medium model,empirical relationships between P-and S-wave velocities,permeability and resistivity and effective pressure are established at logging and seismic scales.Furthermore,relationships between P-wave impedance and permeability,and resistivity and permeability are determined.A comparison between the predicted permeability and logging data demonstrates that the impedance–permeability relationship yields better results in contrast to those of resistivity–permeability relationship.These relationships are further applied to the seismic interpretation of shale oil reservoir in the target layer,enabling the permeability profile predictions based on inverse P-wave impedance.The predicted results are evaluated with actual production data,revealing a better agreement between predicted results and logging data and productivity.
基金supported by the Natural Science Foundation of Jiangsu Province(Grant No.BK20200021)the National Natural Science Foundation of China(Grant No.42174161 and 41974123)the Natural Science Foundation of Heilongjiang Province of China(YQ2023D005).
基金supported by the National Natural Science Foundation of China (Nos.41974123,42174161)the Jiangsu Innovation and Entrepreneurship Plan and the Jiangsu Province Science Fund for Distinguished Young Scholars (grant no.BK20200021).
文摘In recent years,the Yanchang shale-oil formations of the Ordos Basin are rich in reserves with complex lithology and structure characteristics,low porosity and low permeability,and weak anomalies for oil and water discriminations,have been the key targets of unconventional oil/gas resource exploration and development in the relevant areas.The joint acoustic-electrical(AE)properties can be used to interpret reservoir lithology,mineralogy,pore structure,and fluid saturation.To conduct tests of thin section analysis,X-ray diff raction,and ultrasonic and electrical experiments at diff erent pressures and saturation degrees,cores from the shale-oil formations in the Q area of the basin are collected.The variations in AE properties with respect to clay content,porosity,pressure(microfracture),and saturation are analyzed.The experimental results indicate that the rock physics behaviors of sandstones with diff erent clay contents vary significantly.The AE properties of clean sandstones are basically dependent on the microfractures(pressure),while for muddy sandstones,the clay content is an important factor affecting the responses.The target reservoir consists of interbedded sandstone and shale layers.The AE equivalent medium equations and the Gurevich theory are applied to establish the joint models for the diff erent lithologies and simulate the variations in AE properties with respect to fluid type,pore structure,and mineral components.The three-dimensional joint templates of clean and muddy sandstones,as well as shale,are developed based on the elastic and electrical attributes and then calibrated using the experimental and well-log data.The reservoir properties are estimated with the templates and validated by the log data.The results indicate that the joint templates based on lithology characteristics can eff ectively characterize the properties of interbedded sandstone and shale layers.Furthermore,the combined application of AE data provides more beneficial information for the assessment of rock properties,leading to precise estimates that conform with the actual formation conditions.
文摘Prevention of mother-to-child transmission(PMTCT)of HIV with highly active antiretroviral therapy(HARRT)allows the HIV^+pregnant mothers to have vaginal delivery and breastfeed.Here we investigated the maternal plasma immunoglobulin,cytokine secretion and the outcome of the exposed infants among the HIV^+HAART treated pregnan women in Nigeria.In this study,different plasma immunoglobulins and cytokines were measured in the HIV^+HAART treated pregnant mothers.Pooled culture supernatants of B and T lymphocytes showed lower levels of IFN-γ,IL-10 and IL-4.There were lower IFN-γand IL-10 secretions at 1st trimester;however,IL-10 continued to be lower throughout 2nd and 3rd trimesters.TNF-αsecretion significantly decreased as pregnancy progressed to term.There were high plasma IgG and low IgM in the HIV^+HAART treated pregnant women.Plasma IgG was high during 1st and 3rd trimesters.After one year of follow up,all the exposed children were seronegative for HIV-1 and HIV-2.Vaginal delivery and breastfeeding among HIV^+HAART treated mothers have shown to be safe.The use of HAART by the infected mothers and the use of septrin and niverapin by the exposed infants prevented mother to-child transmission of HIV.
文摘The strongest documented seismic disaster ever occurred in the Po Plain area (January 3, 1117, M = 6.5) involved significant damage over a large zone. The genetic mechanism of such </span><span style="font-family:Verdana;">an </span><span style="font-family:Verdana;">event, most probably caused by more than one earthquake, is still </span><span style="font-family:Verdana;">an </span><span style="font-family:Verdana;">object of debate. Above all, the sources so far proposed cannot account for significant features of the observed macroseismic field. In this work, we suggest that the damage in the Verona zone was caused by the activation of a fault in the Lessini tectonic district, while damage in the central Po Plain may be related to a thrust fault located beneath the Giudicarie belt. The effects felt in northern Tuscany might derive from the seismic activ</span><span style="font-family:Verdana;">ation</span><span style="font-family:""><span style="font-family:Verdana;"> of the pre</span><span style="font-family:Verdana;">sumed SW-ward buried prolongation of the Giudicarie fault. The presence of such transpressional lithospheric discontinuity in the Adriatic domain since the upper Miocene and its reactivation (Pliocene-Pleistocene</span><span style="font-family:Verdana;">) as a thrust zone is mainly suggested by an accurate analysis of the observed deformation pattern in the central Mediterranean region. The proposed Giudicarie source may also help to explain the damage observed in the central Po Plain on December 25, 1222, which is not compatible with the seismic sources so far proposed.
基金We thank Shiyue Liu from School of Life Sciences in The Chinese University of Hong Kong for helpful discussions.This work is supported under the PROCORE-France/Hong Kong Joint Research Scheme(F-CUHK402/19)the Research Grants Council,Hong Kong Special Administration Region(AoE/P-02/12,14210517,14207419,N_CUHK407/16)the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant Agreement No.798916.Y.Wang is supported under the Hong Kong PhD Fellowship Scheme.
文摘Detection of small cancer biomarkers with low molecular weight and a low concentration range has always been challenging yet urgent in many clinical applications such as diagnosing early-stage cancer,monitoring treatment and detecting relapse.Here,a highly enhanced plasmonic biosensor that can overcome this challenge is developed using atomically thin two-dimensional phase change nanomaterial.By precisely engineering the configuration with atomically thin materials,the phase singularity has been successfully achieved with a significantly enhanced lateral position shift effect.Based on our knowledge,it is the first experimental demonstration of a lateral position signal change>340μm at a sensing interface from all optical techniques.With this enhanced plasmonic effect,the detection limit has been experimentally demonstrated to be 10^(-15) mol L^(−1) for TNF-α cancer marker,which has been found in various human diseases including inflammatory diseases and different kinds of cancer.The as-reported novel integration of atomically thin Ge_(2)Sb_(2)Te_(5) with plasmonic substrate, which results in a phase singularity and thus a giant lateral position shift, enables the detection of cancer markers with low molecular weight at femtomolar level. These results will definitely hold promising potential in biomedical application and clinical diagnostics.
