音频管理组件(AMU,audio management unit)的BITE(built-in test equipment)使用ARINC429总线接口,其接口器件一般为16位数据总线。基于cPCI总线设计的板卡,使用DEI1016A作为ARINC429总线控制器和CPLD作为总线仲裁器,达到能够使用工业...音频管理组件(AMU,audio management unit)的BITE(built-in test equipment)使用ARINC429总线接口,其接口器件一般为16位数据总线。基于cPCI总线设计的板卡,使用DEI1016A作为ARINC429总线控制器和CPLD作为总线仲裁器,达到能够使用工业控制计算机实现AMU自动测试的目的,并且具有较好的可扩展性。关键词:cPCI;AMU;ARINC429总线;展开更多
In this study, we used the multi-resolution graph-based clustering （MRGC） method for determining the electrofacies （EF） and lithofacies （LF） from well log data obtained from the intraplatform bank gas fields loc...In this study, we used the multi-resolution graph-based clustering （MRGC） method for determining the electrofacies （EF） and lithofacies （LF） from well log data obtained from the intraplatform bank gas fields located in the Amu Darya Basin. The MRGC could automatically determine the optimal number of clusters without prior knowledge about the structure or cluster numbers of the analyzed data set and allowed the users to control the level of detail actually needed to define the EF. Based on the LF identification and successful EF calibration using core data, an MRGC EF partition model including five clusters and a quantitative LF interpretation chart were constructed. The EF clusters 1 to 5 were interpreted as lagoon, anhydrite flat, interbank, low-energy bank, and high-energy bank, and the coincidence rate in the cored interval could reach 85%. We concluded that the MRGC could be accurately applied to predict the LF in non-cored but logged wells. Therefore, continuous EF clusters were partitioned and corresponding LF were characteristics ＆different LF were analyzed interpreted, and the distribution and petrophysical in the framework of sequence stratigraphy.展开更多
Based on the detailed research on petrologic and geochemical characteristics of deposi- tion and diagenesis of Oxfordian carbonate rocks in Amu Darya Basin, Turkmenistan, carbon and oxygen isotopes were analyzed. The ...Based on the detailed research on petrologic and geochemical characteristics of deposi- tion and diagenesis of Oxfordian carbonate rocks in Amu Darya Basin, Turkmenistan, carbon and oxygen isotopes were analyzed. The results show that the paleoenvironmental evolution reflected by the samples with well-preserved original carbon isotopes coincides with the carbon-isotope stratigraphic curve and is almost consistent with the global sea-level curve, the Mid-Oxfordian wide transgression, and the positive carbon-isotope excursion event. The Mid-Oxfordian continuing transgression not only laid the foundation for the development of the Oxfordian reef and shoal reservoirs in Amu Darya Basin but also provided an example for the Oxfordian global transgression and the resulting development of reefs and banks and high-speed organic carbon burial events. The response of oxygen isotopes in diagenetic environment showed that micrite limestones and granular limestones underwent weak diagenetic alteration, and the samples largely retained the original seawater features. Dolomitization and the precipitation of hydrothermal calcites filling solution vugs and fractures before hydrocarbon accumulation occurred in a closed diagenetic environment where the main controlling factor is the temperature, and the diagenetic fluids were from the deep hot brine. The chalkification of the lime- stones after hydrocarbon accumulation occurred in the oilfield water systems.展开更多
High water consumption and inefficient irrigation management in the agriculture sector of the middle and lower reaches of the Amu Darya River Basin(ADRB)have significantly influenced the gradual shrinking of the Aral ...High water consumption and inefficient irrigation management in the agriculture sector of the middle and lower reaches of the Amu Darya River Basin(ADRB)have significantly influenced the gradual shrinking of the Aral Sea and its ecosystem.In this study,we investigated the crop water consumption in the growing seasons and the irrigation water requirement for different crop types in the lower ADRB during 2004–2017.We applied the FAO Penman–Monteith method to estimate reference evapotranspiration(ET0)based on daily climatic data collected from four meteorological stations.Crop evapotranspiration(ETc)of specific crop types was calculated by the crop coefficient.Then,we analyzed the net irrigation requirement(NIR)based on the effective precipitation with crop water requirements.The results indicated that the lowest monthly ET0 values in the lower ADRB were found in December(18.2 mm)and January(16.0 mm),and the highest monthly ET0 values were found in June and July,with similar values of 211.6 mm.The annual ETc reached to 887.2,1002.1,and 492.0 mm for cotton,rice,and wheat,respectively.The average regional NIR ranged from 514.9 to 715.0 mm in the 10 Irrigation System Management Organizations(UISs)in the study area,while the total required irrigation volume for the whole region ranged from 4.2×109 to 11.6×109 m3 during 2004–2017.The percentages of NIR in SIW(surface irrigation water)ranged from 46.4%to 65.2%during the study period,with the exceptions of the drought years of 2008 and 2011,in which there was a significantly less runoff in the Amu Darya River.This study provides an overview for local water authorities to achieve optimal regional water allocation in the study area.展开更多
The shrinkage of the Aral Sea,which is closely related to the Amu Darya River,strongly affects the sustainability of the local natural ecosystem,agricultural production,and human well-being.In this study,we used the B...The shrinkage of the Aral Sea,which is closely related to the Amu Darya River,strongly affects the sustainability of the local natural ecosystem,agricultural production,and human well-being.In this study,we used the Bayesian Estimator of Abrupt change,Seasonal change,and Trend(BEAST)model to detect the historical change points in the variation of the Aral Sea and the Amu Darya River and analyse the causes of the Aral Sea shrinkage during the 1950–2016 period.Further,we applied multifractal detrend cross-correlation analysis(MF-DCCA)and quantitative analysis to investigate the responses of the Aral Sea to the runoff in the Amu Darya River,which is the main source of recharge to the Aral Sea.Our results showed that two significant trend change points in the water volume change of the Aral Sea occurred,in 1961 and 1974.Before 1961,the water volume in the Aral Sea was stable,after which it began to shrink,with a shrinkage rate fluctuating around 15.21 km3/a.After 1974,the water volume of the Aral Sea decreased substantially at a rate of up to 48.97 km3/a,which was the highest value recorded in this study.In addition,although the response of the Aral Sea's water volume to its recharge runoff demonstrated a complex non-linear relationship,the replenishment of the Aral Sea by the runoff in the lower reaches of the Amu Darya River was identified as the dominant factor affecting the Aral Sea shrinkage.Based on the scenario analyses,we concluded that it is possible to slow down the retreat of the Aral Sea and restore its ecosystem by increasing the efficiency of agricultural water use,decreasing agricultural water use in the middle and lower reaches,reducing ineffective evaporation from reservoirs and wetlands,and increasing the water coming from the lower reaches of the Amu Darya River to the 1961–1973 level.These measures would maintain and stabilise the water area and water volume of the Aral Sea in a state of ecological restoration.Therefore,this study focuses on how human consumption of recharge runoff affects the Aral Sea and provides scientific perspective on its ecological conservation and sustainable development.展开更多
Overemphasizing the value of reefs in oil and gas exploration, reef-oriented geologists explain all carbonate platform deposits using the Wilson model. In their eyes, rimmed shelves are more valuable than carbonate ra...Overemphasizing the value of reefs in oil and gas exploration, reef-oriented geologists explain all carbonate platform deposits using the Wilson model. In their eyes, rimmed shelves are more valuable than carbonate ramps. However, organic banks are excellent reservoirs generated by carbonate ramps in the study area, as verified beyond doubt through petroleum exploration, such as this thesis, which investigates the genesis, types, and distribution of carbonate deposition in the north zone of the Amu-Darya Basin. Monoclinal palaeogeomorphology and rudists suggest shallow environments. Given that oolite shoals and rudist patch reefs were observed in the study area, the depositional system is interpreted to be a carbonate ramp. The Callovian-Oxfordian stage consists of nine lithofacies: oolitic limestone, skeletal limestone, micritic limestone, bioturbated limestone, and crystalline limestone, which are grouped into three facies associations presenting outer ramp, mid-ramp, and inner ramp facies associations. Five depositional sequences can be distinguished in the Callovian-Oxfordian stage. Each third-order depositional sequence is composed of transgressive systems tracts (TST) and highstand systems tracts (HST). The TST consists of mudstones with a higher response to natural gamma rays, whereas the HST contains various types of grainstone, with subordinate dolostone. The vertical and lateral distributions of sedimentary facies, and their interpreted depositional environments, revealed a ramp exhibiting a gradual southeast-northwestward environmental change from outer ramp, mid ramp, and inner ramp carbonate facies.展开更多
Lower Cretaceous Shurijeh–Shatlyk Formations host some of the main reservoirs in the Kopeh Dagh-Amu Darya Basin.Exploration in this area so far has focused on the development of structural traps, but recognition of s...Lower Cretaceous Shurijeh–Shatlyk Formations host some of the main reservoirs in the Kopeh Dagh-Amu Darya Basin.Exploration in this area so far has focused on the development of structural traps, but recognition of stratigraphic traps in this area is of increasing importance. Integration of 3D seismic data with borehole data from thirteen wells and five outcrop sections was used to identify potential reservoir intervals and survey the hydrocarbon trap types in the East Kopeh Dagh Foldbelt(NE Iran). Analyses of horizontal slices indicated that the lower Shurijeh was deposited in a braided fluvial system.Generally, three types of channel were identified in the lower Shurijeh Formation: type 1, which is low-sinuosity channels interpreted to be filled with non-reservoir fine-grained facies;type 2, which is a moderately sinuous sand-filled channel with good prospectively;and type 3, which is narrow, high sinuosity channel filled with fine-grained sediments. Results indicate that upper Shurijeh–Shatlyk Formations were deposited in fluvial to delta and shallow marine environments. The identified delta forms the second reservoir zone in the Khangiran Field. Study of the stratigraphic aspects of the Shurijeh succession indicates that both lower and upper Shurijeh reservoirs are stratigraphic reservoir traps that improved during folding.展开更多
Central Asia(CA)is one of the most fragile regions worldwide owing to arid climate and accumulated human activities,and is a global hotspot due to gradually deteriorating ecological environment.The Amu Darya Basin(ADB...Central Asia(CA)is one of the most fragile regions worldwide owing to arid climate and accumulated human activities,and is a global hotspot due to gradually deteriorating ecological environment.The Amu Darya Basin(ADB),as the most economically and demographically important region in CA,is of particular concern.To determine the concentration,source and pollution status of heavy metals(HMs)in surface sediments of the ADB,154samples were collected and analyzed for metals across the basin.Correlation and cluster analysis,and positive matrix factorization model were implemented to understand metals’association and apportion their possible sources.Cumulative frequency distribution and normalization methods were used to determine the geochemical baseline values(GBVs).Then,various pollution indices and ecological risk index were employed to characterize and evaluate the pollution levels and associated risks based on the GBVs.Results indicated that the mean concentrations of HMs showed the following descending order in the surface sediments of ADB:Zn>Cr>Ni>Cu>Pb>Co>Cd.The spatial distribution maps showed that Cr,Ni,and Cu had relatively high enrichment in the irrigated agricultural area;high abundances of Zn,Pb,and Cd were mainly found in the urban areas.Four source factors were identified for these metals,namely natural sources,industrial discharge,agricultural activities,and mixed source of traffic and mining activities,accounting for 33.5%,11.4%,34.2%,and 20.9%of the total contribution,respectively.The GBVs of Cd,Zn,Pb,Cu,Ni,Cr,and Co in the ADB were 0.27,58.9,14.6,20.3,25.8,53.4,and 9.80 mg/kg,respectively,which were similar to the regional background values obtained from lake sediments in the bottom.In general,the assessment results revealed that surface sediments of the ADB were moderately polluted and low ecological risk by HMs.展开更多
The right bank of the Amu Darya Basin enjoys abundant natural gas resources,on which the Callovian-Oxfordian strata in the middle of Block B serve as the major horizons for natural gas production.However,the character...The right bank of the Amu Darya Basin enjoys abundant natural gas resources,on which the Callovian-Oxfordian strata in the middle of Block B serve as the major horizons for natural gas production.However,the characteristics and distribution patterns of the sedimentary microfacies in these strata are yet to be further explored.Based on the analysis of data on drilling,logging,cores,and thin sections from 29 typical wells,as well as the regional sedimentary background,this study inferred that the middle of Block B evolved from the Callovian ramp platform into the Oxfordian rimmed platform.Moreover,this study determined that the inner-ramp intertidal-subtidal shallow-water subfacies mainly developed during the Callovian and transitioned into the shallow shelf subfacies during the Oxfordian.This study identified eight sedimentary microfacies,namely reef knoll,reef-shoal complex,bioclastic shoal,psammitic shoal,bioherm,lime mud mound,intershoal(intermound),and static-water mud.Based on research into the high-precision sequence-sedimentary microfacies framework,this study built a geological model for the development of sedimentary microfacies in the study area.According to this geological model,the sedimentary microfacies in the study area are characterized by vertical alternation of reef-shoal complex,bioclastic(psammitic)shoal,bioherm,and intershoal microfacies.Moreover,they show the development of reef knoll,reef-shoal complex,bioclastic(psammitic)shoal,and bioherm(or lime mud mound)laterally from west to east,with the physical properties of the reservoirs deteriorating from west to east accordingly.The microfacies of reef-shoal complex and the bioclastic(psammitic)shoal predominate in the study area,and their deposition and development are controlled by sequence boundaries and are also affected by paleo-landforms.The Oxfordian reef-shoal complexes were largely inherited from the Callovian uplifts and show lateral seaward progradation.展开更多
Carbonate gas reservoir in the eastern area on the Right Bank of the Amu Darya River,Turkmenistan,are of low-porosity and with developed fractures.In this area,fractures control reservoir properties and natural gas pr...Carbonate gas reservoir in the eastern area on the Right Bank of the Amu Darya River,Turkmenistan,are of low-porosity and with developed fractures.In this area,fractures control reservoir properties and natural gas production,and karst fractures are the most important kind of fractures,so their identification and evaluation are quite necessary.In this paper,fracture types were identified and their occurrence was extracted by using conventional logging and image logging data after core calibration.Then,the distribution characteristics of karst fractures and their controlling effect on reservoirs were studied according to the identification results.And the following research results were obtained.First,karst fractures are mainly of high angle with the characteristic of mono system and the interactive relation of genesis.Second,they are mainly distributed in the upper XVhp layer of CallovianeOxford Stage and the lower XVa2eXVI layer.Third,they are the main effective fractures in this area.The dissolved pores are connected effectively through the expanded karst fractures by dissolution,and consequently reservoirs of high porosity and permeability are formed and they are the important reservoir type and high-yield gas reservoir in this area.Fourth,karst fractures are related to high-yield wells and high-yield layers in this area,and they also control the distribution of high-yield reservoirs in the lower part of CallovianeOxford Stage.It is concluded that by virtue of imaging logging and conventional logging data,karst fractures,unfilled fractures,semi-filled fractures and fullyfilled fractures can be identified and evaluated better.Furthermore,the identification and evaluation of karst fractures deepen the understanding on fractured reservoirs in this area,improve the reservoir evaluation effect,and provide the basis for the target horizon and azimuth optimization of horizontal wells and highly deviated wells.And it is also indicated that the reservoirs with developed karst fractures are the subsequent important drilling targets.展开更多
文摘音频管理组件(AMU,audio management unit)的BITE(built-in test equipment)使用ARINC429总线接口,其接口器件一般为16位数据总线。基于cPCI总线设计的板卡,使用DEI1016A作为ARINC429总线控制器和CPLD作为总线仲裁器,达到能够使用工业控制计算机实现AMU自动测试的目的,并且具有较好的可扩展性。关键词:cPCI;AMU;ARINC429总线;
基金supported by the National Science and Technology Major Project of China(No.2011ZX05029-003)CNPC Science Research and Technology Development Project,China(No.2013D-0904)
文摘In this study, we used the multi-resolution graph-based clustering （MRGC） method for determining the electrofacies （EF） and lithofacies （LF） from well log data obtained from the intraplatform bank gas fields located in the Amu Darya Basin. The MRGC could automatically determine the optimal number of clusters without prior knowledge about the structure or cluster numbers of the analyzed data set and allowed the users to control the level of detail actually needed to define the EF. Based on the LF identification and successful EF calibration using core data, an MRGC EF partition model including five clusters and a quantitative LF interpretation chart were constructed. The EF clusters 1 to 5 were interpreted as lagoon, anhydrite flat, interbank, low-energy bank, and high-energy bank, and the coincidence rate in the cored interval could reach 85%. We concluded that the MRGC could be accurately applied to predict the LF in non-cored but logged wells. Therefore, continuous EF clusters were partitioned and corresponding LF were characteristics ＆different LF were analyzed interpreted, and the distribution and petrophysical in the framework of sequence stratigraphy.
基金supported by the Important National Science & Technology Specific Projects of China(No.2008ZX05030-003-02)
文摘Based on the detailed research on petrologic and geochemical characteristics of deposi- tion and diagenesis of Oxfordian carbonate rocks in Amu Darya Basin, Turkmenistan, carbon and oxygen isotopes were analyzed. The results show that the paleoenvironmental evolution reflected by the samples with well-preserved original carbon isotopes coincides with the carbon-isotope stratigraphic curve and is almost consistent with the global sea-level curve, the Mid-Oxfordian wide transgression, and the positive carbon-isotope excursion event. The Mid-Oxfordian continuing transgression not only laid the foundation for the development of the Oxfordian reef and shoal reservoirs in Amu Darya Basin but also provided an example for the Oxfordian global transgression and the resulting development of reefs and banks and high-speed organic carbon burial events. The response of oxygen isotopes in diagenetic environment showed that micrite limestones and granular limestones underwent weak diagenetic alteration, and the samples largely retained the original seawater features. Dolomitization and the precipitation of hydrothermal calcites filling solution vugs and fractures before hydrocarbon accumulation occurred in a closed diagenetic environment where the main controlling factor is the temperature, and the diagenetic fluids were from the deep hot brine. The chalkification of the lime- stones after hydrocarbon accumulation occurred in the oilfield water systems.
基金This study was supported by the International Cooperation Project of National Natural Science Foundation of China(41761144079)the Strategic Priority Research Program of Chinese Academy of Sciences(XDA20060301)+2 种基金the State's Key Project of Research and Development Plan(2017YFC0404501),the International Partnership Program of Chinese Academy of Sciences(131551KYSB20160002)the project of the Research Center of Ecology and Environment in Central Asia(Y934031)a grant from the Regional Collaborative Innovation Project of Xinjiang Uygur Autonomous Region(2020E01010).
文摘High water consumption and inefficient irrigation management in the agriculture sector of the middle and lower reaches of the Amu Darya River Basin(ADRB)have significantly influenced the gradual shrinking of the Aral Sea and its ecosystem.In this study,we investigated the crop water consumption in the growing seasons and the irrigation water requirement for different crop types in the lower ADRB during 2004–2017.We applied the FAO Penman–Monteith method to estimate reference evapotranspiration(ET0)based on daily climatic data collected from four meteorological stations.Crop evapotranspiration(ETc)of specific crop types was calculated by the crop coefficient.Then,we analyzed the net irrigation requirement(NIR)based on the effective precipitation with crop water requirements.The results indicated that the lowest monthly ET0 values in the lower ADRB were found in December(18.2 mm)and January(16.0 mm),and the highest monthly ET0 values were found in June and July,with similar values of 211.6 mm.The annual ETc reached to 887.2,1002.1,and 492.0 mm for cotton,rice,and wheat,respectively.The average regional NIR ranged from 514.9 to 715.0 mm in the 10 Irrigation System Management Organizations(UISs)in the study area,while the total required irrigation volume for the whole region ranged from 4.2×109 to 11.6×109 m3 during 2004–2017.The percentages of NIR in SIW(surface irrigation water)ranged from 46.4%to 65.2%during the study period,with the exceptions of the drought years of 2008 and 2011,in which there was a significantly less runoff in the Amu Darya River.This study provides an overview for local water authorities to achieve optimal regional water allocation in the study area.
基金supported by the National Natural Science Foundation of China (42230708)the Joint CAS (Chinese Academy of Sciences) & MPG (Max-Planck-Gesellschaft) Research Project (HZXM20225001MI)the Tianshan Talent Project of Xinjiang Uygur Autonomous Region, China (2022TSYCLJ0056)。
文摘The shrinkage of the Aral Sea,which is closely related to the Amu Darya River,strongly affects the sustainability of the local natural ecosystem,agricultural production,and human well-being.In this study,we used the Bayesian Estimator of Abrupt change,Seasonal change,and Trend(BEAST)model to detect the historical change points in the variation of the Aral Sea and the Amu Darya River and analyse the causes of the Aral Sea shrinkage during the 1950–2016 period.Further,we applied multifractal detrend cross-correlation analysis(MF-DCCA)and quantitative analysis to investigate the responses of the Aral Sea to the runoff in the Amu Darya River,which is the main source of recharge to the Aral Sea.Our results showed that two significant trend change points in the water volume change of the Aral Sea occurred,in 1961 and 1974.Before 1961,the water volume in the Aral Sea was stable,after which it began to shrink,with a shrinkage rate fluctuating around 15.21 km3/a.After 1974,the water volume of the Aral Sea decreased substantially at a rate of up to 48.97 km3/a,which was the highest value recorded in this study.In addition,although the response of the Aral Sea's water volume to its recharge runoff demonstrated a complex non-linear relationship,the replenishment of the Aral Sea by the runoff in the lower reaches of the Amu Darya River was identified as the dominant factor affecting the Aral Sea shrinkage.Based on the scenario analyses,we concluded that it is possible to slow down the retreat of the Aral Sea and restore its ecosystem by increasing the efficiency of agricultural water use,decreasing agricultural water use in the middle and lower reaches,reducing ineffective evaporation from reservoirs and wetlands,and increasing the water coming from the lower reaches of the Amu Darya River to the 1961–1973 level.These measures would maintain and stabilise the water area and water volume of the Aral Sea in a state of ecological restoration.Therefore,this study focuses on how human consumption of recharge runoff affects the Aral Sea and provides scientific perspective on its ecological conservation and sustainable development.
文摘Overemphasizing the value of reefs in oil and gas exploration, reef-oriented geologists explain all carbonate platform deposits using the Wilson model. In their eyes, rimmed shelves are more valuable than carbonate ramps. However, organic banks are excellent reservoirs generated by carbonate ramps in the study area, as verified beyond doubt through petroleum exploration, such as this thesis, which investigates the genesis, types, and distribution of carbonate deposition in the north zone of the Amu-Darya Basin. Monoclinal palaeogeomorphology and rudists suggest shallow environments. Given that oolite shoals and rudist patch reefs were observed in the study area, the depositional system is interpreted to be a carbonate ramp. The Callovian-Oxfordian stage consists of nine lithofacies: oolitic limestone, skeletal limestone, micritic limestone, bioturbated limestone, and crystalline limestone, which are grouped into three facies associations presenting outer ramp, mid-ramp, and inner ramp facies associations. Five depositional sequences can be distinguished in the Callovian-Oxfordian stage. Each third-order depositional sequence is composed of transgressive systems tracts (TST) and highstand systems tracts (HST). The TST consists of mudstones with a higher response to natural gamma rays, whereas the HST contains various types of grainstone, with subordinate dolostone. The vertical and lateral distributions of sedimentary facies, and their interpreted depositional environments, revealed a ramp exhibiting a gradual southeast-northwestward environmental change from outer ramp, mid ramp, and inner ramp carbonate facies.
基金the NIOC Exploration Directorate for supporting the projectthe Ferdowsi University of Mashhad for supporting this project(Research Project Code:3/27868)
文摘Lower Cretaceous Shurijeh–Shatlyk Formations host some of the main reservoirs in the Kopeh Dagh-Amu Darya Basin.Exploration in this area so far has focused on the development of structural traps, but recognition of stratigraphic traps in this area is of increasing importance. Integration of 3D seismic data with borehole data from thirteen wells and five outcrop sections was used to identify potential reservoir intervals and survey the hydrocarbon trap types in the East Kopeh Dagh Foldbelt(NE Iran). Analyses of horizontal slices indicated that the lower Shurijeh was deposited in a braided fluvial system.Generally, three types of channel were identified in the lower Shurijeh Formation: type 1, which is low-sinuosity channels interpreted to be filled with non-reservoir fine-grained facies;type 2, which is a moderately sinuous sand-filled channel with good prospectively;and type 3, which is narrow, high sinuosity channel filled with fine-grained sediments. Results indicate that upper Shurijeh–Shatlyk Formations were deposited in fluvial to delta and shallow marine environments. The identified delta forms the second reservoir zone in the Khangiran Field. Study of the stratigraphic aspects of the Shurijeh succession indicates that both lower and upper Shurijeh reservoirs are stratigraphic reservoir traps that improved during folding.
基金Strategic Priority Research Program of Chinese Academy of Sciences,Pan-Third Pole Environment Study for a Green Silk Road,No.XDA2006030101National Natural Science Foundation of China,No.U2003202。
文摘Central Asia(CA)is one of the most fragile regions worldwide owing to arid climate and accumulated human activities,and is a global hotspot due to gradually deteriorating ecological environment.The Amu Darya Basin(ADB),as the most economically and demographically important region in CA,is of particular concern.To determine the concentration,source and pollution status of heavy metals(HMs)in surface sediments of the ADB,154samples were collected and analyzed for metals across the basin.Correlation and cluster analysis,and positive matrix factorization model were implemented to understand metals’association and apportion their possible sources.Cumulative frequency distribution and normalization methods were used to determine the geochemical baseline values(GBVs).Then,various pollution indices and ecological risk index were employed to characterize and evaluate the pollution levels and associated risks based on the GBVs.Results indicated that the mean concentrations of HMs showed the following descending order in the surface sediments of ADB:Zn>Cr>Ni>Cu>Pb>Co>Cd.The spatial distribution maps showed that Cr,Ni,and Cu had relatively high enrichment in the irrigated agricultural area;high abundances of Zn,Pb,and Cd were mainly found in the urban areas.Four source factors were identified for these metals,namely natural sources,industrial discharge,agricultural activities,and mixed source of traffic and mining activities,accounting for 33.5%,11.4%,34.2%,and 20.9%of the total contribution,respectively.The GBVs of Cd,Zn,Pb,Cu,Ni,Cr,and Co in the ADB were 0.27,58.9,14.6,20.3,25.8,53.4,and 9.80 mg/kg,respectively,which were similar to the regional background values obtained from lake sediments in the bottom.In general,the assessment results revealed that surface sediments of the ADB were moderately polluted and low ecological risk by HMs.
基金funded by PetroChina projects(No.2021DJ3102,No.2021DJ3301).
文摘The right bank of the Amu Darya Basin enjoys abundant natural gas resources,on which the Callovian-Oxfordian strata in the middle of Block B serve as the major horizons for natural gas production.However,the characteristics and distribution patterns of the sedimentary microfacies in these strata are yet to be further explored.Based on the analysis of data on drilling,logging,cores,and thin sections from 29 typical wells,as well as the regional sedimentary background,this study inferred that the middle of Block B evolved from the Callovian ramp platform into the Oxfordian rimmed platform.Moreover,this study determined that the inner-ramp intertidal-subtidal shallow-water subfacies mainly developed during the Callovian and transitioned into the shallow shelf subfacies during the Oxfordian.This study identified eight sedimentary microfacies,namely reef knoll,reef-shoal complex,bioclastic shoal,psammitic shoal,bioherm,lime mud mound,intershoal(intermound),and static-water mud.Based on research into the high-precision sequence-sedimentary microfacies framework,this study built a geological model for the development of sedimentary microfacies in the study area.According to this geological model,the sedimentary microfacies in the study area are characterized by vertical alternation of reef-shoal complex,bioclastic(psammitic)shoal,bioherm,and intershoal microfacies.Moreover,they show the development of reef knoll,reef-shoal complex,bioclastic(psammitic)shoal,and bioherm(or lime mud mound)laterally from west to east,with the physical properties of the reservoirs deteriorating from west to east accordingly.The microfacies of reef-shoal complex and the bioclastic(psammitic)shoal predominate in the study area,and their deposition and development are controlled by sequence boundaries and are also affected by paleo-landforms.The Oxfordian reef-shoal complexes were largely inherited from the Callovian uplifts and show lateral seaward progradation.
文摘Carbonate gas reservoir in the eastern area on the Right Bank of the Amu Darya River,Turkmenistan,are of low-porosity and with developed fractures.In this area,fractures control reservoir properties and natural gas production,and karst fractures are the most important kind of fractures,so their identification and evaluation are quite necessary.In this paper,fracture types were identified and their occurrence was extracted by using conventional logging and image logging data after core calibration.Then,the distribution characteristics of karst fractures and their controlling effect on reservoirs were studied according to the identification results.And the following research results were obtained.First,karst fractures are mainly of high angle with the characteristic of mono system and the interactive relation of genesis.Second,they are mainly distributed in the upper XVhp layer of CallovianeOxford Stage and the lower XVa2eXVI layer.Third,they are the main effective fractures in this area.The dissolved pores are connected effectively through the expanded karst fractures by dissolution,and consequently reservoirs of high porosity and permeability are formed and they are the important reservoir type and high-yield gas reservoir in this area.Fourth,karst fractures are related to high-yield wells and high-yield layers in this area,and they also control the distribution of high-yield reservoirs in the lower part of CallovianeOxford Stage.It is concluded that by virtue of imaging logging and conventional logging data,karst fractures,unfilled fractures,semi-filled fractures and fullyfilled fractures can be identified and evaluated better.Furthermore,the identification and evaluation of karst fractures deepen the understanding on fractured reservoirs in this area,improve the reservoir evaluation effect,and provide the basis for the target horizon and azimuth optimization of horizontal wells and highly deviated wells.And it is also indicated that the reservoirs with developed karst fractures are the subsequent important drilling targets.
