Based on the sheet, scanning electron microscope and high pressure mercury analysis method, this paper takes Jiyuan oilfield-Ma Jia mountain district 4 5 sandstone reservoir as the research object, from the reservoir ...Based on the sheet, scanning electron microscope and high pressure mercury analysis method, this paper takes Jiyuan oilfield-Ma Jia mountain district 4 5 sandstone reservoir as the research object, from the reservoir petrology, pore type and porosity, permeability, the system analyzed the reservoir characteristics and its control factors. The results show that the sandstone in the 4 5 section of Baoziwan-Majiashan area of Jiyuan oilfield is fine in size and high in filling content. The pore types were dominated by intergranular pores and dissolved pores, with a low face rate. The reservoir property is relatively poor, with mean porosity of 11.11% and mean permeability of 1.16 × 10<sup>−</sup><sup>3</sup> µm<sup>2</sup>. In the low porous, low otonic background, the development of relatively high pore hypertonic areas. Compaction and cementation should play a destructive role in reservoir properties, and dissolution should play a positive role in reservoir properties. Compaction adjusts the migration of clay minerals and miscellaneous bases in the original sediment in the study area, greatly reducing the porosity and permeability of the reservoir;the development of the cement cement, carbonate cementation and some quartz secondary compounds reduces the storage space;the dissolution effect, especially the secondary dissolution pores of the reservoir, which obviously improves the properties of the reservoir.展开更多
Submarine canyon is an important channel for long-distance sediment transport, and an important part of deepwater sedimentary system. The large-scale Rizhao Canyons have been discovered for the first time in 2015 in t...Submarine canyon is an important channel for long-distance sediment transport, and an important part of deepwater sedimentary system. The large-scale Rizhao Canyons have been discovered for the first time in 2015 in the continental slope area of the western South China Sea. Based on the interpretation and analysis of multi-beam bathymetry and two-dimensional multi-channel seismic data, the geology of the canyons has however not been studied yet. In this paper, the morphology and distribution characteristics of the canyon are carefully described,the sedimentary filling structure and its evolution process of the canyon are analyzed, and then its controlling factors are discussed. The results show that Rizhao Canyons group is a large slope restricted canyon group composed of one east-west west main and nine branch canyons extending to the south. The canyon was formed from the late Miocene to the Quaternary. The east-west main canyon is located in the transition zone between the northern terrace and the southern Zhongjiannan Slope, and it is mainly formed by the scouring and erosion of the material source from the west, approximately along the slope direction. Its development and evolution is mainly controlled by sediment supply and topographic conditions, the development of 9 branch canyons is mainly controlled by gravity flow and collapse from the east-west main canyon. This understanding result is a supplement to the study of “source-channel–sink” sedimentary system in the west of the South China Sea, and has important guiding significance for the study of marine geological hazards.展开更多
Marine shale gas resources have great potential in the south of the Sichuan Basin in China.At present,the high-quality shale gas resources at depth of 2000–3500 m are under effective development,and strategic breakth...Marine shale gas resources have great potential in the south of the Sichuan Basin in China.At present,the high-quality shale gas resources at depth of 2000–3500 m are under effective development,and strategic breakthroughs have been made in deeper shale gas resources at depth of 3500–4500 m.To promote the effective production of shale gas in this area,this study examines key factors controlling high shale gas production and presents the next exploration direction in the southern Sichuan Basin based on summarizing the geological understandings from the Lower Silurian Longmaxi Formation shale gas exploration combined with the latest results of geological evaluation.The results show that:(1)The relative sea depth in marine shelf sedimentary environment controls the development and distribution of reservoirs.In the relatively deep water area in deep-water shelf,grade-I reservoirs with a larger continuous thickness develop.The relative depth of sea in marine shelf sedimentary environment can be determined by redox conditions.The research shows that the uranium to thorium mass ratio greater than 1.25 indicates relatively deep water in anoxic reduction environment,and the uranium to thorium mass ratio of 0.75–1.25 indicates semi-deep water in weak reduction and weak oxidation environment,and the uranium to thorium mass ratio less than 0.75 indicates relatively shallow water in strong oxidation environment.(2)The propped fractures in shale reservoirs subject to fracturing treatment are generally 10–12 m high,if grade-I reservoirs are more than 10 m in continuous thickness,then all the propped section would be high-quality reserves;in this case,the longer the continuous thickness of penetrated grade-I reservoirs,the higher the production will be.(3)The shale gas reservoirs at 3500–4500 m depth in southern Sichuan are characterized by high formation pressure,high pressure coefficient,well preserved pores,good pore structure and high proportion of free gas,making them the most favorable new field for shale gas exploration;and the pressure coefficient greater than 1.2 is a necessary condition for shale gas wells to obtain high production.(4)High production wells in the deep shale gas reservoirs are those in areas where Long11-Long13 sub-beds are more than 10 m thick,with 1500 m long horizontal section,grade-I reservoirs penetration rate of over 90%,and fractured by dense cutting+high intensity sand injection+large displacement+large liquid volume.(5)The relatively deep-water area in the deep-water shelf and the area at depth of 3500–4500 m well overlap in the southern Sichuan,and the overlapping area is the most favorable shale gas exploration and development zones in the southern Sichuan in the future.With advancement in theory and technology,annual shale gas production in the southern Sichuan is expected to reach 450×108 m3.展开更多
There are abundant coal and coalbed methane(CBM)resources in the Xishanyao Formation in the western region of the southern Junggar Basin,and the prospects for CBM exploration and development are promising.To promote t...There are abundant coal and coalbed methane(CBM)resources in the Xishanyao Formation in the western region of the southern Junggar Basin,and the prospects for CBM exploration and development are promising.To promote the exploration and development of the CBM resources of the Xishanyao Formation in this area,we studied previous coalfield survey data and CBM geological exploration data.Then,we analyzed the relationships between the gas content and methane concentration vs.coal seam thickness,burial depth,coal reservoir physical characteristics,hydrogeological conditions,and roof and floor lithology.In addition,we briefly discuss the main factors influencing CBM accumulation.First,we found that the coal strata of the Xishanyao Formation in the study area are relatively simple in structure,and the coal seam has a large thickness and burial depth,as well as moderately good roof and floor conditions.The hydrogeological conditions and coal reservoir physical characteristics are also conducive to the enrichment and a high yield of CBM.We believe that the preservation of CBM resources in the study area is mainly controlled by the structure,burial depth,and hydrogeological conditions.Furthermore,on the basis of the above results,the coal seam of the Xishanyao Formation in the synclinal shaft and buried at depths of 700-1000 m should be the first considered for development.展开更多
Analysis and study of clastic and clay minerals of surface sediments and their chemical composition in the sea area northwest of the Antarctic Peninsula enable the authors to divide this area basically into four miner...Analysis and study of clastic and clay minerals of surface sediments and their chemical composition in the sea area northwest of the Antarctic Peninsula enable the authors to divide this area basically into four mineralogical provinces: (1) the mineral ogical province of coast and island shelf of the Southern Shetland Islands, (2) the mineral ogical province of the eastern Bransfield Strait, (3) the mineral ogical province of the western Bransfield Strait, and (4)the mineral ogical province of the western Antarctic Peninsula. Finally, the relationships between the mineral distribution and geologic, structure, material sources, glaciers, currents, and environments are briefly described.展开更多
An investigation was carried out in the Y3 seamount area of the Western Pacific Ocean in December 2014,and the distribution of dissolved inorganic carbon(DIC)and its relationship with environmental factors in this are...An investigation was carried out in the Y3 seamount area of the Western Pacific Ocean in December 2014,and the distribution of dissolved inorganic carbon(DIC)and its relationship with environmental factors in this area were explored.The results show that DIC concentration was higher in the adjacent waters of the Y3 seamount area,and the uplift of DIC isolines at the stations was close to the seamount.Meanwhile,interaction between the North Equatorial Current(NEC)and the Y3 seamount affected the DIC distribution,i.e.,the upwelling in the same direction of the NEC was obvious,resulting in a decreasing trend of average concentration of DIC in the 200 m water column from the top to the two sides in this direction but in the cross direction.The DIC concentration increased with the water depth increase,and its distribution was affected by various environmental factors.In the surface water,high temperature was a decisive factor for the decrease of the DIC concentration,but the photosynthesis of phytoplankton showing only a weak influence.In the North Pacific Tropic Water(NPTW),DIC production rate from organic matter decomposition was higher than that of DIC consumption by phytoplankton photosynthesis,leading to a continual increase of DIC.In the North Pacific Intermediate Water(NPIW),organic matter decomposition played a leading role in the increase of DIC.In the deep water,decomposition of organic matter weakened,and the dissolution of CaCO3 controlled the carbonate system,and DIC had the smallest variation range.展开更多
The material sources and control factors of rare earth elements(REEs) for 25 borehole bulk samples from the Late Permian Longtan Formation in Mount Huaying(borehole number:ZK10-6),Sichuan Province,South China,were inv...The material sources and control factors of rare earth elements(REEs) for 25 borehole bulk samples from the Late Permian Longtan Formation in Mount Huaying(borehole number:ZK10-6),Sichuan Province,South China,were investigated.All samples were determined by inductively coupled plasma mass spectrometry(ICP-MS).The chondrite-normalized distribution patterns of mudstone samples are uniform.All samples belong to the light rare earth element(LREE)-rich type and are enriched in LREEs relative to heavy rare earth elements(HREEs).The distribution curves of REEs in mudstone are highly similar to Mount Emei basalt and the three periods of REEs enrichment correspond to three Mount Emei basalt eruption cycles in Longtan period.The results indicate that REE patterns are not controlled by materials from the seawater or land plants.The predominant sources of REEs are from terrigenous material as indicated by negative Eu anomaly.So,the sources of REEs are controlled by terrigenous material,and the Mount Emei basalt is the predominant source of terrigenous material.Thus,transgression-regression is another control factor of REEs enrichment.展开更多
Introduction: Pre-eclampsia is a major cause of maternal and prenatal morbidity and mortality, that complicates 2% to 8% of pregnancies worldwide. The aim of this study was to determine the predictive factors for pre-...Introduction: Pre-eclampsia is a major cause of maternal and prenatal morbidity and mortality, that complicates 2% to 8% of pregnancies worldwide. The aim of this study was to determine the predictive factors for pre-eclampsia in two hospitals in the city of Yaoundé. Methods: A case-control study was conducted at the Gynaecology & Obstetrics department of the Yaoundé Gynaeco-Obstetric and Paediatric Hospital (YGOPH) and the Main Maternity of the Yaoundé Central Hospital (MM-YCH) from February 1 to July 30, 2022. The cases were all pregnant women presenting with pre-eclampsia. The control group included pregnant women without pre-eclampsia. Descriptive statistics followed by logistic regression analyses were conducted with level of significance set at p-value Results: Included in the study were 33 cases and 132 controls, giving a total of 165 participants. The predictive factors for pre-eclampsia after multivariate analysis were: primiparity (aOR = 51.86, 95% CI: 3.01 - 1230.96, p = 0.045), duration of exposure to partner’s sperm Conclusion: The odds of pre-eclampsia increased with primiparity, duration of exposure to partner’s sperm < 3 months, personal history of pre-eclampsia and maternal history of pre-eclampsia. Recognition of these predictor factors would improve the ability to diagnose and monitor women likely to develop pre-eclampsia before the onset of disease for timely interventions.展开更多
The late Paleozoic Fengcheng Formation shale(LPF shale)in the Junggar Basin,NW China,is the oldest alkaline source rock discovered in the world,providing a unique perspective with which to explore organic matter(OM)en...The late Paleozoic Fengcheng Formation shale(LPF shale)in the Junggar Basin,NW China,is the oldest alkaline source rock discovered in the world,providing a unique perspective with which to explore organic matter(OM)enrichment in alkaline lake environments.Combined with the organic carbon isotope profile and paleoenvironmental proxies,this study reveals that the LPF shale was deposited in an arid climate with high salinity and a strong reducing environment,accompanied by frequent volcanic activity.High TOC values are concentrated in two intervals with frequent fluctuations in OM types.A negative excursion due to changes in sedimentary OM source is found in the δ^(13)C_(org) profile.The excursion corresponds to the OM enrichment interval and is accompanied by abnormally high values of Sr/Ba and Sr/Cu.This implies that the extreme arid climate has led to high salinity,resulting in strong reducibility and changes in paleontological assemblages,which in turn controlled the differential enrichment of OM.The Fengcheng Fm.high-quality source rocks are the result of the combined action of climatic events,volcanism,high-salinity water environment and superior hydrocarbon-generating organisms.The results provide new insights into the formation conditions of terrestrial alkaline high-quality source rocks and the factors controlling alkaline OM enrichment.展开更多
Determining the main controlling factors of earthquake-triggered geohazards is a prerequisite for studying earthquake geohazards and post-disaster emergency response.By studying these factors,the geomorphic and geolog...Determining the main controlling factors of earthquake-triggered geohazards is a prerequisite for studying earthquake geohazards and post-disaster emergency response.By studying these factors,the geomorphic and geological factors controlling the nature,condition,and distribution of earthquake-induced geohazards can be analyzed.Such insights facilitate earthquake disaster prediction and emergency response planning.The authors combined field investigations and spatial data analysis to examine geohazards induced by seismic events,examining ten earthquakes including the Wenchuan,Yushu,Lushan events,to elucidate the main control factors of seismic geohazard.The authors observed that seismic geohazard occurrence is usually affected by many factors,among which active nature of the seismogenic fault,seismic peak ground acceleration(PGA),topographic slope and geomorphic height differences,and distance from the fault zone and river system are the most important.Compared with strike-slip earthquakes,thrust earthquakes induce more high-altitude and high-speed remote landslides,which can cause great harm.Slopes of 0°–40°are prone to secondary seismic geohazards,which are mainly concentrated 0–6 km from the river system.Secondary geohazards are not only related to seismogenic fault but also influenced by the associated faults in the earthquake area.The maximum seismic PGA and secondary seismic geohazard number are positively correlated,and the horizontal and vertical ground motions play leading and promoting roles in secondary geohazard formation,respectively.Through the research,the spatial distribution of seismic geohazards is predicted,providing a basis for the formulation of emergency response plans following disasters.展开更多
The natural cracking of crude oils in deep reservoirs has gained great interest due to continuously increasing depth of petroleum exploration and exploitation.Complex oil compositions and surroundings as well as compl...The natural cracking of crude oils in deep reservoirs has gained great interest due to continuously increasing depth of petroleum exploration and exploitation.Complex oil compositions and surroundings as well as complicated geological evolutions make oil cracking in nature much more complex than industrial pyrolysis.So far,numerous studies,focused on this topic,have made considerable progress although there still exist some drawbacks.However,a comprehensive review on crude oil cracking is yet to be conducted.This article systematically reviews the controlling factors of oil cracking from six aspects,namely,oil compositions,temperature and time,pressure,water,minerals and solid organic matter.We compare previous experimental and modelling results and present new field cases.In the following,we evaluate the prevailing estimation methods for the extent of oil cracking,and elucidate other factors that may interfere with the application of these estimation methods.This review will be helpful for further investigations of crude oil cracking and provides a guide for estimation of the cracking extent of crude oils.展开更多
Based on the contents of six heavy metal elements in surface sediments from coastal areas of Fujian Province,the distribution characteristics and controlling factors of six heavy metals in a bay-island-estuary system(...Based on the contents of six heavy metal elements in surface sediments from coastal areas of Fujian Province,the distribution characteristics and controlling factors of six heavy metals in a bay-island-estuary system(BIES)were studied.This paper focuses on the influence of the hydrodynamic environment,and systematically discusses how grain size compositions,chemical environment,tidal current,ocean circulation and human activities influence the distribution and transportation of the heavy metals.The results indicated that the distribution and migration of Cu,Pb,Zn and Cr elements were mainly controlled by natural factors such as regional geological background,grain size compositions,and tidal residual currents.In contrast,As and Hg was mainly affected by human factors such as agriculture and industrial manufacturing.In the BIES,where the chemical environment exerted limited influence,the accumulation and migration of heavy metals are mainly influenced by human activities and enhanced by estuary processes as well as the complex sedimentary dynamic environment caused by many bays and islands.展开更多
Based on the combination of core observation,experimental analysis and testingand geological analysis,the main controlling factors of shale oil enrichment in the Lower Permian Fengcheng Formation in the Mahu Sag of th...Based on the combination of core observation,experimental analysis and testingand geological analysis,the main controlling factors of shale oil enrichment in the Lower Permian Fengcheng Formation in the Mahu Sag of the Junggar Basin are clarified,and a shale oil enrichment model is established.The results show that the enrichment of shale oil in the Fengcheng Formation in the Mahu Sag is controlled by the organic abundance,organic type,reservoir capacity and the amount of migration hydrocarbon in shale.The abundance of organic matter provides the material basis for shale oil enrichment,and the shales containing typesⅠandⅡorganic matters have good oil content.The reservoir capacity controls shale oil enrichment.Macropores are the main space for shale oil enrichment in the Fengcheng Formation,and pore size and fracture scale directly control the degree of shale oil enrichment.The migration of hydrocarbons in shale affects shale oil enrichment.The shale that has expelled hydrocarbons has poor oil content,while the shale that has received hydrocarbons migrated from other strata has good oil content.Lithofacies reflect the hydrocarbon generation and storage capacity comprehensively.The laminated felsic shale,laminated lime-dolomitic shale and thick-layered felsic shale have good oil content,and they are favorable lithofacies for shale oil enrichment.Under the control of these factors,relative migration of hydrocarbons occurred within the Fengcheng shale,which leads to the the difference in the enrichment process of shale oil.Accordingly,the enrichment mode of shale oil in Fengcheng Formation is established as"in-situ enrichment"and"migration enrichment".By superimposing favorable lithofacies and main controlling factors of enrichment,the sweet spot of shale oil in the Fengcheng Formation can be selected which has great significance for the exploration and development of shale oil.展开更多
The behavior and controlling factors of natural gas adsorption in the Jurassic continental shale in the northeastern Sichuan Basin are studied based on the organic geochemical features,mineral compositions and pore st...The behavior and controlling factors of natural gas adsorption in the Jurassic continental shale in the northeastern Sichuan Basin are studied based on the organic geochemical features,mineral compositions and pore structure parameters through a series of experiments on samples from the shale.Results show that the total gas content of the shale measured on-site is 0.1-5.3 cm^(3)/g,with an average of 0.7 cm^(3)/g.The methane isothermal adsorption curves show a trend of increasing first and then decreasing,indicating an obvious excessive adsorption.The shale has a maximum adsorption capacity(V^(L))of 0.44-3.59 cm^(3)/g,with an average of 1.64 cm^(3)/g,lower than that of marine shale in the same basin.The organic matter content and pore structure characteristics are identified as the two main factors controlling the adsorption capacity of the shale.Micropores in the shale are the main storage space for gas to be adsorbed.Due to well developed shell laminae and interlayers in the shale,calcite plays a more important role than clay minerals in affecting the adsorption of gas to the rock.The formation temperature and water content also significantly inhibit the gas adsorption to the shale.Compared with marine shale in the basin,the Jurassic continental shale is more heterogeneous and lower in TOC values.Furthermore,with a more widely developed clayey shale lithofacies and shell limy shale lithofacies as well as relatively less developed organic pores and micropores,the continental shale is inferior to marine shale in terms of gas adsorption capacity.展开更多
Reducing ammonia(NH3) and nitrous oxide(N2O) emissions have great effects on mitigating nitrogen(N) nutrient loss and greenhouse gas emissions. Controlled release urea(CRU) can control the N release rate, which reduce...Reducing ammonia(NH3) and nitrous oxide(N2O) emissions have great effects on mitigating nitrogen(N) nutrient loss and greenhouse gas emissions. Controlled release urea(CRU) can control the N release rate, which reduces reactive N loss and increases nitrogen use efficiency relative to conventional urea(CU). However, the crucial factors influencing the responses of NH3and N2O emissions to CRU relative to CU are still unclear. In this study, we evaluated the responses of NH3and N2O emissions to CRU based on collected field data with a meta-analysis. CRU reduced the NH3and N2O emissions by 32.7 and 25.0% compared with CU, respectively. According to subgroup analysis, CRU presented better mitigation of NH3and N2O emissions in soils with pH 6.5–7.5(–47.9 and –23.7%) relative to either pH<6.5(–28.5and –21.4%) or pH>7.5(–29.3 and –17.3%), and in the rice season(–34.8 and –29.1%) relative to the wheat season(–19.8 and –22.8%). The responses of NH3and N2O emissions to CRU increased from rainfed(–30.5 and –17.0%) to irrigated(–32.5 and –22.9%), and then to paddy(–34.8 and –29.1%) systems. In addition, the response of N2O emission mitigation increased with increases in soil total nitrogen(TN);however, soil TN did not significantly affect the response of NH3volatilization. The reduction in NH3emission was greater in sandy-textured soil(–57.7%) relative to loam-textured(–32.9%) and clay-textured(–32.3%) soils, whereas soil texture did not affect N2O emission. Overall, CRU was a good option for reducing the NH3and N2O emissions relative to CU in agricultural production. This analysis improves our understanding of the crucial environmental and management factors influencing the mitigation of NH3and N2O emissions under CRU application, and these site-specific factors should be considered when applying CRU to reduce reactive N loss and increase NUE.展开更多
Reinforcement learning(RL) has roots in dynamic programming and it is called adaptive/approximate dynamic programming(ADP) within the control community. This paper reviews recent developments in ADP along with RL and ...Reinforcement learning(RL) has roots in dynamic programming and it is called adaptive/approximate dynamic programming(ADP) within the control community. This paper reviews recent developments in ADP along with RL and its applications to various advanced control fields. First, the background of the development of ADP is described, emphasizing the significance of regulation and tracking control problems. Some effective offline and online algorithms for ADP/adaptive critic control are displayed, where the main results towards discrete-time systems and continuous-time systems are surveyed, respectively.Then, the research progress on adaptive critic control based on the event-triggered framework and under uncertain environment is discussed, respectively, where event-based design, robust stabilization, and game design are reviewed. Moreover, the extensions of ADP for addressing control problems under complex environment attract enormous attention. The ADP architecture is revisited under the perspective of data-driven and RL frameworks,showing how they promote ADP formulation significantly.Finally, several typical control applications with respect to RL and ADP are summarized, particularly in the fields of wastewater treatment processes and power systems, followed by some general prospects for future research. Overall, the comprehensive survey on ADP and RL for advanced control applications has d emonstrated its remarkable potential within the artificial intelligence era. In addition, it also plays a vital role in promoting environmental protection and industrial intelligence.展开更多
Peanut stem rot caused by Sclerotium rolfsii is a soil-borne disease,and it has become the main disease of peanut in Yimeng mountainous area.S.rolfsii survives the winter as mycelia and sclerotia in soil and debris,be...Peanut stem rot caused by Sclerotium rolfsii is a soil-borne disease,and it has become the main disease of peanut in Yimeng mountainous area.S.rolfsii survives the winter as mycelia and sclerotia in soil and debris,becoming the primary source of infection in the following year.The disease resistance of peanut varieties,high temperature and humidity,and cultivation measures are the pathogenic factors affecting the occurrence of peanut stem rot.The disease can be effectively controlled by screening disease-resistant varieties and seed chemical treatment,improving soil by deep tillage and crop rotation,carrying out flowing water management of affected field,cutting off transmission routes,and strengthening seed dressing and triple spraying control.展开更多
Introduction: Cardiovascular diseases are the leading cause of mortality in type 2 diabetics patients. Our work aimed to assess the level of control of type 2 diabetes and associated cardiovascular risk factors. Patie...Introduction: Cardiovascular diseases are the leading cause of mortality in type 2 diabetics patients. Our work aimed to assess the level of control of type 2 diabetes and associated cardiovascular risk factors. Patients and study method: This was an observational cross-sectional study of type 2 diabetics patients. The parameters studied were: sociodemographic data, lifestyle, anthropometric data, levels of control of diabetes by the level of HbA1C, blood pressure measured at the office and cholesterol. Results: 326 type 2 diabetics patients were collected. The sex-ratio was 0.35. The average age of the patients was 58 ± 11 years. A physical inactivity remained present in 79 patients (24.23%), 2 patients (0.61%) continued to smoke. The prevalence of obesity was 21.16% (n = 69) or 25% of women and 10.4% of men (p = 0.01). Abdominal obesity was observed in 151 patients (46.31%), 139 of whom were female and 12 male (p = 0.001). Diabetes was sufficiently controlled in 65.34% of patients (n = 213) while cholesterolemia and hypertension were controlled in 33.44% and 8.33% of patients respectively. Conclusion: Type 2 diabetes was frequently associated with other cardiovascular risk factors. Control of diabetes and these factors was insufficient. Therapeutic education of type 2 diabetics patients needed to be improved.展开更多
文摘Based on the sheet, scanning electron microscope and high pressure mercury analysis method, this paper takes Jiyuan oilfield-Ma Jia mountain district 4 5 sandstone reservoir as the research object, from the reservoir petrology, pore type and porosity, permeability, the system analyzed the reservoir characteristics and its control factors. The results show that the sandstone in the 4 5 section of Baoziwan-Majiashan area of Jiyuan oilfield is fine in size and high in filling content. The pore types were dominated by intergranular pores and dissolved pores, with a low face rate. The reservoir property is relatively poor, with mean porosity of 11.11% and mean permeability of 1.16 × 10<sup>−</sup><sup>3</sup> µm<sup>2</sup>. In the low porous, low otonic background, the development of relatively high pore hypertonic areas. Compaction and cementation should play a destructive role in reservoir properties, and dissolution should play a positive role in reservoir properties. Compaction adjusts the migration of clay minerals and miscellaneous bases in the original sediment in the study area, greatly reducing the porosity and permeability of the reservoir;the development of the cement cement, carbonate cementation and some quartz secondary compounds reduces the storage space;the dissolution effect, especially the secondary dissolution pores of the reservoir, which obviously improves the properties of the reservoir.
基金The Major Special Project of Guangdong Provincial Laboratory of Southern Marine Science and Engineering(Guangzhou) under contract No. GML2019ZD0207the National Natural Science Foundation of China under contract No. U20A20100the China Geological Survey Project under contract Nos DD20221712, DD20221719 and DD20191002。
文摘Submarine canyon is an important channel for long-distance sediment transport, and an important part of deepwater sedimentary system. The large-scale Rizhao Canyons have been discovered for the first time in 2015 in the continental slope area of the western South China Sea. Based on the interpretation and analysis of multi-beam bathymetry and two-dimensional multi-channel seismic data, the geology of the canyons has however not been studied yet. In this paper, the morphology and distribution characteristics of the canyon are carefully described,the sedimentary filling structure and its evolution process of the canyon are analyzed, and then its controlling factors are discussed. The results show that Rizhao Canyons group is a large slope restricted canyon group composed of one east-west west main and nine branch canyons extending to the south. The canyon was formed from the late Miocene to the Quaternary. The east-west main canyon is located in the transition zone between the northern terrace and the southern Zhongjiannan Slope, and it is mainly formed by the scouring and erosion of the material source from the west, approximately along the slope direction. Its development and evolution is mainly controlled by sediment supply and topographic conditions, the development of 9 branch canyons is mainly controlled by gravity flow and collapse from the east-west main canyon. This understanding result is a supplement to the study of “source-channel–sink” sedimentary system in the west of the South China Sea, and has important guiding significance for the study of marine geological hazards.
基金Supported by the China National Science and Technology Major Project(2016ZX05062)the PetroChina Science and Technology Major Project(2016E-0611)
文摘Marine shale gas resources have great potential in the south of the Sichuan Basin in China.At present,the high-quality shale gas resources at depth of 2000–3500 m are under effective development,and strategic breakthroughs have been made in deeper shale gas resources at depth of 3500–4500 m.To promote the effective production of shale gas in this area,this study examines key factors controlling high shale gas production and presents the next exploration direction in the southern Sichuan Basin based on summarizing the geological understandings from the Lower Silurian Longmaxi Formation shale gas exploration combined with the latest results of geological evaluation.The results show that:(1)The relative sea depth in marine shelf sedimentary environment controls the development and distribution of reservoirs.In the relatively deep water area in deep-water shelf,grade-I reservoirs with a larger continuous thickness develop.The relative depth of sea in marine shelf sedimentary environment can be determined by redox conditions.The research shows that the uranium to thorium mass ratio greater than 1.25 indicates relatively deep water in anoxic reduction environment,and the uranium to thorium mass ratio of 0.75–1.25 indicates semi-deep water in weak reduction and weak oxidation environment,and the uranium to thorium mass ratio less than 0.75 indicates relatively shallow water in strong oxidation environment.(2)The propped fractures in shale reservoirs subject to fracturing treatment are generally 10–12 m high,if grade-I reservoirs are more than 10 m in continuous thickness,then all the propped section would be high-quality reserves;in this case,the longer the continuous thickness of penetrated grade-I reservoirs,the higher the production will be.(3)The shale gas reservoirs at 3500–4500 m depth in southern Sichuan are characterized by high formation pressure,high pressure coefficient,well preserved pores,good pore structure and high proportion of free gas,making them the most favorable new field for shale gas exploration;and the pressure coefficient greater than 1.2 is a necessary condition for shale gas wells to obtain high production.(4)High production wells in the deep shale gas reservoirs are those in areas where Long11-Long13 sub-beds are more than 10 m thick,with 1500 m long horizontal section,grade-I reservoirs penetration rate of over 90%,and fractured by dense cutting+high intensity sand injection+large displacement+large liquid volume.(5)The relatively deep-water area in the deep-water shelf and the area at depth of 3500–4500 m well overlap in the southern Sichuan,and the overlapping area is the most favorable shale gas exploration and development zones in the southern Sichuan in the future.With advancement in theory and technology,annual shale gas production in the southern Sichuan is expected to reach 450×108 m3.
基金the China Geological Survey Project of Chinese Oil and Gas Strategic Petroleum Prospects Investigation and Evaluation(Grant No.1211302108025—2 and No.DD20160204).
文摘There are abundant coal and coalbed methane(CBM)resources in the Xishanyao Formation in the western region of the southern Junggar Basin,and the prospects for CBM exploration and development are promising.To promote the exploration and development of the CBM resources of the Xishanyao Formation in this area,we studied previous coalfield survey data and CBM geological exploration data.Then,we analyzed the relationships between the gas content and methane concentration vs.coal seam thickness,burial depth,coal reservoir physical characteristics,hydrogeological conditions,and roof and floor lithology.In addition,we briefly discuss the main factors influencing CBM accumulation.First,we found that the coal strata of the Xishanyao Formation in the study area are relatively simple in structure,and the coal seam has a large thickness and burial depth,as well as moderately good roof and floor conditions.The hydrogeological conditions and coal reservoir physical characteristics are also conducive to the enrichment and a high yield of CBM.We believe that the preservation of CBM resources in the study area is mainly controlled by the structure,burial depth,and hydrogeological conditions.Furthermore,on the basis of the above results,the coal seam of the Xishanyao Formation in the synclinal shaft and buried at depths of 700-1000 m should be the first considered for development.
文摘Analysis and study of clastic and clay minerals of surface sediments and their chemical composition in the sea area northwest of the Antarctic Peninsula enable the authors to divide this area basically into four mineralogical provinces: (1) the mineral ogical province of coast and island shelf of the Southern Shetland Islands, (2) the mineral ogical province of the eastern Bransfield Strait, (3) the mineral ogical province of the western Bransfield Strait, and (4)the mineral ogical province of the western Antarctic Peninsula. Finally, the relationships between the mineral distribution and geologic, structure, material sources, glaciers, currents, and environments are briefly described.
基金the Science&Technology Basic Resources Investigation Program of China(No.2017TY100802)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA19060401)the National Natural Science Foundation of China(No.91958103)。
文摘An investigation was carried out in the Y3 seamount area of the Western Pacific Ocean in December 2014,and the distribution of dissolved inorganic carbon(DIC)and its relationship with environmental factors in this area were explored.The results show that DIC concentration was higher in the adjacent waters of the Y3 seamount area,and the uplift of DIC isolines at the stations was close to the seamount.Meanwhile,interaction between the North Equatorial Current(NEC)and the Y3 seamount affected the DIC distribution,i.e.,the upwelling in the same direction of the NEC was obvious,resulting in a decreasing trend of average concentration of DIC in the 200 m water column from the top to the two sides in this direction but in the cross direction.The DIC concentration increased with the water depth increase,and its distribution was affected by various environmental factors.In the surface water,high temperature was a decisive factor for the decrease of the DIC concentration,but the photosynthesis of phytoplankton showing only a weak influence.In the North Pacific Tropic Water(NPTW),DIC production rate from organic matter decomposition was higher than that of DIC consumption by phytoplankton photosynthesis,leading to a continual increase of DIC.In the North Pacific Intermediate Water(NPIW),organic matter decomposition played a leading role in the increase of DIC.In the deep water,decomposition of organic matter weakened,and the dissolution of CaCO3 controlled the carbonate system,and DIC had the smallest variation range.
基金supported by the National High Technology Research and Development Program of China (863)(grant no.2007AA06Z220)Important Project of the Ministry of Education(grant no.307014)the Huainan Mining Group program
基金Project(40839910) supported by the National Natural Science Foundation of China
文摘The material sources and control factors of rare earth elements(REEs) for 25 borehole bulk samples from the Late Permian Longtan Formation in Mount Huaying(borehole number:ZK10-6),Sichuan Province,South China,were investigated.All samples were determined by inductively coupled plasma mass spectrometry(ICP-MS).The chondrite-normalized distribution patterns of mudstone samples are uniform.All samples belong to the light rare earth element(LREE)-rich type and are enriched in LREEs relative to heavy rare earth elements(HREEs).The distribution curves of REEs in mudstone are highly similar to Mount Emei basalt and the three periods of REEs enrichment correspond to three Mount Emei basalt eruption cycles in Longtan period.The results indicate that REE patterns are not controlled by materials from the seawater or land plants.The predominant sources of REEs are from terrigenous material as indicated by negative Eu anomaly.So,the sources of REEs are controlled by terrigenous material,and the Mount Emei basalt is the predominant source of terrigenous material.Thus,transgression-regression is another control factor of REEs enrichment.
文摘Introduction: Pre-eclampsia is a major cause of maternal and prenatal morbidity and mortality, that complicates 2% to 8% of pregnancies worldwide. The aim of this study was to determine the predictive factors for pre-eclampsia in two hospitals in the city of Yaoundé. Methods: A case-control study was conducted at the Gynaecology & Obstetrics department of the Yaoundé Gynaeco-Obstetric and Paediatric Hospital (YGOPH) and the Main Maternity of the Yaoundé Central Hospital (MM-YCH) from February 1 to July 30, 2022. The cases were all pregnant women presenting with pre-eclampsia. The control group included pregnant women without pre-eclampsia. Descriptive statistics followed by logistic regression analyses were conducted with level of significance set at p-value Results: Included in the study were 33 cases and 132 controls, giving a total of 165 participants. The predictive factors for pre-eclampsia after multivariate analysis were: primiparity (aOR = 51.86, 95% CI: 3.01 - 1230.96, p = 0.045), duration of exposure to partner’s sperm Conclusion: The odds of pre-eclampsia increased with primiparity, duration of exposure to partner’s sperm < 3 months, personal history of pre-eclampsia and maternal history of pre-eclampsia. Recognition of these predictor factors would improve the ability to diagnose and monitor women likely to develop pre-eclampsia before the onset of disease for timely interventions.
基金supported by the National Natural Science Foundation of China(Grant Nos.41872128,42202133)the Strategic Cooperation Technology Projects of the CNPC and CUPB(Grant No.ZLZX2020-01-05)。
文摘The late Paleozoic Fengcheng Formation shale(LPF shale)in the Junggar Basin,NW China,is the oldest alkaline source rock discovered in the world,providing a unique perspective with which to explore organic matter(OM)enrichment in alkaline lake environments.Combined with the organic carbon isotope profile and paleoenvironmental proxies,this study reveals that the LPF shale was deposited in an arid climate with high salinity and a strong reducing environment,accompanied by frequent volcanic activity.High TOC values are concentrated in two intervals with frequent fluctuations in OM types.A negative excursion due to changes in sedimentary OM source is found in the δ^(13)C_(org) profile.The excursion corresponds to the OM enrichment interval and is accompanied by abnormally high values of Sr/Ba and Sr/Cu.This implies that the extreme arid climate has led to high salinity,resulting in strong reducibility and changes in paleontological assemblages,which in turn controlled the differential enrichment of OM.The Fengcheng Fm.high-quality source rocks are the result of the combined action of climatic events,volcanism,high-salinity water environment and superior hydrocarbon-generating organisms.The results provide new insights into the formation conditions of terrestrial alkaline high-quality source rocks and the factors controlling alkaline OM enrichment.
基金supported by the National Natural Science Foundation of China(41977258)the National Key Research and Development Program of China(2017YFC1501005 and 2018YFC1504704)。
文摘Determining the main controlling factors of earthquake-triggered geohazards is a prerequisite for studying earthquake geohazards and post-disaster emergency response.By studying these factors,the geomorphic and geological factors controlling the nature,condition,and distribution of earthquake-induced geohazards can be analyzed.Such insights facilitate earthquake disaster prediction and emergency response planning.The authors combined field investigations and spatial data analysis to examine geohazards induced by seismic events,examining ten earthquakes including the Wenchuan,Yushu,Lushan events,to elucidate the main control factors of seismic geohazard.The authors observed that seismic geohazard occurrence is usually affected by many factors,among which active nature of the seismogenic fault,seismic peak ground acceleration(PGA),topographic slope and geomorphic height differences,and distance from the fault zone and river system are the most important.Compared with strike-slip earthquakes,thrust earthquakes induce more high-altitude and high-speed remote landslides,which can cause great harm.Slopes of 0°–40°are prone to secondary seismic geohazards,which are mainly concentrated 0–6 km from the river system.Secondary geohazards are not only related to seismogenic fault but also influenced by the associated faults in the earthquake area.The maximum seismic PGA and secondary seismic geohazard number are positively correlated,and the horizontal and vertical ground motions play leading and promoting roles in secondary geohazard formation,respectively.Through the research,the spatial distribution of seismic geohazards is predicted,providing a basis for the formulation of emergency response plans following disasters.
基金This study is supported by the National Natural Science Foundation of China(Grants 41730424,41961144023 and 42002162)。
文摘The natural cracking of crude oils in deep reservoirs has gained great interest due to continuously increasing depth of petroleum exploration and exploitation.Complex oil compositions and surroundings as well as complicated geological evolutions make oil cracking in nature much more complex than industrial pyrolysis.So far,numerous studies,focused on this topic,have made considerable progress although there still exist some drawbacks.However,a comprehensive review on crude oil cracking is yet to be conducted.This article systematically reviews the controlling factors of oil cracking from six aspects,namely,oil compositions,temperature and time,pressure,water,minerals and solid organic matter.We compare previous experimental and modelling results and present new field cases.In the following,we evaluate the prevailing estimation methods for the extent of oil cracking,and elucidate other factors that may interfere with the application of these estimation methods.This review will be helpful for further investigations of crude oil cracking and provides a guide for estimation of the cracking extent of crude oils.
基金the Science and Technology Project of China Huaneng Group Co.,Ltd.,Study on the Development and Utilization of the Island Site of Xiapu Nuclear Power Plant(No.HNKJ20-H18)。
文摘Based on the contents of six heavy metal elements in surface sediments from coastal areas of Fujian Province,the distribution characteristics and controlling factors of six heavy metals in a bay-island-estuary system(BIES)were studied.This paper focuses on the influence of the hydrodynamic environment,and systematically discusses how grain size compositions,chemical environment,tidal current,ocean circulation and human activities influence the distribution and transportation of the heavy metals.The results indicated that the distribution and migration of Cu,Pb,Zn and Cr elements were mainly controlled by natural factors such as regional geological background,grain size compositions,and tidal residual currents.In contrast,As and Hg was mainly affected by human factors such as agriculture and industrial manufacturing.In the BIES,where the chemical environment exerted limited influence,the accumulation and migration of heavy metals are mainly influenced by human activities and enhanced by estuary processes as well as the complex sedimentary dynamic environment caused by many bays and islands.
文摘Based on the combination of core observation,experimental analysis and testingand geological analysis,the main controlling factors of shale oil enrichment in the Lower Permian Fengcheng Formation in the Mahu Sag of the Junggar Basin are clarified,and a shale oil enrichment model is established.The results show that the enrichment of shale oil in the Fengcheng Formation in the Mahu Sag is controlled by the organic abundance,organic type,reservoir capacity and the amount of migration hydrocarbon in shale.The abundance of organic matter provides the material basis for shale oil enrichment,and the shales containing typesⅠandⅡorganic matters have good oil content.The reservoir capacity controls shale oil enrichment.Macropores are the main space for shale oil enrichment in the Fengcheng Formation,and pore size and fracture scale directly control the degree of shale oil enrichment.The migration of hydrocarbons in shale affects shale oil enrichment.The shale that has expelled hydrocarbons has poor oil content,while the shale that has received hydrocarbons migrated from other strata has good oil content.Lithofacies reflect the hydrocarbon generation and storage capacity comprehensively.The laminated felsic shale,laminated lime-dolomitic shale and thick-layered felsic shale have good oil content,and they are favorable lithofacies for shale oil enrichment.Under the control of these factors,relative migration of hydrocarbons occurred within the Fengcheng shale,which leads to the the difference in the enrichment process of shale oil.Accordingly,the enrichment mode of shale oil in Fengcheng Formation is established as"in-situ enrichment"and"migration enrichment".By superimposing favorable lithofacies and main controlling factors of enrichment,the sweet spot of shale oil in the Fengcheng Formation can be selected which has great significance for the exploration and development of shale oil.
基金This research is financially supported by the National Science and Technology Major Project(2017ZX05036004)the China Petroleum&Chemical Corporation Technology Development Project(G5800-20-ZS-HX042).
文摘The behavior and controlling factors of natural gas adsorption in the Jurassic continental shale in the northeastern Sichuan Basin are studied based on the organic geochemical features,mineral compositions and pore structure parameters through a series of experiments on samples from the shale.Results show that the total gas content of the shale measured on-site is 0.1-5.3 cm^(3)/g,with an average of 0.7 cm^(3)/g.The methane isothermal adsorption curves show a trend of increasing first and then decreasing,indicating an obvious excessive adsorption.The shale has a maximum adsorption capacity(V^(L))of 0.44-3.59 cm^(3)/g,with an average of 1.64 cm^(3)/g,lower than that of marine shale in the same basin.The organic matter content and pore structure characteristics are identified as the two main factors controlling the adsorption capacity of the shale.Micropores in the shale are the main storage space for gas to be adsorbed.Due to well developed shell laminae and interlayers in the shale,calcite plays a more important role than clay minerals in affecting the adsorption of gas to the rock.The formation temperature and water content also significantly inhibit the gas adsorption to the shale.Compared with marine shale in the basin,the Jurassic continental shale is more heterogeneous and lower in TOC values.Furthermore,with a more widely developed clayey shale lithofacies and shell limy shale lithofacies as well as relatively less developed organic pores and micropores,the continental shale is inferior to marine shale in terms of gas adsorption capacity.
基金financially supported by the Smart Fertilization Project (05)the National Key Research & Development Program of China (2022YFD1700605)。
文摘Reducing ammonia(NH3) and nitrous oxide(N2O) emissions have great effects on mitigating nitrogen(N) nutrient loss and greenhouse gas emissions. Controlled release urea(CRU) can control the N release rate, which reduces reactive N loss and increases nitrogen use efficiency relative to conventional urea(CU). However, the crucial factors influencing the responses of NH3and N2O emissions to CRU relative to CU are still unclear. In this study, we evaluated the responses of NH3and N2O emissions to CRU based on collected field data with a meta-analysis. CRU reduced the NH3and N2O emissions by 32.7 and 25.0% compared with CU, respectively. According to subgroup analysis, CRU presented better mitigation of NH3and N2O emissions in soils with pH 6.5–7.5(–47.9 and –23.7%) relative to either pH<6.5(–28.5and –21.4%) or pH>7.5(–29.3 and –17.3%), and in the rice season(–34.8 and –29.1%) relative to the wheat season(–19.8 and –22.8%). The responses of NH3and N2O emissions to CRU increased from rainfed(–30.5 and –17.0%) to irrigated(–32.5 and –22.9%), and then to paddy(–34.8 and –29.1%) systems. In addition, the response of N2O emission mitigation increased with increases in soil total nitrogen(TN);however, soil TN did not significantly affect the response of NH3volatilization. The reduction in NH3emission was greater in sandy-textured soil(–57.7%) relative to loam-textured(–32.9%) and clay-textured(–32.3%) soils, whereas soil texture did not affect N2O emission. Overall, CRU was a good option for reducing the NH3and N2O emissions relative to CU in agricultural production. This analysis improves our understanding of the crucial environmental and management factors influencing the mitigation of NH3and N2O emissions under CRU application, and these site-specific factors should be considered when applying CRU to reduce reactive N loss and increase NUE.
基金supported in part by the National Natural Science Foundation of China(62222301, 62073085, 62073158, 61890930-5, 62021003)the National Key Research and Development Program of China (2021ZD0112302, 2021ZD0112301, 2018YFC1900800-5)Beijing Natural Science Foundation (JQ19013)。
文摘Reinforcement learning(RL) has roots in dynamic programming and it is called adaptive/approximate dynamic programming(ADP) within the control community. This paper reviews recent developments in ADP along with RL and its applications to various advanced control fields. First, the background of the development of ADP is described, emphasizing the significance of regulation and tracking control problems. Some effective offline and online algorithms for ADP/adaptive critic control are displayed, where the main results towards discrete-time systems and continuous-time systems are surveyed, respectively.Then, the research progress on adaptive critic control based on the event-triggered framework and under uncertain environment is discussed, respectively, where event-based design, robust stabilization, and game design are reviewed. Moreover, the extensions of ADP for addressing control problems under complex environment attract enormous attention. The ADP architecture is revisited under the perspective of data-driven and RL frameworks,showing how they promote ADP formulation significantly.Finally, several typical control applications with respect to RL and ADP are summarized, particularly in the fields of wastewater treatment processes and power systems, followed by some general prospects for future research. Overall, the comprehensive survey on ADP and RL for advanced control applications has d emonstrated its remarkable potential within the artificial intelligence era. In addition, it also plays a vital role in promoting environmental protection and industrial intelligence.
基金Peanut Innovation Team Project of Shandong Agricultural Industry Research System(SDAIT-05-022)Special Fund Project of Agricultural Technology Extension of Shandong Province(SDTG-2016-08).
文摘Peanut stem rot caused by Sclerotium rolfsii is a soil-borne disease,and it has become the main disease of peanut in Yimeng mountainous area.S.rolfsii survives the winter as mycelia and sclerotia in soil and debris,becoming the primary source of infection in the following year.The disease resistance of peanut varieties,high temperature and humidity,and cultivation measures are the pathogenic factors affecting the occurrence of peanut stem rot.The disease can be effectively controlled by screening disease-resistant varieties and seed chemical treatment,improving soil by deep tillage and crop rotation,carrying out flowing water management of affected field,cutting off transmission routes,and strengthening seed dressing and triple spraying control.
文摘Introduction: Cardiovascular diseases are the leading cause of mortality in type 2 diabetics patients. Our work aimed to assess the level of control of type 2 diabetes and associated cardiovascular risk factors. Patients and study method: This was an observational cross-sectional study of type 2 diabetics patients. The parameters studied were: sociodemographic data, lifestyle, anthropometric data, levels of control of diabetes by the level of HbA1C, blood pressure measured at the office and cholesterol. Results: 326 type 2 diabetics patients were collected. The sex-ratio was 0.35. The average age of the patients was 58 ± 11 years. A physical inactivity remained present in 79 patients (24.23%), 2 patients (0.61%) continued to smoke. The prevalence of obesity was 21.16% (n = 69) or 25% of women and 10.4% of men (p = 0.01). Abdominal obesity was observed in 151 patients (46.31%), 139 of whom were female and 12 male (p = 0.001). Diabetes was sufficiently controlled in 65.34% of patients (n = 213) while cholesterolemia and hypertension were controlled in 33.44% and 8.33% of patients respectively. Conclusion: Type 2 diabetes was frequently associated with other cardiovascular risk factors. Control of diabetes and these factors was insufficient. Therapeutic education of type 2 diabetics patients needed to be improved.
