For the sake of improving the reliability of the method for well pattern density optimization of tight sandstone gas reservoir and effectively demonstrate the relationship between well pattern density and recovery eff...For the sake of improving the reliability of the method for well pattern density optimization of tight sandstone gas reservoir and effectively demonstrate the relationship between well pattern density and recovery efficiency, the well interference probability curve of the target study area in the Sulige Gas Field was plotted by establishing the calculation method for well interference probability. Then, a new method suitable for well pattern density optimization and recovery efficiency evaluation of tight sandstone gas reservoirs was established. Finally, this new method was applied in three encryption test areas of the Sulige Gas Field. And the following research results were obtained. First, the well interference probability of tight sandstone gas reservoir is heavily dependent on the well pattern density. With the increase of the well pattern density, the well interference probability presents a gradual increasing trend. And the well interference probability doesn't reach or approach to 1 until the well pattern density reaches a higher value. Second, in the three encryption test areas of the Sulige Gas Field, the economically optimal well pattern density is in the range of 2.6-3.1 wells/km^(2), and its corresponding recovery efficiency is 36.6-39.8% and corresponding well interference probability is 28-33%, while the economic limit well pattern density is in the range of 5.2-6.6 wells/km^(2), and its corresponding recovery efficiency is 46.8-49.8% and corresponding well interference probability is 83-89%. Third, the well interference probability corresponding to the economically optimal well pattern density of tight sandstone gas reservoir in the Sulige Gas Field is about 30%, and that corresponding to the economic limit well pattern density is about 85%. In conclusion, by virtue of this new method, the economically optimal well pattern density and the economic limit well pattern density and their corresponding recovery efficiencies can be calculated, so as to realize the well pattern optimization and recovery efficiency evaluation of tight sandstone gas reservoirs. The research results can provide theoretical support for the economic and efficient development of the Sulige Gas Field, and useful reference for the benefit development of the same type of gas reservoirs.展开更多
As a typical tight sandstone gasfield with strong heterogeneity,the Sulige Gas Field in the Ordos Basin faces major challenges in its development because the reservoirs in the gasfield are small in effective sand scal...As a typical tight sandstone gasfield with strong heterogeneity,the Sulige Gas Field in the Ordos Basin faces major challenges in its development because the reservoirs in the gasfield are small in effective sand scale,rapid in lithologic change,strong in plane heterogeneity,and poor in connectivity.How to scientifically deploy development wells to improve the recovery is the most important issue for the successful development of this kind of gasfields.Therefore,a well inference analysis was conducted tofigure out the impact of well pattern density on the recovery based on the research of many years in gasfield development methods and the summary of practical effect.In this paper,we put forward for thefirst time the concept of inter-well interference probability,and present the relationship between the probability of inter-well interference and well pattern density of the Sulige Gas Field.Then we established a mathematical model for the optimization of development well pattern by combiningfine sand anatomy,reservoir engineering,numerical simulation and economic evaluation,and obtained a quantitative relationship between recovery and well pattern density.Furthermore,on the basis of comprehensive analysis,a reasonable development well pattern was designed for the Sulige Gas Field:this well pattern is parallelogram in shape,with a density of 3.1 wells/km2,well spacing of 500 m,and row spacing of 650 m.Development practices have confirmed that this scheme is capable of achieving better economic benefits,producing geological reserves as far as possible and improving the ultimate recovery of such gasfields.展开更多
Road network is a corridor system that interacts with surrounding landscapes,and understanding their interaction helps to develop an optimal plan for sustainable transportation and land use.This study investigates the...Road network is a corridor system that interacts with surrounding landscapes,and understanding their interaction helps to develop an optimal plan for sustainable transportation and land use.This study investigates the relationships between road centrality and landscape patterns in the Wuhan Metropolitan Area,China.The densities of centrality measures,including closeness,betweenness,and straightness,are calculated by kernel density estimation(KDE).The landscape patterns are characterized by four landscape metrics,including percentage of landscape(PLAND),Shannon′s diversity index(SHDI),mean patch size(MPS),and mean shape index(MSI).Spearman rank correlation analysis is then used to quantify their relationships at both landscape and class levels.The results show that the centrality measures can reflect the hierarchy of road network as they associate with road grade.Further analysis exhibit that as centrality densities increase,the whole landscape becomes more fragmented and regular.At the class level,the forest gradually decreases and becomes fragmented,while the construction land increases and turns to more compact.Therefore,these findings indicate that the ability and potential applications of centrality densities estimated by KDE in quantifying the relationships between roads and landscapes,can provide detailed information and valuable guidance for transportation and land-use planning as well as a new insight into ecological effects of roads.展开更多
Communities of bacteria,especially symbionts,are vital for the growth and development of insects and other arthropods,including Bemisia tabaci Mediterranean(MED),a destructive and invasive insect pest.However,the infe...Communities of bacteria,especially symbionts,are vital for the growth and development of insects and other arthropods,including Bemisia tabaci Mediterranean(MED),a destructive and invasive insect pest.However,the infection density patterns and influence factors of bacteria in whiteflies,which mainly include symbionts,remain largely unclear.To reveal the different density patterns of Cardinium in B.tabaci MED popula-tions and the impacts of high temperatures on whiteflies with different Cardinium density infection patterns,2 isofemale lines isolated from B.tabaci MED from the same geo-graphical population of China and from B.tabaci MED collected from other countries and locations were examined using several techniques and methods,including fluorescence in situ hybridization(FISH),quantitative real-time polymerase chain reaction(qPCR),16S rRNA gene sequencing,and 2b-RAD sequencing.The results showed that there were 2 different infection density patterns of Cardinium in B.tabaci MED(including 1 high-density pattern and 1 low-density pattern).For whiteflies with low-density Cardinium,conventional PCR could not detect Cardinium,but the other techniques confirmed that there was a low level of Cardinium within hosts.High temperature significantly decreased the diversity of bacterial communities:the relative titer of Cardinium increased but the density of Rickettsia decreased in the isofemale line with high-density Cardinium.How-ever,high temperature did not influence the diversity and symbiont density in the line with low-density Cardinium.Moreover,high temperature influenced the functions of bacterial communities in whiteflies with high-density Cardinium but did not affect the bacterial functions in whiteflies with low-density Cardinium.Our results provide novel insights into the complex associations between symbionts and host insects.展开更多
基金Project supported by the National Natural Science Foundation of China“Basic theoretical research on development of ultra-deep natural gas reservoir”(No.U1762216).
文摘For the sake of improving the reliability of the method for well pattern density optimization of tight sandstone gas reservoir and effectively demonstrate the relationship between well pattern density and recovery efficiency, the well interference probability curve of the target study area in the Sulige Gas Field was plotted by establishing the calculation method for well interference probability. Then, a new method suitable for well pattern density optimization and recovery efficiency evaluation of tight sandstone gas reservoirs was established. Finally, this new method was applied in three encryption test areas of the Sulige Gas Field. And the following research results were obtained. First, the well interference probability of tight sandstone gas reservoir is heavily dependent on the well pattern density. With the increase of the well pattern density, the well interference probability presents a gradual increasing trend. And the well interference probability doesn't reach or approach to 1 until the well pattern density reaches a higher value. Second, in the three encryption test areas of the Sulige Gas Field, the economically optimal well pattern density is in the range of 2.6-3.1 wells/km^(2), and its corresponding recovery efficiency is 36.6-39.8% and corresponding well interference probability is 28-33%, while the economic limit well pattern density is in the range of 5.2-6.6 wells/km^(2), and its corresponding recovery efficiency is 46.8-49.8% and corresponding well interference probability is 83-89%. Third, the well interference probability corresponding to the economically optimal well pattern density of tight sandstone gas reservoir in the Sulige Gas Field is about 30%, and that corresponding to the economic limit well pattern density is about 85%. In conclusion, by virtue of this new method, the economically optimal well pattern density and the economic limit well pattern density and their corresponding recovery efficiencies can be calculated, so as to realize the well pattern optimization and recovery efficiency evaluation of tight sandstone gas reservoirs. The research results can provide theoretical support for the economic and efficient development of the Sulige Gas Field, and useful reference for the benefit development of the same type of gas reservoirs.
文摘As a typical tight sandstone gasfield with strong heterogeneity,the Sulige Gas Field in the Ordos Basin faces major challenges in its development because the reservoirs in the gasfield are small in effective sand scale,rapid in lithologic change,strong in plane heterogeneity,and poor in connectivity.How to scientifically deploy development wells to improve the recovery is the most important issue for the successful development of this kind of gasfields.Therefore,a well inference analysis was conducted tofigure out the impact of well pattern density on the recovery based on the research of many years in gasfield development methods and the summary of practical effect.In this paper,we put forward for thefirst time the concept of inter-well interference probability,and present the relationship between the probability of inter-well interference and well pattern density of the Sulige Gas Field.Then we established a mathematical model for the optimization of development well pattern by combiningfine sand anatomy,reservoir engineering,numerical simulation and economic evaluation,and obtained a quantitative relationship between recovery and well pattern density.Furthermore,on the basis of comprehensive analysis,a reasonable development well pattern was designed for the Sulige Gas Field:this well pattern is parallelogram in shape,with a density of 3.1 wells/km2,well spacing of 500 m,and row spacing of 650 m.Development practices have confirmed that this scheme is capable of achieving better economic benefits,producing geological reserves as far as possible and improving the ultimate recovery of such gasfields.
基金Under the auspices of National Key Technology Research and Development Program of China(No.2012BAH28B02)
文摘Road network is a corridor system that interacts with surrounding landscapes,and understanding their interaction helps to develop an optimal plan for sustainable transportation and land use.This study investigates the relationships between road centrality and landscape patterns in the Wuhan Metropolitan Area,China.The densities of centrality measures,including closeness,betweenness,and straightness,are calculated by kernel density estimation(KDE).The landscape patterns are characterized by four landscape metrics,including percentage of landscape(PLAND),Shannon′s diversity index(SHDI),mean patch size(MPS),and mean shape index(MSI).Spearman rank correlation analysis is then used to quantify their relationships at both landscape and class levels.The results show that the centrality measures can reflect the hierarchy of road network as they associate with road grade.Further analysis exhibit that as centrality densities increase,the whole landscape becomes more fragmented and regular.At the class level,the forest gradually decreases and becomes fragmented,while the construction land increases and turns to more compact.Therefore,these findings indicate that the ability and potential applications of centrality densities estimated by KDE in quantifying the relationships between roads and landscapes,can provide detailed information and valuable guidance for transportation and land-use planning as well as a new insight into ecological effects of roads.
基金supported by the National Natural Science Foundation of China(31872030)the Taishan Scholar Foundation of Shandong Province of China,the First Class Grassland Science Discipline Program of Shandong Province,China,and the Qingdao Agricultural University High-level Talent Fund(663-1121025).
文摘Communities of bacteria,especially symbionts,are vital for the growth and development of insects and other arthropods,including Bemisia tabaci Mediterranean(MED),a destructive and invasive insect pest.However,the infection density patterns and influence factors of bacteria in whiteflies,which mainly include symbionts,remain largely unclear.To reveal the different density patterns of Cardinium in B.tabaci MED popula-tions and the impacts of high temperatures on whiteflies with different Cardinium density infection patterns,2 isofemale lines isolated from B.tabaci MED from the same geo-graphical population of China and from B.tabaci MED collected from other countries and locations were examined using several techniques and methods,including fluorescence in situ hybridization(FISH),quantitative real-time polymerase chain reaction(qPCR),16S rRNA gene sequencing,and 2b-RAD sequencing.The results showed that there were 2 different infection density patterns of Cardinium in B.tabaci MED(including 1 high-density pattern and 1 low-density pattern).For whiteflies with low-density Cardinium,conventional PCR could not detect Cardinium,but the other techniques confirmed that there was a low level of Cardinium within hosts.High temperature significantly decreased the diversity of bacterial communities:the relative titer of Cardinium increased but the density of Rickettsia decreased in the isofemale line with high-density Cardinium.How-ever,high temperature did not influence the diversity and symbiont density in the line with low-density Cardinium.Moreover,high temperature influenced the functions of bacterial communities in whiteflies with high-density Cardinium but did not affect the bacterial functions in whiteflies with low-density Cardinium.Our results provide novel insights into the complex associations between symbionts and host insects.
