The fracture volume is gradually changed with the depletion of fracture pressure during the production process.However,there are few flowback models available so far that can estimate the fracture volume loss using pr...The fracture volume is gradually changed with the depletion of fracture pressure during the production process.However,there are few flowback models available so far that can estimate the fracture volume loss using pressure transient and rate transient data.The initial flowback involves producing back the fracturing fuid after hydraulic fracturing,while the second flowback involves producing back the preloading fluid injected into the parent wells before fracturing of child wells.The main objective of this research is to compare the initial and second flowback data to capture the changes in fracture volume after production and preload processes.Such a comparison is useful for evaluating well performance and optimizing frac-turing operations.We construct rate-normalized pressure(RNP)versus material balance time(MBT)diagnostic plots using both initial and second flowback data(FB;and FBs,respectively)of six multi-fractured horizontal wells completed in Niobrara and Codell formations in DJ Basin.In general,the slope of RNP plot during the FB,period is higher than that during the FB;period,indicating a potential loss of fracture volume from the FB;to the FB,period.We estimate the changes in effective fracture volume(Ver)by analyzing the changes in the RNP slope and total compressibility between these two flowback periods.Ver during FB,is in general 3%-45%lower than that during FB:.We also compare the drive mechanisms for the two flowback periods by calculating the compaction-drive index(CDI),hydrocarbon-drive index(HDI),and water-drive index(WDI).The dominant drive mechanism during both flowback periods is CDI,but its contribution is reduced by 16%in the FB,period.This drop is generally compensated by a relatively higher HDI during this period.The loss of effective fracture volume might be attributed to the pressure depletion in fractures,which occurs during the production period and can extend 800 days.展开更多
The proposed Tuen Mun-Chek Lap Kok Link(TM-CLKL)project comprises a 9-km-long dual two-lane carriageway between Tuen Mun and North Lantau,Hong Kong.Construction of the two tunnels at the Northern Landfall Fall was car...The proposed Tuen Mun-Chek Lap Kok Link(TM-CLKL)project comprises a 9-km-long dual two-lane carriageway between Tuen Mun and North Lantau,Hong Kong.Construction of the two tunnels at the Northern Landfall Fall was carried out by two TBMs:the northbound is referred to as ML03 and has an excavated diameter of 17.63 m,and the southbound is referred to as ML02 and has an excavated diameter of 14.00 m.The use of TBMs minimized the amount of dredging and removal of soft marine deposits,resulting in less impact to the environment within and near the work site of the project.Ground treatment in the form of deep vibro-compaction was carried out at the sand fill and band drains installed in the marine deposit.A surcharge was also added above the final formation level to limit the residual settlement and differential settlement of the reclaimed land to less than 500 mm and 1 in 300,respectively,for a design life of 50 years.Finite element analyses were performed to predict the settlement trough under different confinement pressures along the tunnel alignment.Extensive monitoring of the ground movement was carried out during the driving of the two TBMs to ensure that the design confinement pressure of the slurry would not cause excessive settlement,heave,or blow out at the shallow tunnel sections or different facilities along the tunnel alignment.The monitoring data was then used to back-calculate the percentage of volume loss,which is a key index describing the behavior of the ground during excavation.The monitoring data showed that the measured settlement and back-calculated volume loss were much lower than the predicted values.展开更多
Landsat images, real-time kinematic GPS measurements, and topographic maps were used to determine changes in ice elevation, volume, and areal extent of the Laohugou No. 12 glacier (Qilian Mountains, China) between 195...Landsat images, real-time kinematic GPS measurements, and topographic maps were used to determine changes in ice elevation, volume, and areal extent of the Laohugou No. 12 glacier (Qilian Mountains, China) between 1957 and 2007. The glacier experienced significant thinning and areal shrinkage in the ablation zone, but slight thickening in part of the accumulation zone. Elevation decreased by 18.6±5.4 m between 1957 and 2007 in the regions covered by the GPS measurements. The total volume loss for the entire glacier was estimated to be 0.218 km3 using a third-order polynomial fit method. The area diminished by 0.28 km2 between 1957 and 1994, 0.26 km2 between 1994 and 2000, and 0.28 km2 between 2000 and 2007, suggesting that the rate of loss in glacial coverage has increased since the mid-1990s. Significant increases in annual mean air temperature may have contributed to shrinkage and thinning of the glacier.展开更多
There is a coupling of thermal, mechanical, chemical and fluidal processes in a continental shear zone. Both Xincheng - Xishui and Hetai shear zones are typical continental crust shear zones of greenschist facies envi...There is a coupling of thermal, mechanical, chemical and fluidal processes in a continental shear zone. Both Xincheng - Xishui and Hetai shear zones are typical continental crust shear zones of greenschist facies environment. The representative mylonite zones of the shear zones are studied with whole rock major and trace element analyses. The chemical compositional variation tendencies in both shear zones are very similar and the gain - loss ratios of various components in the mylonitic rocks are reflected in the mass balance equations. The enrichment of those immobile high - field- strengh elements is considered to be related to the volume loss of the mylonitic rocks in a shear zone. Based on the volume loss expression Cs /Co = 1/(1- V), the fractional volume losses (V) are 37.5% and 36.5%-42.3% respectively for mylonites and ultramylonites in the Xincheng-Xishui shear zone and 11 % and 28% respectively for mylonites and phyllonites in the Hetai shear zone. The high volume loss and large removal of SiO2 from the system imply that there is a large amount of percolating fluids in the shear zones. From the SiO2 loss, the fluid/rock ratios (N) are calculated as Nmyl = 113 - 563, Nultramyl= 133-664 for the Xincheng-Xishui shear zone and Nmyl=42-208, Nphyl=110-550 for the Hetai shear zone. Such a large amount of percolating fluid must have profoundly affected the rheological behavior, chemical behavior and metallogenesis of the shear zones.展开更多
On the basis of field geology, three typical ductile shear zones in the southern part of the Tancheng-Lujiang fault belt have been chosen for a detailed study. Altogether ten samples of the tectonites have been collec...On the basis of field geology, three typical ductile shear zones in the southern part of the Tancheng-Lujiang fault belt have been chosen for a detailed study. Altogether ten samples of the tectonites have been collected for this study. The paper is focused on a comprehensive study of the tectonites in the medium-lower horizons of the ductile shear zones. The mineral compositions of the rocks are analyzed with EPMA and some typical whole-rock samples analyzed by chemical and ICP methods. Based on the comprehensive study of the characteristics of the deformation, the mineral assemblages and the changes of chemical composition of the bulk rocks, this paper presents a discussion on the relationship between the volume loss, the fluid flow and compositional changes during mylonitization of the ductile shear zones in this region. Our study shows that there are a large amount of fluids flowing through the shear zones during the process of mylonization, accompanied by the loss of rock volume and migration of elements and components. Modelling calculation results under different saturation conditions of fluids show that the maximum volume loss of the tectonites is about 60% relative to their protolith, while the fluid/rock ratio ranges from 10 to 103 in different ductile shear zones.展开更多
Acid deposition has caused serious damage to the forests of China. In this paper, the quantification theory I is used to calculate the forest volume loss caused by acid disposition in seven provinces of south China. T...Acid deposition has caused serious damage to the forests of China. In this paper, the quantification theory I is used to calculate the forest volume loss caused by acid disposition in seven provinces of south China. The results showed that contribution rates of acid deposition to forest volume loss in seven provinces of south China vary from 24 5% to 37 91%; the volume loss rates range from 7% to 20%. Total volume losses per year are 1 0145×10 6 m 3, of which Zhejiang Province is the greatest, totalling 3 841×10 5 m 3, while Anhui Province is the least, amounting to 1 59×10 4 m 3.展开更多
For the evaluation of cavitation erosion resistance of metallic materials,it has always been a time-consuming technical problem.This paper innovatively proposed a parameter named cavitation hardening rate to character...For the evaluation of cavitation erosion resistance of metallic materials,it has always been a time-consuming technical problem.This paper innovatively proposed a parameter named cavitation hardening rate to characterize the plastic deformation and work hardening behavior of metallic materials during the cavitation process and then found a positive correlation between cavitation hardening rate and strain hardening index.Finally,the relationship between cavitation volume loss and strain hardening index was obtained,and a simple and rapid evaluation method for cavitation erosion resistance was established.展开更多
文摘The fracture volume is gradually changed with the depletion of fracture pressure during the production process.However,there are few flowback models available so far that can estimate the fracture volume loss using pressure transient and rate transient data.The initial flowback involves producing back the fracturing fuid after hydraulic fracturing,while the second flowback involves producing back the preloading fluid injected into the parent wells before fracturing of child wells.The main objective of this research is to compare the initial and second flowback data to capture the changes in fracture volume after production and preload processes.Such a comparison is useful for evaluating well performance and optimizing frac-turing operations.We construct rate-normalized pressure(RNP)versus material balance time(MBT)diagnostic plots using both initial and second flowback data(FB;and FBs,respectively)of six multi-fractured horizontal wells completed in Niobrara and Codell formations in DJ Basin.In general,the slope of RNP plot during the FB,period is higher than that during the FB;period,indicating a potential loss of fracture volume from the FB;to the FB,period.We estimate the changes in effective fracture volume(Ver)by analyzing the changes in the RNP slope and total compressibility between these two flowback periods.Ver during FB,is in general 3%-45%lower than that during FB:.We also compare the drive mechanisms for the two flowback periods by calculating the compaction-drive index(CDI),hydrocarbon-drive index(HDI),and water-drive index(WDI).The dominant drive mechanism during both flowback periods is CDI,but its contribution is reduced by 16%in the FB,period.This drop is generally compensated by a relatively higher HDI during this period.The loss of effective fracture volume might be attributed to the pressure depletion in fractures,which occurs during the production period and can extend 800 days.
文摘The proposed Tuen Mun-Chek Lap Kok Link(TM-CLKL)project comprises a 9-km-long dual two-lane carriageway between Tuen Mun and North Lantau,Hong Kong.Construction of the two tunnels at the Northern Landfall Fall was carried out by two TBMs:the northbound is referred to as ML03 and has an excavated diameter of 17.63 m,and the southbound is referred to as ML02 and has an excavated diameter of 14.00 m.The use of TBMs minimized the amount of dredging and removal of soft marine deposits,resulting in less impact to the environment within and near the work site of the project.Ground treatment in the form of deep vibro-compaction was carried out at the sand fill and band drains installed in the marine deposit.A surcharge was also added above the final formation level to limit the residual settlement and differential settlement of the reclaimed land to less than 500 mm and 1 in 300,respectively,for a design life of 50 years.Finite element analyses were performed to predict the settlement trough under different confinement pressures along the tunnel alignment.Extensive monitoring of the ground movement was carried out during the driving of the two TBMs to ensure that the design confinement pressure of the slurry would not cause excessive settlement,heave,or blow out at the shallow tunnel sections or different facilities along the tunnel alignment.The monitoring data was then used to back-calculate the percentage of volume loss,which is a key index describing the behavior of the ground during excavation.The monitoring data showed that the measured settlement and back-calculated volume loss were much lower than the predicted values.
基金supported by the Ministry of Science and Technology of the People’s Republic of China (Grant No. 2006FY110200)the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. KZCX2-YW-GJ04)the Global Change Research Program of China (Grant No. 2010CB951401)
文摘Landsat images, real-time kinematic GPS measurements, and topographic maps were used to determine changes in ice elevation, volume, and areal extent of the Laohugou No. 12 glacier (Qilian Mountains, China) between 1957 and 2007. The glacier experienced significant thinning and areal shrinkage in the ablation zone, but slight thickening in part of the accumulation zone. Elevation decreased by 18.6±5.4 m between 1957 and 2007 in the regions covered by the GPS measurements. The total volume loss for the entire glacier was estimated to be 0.218 km3 using a third-order polynomial fit method. The area diminished by 0.28 km2 between 1957 and 1994, 0.26 km2 between 1994 and 2000, and 0.28 km2 between 2000 and 2007, suggesting that the rate of loss in glacial coverage has increased since the mid-1990s. Significant increases in annual mean air temperature may have contributed to shrinkage and thinning of the glacier.
基金The study is sponsored by the National Natural Science Foundation of China (No.49172090 ) and supported by the Open Laboratory of Crust- Mantle Constitution, Recycling and Dynamics of Ministry of Geology and Mineral Resources
文摘There is a coupling of thermal, mechanical, chemical and fluidal processes in a continental shear zone. Both Xincheng - Xishui and Hetai shear zones are typical continental crust shear zones of greenschist facies environment. The representative mylonite zones of the shear zones are studied with whole rock major and trace element analyses. The chemical compositional variation tendencies in both shear zones are very similar and the gain - loss ratios of various components in the mylonitic rocks are reflected in the mass balance equations. The enrichment of those immobile high - field- strengh elements is considered to be related to the volume loss of the mylonitic rocks in a shear zone. Based on the volume loss expression Cs /Co = 1/(1- V), the fractional volume losses (V) are 37.5% and 36.5%-42.3% respectively for mylonites and ultramylonites in the Xincheng-Xishui shear zone and 11 % and 28% respectively for mylonites and phyllonites in the Hetai shear zone. The high volume loss and large removal of SiO2 from the system imply that there is a large amount of percolating fluids in the shear zones. From the SiO2 loss, the fluid/rock ratios (N) are calculated as Nmyl = 113 - 563, Nultramyl= 133-664 for the Xincheng-Xishui shear zone and Nmyl=42-208, Nphyl=110-550 for the Hetai shear zone. Such a large amount of percolating fluid must have profoundly affected the rheological behavior, chemical behavior and metallogenesis of the shear zones.
基金This study was supported by the National Key Project "Study of the Natural Gas Fault System in the Tancheng-Lujiang Fault Belt (No. 95-101-01)" of the Ninth Five-Year Plan Period and the National Natural Science Foundation of China Grant 48970172.
文摘On the basis of field geology, three typical ductile shear zones in the southern part of the Tancheng-Lujiang fault belt have been chosen for a detailed study. Altogether ten samples of the tectonites have been collected for this study. The paper is focused on a comprehensive study of the tectonites in the medium-lower horizons of the ductile shear zones. The mineral compositions of the rocks are analyzed with EPMA and some typical whole-rock samples analyzed by chemical and ICP methods. Based on the comprehensive study of the characteristics of the deformation, the mineral assemblages and the changes of chemical composition of the bulk rocks, this paper presents a discussion on the relationship between the volume loss, the fluid flow and compositional changes during mylonitization of the ductile shear zones in this region. Our study shows that there are a large amount of fluids flowing through the shear zones during the process of mylonization, accompanied by the loss of rock volume and migration of elements and components. Modelling calculation results under different saturation conditions of fluids show that the maximum volume loss of the tectonites is about 60% relative to their protolith, while the fluid/rock ratio ranges from 10 to 103 in different ductile shear zones.
文摘Acid deposition has caused serious damage to the forests of China. In this paper, the quantification theory I is used to calculate the forest volume loss caused by acid disposition in seven provinces of south China. The results showed that contribution rates of acid deposition to forest volume loss in seven provinces of south China vary from 24 5% to 37 91%; the volume loss rates range from 7% to 20%. Total volume losses per year are 1 0145×10 6 m 3, of which Zhejiang Province is the greatest, totalling 3 841×10 5 m 3, while Anhui Province is the least, amounting to 1 59×10 4 m 3.
基金funded by the National Key Research and Development Program of China(2022YFB3705803)the National Natural Science Foundation of China(No.52031007)+1 种基金the Natural Science Foundation of Tianjin(22JCQNJC00950)the Scientific and Technological Project of Yunnan Precious Metals Laboratory(YPML-2023050275).
文摘For the evaluation of cavitation erosion resistance of metallic materials,it has always been a time-consuming technical problem.This paper innovatively proposed a parameter named cavitation hardening rate to characterize the plastic deformation and work hardening behavior of metallic materials during the cavitation process and then found a positive correlation between cavitation hardening rate and strain hardening index.Finally,the relationship between cavitation volume loss and strain hardening index was obtained,and a simple and rapid evaluation method for cavitation erosion resistance was established.
