To investigate the situation of conventional oil and gas, this paper examines the global oil and gas discoveries, proved reserves, production, consumption and price. All the influencing factors can be subjected to ris...To investigate the situation of conventional oil and gas, this paper examines the global oil and gas discoveries, proved reserves, production, consumption and price. All the influencing factors can be subjected to risk and opportunity analyses, so in the paper, we build upon a risk-opportunity analysis framework, which is a new train of thought. To forecast the peak time of oil and gas production, we used the methods of multi-Hubbert model forecasting and data forecasting. Our results showed that the world oil production will reach a peak between 2010 and 2015 and the gas production will reach a peak around 2030 Oil peak is coming and gas peak is on the way. The main purpose of forecasting oil and gas production peak is give people enough time for preparing mitigation and adaptation plans. This means taking decisive action well before the problem is obvious.展开更多
The Xiuwacu deposit is a large magmatic hydrothermal Mo-W-Cu deposit, and also a typical representative of the late Triassic mineralization in Geza Arc (Lai AQ et al., 2016;Liu XL et al., 2017). The Xiuwacu pluton int...The Xiuwacu deposit is a large magmatic hydrothermal Mo-W-Cu deposit, and also a typical representative of the late Triassic mineralization in Geza Arc (Lai AQ et al., 2016;Liu XL et al., 2017). The Xiuwacu pluton intruded into the Lamaya Formation, and contains two periods of rocks bounded by intrusive contact. Nonetheless, most of the intrusive boundaries were superposed by later fault structures.展开更多
Objective The giant Nyainqentanglha granitic batholith, located in the Lhasa Terrane, is the youngest granite pluton emplaced at 18.3–11.0 Ma during the Miocene epoch. A series of NE-striking sinistral normal ductile...Objective The giant Nyainqentanglha granitic batholith, located in the Lhasa Terrane, is the youngest granite pluton emplaced at 18.3–11.0 Ma during the Miocene epoch. A series of NE-striking sinistral normal ductile shear zones developed on its north and south sides. The ductile shear zones are considered to be the western boundary faults of the Yadong-Gulu rift system and have the potential to provide critical temporal constraints for the large-scale East–West extension event in the Tibetan Plateau.展开更多
The Liwu stratiform copper deposit is located in the northwestern Jianglang dome,western China.Current studies mainly focus on the genetic type and mineralization of this deposit.Detailed fluid inclusion characteristi...The Liwu stratiform copper deposit is located in the northwestern Jianglang dome,western China.Current studies mainly focus on the genetic type and mineralization of this deposit.Detailed fluid inclusion characteristics of metallogenic period quartz veins were studied to reveal the ore-forming fluid features.Laser Raman analysis indicates that the ore-forming fluids is a H_(2)O-NaCl-CH_(4)(-CO_(2))system.Fluid inclusions microthermometry shows a homogenization temperature of 181-375°C and a salinity of 5.26%-16.99%for the disseminated-banded Cu-Zn mineralization;but a homogenization temperature of 142-343°C and a salinity of 5.41%-21.19%for the massive-veined Cu-Zn mineralization.These features suggest a medium-high temperature and a medium salinity for the ore-forming fluids.H-O isotopic data indicates that the ore-forming fluids were mainly from the metamorphic and magmatic water,plus minor formation water.And sulfur isotopic data indicates that sulfur was mainly derived from the formation and magmatic rocks.Metallogenesis of the disseminated-banded mineralization was mainly correlated with fluid mixing and water-rock reaction;whereas that of the massive-veined mineralization was mainly correlated with fluid boiling.The genetic type of the deposit is a medium-high temperature hydrothermal deposit related to magmatism and controlled by shear zones.This study is beneficial to understand the stratiform copper deposit.展开更多
Evaluation of possible leakage pathways of CO_(2) injected into geological formations for storage is essential for successful Carbon Capture and Storage(CCS).A channel in the borehole cement,which secures the borehole...Evaluation of possible leakage pathways of CO_(2) injected into geological formations for storage is essential for successful Carbon Capture and Storage(CCS).A channel in the borehole cement,which secures the borehole casing to the formation,may allow CO_(2) to escape.Risk assessment and remediation decisions about the pres-ence of such channels depend on channel parameters:radial position r from the center of the borehole;channel thickness d;azimuthal positionφof the channel;and az-imuthal extentθof the channel.Current state-of-the-art cement-bond logging technology,which uses only the first arrival at a centralized borehole receiver,can diagnose limited details about CO_(2) leak channels.To accurately characterize the possible leak paths in the cement,we use a 3-dimensional finite-difference method to investigate the use of the abundant data collected by a modernized monopole sonic tool that contains an array of azimuthally distributed receivers.We also investigate how to improve the tool design to acquire even more useful information.For cases where borehole fluid is either water or supercritical CO_(2),we investigate various receiver geometries,multi-modal analyses of multi-frequency data to discover the type of logging tool that provides the best information for CCS management.We find that an appropriate choice of wave modes,source frequencies,source polarities,and receiver locations and off-sets provides sensitivity to d,φ,θ.The amplitude of the first arrival from a monopole source is sensitive toθ.Amplitudes at receivers at different azimuths are sensitive toφ.The slow Stoneley mode(ST2)velocity is sensitive to d,but ST2 is not easy to pick whenθand d are small.Further improvement is necessary to provide comprehensive information about possible flow channels in casing cement.展开更多
We present theoretical and experimental studies on the effects of formationproperties on seismoelectric conversions in fluid-filled boreholes. First, we derive thetheoretical formulations for seismoelectric responses ...We present theoretical and experimental studies on the effects of formationproperties on seismoelectric conversions in fluid-filled boreholes. First, we derive thetheoretical formulations for seismoelectric responses for an acoustic source in a borehole.Then, we compute the electric fields in boreholes penetrating formations withdifferent permeability and porosity, and then we analyze the sensitivity of the convertedelectric fields to formation permeability and porosity. We also describe the laboratoryresults of the seismoelectric and seismomagnetic fields induced by an acousticsource in borehole models to confirm our theoretical and numerical developmentsqualitatively. We use a piezoelectric transducer to generate acoustic waves and a pointelectrode to receive the localized seismoelectric fields in layered boreholes and theelectric component of electromagnetic waves in a fractured borehole model. Numericalresults show that the magnitude ratio of the converted electric wave to the acousticpressure increases with the porosity and permeability increases in both fast and slowformations. Furthermore, the converted electric signal is sensitive to the formationpermeability for the same source frequency and formation porosity. Our experimentsvalidate our theoretical results qualitatively. An acoustic wave at a fracture intersectinga borehole induces a radiating electromagnetic wave.展开更多
Borehole acoustic logging-while-drilling (LWD) for formation evaluationhas become an indispensable part of hydrocarbon reservoir assessment [F. Citt ´a, C. Rus-sell, R. Deady and D. Hinz, The Leading Edge, 23 (20...Borehole acoustic logging-while-drilling (LWD) for formation evaluationhas become an indispensable part of hydrocarbon reservoir assessment [F. Citt ´a, C. Rus-sell, R. Deady and D. Hinz, The Leading Edge, 23 (2004), pp. 566-573]. However,the detection of acoustic formation arrivals over tool mode contamination has beena challenging problem in acoustic LWD technology. In this paper we propose a newmethod for separating tool waves from formation acoustic waves in acoustic LWD.This method is to measure the seismoelectric signal excited by the LWD acoustic waves.The LWD tool waves which propagate along the rigid tool rim can not excite any elec-tric signal. This is due to the effectively grounding of the drill string during the LWDprocess makes it impossible to accumulate any excess charge at the conductive tool —borehole fluid interface. Therefore, there should be no contribution by the tool modesto the recorded seismoelectric signals. To theoretically understand the seismoelectricconversion in the LWD geometry, we calculate the synthetic waveforms for the multi-pole LWD seismoelectric signals based on Pride’s theory [S. R. Pride, Phys. Rev. B, 50(1994), pp. 15678-15696]. The synthetic waveforms for the electric field induced by theLWD-acoustic-wave along the borehole wall demonstrate the absence of the tool mode.We also designed the laboratory experiments to collect simulated LWD monopole anddipole acoustic and seismoelectric signals in a borehole in sandstone. By analyzing thespectrum of acoustic and electric signals, we can detect and filter out the differencebetween the two signals, which are the mainly tool modes and noise.展开更多
The Qushenla Formation volcanic rocks are widely exposed in the northern margin of the Bangong-Nujiang suture zone(BNSZ).Research on these rocks is of great significance for understanding the tectonic evolution of the...The Qushenla Formation volcanic rocks are widely exposed in the northern margin of the Bangong-Nujiang suture zone(BNSZ).Research on these rocks is of great significance for understanding the tectonic evolution of the Bangong-Nujiang Tethys Ocean(BNTO).In this study,a systematic geological survey was conducted on the Qushenla Formation volcanic rocks that are widely exposed in the Nawucuo area,in the northern margin of the western segment along the BNSZ.The whole-rock geochemistry,zircon U-Pb dating,and in situ zircon Lu-Hf isotopes were carried out in this study,aiming to constrain the formation age,rock genesis,magma source and tectonic setting of the volcanic rocks.The zircon U-Pb dating shows that the Qushenla Formation volcanic rocks in the western BNSZ erupted during the period of 120–108 Ma,i.e.,Early Cretaceous.The Qushenla Formation volcanic rocks are a suite of intermediate-basic volcanic and pyroclastic rocks belonging to the medium-K calc-alkaline series.They are relatively enriched in light rare earth elements(LREEs)and incompatible elements such as Rb,K,La,Th,Sm,and Hf,whereas depleted in heavy REEs(HREEs)and high field strength elements(HFSEs)such as Nb,P,Zr,and Ti.The in situ zirconεHf(t)values of the volcanic rocks range from 8.95 to 12.57,with an average of 10.40.The Mg#,Th/La and Th/Ce values are between those of the mantle-derived magma and the continental crust.The formation of the Qushenla Formation volcanic rocks can be explained through the following process:(1)As the nospheric materials that upwelled during the rollback of the subducting Tethys Ocean slab induced the large-scale partial melting of the mantle wedge and the formation of the initial basaltic magma.(2)These mantle-derived magmas ascended and induced the partial melting of the lower crust to generate peraluminous melts.(3)The mixing of the peraluminous melts and mantle-derived melts generated the initial magma with homogeneous Sr-Nd isotope compositions.(4)Last,the eruption of the magma produced the widespread Qushenla Formation volcanic rocks at the surface.When combining this information with the regional geological background,it is believed that the Qushenla Formation volcanic rocks,the Meiriqicuo Formation volcanic rocks and the Late Jurassic–Early Cretaceous intrusive rocks together constitute the tectonic magmatic arc of the active continental margin on the southern margin of Qiangtang,which was formed in the tectonic setting of the northward subduction of the Bangong-Nujiang oceanic crust beneath the Qiangtang Block.展开更多
文摘To investigate the situation of conventional oil and gas, this paper examines the global oil and gas discoveries, proved reserves, production, consumption and price. All the influencing factors can be subjected to risk and opportunity analyses, so in the paper, we build upon a risk-opportunity analysis framework, which is a new train of thought. To forecast the peak time of oil and gas production, we used the methods of multi-Hubbert model forecasting and data forecasting. Our results showed that the world oil production will reach a peak between 2010 and 2015 and the gas production will reach a peak around 2030 Oil peak is coming and gas peak is on the way. The main purpose of forecasting oil and gas production peak is give people enough time for preparing mitigation and adaptation plans. This means taking decisive action well before the problem is obvious.
文摘The Xiuwacu deposit is a large magmatic hydrothermal Mo-W-Cu deposit, and also a typical representative of the late Triassic mineralization in Geza Arc (Lai AQ et al., 2016;Liu XL et al., 2017). The Xiuwacu pluton intruded into the Lamaya Formation, and contains two periods of rocks bounded by intrusive contact. Nonetheless, most of the intrusive boundaries were superposed by later fault structures.
基金financially supported by the China Geological Survey(grant No.DD20190147)the National Natural Science Foundation of China(grant No.41863005)the Guangxi Natural Science Foundation(grant No.2017GXNSFBA198203)。
文摘Objective The giant Nyainqentanglha granitic batholith, located in the Lhasa Terrane, is the youngest granite pluton emplaced at 18.3–11.0 Ma during the Miocene epoch. A series of NE-striking sinistral normal ductile shear zones developed on its north and south sides. The ductile shear zones are considered to be the western boundary faults of the Yadong-Gulu rift system and have the potential to provide critical temporal constraints for the large-scale East–West extension event in the Tibetan Plateau.
基金financially supported by National Natural Science Foundation of China(42272106,41202067)Open Fund of State Key Laboratory for Mineral Deposits Research,Nanjing University(2019-LAMD-K12)China Geological Survey(DD20211386,DD20211392,DD20179603).
文摘The Liwu stratiform copper deposit is located in the northwestern Jianglang dome,western China.Current studies mainly focus on the genetic type and mineralization of this deposit.Detailed fluid inclusion characteristics of metallogenic period quartz veins were studied to reveal the ore-forming fluid features.Laser Raman analysis indicates that the ore-forming fluids is a H_(2)O-NaCl-CH_(4)(-CO_(2))system.Fluid inclusions microthermometry shows a homogenization temperature of 181-375°C and a salinity of 5.26%-16.99%for the disseminated-banded Cu-Zn mineralization;but a homogenization temperature of 142-343°C and a salinity of 5.41%-21.19%for the massive-veined Cu-Zn mineralization.These features suggest a medium-high temperature and a medium salinity for the ore-forming fluids.H-O isotopic data indicates that the ore-forming fluids were mainly from the metamorphic and magmatic water,plus minor formation water.And sulfur isotopic data indicates that sulfur was mainly derived from the formation and magmatic rocks.Metallogenesis of the disseminated-banded mineralization was mainly correlated with fluid mixing and water-rock reaction;whereas that of the massive-veined mineralization was mainly correlated with fluid boiling.The genetic type of the deposit is a medium-high temperature hydrothermal deposit related to magmatism and controlled by shear zones.This study is beneficial to understand the stratiform copper deposit.
基金supported by the Founding Members Consortium of the Earth Resources Laboratory of the Massachusetts Institute of Technology(MIT)and the MIT Energy Initiative Seed Fund Award No.015728-00149.
文摘Evaluation of possible leakage pathways of CO_(2) injected into geological formations for storage is essential for successful Carbon Capture and Storage(CCS).A channel in the borehole cement,which secures the borehole casing to the formation,may allow CO_(2) to escape.Risk assessment and remediation decisions about the pres-ence of such channels depend on channel parameters:radial position r from the center of the borehole;channel thickness d;azimuthal positionφof the channel;and az-imuthal extentθof the channel.Current state-of-the-art cement-bond logging technology,which uses only the first arrival at a centralized borehole receiver,can diagnose limited details about CO_(2) leak channels.To accurately characterize the possible leak paths in the cement,we use a 3-dimensional finite-difference method to investigate the use of the abundant data collected by a modernized monopole sonic tool that contains an array of azimuthally distributed receivers.We also investigate how to improve the tool design to acquire even more useful information.For cases where borehole fluid is either water or supercritical CO_(2),we investigate various receiver geometries,multi-modal analyses of multi-frequency data to discover the type of logging tool that provides the best information for CCS management.We find that an appropriate choice of wave modes,source frequencies,source polarities,and receiver locations and off-sets provides sensitivity to d,φ,θ.The amplitude of the first arrival from a monopole source is sensitive toθ.Amplitudes at receivers at different azimuths are sensitive toφ.The slow Stoneley mode(ST2)velocity is sensitive to d,but ST2 is not easy to pick whenθand d are small.Further improvement is necessary to provide comprehensive information about possible flow channels in casing cement.
文摘We present theoretical and experimental studies on the effects of formationproperties on seismoelectric conversions in fluid-filled boreholes. First, we derive thetheoretical formulations for seismoelectric responses for an acoustic source in a borehole.Then, we compute the electric fields in boreholes penetrating formations withdifferent permeability and porosity, and then we analyze the sensitivity of the convertedelectric fields to formation permeability and porosity. We also describe the laboratoryresults of the seismoelectric and seismomagnetic fields induced by an acousticsource in borehole models to confirm our theoretical and numerical developmentsqualitatively. We use a piezoelectric transducer to generate acoustic waves and a pointelectrode to receive the localized seismoelectric fields in layered boreholes and theelectric component of electromagnetic waves in a fractured borehole model. Numericalresults show that the magnitude ratio of the converted electric wave to the acousticpressure increases with the porosity and permeability increases in both fast and slowformations. Furthermore, the converted electric signal is sensitive to the formationpermeability for the same source frequency and formation porosity. Our experimentsvalidate our theoretical results qualitatively. An acoustic wave at a fracture intersectinga borehole induces a radiating electromagnetic wave.
文摘Borehole acoustic logging-while-drilling (LWD) for formation evaluationhas become an indispensable part of hydrocarbon reservoir assessment [F. Citt ´a, C. Rus-sell, R. Deady and D. Hinz, The Leading Edge, 23 (2004), pp. 566-573]. However,the detection of acoustic formation arrivals over tool mode contamination has beena challenging problem in acoustic LWD technology. In this paper we propose a newmethod for separating tool waves from formation acoustic waves in acoustic LWD.This method is to measure the seismoelectric signal excited by the LWD acoustic waves.The LWD tool waves which propagate along the rigid tool rim can not excite any elec-tric signal. This is due to the effectively grounding of the drill string during the LWDprocess makes it impossible to accumulate any excess charge at the conductive tool —borehole fluid interface. Therefore, there should be no contribution by the tool modesto the recorded seismoelectric signals. To theoretically understand the seismoelectricconversion in the LWD geometry, we calculate the synthetic waveforms for the multi-pole LWD seismoelectric signals based on Pride’s theory [S. R. Pride, Phys. Rev. B, 50(1994), pp. 15678-15696]. The synthetic waveforms for the electric field induced by theLWD-acoustic-wave along the borehole wall demonstrate the absence of the tool mode.We also designed the laboratory experiments to collect simulated LWD monopole anddipole acoustic and seismoelectric signals in a borehole in sandstone. By analyzing thespectrum of acoustic and electric signals, we can detect and filter out the differencebetween the two signals, which are the mainly tool modes and noise.
基金financially supported by the National Key R&D Program Project(No.2022YFC2905001)the National Natural Science Foundation of China(Nos.42230813,42272093)+1 种基金the Basal Research Fund of Chinese Academy of Geological Sciences(Nos.KJ2102,KK2116,KK2017)the Geological Survey Program of China(No.DD20221684)。
文摘The Qushenla Formation volcanic rocks are widely exposed in the northern margin of the Bangong-Nujiang suture zone(BNSZ).Research on these rocks is of great significance for understanding the tectonic evolution of the Bangong-Nujiang Tethys Ocean(BNTO).In this study,a systematic geological survey was conducted on the Qushenla Formation volcanic rocks that are widely exposed in the Nawucuo area,in the northern margin of the western segment along the BNSZ.The whole-rock geochemistry,zircon U-Pb dating,and in situ zircon Lu-Hf isotopes were carried out in this study,aiming to constrain the formation age,rock genesis,magma source and tectonic setting of the volcanic rocks.The zircon U-Pb dating shows that the Qushenla Formation volcanic rocks in the western BNSZ erupted during the period of 120–108 Ma,i.e.,Early Cretaceous.The Qushenla Formation volcanic rocks are a suite of intermediate-basic volcanic and pyroclastic rocks belonging to the medium-K calc-alkaline series.They are relatively enriched in light rare earth elements(LREEs)and incompatible elements such as Rb,K,La,Th,Sm,and Hf,whereas depleted in heavy REEs(HREEs)and high field strength elements(HFSEs)such as Nb,P,Zr,and Ti.The in situ zirconεHf(t)values of the volcanic rocks range from 8.95 to 12.57,with an average of 10.40.The Mg#,Th/La and Th/Ce values are between those of the mantle-derived magma and the continental crust.The formation of the Qushenla Formation volcanic rocks can be explained through the following process:(1)As the nospheric materials that upwelled during the rollback of the subducting Tethys Ocean slab induced the large-scale partial melting of the mantle wedge and the formation of the initial basaltic magma.(2)These mantle-derived magmas ascended and induced the partial melting of the lower crust to generate peraluminous melts.(3)The mixing of the peraluminous melts and mantle-derived melts generated the initial magma with homogeneous Sr-Nd isotope compositions.(4)Last,the eruption of the magma produced the widespread Qushenla Formation volcanic rocks at the surface.When combining this information with the regional geological background,it is believed that the Qushenla Formation volcanic rocks,the Meiriqicuo Formation volcanic rocks and the Late Jurassic–Early Cretaceous intrusive rocks together constitute the tectonic magmatic arc of the active continental margin on the southern margin of Qiangtang,which was formed in the tectonic setting of the northward subduction of the Bangong-Nujiang oceanic crust beneath the Qiangtang Block.
