Taking the Paleogene salt strata in the west of Kuqa foreland thrust belt as study object, the deformation features of salt structure in the compression direction and perpendicular to the compression direction were ex...Taking the Paleogene salt strata in the west of Kuqa foreland thrust belt as study object, the deformation features of salt structure in the compression direction and perpendicular to the compression direction were examined to find out the control factors and formation mechanisms of the salt structures. By using the three-dimensional discrete element numerical simulation method, the formation mechanisms of typical salt structures of western Kuqa foreland thrust belt in Keshen and Dabei work areas were comprehensively analyzed. The simulation results show that the salt deformation in Keshen and Dabei work areas is of forward spread type, with deformation concentrated in the piedmont zone;the salt deformation is affected by the early uplift near the compression end, pre-existing basement faults, synsedimentary process and the initial salt depocenter;in the direction perpendicular to the compression direction, salt rocks near the compression end have strong lateral mobility with the velocity component moving towards the middle part, and the closer to the middle, the larger the velocity will be, so that salt rocks will aggregate towards the middle and deform intensely, forming complex folds and separation of salt structures from salt source, and local outcrop with thrust faults. Compared with 2 D simulation, 3 D simulation can analyze salt structures in the principal stress direction and direction perpendicular to the principal stress, give us a full view of the formation mechanisms of salt structures, and guide the exploration of oil and gas reservoirs related to salt structures.展开更多
The study on Lower Cambrian dolostones in Tarim Basin can improve our understanding of ancient and deeply buried carbonate reservoirs.In this research,diagenetic fluid characteristics and their control on porosity evo...The study on Lower Cambrian dolostones in Tarim Basin can improve our understanding of ancient and deeply buried carbonate reservoirs.In this research,diagenetic fluid characteristics and their control on porosity evolution have been revealed by studying the petrography and in situ geochemistry of different dolomites.Three types of diagenetic fluids were identified:(1) Replacive dolomites were deviated from shallow burial dolomitizing fluids,which might probably be concentrated ancient seawater at early stage.(2) Fine-to-medium crystalline,planar-e diamond pore-filling dolomites(Fd1) were likely slowly and sufficiently crystallized from deep-circulating crustal hydrothermal fluids during Devonian.(3) Coarse crystalline,non-planar-a saddle pore-filling dolomites(Fd2) might rapidly and insufficiently crystallize from magmatic hydrothermal fluids during Permian.Early dolomitizing fluids did not increase the porosity,but transformed the primary pores to dissolution pores through dolomitization.Deep-circulating crustal hydrothermal fluids significantly increased porosity in the early stages by dissolving and then slightly decreased the porosity in the late stage due to Fd1 precipitation.Magmatic hydrothermal fluids only precipitated the Fd2 dolomites and slightly decreased the porosity.In summary,Devonian deep-circulating crustal hydrothermal fluids dominated the porosity evolution of the Lower Cambrian dolostone reservoir in the Tarim Basin.展开更多
The high-pressure and high-temperature structural behavior of FeP2 is investigated by means of synchrotron x-ray powder diffraction combined with a laser heating technique up to 70GPa and at least 1800K.No phase trans...The high-pressure and high-temperature structural behavior of FeP2 is investigated by means of synchrotron x-ray powder diffraction combined with a laser heating technique up to 70GPa and at least 1800K.No phase transition of FeP2 occurs up to 68GPa at room temperature.While a new phase of FeP2 assigned to the CuAl2-type structure (14/mcm,Z =4) is observed at 70GPa after laser-heating.This new phase presents a quenchable property on decompression to ambient conditions.Our results update previous experimental data and are consistent with theoretical studies.展开更多
The method of random forest was used to classify the heavy mineral assemblages of 2 418 Jurassic samples in the southern Junggar Basin, and determine the distribution of the heavy mineral assemblages from the same pro...The method of random forest was used to classify the heavy mineral assemblages of 2 418 Jurassic samples in the southern Junggar Basin, and determine the distribution of the heavy mineral assemblages from the same provenance systems. Based on the analysis of heavy minerals assemblages, ZTR index, sedimentary characteristics, U-Pb zircon ages, whole-rock geochemical and paleocurrent direction analysis, the study reveals that five important provenances were providing sediments to the southern Junggar Basin in the Jurassic period: The North Tianshan(NTS), Central Tianshan(CTS), Bogda Mountains, Zhayier Mountains and Kalamaili Mountains. During the Early Jurassic, NTS-CTS, Kalamaili Mountains and Zhayier Mountains are primary provenances, Bogda Mountains started to uplift and supply clastic materials in the Middle Jurassic. There are three sedimentary area in the Jurassic of southern Junggar Basin: the western part, the central part and the eastern part. In the western part, the clastic materials of the Early Jurassic was mainly from NTS blocks and Zhayier Mountains, and the sediments were dominantly derived from the Zhayier Mountains during the Middle–Late Jurassic. In the central part, the main provenance of the Early Jurassic switched from NTS to CTS. In the Xishanyao Formation, the main source went back to NTS again. The NTS was the primary provenance during the sedimentary periods of Toutunhe Formation and Qigu Formation. In the eastern part, the contribution of CTS and Kalamaili Mountains were considered as major provenances in the Early Jurassic-Xishanyao Formation, small proportion of sediments were from NTS. The Bogda mountains uplifted and started to provide sediments to the Junggar Basin in the sedimentary period of Xishanyao Formation, and became the major source during the Toutunhe Formation period, with small amount of sediments from CTS. The provenance from CTS was hindered during the sedimentary period of Qigu Formation owing to the uplifting of the Bogda mountains, and the sediments were mainly from the Bogda mountains and NTS.展开更多
PbA13（PO4）2（OH,H20）6, an important environmental mineral, is in-situ studied by synchrotron x-ray diffraction （XRD） and Raman scattering combined with diamond anvil cells （DACs） at pressures up to - 11.0 GPa a...PbA13（PO4）2（OH,H20）6, an important environmental mineral, is in-situ studied by synchrotron x-ray diffraction （XRD） and Raman scattering combined with diamond anvil cells （DACs） at pressures up to - 11.0 GPa and room temper- ature. The XRD results indicate that plumbogummite does not undergo a phase transition between 0 GPa and 10.9 GPa. Moreover, the c axis is more compressible than the a axis, revealing its anisotropic behavior. The pressure-volume data are fitted to the third-order Birch-Murnaghan equation of state to yield the plumbogummite bulk modulus K0 of 68（ I ） GPa and KU of 6.1. The [PO4]3 and [HPO4]2 Raman vibrational modes exhibit scale nearly linearly as a function of pressure. The [PO4]3 stretching modes are generally more sensitive to pressure than the bending modes. The Grfineisen parameters range from -0.07 to 1.19, with an arithmetic mean of approximately 0.39.展开更多
Quasihydrostatic limit of LiF as a pressure transmitting medium is investigated by synchrotron radiation x-ray diffraction combined with the diamond anvil cells technique up to 60 GPa at room temperature. The equation...Quasihydrostatic limit of LiF as a pressure transmitting medium is investigated by synchrotron radiation x-ray diffraction combined with the diamond anvil cells technique up to 60 GPa at room temperature. The equation-of- state parameters of LiF are determined to be Vo = 65.7（2）A3 Bo = 58（3） GPa and B＇0 = 4.9（2） in the silicon oil environment; Vo = 67.4（3） A3, Bo = 51（3） GPa and B＇0 = 4.7（2） without pressure transmitting medium. The full width at half maximum of LiF （111） peak increases with the increase of pressure in two independent experiments. The pressure distribution in the sample chamber is estimated by line-scanning x-ray diffraction measurements across the chamber＇s center, which presents as homogeneous with Pmax - Pmin Of about 1 GPa below 40 GPa.展开更多
The Raman spectroscopy of n-pentadecane is investigated in a moissanite anvil cell at normal temperatures and a diamond anvil cell under pressure to about 3000MPa and at temperature from 298 to 573K. Result indicates ...The Raman spectroscopy of n-pentadecane is investigated in a moissanite anvil cell at normal temperatures and a diamond anvil cell under pressure to about 3000MPa and at temperature from 298 to 573K. Result indicates that at room temperature the vibration modes, assigned to the symmetric and asymmetric stretching of CH3 and CH2 stretching, shift to higher frequency and display a pressure dependent quasi-linear curve. A liquid-solid phase transition appears at a pressure of 150 MPa. The high temperature solidus line of n-pentadecane follows a quadratic function of P = 0.02369T^2 - 9.117T ＋ 725.58, in agreement with previous conclusion derived from studies of other hydrocarbons. Upon phase transition, fitting the experimental data obtained in a temperature range of 283 553 K to the Clausius-Clapeyron equation allows one to define the thermodynamic parameters of n-pentadecane of dP/dT = 0.04738T - 9.117.展开更多
An in-situ Raman spectroscopic study of gypsum-anhydrite transition under a saturated water condition at high pressure and high temperature is performed using a hydrothermal diamond anvil cell (HDAC).The experimental ...An in-situ Raman spectroscopic study of gypsum-anhydrite transition under a saturated water condition at high pressure and high temperature is performed using a hydrothermal diamond anvil cell (HDAC).The experimental results show that gypsum dissolvs in water at ambient temperature and above 496 MPa.With increasing temperature,the anhydrite (CaSO4) phase precipitates at 250 320℃ in the pressure range of 1.0 1.5 GPa,indicating that under a saturated water condition,both stable conditions of pressure and temperature and high levels of Ca and SO4 ion concentrations in aqueous solution are essential for the formation of anhydrite.A linear relationship between the pressure and temperature for the precipitation of anhydrite is established as P(GPa) =0.0068T - 0.7126 (250℃≤T≤320℃).Anhydrite remained stable during rapid cooling of the sample chamber,showing that the gypsum-anhydrite transition involving both dissolution and precipitation processes is irreversible at high pressure and high temperature.展开更多
In situ high-pressure experiments of Co2P are carried out by means of angle dispersive X-ray diffraction with diamond anvil cell technique. No phase transition is observed in the present pressure range up to 15 GPa at...In situ high-pressure experiments of Co2P are carried out by means of angle dispersive X-ray diffraction with diamond anvil cell technique. No phase transition is observed in the present pressure range up to 15 GPa at room temperature, even at high temperature and 15 GPa. Results of compression for Co2P are well presented by the second-order Birch-Murnaghan equation of state with V0 = 130.99（2） Aa （1 A=0.1 nm） and K0 = 160（3） GPa. Axial compressibilities are described by compressional modulus of the axis： Ka = 123（2） GPa, Kb = 167（8） GPa and Kc = 220（7） GPa. Theoretical calculations further support the experimental results and indicate that C23-type Co2P is stable at high pressure compared with the C22-type phase.展开更多
The evolution process and petroleum significance of two groups of fault structures,the NW-SE trending and near EW trending ones in the Cenozoic of Dongping-Niuzhong area of the Altyn slope,Qaidam Basin,were investigat...The evolution process and petroleum significance of two groups of fault structures,the NW-SE trending and near EW trending ones in the Cenozoic of Dongping-Niuzhong area of the Altyn slope,Qaidam Basin,were investigated using high precision 3-D seismic data.The NW-SE faults were generated in Oligocene,causing the formation of a series of folds related to transpression faults in the Niuzhong and Dongping area.After the Miocene,with the continuous extension of the Altyn Tagh strike-slip fault zone,the EW trending faults began to develop massively in Altyn slope.The activity of near EW trending faults and large-scale uplift of the bedrock in the northern Niuzhong area shared most of the compression torsion in Niuzhong and Dongping area,consequently,the activity of NW-SE trending faults weakened significantly after the Miocene.Then good hydrocarbon source rocks developed in the inherited Jurassic sags.The faults were effective pathways for oil and gas migration in Dongping and Niuzhong areas,and the oil and gas charging time matched well with the formation period of the NW-SE trending faults and their related structures,making the fault-related anticlines favorable targets for oil and gas accumulation.The Niuzhong area has been less affected by the Cenozoic movement after the Miocene,and thus has better conditions for gas reservoir preservation.展开更多
It is important to predict the fracture distribution in the tight reservoirs of the Ordos Basin because fracturing is very crucial for the reconstruction of the low-permeability reservoirs. Three-dimensional finite el...It is important to predict the fracture distribution in the tight reservoirs of the Ordos Basin because fracturing is very crucial for the reconstruction of the low-permeability reservoirs. Three-dimensional finite element models are used to predict the fracture orientation and distribution of the Triassic Yanchang Formation in the Longdong area, southern Ordos Basin. The numerical modeling is based on the distribution of sand bodies in the Chang 7a and 72 members, and the different forces that have been exerted along each boundary of the basin in the Late Mesozoic and the Cenozoic. The calculated results demonstrate that the fracture orientations in the Late Mesozoic and the Ceno- zoic are NW-EW and NNE-ENE, respectively. In this paper, the two-factor method is applied to analyze the distribution of fracture density. The distribution maps of predicted fracture density in the Chang 71 and 72 members are obtained, indicating that the tectonic movement in the Late Mesozoic has a greater influence on the fracture development than that in the Cenozoic. The average fracture densities in the Chang 71 and 72 members are similar, but there are differences in their distributions. Compared with other geological elements, the lithology and the layer thickness are the primary factors that control the stress distribution in the study area, which further determine the fracture distribution in the stable Ordos Basin. The predicted fracture density and the two-factor method can be utilized to guide future exploration in the tight-sand reservoirs.展开更多
The 6-AIOOH can transport water into the deep mantle along cold subducting slab geotherm. We investigate the hydrogen-bond symmetrization behavior of 6-AIOOH under the relevant pressure-temperature condition of the lo...The 6-AIOOH can transport water into the deep mantle along cold subducting slab geotherm. We investigate the hydrogen-bond symmetrization behavior of 6-AIOOH under the relevant pressure-temperature condition of the lower mantle using ab initio molecular dynamics （MD）. The static symmetrization pressure of 30.0 GPa can be reduced to 17.0 GPa at 30014 by finite-temperature （T） statistics, closer to the experimental observation of ~10.0 GPa. The symmetrization pressure obtained by MD simulation is related to T by P （GPa） = 13.9 （GPa） ＋ 0.01 （GPa/K） x T （K）. We conclude that 6-AIOOH in the lower mantle exists with symmetric hydrogen bond from its birthplace, or someplace slightly deeper, to the core-mantle boundary （CM13） along cold subducting slab geotherm, The bulk modulus decreases with T and increases anomalously upon symmetrization： Ko （GPa） = 181 （GPa） - 0,013 （GPa/K） x T （K） for 6-AIOOH with asymmetric hydrogen bond, and Ko （OPa） = 216 （GPa） - 0.013 （GPa/K） × T （K） for 6-AIOOH with symmetric hydrogen bond. Our results provide an important insight into the existent form and properties of 6-AIOOH in the lower mantle.展开更多
In situ high pressure experiment of V_(2)O_(3) is carried out by means of synchrotron radiation angle dispersive x-ray diffraction with the diamond anvil cell technique up to about 42 GPa at room temperature.A reversi...In situ high pressure experiment of V_(2)O_(3) is carried out by means of synchrotron radiation angle dispersive x-ray diffraction with the diamond anvil cell technique up to about 42 GPa at room temperature.A reversible phase transition unreported previously is observed at above 31 GPa.The c-axis compressibility of corundum-type V_(2)O_(3) shows an abnormal behavior,i.e.,the axial length increasing up to 9 GPa then decreasing at higher pressures,which could be attributed to the 3d electronic interaction.The results of compression for V_(2)O_(3) are described by the second-order Birch–Murnaghan equation of state with V0=300.2(4)A^(3) and B0=255(9)GPa.展开更多
The synthesized monoclinic（B-type） phase of Y2O3 has been investigated by in situ angle-dispersive x-ray diffraction in a diamond anvil cell up to 44 GPa at room temperature. A phase transition occurs from monoclini...The synthesized monoclinic（B-type） phase of Y2O3 has been investigated by in situ angle-dispersive x-ray diffraction in a diamond anvil cell up to 44 GPa at room temperature. A phase transition occurs from monoclinic（B-type） to hexagonal（A-type） phase at 23.5 GPa and these two phases coexist even at the highest pressure. Parameters of isothermal equation of state are V0= 69.0（1）A3, K0= 159（3） GPa, K0= 4（fixed） for the B-type phase and V0= 67.8（2） A3, K0= 156（3） GPa,K＇0= 4fixed for the A-type phase. The structural anisotropy increases with increasing pressure for both phases.展开更多
In situ high-pressure x-ray absorption fine structure(EXAFS)measurements on the Zn K-edge in zincblende ZnS are performed up to 31.7 GPa at room temperature using a synchrotron radiation x-ray re-focused by a polycapi...In situ high-pressure x-ray absorption fine structure(EXAFS)measurements on the Zn K-edge in zincblende ZnS are performed up to 31.7 GPa at room temperature using a synchrotron radiation x-ray re-focused by a polycapillary half-lens in the classic energy-scanning transmission mode.The present XAFS data illustrate that ZnS undergoes a phase transition from zincblende F43m to rocksalt Fm3m at 16.9 GPa,accompanied by the increase of the first shell coordination number of the absorption zinc atoms and the unit-cell volume collapse of~14%.The isothermal equation of state of the F43m ZnS is well presented by the third-order Birch–Murnaghan equation of state with V0=158.6±0.8?3,B0=87±5 GPa and B0'=4(fixed).The high-pressure behavior of ZnS from the XAFS spectra is consistent with the previous high-pressure XRD results.In addition,the present experimental method demonstrates that the large divergent x-ray micro-beam induced by a polycapillary half-lens can suppress effectively the glitches from single crystal diamond anvil and improve significantly the quality of the XAFS data,which will shed light on the high-pressure XAFS applications.展开更多
From Raman spectroscopic study on OH stretching bands,the local statistical interpretation for water structure is proposed.Due to the closely structural relationship between amorphous solids and liquids,the structural...From Raman spectroscopic study on OH stretching bands,the local statistical interpretation for water structure is proposed.Due to the closely structural relationship between amorphous solids and liquids,the structural model is extended to investigate the amorphous solids,which indicates that various intensity of potential can be expected around an atom(molecule).From this,a local statistical order parameter is proposed to understand the short-range order and long-range disorder.The order parameter is influenced by the cooling rate in the glass formation,which means that glass is formed with a slower cooling rate,and has higher structural order.For amorphous solids,the geometric topology is closely related to chemical bonding type,such as covalent bond and metallic bond.展开更多
基金Supported by the China National Science and Technology Major Project(2016ZX05033002,2016ZX05033001).
文摘Taking the Paleogene salt strata in the west of Kuqa foreland thrust belt as study object, the deformation features of salt structure in the compression direction and perpendicular to the compression direction were examined to find out the control factors and formation mechanisms of the salt structures. By using the three-dimensional discrete element numerical simulation method, the formation mechanisms of typical salt structures of western Kuqa foreland thrust belt in Keshen and Dabei work areas were comprehensively analyzed. The simulation results show that the salt deformation in Keshen and Dabei work areas is of forward spread type, with deformation concentrated in the piedmont zone;the salt deformation is affected by the early uplift near the compression end, pre-existing basement faults, synsedimentary process and the initial salt depocenter;in the direction perpendicular to the compression direction, salt rocks near the compression end have strong lateral mobility with the velocity component moving towards the middle part, and the closer to the middle, the larger the velocity will be, so that salt rocks will aggregate towards the middle and deform intensely, forming complex folds and separation of salt structures from salt source, and local outcrop with thrust faults. Compared with 2 D simulation, 3 D simulation can analyze salt structures in the principal stress direction and direction perpendicular to the principal stress, give us a full view of the formation mechanisms of salt structures, and guide the exploration of oil and gas reservoirs related to salt structures.
基金funded by the National Basic Research Program of China (Grant 2012CB214801)Tarim Oilfield Branch of Petro China (Grant 041013100042)。
文摘The study on Lower Cambrian dolostones in Tarim Basin can improve our understanding of ancient and deeply buried carbonate reservoirs.In this research,diagenetic fluid characteristics and their control on porosity evolution have been revealed by studying the petrography and in situ geochemistry of different dolomites.Three types of diagenetic fluids were identified:(1) Replacive dolomites were deviated from shallow burial dolomitizing fluids,which might probably be concentrated ancient seawater at early stage.(2) Fine-to-medium crystalline,planar-e diamond pore-filling dolomites(Fd1) were likely slowly and sufficiently crystallized from deep-circulating crustal hydrothermal fluids during Devonian.(3) Coarse crystalline,non-planar-a saddle pore-filling dolomites(Fd2) might rapidly and insufficiently crystallize from magmatic hydrothermal fluids during Permian.Early dolomitizing fluids did not increase the porosity,but transformed the primary pores to dissolution pores through dolomitization.Deep-circulating crustal hydrothermal fluids significantly increased porosity in the early stages by dissolving and then slightly decreased the porosity in the late stage due to Fd1 precipitation.Magmatic hydrothermal fluids only precipitated the Fd2 dolomites and slightly decreased the porosity.In summary,Devonian deep-circulating crustal hydrothermal fluids dominated the porosity evolution of the Lower Cambrian dolostone reservoir in the Tarim Basin.
基金Supported by the National Natural Science Foundation of China under Grant Nos 40972029 and 11079009.
文摘The high-pressure and high-temperature structural behavior of FeP2 is investigated by means of synchrotron x-ray powder diffraction combined with a laser heating technique up to 70GPa and at least 1800K.No phase transition of FeP2 occurs up to 68GPa at room temperature.While a new phase of FeP2 assigned to the CuAl2-type structure (14/mcm,Z =4) is observed at 70GPa after laser-heating.This new phase presents a quenchable property on decompression to ambient conditions.Our results update previous experimental data and are consistent with theoretical studies.
基金Supported by the China National Science and Technology Major Project(2017ZX05008-001)
文摘The method of random forest was used to classify the heavy mineral assemblages of 2 418 Jurassic samples in the southern Junggar Basin, and determine the distribution of the heavy mineral assemblages from the same provenance systems. Based on the analysis of heavy minerals assemblages, ZTR index, sedimentary characteristics, U-Pb zircon ages, whole-rock geochemical and paleocurrent direction analysis, the study reveals that five important provenances were providing sediments to the southern Junggar Basin in the Jurassic period: The North Tianshan(NTS), Central Tianshan(CTS), Bogda Mountains, Zhayier Mountains and Kalamaili Mountains. During the Early Jurassic, NTS-CTS, Kalamaili Mountains and Zhayier Mountains are primary provenances, Bogda Mountains started to uplift and supply clastic materials in the Middle Jurassic. There are three sedimentary area in the Jurassic of southern Junggar Basin: the western part, the central part and the eastern part. In the western part, the clastic materials of the Early Jurassic was mainly from NTS blocks and Zhayier Mountains, and the sediments were dominantly derived from the Zhayier Mountains during the Middle–Late Jurassic. In the central part, the main provenance of the Early Jurassic switched from NTS to CTS. In the Xishanyao Formation, the main source went back to NTS again. The NTS was the primary provenance during the sedimentary periods of Toutunhe Formation and Qigu Formation. In the eastern part, the contribution of CTS and Kalamaili Mountains were considered as major provenances in the Early Jurassic-Xishanyao Formation, small proportion of sediments were from NTS. The Bogda mountains uplifted and started to provide sediments to the Junggar Basin in the sedimentary period of Xishanyao Formation, and became the major source during the Toutunhe Formation period, with small amount of sediments from CTS. The provenance from CTS was hindered during the sedimentary period of Qigu Formation owing to the uplifting of the Bogda mountains, and the sediments were mainly from the Bogda mountains and NTS.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.41473056 and 41472037)
文摘PbA13（PO4）2（OH,H20）6, an important environmental mineral, is in-situ studied by synchrotron x-ray diffraction （XRD） and Raman scattering combined with diamond anvil cells （DACs） at pressures up to - 11.0 GPa and room temper- ature. The XRD results indicate that plumbogummite does not undergo a phase transition between 0 GPa and 10.9 GPa. Moreover, the c axis is more compressible than the a axis, revealing its anisotropic behavior. The pressure-volume data are fitted to the third-order Birch-Murnaghan equation of state to yield the plumbogummite bulk modulus K0 of 68（ I ） GPa and KU of 6.1. The [PO4]3 and [HPO4]2 Raman vibrational modes exhibit scale nearly linearly as a function of pressure. The [PO4]3 stretching modes are generally more sensitive to pressure than the bending modes. The Grfineisen parameters range from -0.07 to 1.19, with an arithmetic mean of approximately 0.39.
基金Supported by the National Natural Science Foundation of China under Grant No U1232204.
文摘Quasihydrostatic limit of LiF as a pressure transmitting medium is investigated by synchrotron radiation x-ray diffraction combined with the diamond anvil cells technique up to 60 GPa at room temperature. The equation-of- state parameters of LiF are determined to be Vo = 65.7（2）A3 Bo = 58（3） GPa and B＇0 = 4.9（2） in the silicon oil environment; Vo = 67.4（3） A3, Bo = 51（3） GPa and B＇0 = 4.7（2） without pressure transmitting medium. The full width at half maximum of LiF （111） peak increases with the increase of pressure in two independent experiments. The pressure distribution in the sample chamber is estimated by line-scanning x-ray diffraction measurements across the chamber＇s center, which presents as homogeneous with Pmax - Pmin Of about 1 GPa below 40 GPa.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10299040 and 40173019, and the Research Fund for the Doctoral Programme of Higher Education under Grant No 20030001053. We are grateful to Mr Jing-Qiu Ren at Peking University for technical assistance.
文摘The Raman spectroscopy of n-pentadecane is investigated in a moissanite anvil cell at normal temperatures and a diamond anvil cell under pressure to about 3000MPa and at temperature from 298 to 573K. Result indicates that at room temperature the vibration modes, assigned to the symmetric and asymmetric stretching of CH3 and CH2 stretching, shift to higher frequency and display a pressure dependent quasi-linear curve. A liquid-solid phase transition appears at a pressure of 150 MPa. The high temperature solidus line of n-pentadecane follows a quadratic function of P = 0.02369T^2 - 9.117T ＋ 725.58, in agreement with previous conclusion derived from studies of other hydrocarbons. Upon phase transition, fitting the experimental data obtained in a temperature range of 283 553 K to the Clausius-Clapeyron equation allows one to define the thermodynamic parameters of n-pentadecane of dP/dT = 0.04738T - 9.117.
基金Supported by the National Natural Science Foundation of China under Grant No 40873047.
文摘An in-situ Raman spectroscopic study of gypsum-anhydrite transition under a saturated water condition at high pressure and high temperature is performed using a hydrothermal diamond anvil cell (HDAC).The experimental results show that gypsum dissolvs in water at ambient temperature and above 496 MPa.With increasing temperature,the anhydrite (CaSO4) phase precipitates at 250 320℃ in the pressure range of 1.0 1.5 GPa,indicating that under a saturated water condition,both stable conditions of pressure and temperature and high levels of Ca and SO4 ion concentrations in aqueous solution are essential for the formation of anhydrite.A linear relationship between the pressure and temperature for the precipitation of anhydrite is established as P(GPa) =0.0068T - 0.7126 (250℃≤T≤320℃).Anhydrite remained stable during rapid cooling of the sample chamber,showing that the gypsum-anhydrite transition involving both dissolution and precipitation processes is irreversible at high pressure and high temperature.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 40972029 and 41072027)
文摘In situ high-pressure experiments of Co2P are carried out by means of angle dispersive X-ray diffraction with diamond anvil cell technique. No phase transition is observed in the present pressure range up to 15 GPa at room temperature, even at high temperature and 15 GPa. Results of compression for Co2P are well presented by the second-order Birch-Murnaghan equation of state with V0 = 130.99（2） Aa （1 A=0.1 nm） and K0 = 160（3） GPa. Axial compressibilities are described by compressional modulus of the axis： Ka = 123（2） GPa, Kb = 167（8） GPa and Kc = 220（7） GPa. Theoretical calculations further support the experimental results and indicate that C23-type Co2P is stable at high pressure compared with the C22-type phase.
基金Supported by the PetroChina Project(2016ZX05003-006).
文摘The evolution process and petroleum significance of two groups of fault structures,the NW-SE trending and near EW trending ones in the Cenozoic of Dongping-Niuzhong area of the Altyn slope,Qaidam Basin,were investigated using high precision 3-D seismic data.The NW-SE faults were generated in Oligocene,causing the formation of a series of folds related to transpression faults in the Niuzhong and Dongping area.After the Miocene,with the continuous extension of the Altyn Tagh strike-slip fault zone,the EW trending faults began to develop massively in Altyn slope.The activity of near EW trending faults and large-scale uplift of the bedrock in the northern Niuzhong area shared most of the compression torsion in Niuzhong and Dongping area,consequently,the activity of NW-SE trending faults weakened significantly after the Miocene.Then good hydrocarbon source rocks developed in the inherited Jurassic sags.The faults were effective pathways for oil and gas migration in Dongping and Niuzhong areas,and the oil and gas charging time matched well with the formation period of the NW-SE trending faults and their related structures,making the fault-related anticlines favorable targets for oil and gas accumulation.The Niuzhong area has been less affected by the Cenozoic movement after the Miocene,and thus has better conditions for gas reservoir preservation.
基金funded by the National Natural Science Foundations of China(Grant Nos.40772121 and 41530207)State Key Projects of Petroleum(Nos.2008ZX05029001,2011ZX05029-001 and 2014A0213)Research and Development Foundations of the Huaneng Clean Energy Research Institute(TY-15-CERI02)
文摘It is important to predict the fracture distribution in the tight reservoirs of the Ordos Basin because fracturing is very crucial for the reconstruction of the low-permeability reservoirs. Three-dimensional finite element models are used to predict the fracture orientation and distribution of the Triassic Yanchang Formation in the Longdong area, southern Ordos Basin. The numerical modeling is based on the distribution of sand bodies in the Chang 7a and 72 members, and the different forces that have been exerted along each boundary of the basin in the Late Mesozoic and the Cenozoic. The calculated results demonstrate that the fracture orientations in the Late Mesozoic and the Ceno- zoic are NW-EW and NNE-ENE, respectively. In this paper, the two-factor method is applied to analyze the distribution of fracture density. The distribution maps of predicted fracture density in the Chang 71 and 72 members are obtained, indicating that the tectonic movement in the Late Mesozoic has a greater influence on the fracture development than that in the Cenozoic. The average fracture densities in the Chang 71 and 72 members are similar, but there are differences in their distributions. Compared with other geological elements, the lithology and the layer thickness are the primary factors that control the stress distribution in the study area, which further determine the fracture distribution in the stable Ordos Basin. The predicted fracture density and the two-factor method can be utilized to guide future exploration in the tight-sand reservoirs.
基金Supported by the National Natural Science Foundation of China under Grant Nos U1232204,41473056,11422431 and 11634001the National Key Research and Development Program of China under Grant No 2016YFA0300901the National Basic Research Program of China under Grant No 2013CB934600
文摘The 6-AIOOH can transport water into the deep mantle along cold subducting slab geotherm. We investigate the hydrogen-bond symmetrization behavior of 6-AIOOH under the relevant pressure-temperature condition of the lower mantle using ab initio molecular dynamics （MD）. The static symmetrization pressure of 30.0 GPa can be reduced to 17.0 GPa at 30014 by finite-temperature （T） statistics, closer to the experimental observation of ~10.0 GPa. The symmetrization pressure obtained by MD simulation is related to T by P （GPa） = 13.9 （GPa） ＋ 0.01 （GPa/K） x T （K）. We conclude that 6-AIOOH in the lower mantle exists with symmetric hydrogen bond from its birthplace, or someplace slightly deeper, to the core-mantle boundary （CM13） along cold subducting slab geotherm, The bulk modulus decreases with T and increases anomalously upon symmetrization： Ko （GPa） = 181 （GPa） - 0,013 （GPa/K） x T （K） for 6-AIOOH with asymmetric hydrogen bond, and Ko （OPa） = 216 （GPa） - 0.013 （GPa/K） × T （K） for 6-AIOOH with symmetric hydrogen bond. Our results provide an important insight into the existent form and properties of 6-AIOOH in the lower mantle.
基金Supported by the National Natural Science Foundation of China(11079009,41072027)Shanghai Synchrotron Radiation Facility(No Vr-11041).
文摘In situ high pressure experiment of V_(2)O_(3) is carried out by means of synchrotron radiation angle dispersive x-ray diffraction with the diamond anvil cell technique up to about 42 GPa at room temperature.A reversible phase transition unreported previously is observed at above 31 GPa.The c-axis compressibility of corundum-type V_(2)O_(3) shows an abnormal behavior,i.e.,the axial length increasing up to 9 GPa then decreasing at higher pressures,which could be attributed to the 3d electronic interaction.The results of compression for V_(2)O_(3) are described by the second-order Birch–Murnaghan equation of state with V0=300.2(4)A^(3) and B0=255(9)GPa.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U1232204 and 41502029)China Postdoctoral Science Foundation(Grant No.2015M580679)
文摘The synthesized monoclinic（B-type） phase of Y2O3 has been investigated by in situ angle-dispersive x-ray diffraction in a diamond anvil cell up to 44 GPa at room temperature. A phase transition occurs from monoclinic（B-type） to hexagonal（A-type） phase at 23.5 GPa and these two phases coexist even at the highest pressure. Parameters of isothermal equation of state are V0= 69.0（1）A3, K0= 159（3） GPa, K0= 4（fixed） for the B-type phase and V0= 67.8（2） A3, K0= 156（3） GPa,K＇0= 4fixed for the A-type phase. The structural anisotropy increases with increasing pressure for both phases.
基金the National Natural Science Foundation of China under Grant Nos 11079009 and 10979060.
文摘In situ high-pressure x-ray absorption fine structure(EXAFS)measurements on the Zn K-edge in zincblende ZnS are performed up to 31.7 GPa at room temperature using a synchrotron radiation x-ray re-focused by a polycapillary half-lens in the classic energy-scanning transmission mode.The present XAFS data illustrate that ZnS undergoes a phase transition from zincblende F43m to rocksalt Fm3m at 16.9 GPa,accompanied by the increase of the first shell coordination number of the absorption zinc atoms and the unit-cell volume collapse of~14%.The isothermal equation of state of the F43m ZnS is well presented by the third-order Birch–Murnaghan equation of state with V0=158.6±0.8?3,B0=87±5 GPa and B0'=4(fixed).The high-pressure behavior of ZnS from the XAFS spectra is consistent with the previous high-pressure XRD results.In addition,the present experimental method demonstrates that the large divergent x-ray micro-beam induced by a polycapillary half-lens can suppress effectively the glitches from single crystal diamond anvil and improve significantly the quality of the XAFS data,which will shed light on the high-pressure XAFS applications.
基金Supported by the National Natural Science Foundation of China under Grant Nos 41073048.
文摘From Raman spectroscopic study on OH stretching bands,the local statistical interpretation for water structure is proposed.Due to the closely structural relationship between amorphous solids and liquids,the structural model is extended to investigate the amorphous solids,which indicates that various intensity of potential can be expected around an atom(molecule).From this,a local statistical order parameter is proposed to understand the short-range order and long-range disorder.The order parameter is influenced by the cooling rate in the glass formation,which means that glass is formed with a slower cooling rate,and has higher structural order.For amorphous solids,the geometric topology is closely related to chemical bonding type,such as covalent bond and metallic bond.
