Migration pathways and distances of the oils in reservoir are thought to affect the distribution of pyrrolic compounds such as carbazole,its alkyl derivatives(alkylated carbazoles)and benzocarbazoles,although other fa...Migration pathways and distances of the oils in reservoir are thought to affect the distribution of pyrrolic compounds such as carbazole,its alkyl derivatives(alkylated carbazoles)and benzocarbazoles,although other factors,including maturity and depositional environments may also affect the distribution of these organic nitrogen compounds.In this study,14 oil samples produced from conventional reservoirs in Pauls Valley,south Oklahoma were investigated using organic geochemical techniques.The sterane and hopane fingerprints suggest that most of the oils were sourced from the Devonian Woodford shale.Maturity parameters consistently indicate that the maturity level of the studied samples are all of similar maturity(Rc=~0.7%),suggesting the distribution of the organic nitrogen organic compounds is possibly reflecting variations in relative migration distances.The distribution of alkylcarbazoles revealed a preferential enrichment during migration,with the nitrogen-shielded alkylcarbazole tending to be enriched relative to the nitrogen-semi-shielded alkylcarbozoles particularly in oils produced close to the Arbuckle uplift to the east.Correspondingly,another family of pyrrolic compounds,benzocarbazoles,whose distributions also indicated that the Pauls Valley Woodford oils came from deeper part of the Anadarko Basin as the benzo-[a]/([a]+[c])-carbazole ratios decrease eastwards.In more specific migration systems,although the pyrrolic compound indicators are potentially disturbed by the structural complexes,the general migration directions suggest that the studied oils in Pauls Valley Hunton uplift were sourced from the deep basin area,and migrate upwards in porous sediments due to the buoyancy.This study investigates the feasibility of using pyrrolic compounds to estimate relative migration distances and will aid in the interpretation of migration history by using the distribution of carbazole,alkylated carbazoles,benzocarbazoles isomers in the Anadarko and Ardmore Basin petroleum systems.展开更多
Horizontal gene transfer(HGT)in the microbiome has profound consequences for human health and disease.The spread of antibiotic resistance genes,virulence,and pathogenicity determinants predominantly occurs by way of H...Horizontal gene transfer(HGT)in the microbiome has profound consequences for human health and disease.The spread of antibiotic resistance genes,virulence,and pathogenicity determinants predominantly occurs by way of HGT.Evidence exists of extensive horizontal transfer in the human gut microbiome.Phage transduction is a type of HGT event in which a bacteriophage transfers non-viral DNA from one bacterial host cell to another.The abundance of tailed bacteriophages in the human gut suggests that transduction could act as a significant mode of HGT in the gut microbiome.Here we review in detail the known mechanisms of phage-mediated HGT,namely specialized and generalized transduction,lateral transduction,gene-transfer agents,and molecular piracy,as well as methods used to detect phage-mediated HGT,and discuss its potential implications for the human gut microbiome.展开更多
This study presents an example illustrating the role of in situ 3D stress path method in simulating the roof damage development observed in the Mine-by tunnel at Underground Research Laboratory(URL)located in Manitoba...This study presents an example illustrating the role of in situ 3D stress path method in simulating the roof damage development observed in the Mine-by tunnel at Underground Research Laboratory(URL)located in Manitoba,Canada.The 3D stress path,at the point 1 cm in the crown of the Mine-by tunnel,was applied to a cubic Lac du Bonnet(LdB)granite sample to further understand the roof damage process and the associated seismicity.After careful calibrations,a numerical model was used to reproduce the experiment,which produced similar seismicity processes and source mechanisms.Acoustic emission(AE)events obtained from laboratory and numerical modeling were converted to locations in relation to the tunnel face and were compared to the feld microseismicity(MS)occurring in the upper notch region of the Mine-by tunnel.The crack development and damage mechanism are carefully illustrated.The diference between tests and feld monitoring was discussed.The intermediate principal stress(σ_(2))unloading process was carried out in numerical simulation to investigate its role in rock damage development.The results clearly showedσ_(2)could play a signifcant role both in damage development and failure mode.It should be considered when predicting the damage region in underground excavations.This study highlights the potential role of laboratory and numerical stress path tests to investigate fracture processes and mechanisms occurring during engineering activities such as tunnel excavation.展开更多
N\|alkanes in extracts from possible carbonate source rocks of the Lower Ordovician Majiagou Formation in the central gas field of the Shanganning Basin and the Upper Sinian Dengying Formation in the Weiyuan gas field...N\|alkanes in extracts from possible carbonate source rocks of the Lower Ordovician Majiagou Formation in the central gas field of the Shanganning Basin and the Upper Sinian Dengying Formation in the Weiyuan gas field of the Sichuan Basin, are characterized by bimodal distributions with the dominant carbon numbers in the range C\- 17 \|C\- 21 and C\- 25 \|C\- 29 . In most samples, the lower carbon number components are present in greater abundance than the higher carbon number ones. Most samples contain significant concentrations of waxy hydrocarbons(C\- 22+ ) with C\- 21- /C\- 22+ ratios between 0.50 to 3.16, and an average value of 1.34. The n\|alkanes in extracts of outcrops and shallow core samples of Upper Proterozoic and Lower Palaeozoic carbonate rocks in the western and southern parts of the North China Basin are of unimodal distributions dominated by n\|alkanes maximizing in the C\- 25 \|C\- 29 range. These extracts have very high concentrations of waxy hydrocarbons with C\- 21- /C\- 22+ ratios all <1.0, ranging from 0 14 to 0 90 and averaging 0.36. All of the extracts have a marked odd/even predominance in the high molecular weight n\|alkane range regardless of whether they are from shallow or deep cores or outcrop samples. Simulation experiments were performed using typical sapropelic\|type kerogens from the immature Sinian Lower Xiamalin Formation carbonate\|rich shales collected at Jixian, Hebei Province, North China Basin, and the contemporary microplanktonic blue\|green algae Spirulina subsala. Results indicate that the unusual distribution of n\|alkanes in the extracts of Upper Proterozoic and Lower Palaeozoic carbonate rocks possibly originated from algae in the source rocks at high levels of maturity and overmaturity.展开更多
基金National Key Technology Research and Development Program of the Ministry of Science and Technology of China(2015BAD22B01-02)National International Cooperation in Science and Technology Special Program(2014DFG72150)111 Project(B12007)
基金the support from the Organic Geochemistry Lab of the OU and Oklahoma Geological Survey。
文摘Migration pathways and distances of the oils in reservoir are thought to affect the distribution of pyrrolic compounds such as carbazole,its alkyl derivatives(alkylated carbazoles)and benzocarbazoles,although other factors,including maturity and depositional environments may also affect the distribution of these organic nitrogen compounds.In this study,14 oil samples produced from conventional reservoirs in Pauls Valley,south Oklahoma were investigated using organic geochemical techniques.The sterane and hopane fingerprints suggest that most of the oils were sourced from the Devonian Woodford shale.Maturity parameters consistently indicate that the maturity level of the studied samples are all of similar maturity(Rc=~0.7%),suggesting the distribution of the organic nitrogen organic compounds is possibly reflecting variations in relative migration distances.The distribution of alkylcarbazoles revealed a preferential enrichment during migration,with the nitrogen-shielded alkylcarbazole tending to be enriched relative to the nitrogen-semi-shielded alkylcarbozoles particularly in oils produced close to the Arbuckle uplift to the east.Correspondingly,another family of pyrrolic compounds,benzocarbazoles,whose distributions also indicated that the Pauls Valley Woodford oils came from deeper part of the Anadarko Basin as the benzo-[a]/([a]+[c])-carbazole ratios decrease eastwards.In more specific migration systems,although the pyrrolic compound indicators are potentially disturbed by the structural complexes,the general migration directions suggest that the studied oils in Pauls Valley Hunton uplift were sourced from the deep basin area,and migrate upwards in porous sediments due to the buoyancy.This study investigates the feasibility of using pyrrolic compounds to estimate relative migration distances and will aid in the interpretation of migration history by using the distribution of carbazole,alkylated carbazoles,benzocarbazoles isomers in the Anadarko and Ardmore Basin petroleum systems.
基金financial support from Science Foundation Ireland[grant number SFI/12/RC/2273_P2]and Wellcome Trust under a Wellcome Trust Research Career Development Fellowship[220646/Z/20/Z](A.N.S.)whole,or in part,by the Wellcome Trust[220646/Z/20/Z].
文摘Horizontal gene transfer(HGT)in the microbiome has profound consequences for human health and disease.The spread of antibiotic resistance genes,virulence,and pathogenicity determinants predominantly occurs by way of HGT.Evidence exists of extensive horizontal transfer in the human gut microbiome.Phage transduction is a type of HGT event in which a bacteriophage transfers non-viral DNA from one bacterial host cell to another.The abundance of tailed bacteriophages in the human gut suggests that transduction could act as a significant mode of HGT in the gut microbiome.Here we review in detail the known mechanisms of phage-mediated HGT,namely specialized and generalized transduction,lateral transduction,gene-transfer agents,and molecular piracy,as well as methods used to detect phage-mediated HGT,and discuss its potential implications for the human gut microbiome.
基金support for this study is provided by the open fund of State Key Laboratory of Coal Mine Disaster Dynamics and Control(2011DA105287-FW201901)the National Natural Science Foundation of China(51704278)。
文摘This study presents an example illustrating the role of in situ 3D stress path method in simulating the roof damage development observed in the Mine-by tunnel at Underground Research Laboratory(URL)located in Manitoba,Canada.The 3D stress path,at the point 1 cm in the crown of the Mine-by tunnel,was applied to a cubic Lac du Bonnet(LdB)granite sample to further understand the roof damage process and the associated seismicity.After careful calibrations,a numerical model was used to reproduce the experiment,which produced similar seismicity processes and source mechanisms.Acoustic emission(AE)events obtained from laboratory and numerical modeling were converted to locations in relation to the tunnel face and were compared to the feld microseismicity(MS)occurring in the upper notch region of the Mine-by tunnel.The crack development and damage mechanism are carefully illustrated.The diference between tests and feld monitoring was discussed.The intermediate principal stress(σ_(2))unloading process was carried out in numerical simulation to investigate its role in rock damage development.The results clearly showedσ_(2)could play a signifcant role both in damage development and failure mode.It should be considered when predicting the damage region in underground excavations.This study highlights the potential role of laboratory and numerical stress path tests to investigate fracture processes and mechanisms occurring during engineering activities such as tunnel excavation.
基金This research project was financially supported by the Chinese Academy of Sciences (GrantNo .KZCX2 111)
文摘N\|alkanes in extracts from possible carbonate source rocks of the Lower Ordovician Majiagou Formation in the central gas field of the Shanganning Basin and the Upper Sinian Dengying Formation in the Weiyuan gas field of the Sichuan Basin, are characterized by bimodal distributions with the dominant carbon numbers in the range C\- 17 \|C\- 21 and C\- 25 \|C\- 29 . In most samples, the lower carbon number components are present in greater abundance than the higher carbon number ones. Most samples contain significant concentrations of waxy hydrocarbons(C\- 22+ ) with C\- 21- /C\- 22+ ratios between 0.50 to 3.16, and an average value of 1.34. The n\|alkanes in extracts of outcrops and shallow core samples of Upper Proterozoic and Lower Palaeozoic carbonate rocks in the western and southern parts of the North China Basin are of unimodal distributions dominated by n\|alkanes maximizing in the C\- 25 \|C\- 29 range. These extracts have very high concentrations of waxy hydrocarbons with C\- 21- /C\- 22+ ratios all <1.0, ranging from 0 14 to 0 90 and averaging 0.36. All of the extracts have a marked odd/even predominance in the high molecular weight n\|alkane range regardless of whether they are from shallow or deep cores or outcrop samples. Simulation experiments were performed using typical sapropelic\|type kerogens from the immature Sinian Lower Xiamalin Formation carbonate\|rich shales collected at Jixian, Hebei Province, North China Basin, and the contemporary microplanktonic blue\|green algae Spirulina subsala. Results indicate that the unusual distribution of n\|alkanes in the extracts of Upper Proterozoic and Lower Palaeozoic carbonate rocks possibly originated from algae in the source rocks at high levels of maturity and overmaturity.
