Pore pressure is an important parameter in coalbed methane(CBM)exploration and development;however,the distribution pattern and mechanism for pore pressure differences in the Upper Permian CBM reservoirs are poorly un...Pore pressure is an important parameter in coalbed methane(CBM)exploration and development;however,the distribution pattern and mechanism for pore pressure differences in the Upper Permian CBM reservoirs are poorly understood in the western Guizhou region of South China.In this study,lateral and vertical variations and mechanisms for pore pressure differences are analyzed based on 126 injection-falloff and in-situ stress well test data measured in Permian coal reservoirs.Generally,based on the pore pressure gradient and coefficient in coal reservoirs of the western Guizhou region,five zones can be delineated laterally:the mining areas of Zhina,northem Liupanshui,northern Guizhou,northwestern Guizhou and southern Liupanshui.Vertically,there are two main typical patterns:i)the pore pressure gradient(or coefficient)is nearly unchanged in different coal reservoirs,and ii)the pore pressure gradient(or coefficient)has cyclic variations in a borehole profile with multiple coal seams,which suggests the existence of a"superimposed CBM system".The mechanism analysis indicates that coal permeability,thermal evolution stage and hydrocarbon generation contribute little to pore pressure differences in coal reservoirs in the western Guizhou region.The present-day in-situ stress field,basement structure and tectonic activity may be the dominant factors affecting lateral pore pressure differences.The sealing capacity of caprocks and the present-day in-situ stress field are significant para-meters causing vertical pore pressure differences in coal reservoirs.These results are expected to provide new geological references for CBM exploration and develop-ment in the western Guizhou region.展开更多
[Objective] The study aimed to carry out the regionalization of climate suitability about spring potato planting in Western Guizhou on the basis of GIS technology. [Method] Based on the climatic data of 15 meteorologi...[Objective] The study aimed to carry out the regionalization of climate suitability about spring potato planting in Western Guizhou on the basis of GIS technology. [Method] Based on the climatic data of 15 meteorological stations in Western Guizhou during the growing period of spring potato from March to August in 1978-2010, the regionalization indicators of climate suitability about spring potato planting were determined according to the correlation between climatic factors and meteorological yield of spring potato. Afterwards, on the basis of climitic data and corresponding basic geographical information like longitude, latitude, altitude, slope and aspect, the spatial analysis models of division indicators about spring potato planting in Western Guizhou were established by using GIS spatial overlay analysis and used to carry out the township-level regionalization of climate suitability about spring potato planting in Western Guizhou with 100 m×100 m grids. [Result] Based on the relationship between meteorological yield of spring potato and climatic factors in Western Guizhou from 1978 to 2010, eight climatic division indicators, including altitude, average temperature,>10 ℃ active accumulated temperature, precipitation and sunshine hours in the growth stage, average temperature in July, average temperature difference between day and night from July to August, and precipitation from May to July, were chosen for spring potato planting, and each indicator had three levels, namely the most suitable, suitable and sub-suitable. Meanwhile, Western Guizhou was grouped into three areas according to these indicators, including the most suitable area, suitable area and sub-suitable area, and their area accounted for 52%, 45% and 3% of total area of the whole province respectively. [Conclusion] The research could provide scientific references for the production layout and species selection of spring potato in Western Guizhou.展开更多
基金supported by Natural Science Foundation of Jiangsu Province,China(No.BK20201349)National Natural Science Foundation of China(Grant Nos.41702130 and 41971335)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Pore pressure is an important parameter in coalbed methane(CBM)exploration and development;however,the distribution pattern and mechanism for pore pressure differences in the Upper Permian CBM reservoirs are poorly understood in the western Guizhou region of South China.In this study,lateral and vertical variations and mechanisms for pore pressure differences are analyzed based on 126 injection-falloff and in-situ stress well test data measured in Permian coal reservoirs.Generally,based on the pore pressure gradient and coefficient in coal reservoirs of the western Guizhou region,five zones can be delineated laterally:the mining areas of Zhina,northem Liupanshui,northern Guizhou,northwestern Guizhou and southern Liupanshui.Vertically,there are two main typical patterns:i)the pore pressure gradient(or coefficient)is nearly unchanged in different coal reservoirs,and ii)the pore pressure gradient(or coefficient)has cyclic variations in a borehole profile with multiple coal seams,which suggests the existence of a"superimposed CBM system".The mechanism analysis indicates that coal permeability,thermal evolution stage and hydrocarbon generation contribute little to pore pressure differences in coal reservoirs in the western Guizhou region.The present-day in-situ stress field,basement structure and tectonic activity may be the dominant factors affecting lateral pore pressure differences.The sealing capacity of caprocks and the present-day in-situ stress field are significant para-meters causing vertical pore pressure differences in coal reservoirs.These results are expected to provide new geological references for CBM exploration and develop-ment in the western Guizhou region.
基金Supported by Meteorological Anti-poverty Project of China Meteorological Administration(CMATG2009FP08)Open Foundation of Guizhou Meteorological Bureau(KF[2008]01)Land-saving Science and Technology Cooperation Agreement about Potato(52020-2009-01-01)
文摘[Objective] The study aimed to carry out the regionalization of climate suitability about spring potato planting in Western Guizhou on the basis of GIS technology. [Method] Based on the climatic data of 15 meteorological stations in Western Guizhou during the growing period of spring potato from March to August in 1978-2010, the regionalization indicators of climate suitability about spring potato planting were determined according to the correlation between climatic factors and meteorological yield of spring potato. Afterwards, on the basis of climitic data and corresponding basic geographical information like longitude, latitude, altitude, slope and aspect, the spatial analysis models of division indicators about spring potato planting in Western Guizhou were established by using GIS spatial overlay analysis and used to carry out the township-level regionalization of climate suitability about spring potato planting in Western Guizhou with 100 m×100 m grids. [Result] Based on the relationship between meteorological yield of spring potato and climatic factors in Western Guizhou from 1978 to 2010, eight climatic division indicators, including altitude, average temperature,>10 ℃ active accumulated temperature, precipitation and sunshine hours in the growth stage, average temperature in July, average temperature difference between day and night from July to August, and precipitation from May to July, were chosen for spring potato planting, and each indicator had three levels, namely the most suitable, suitable and sub-suitable. Meanwhile, Western Guizhou was grouped into three areas according to these indicators, including the most suitable area, suitable area and sub-suitable area, and their area accounted for 52%, 45% and 3% of total area of the whole province respectively. [Conclusion] The research could provide scientific references for the production layout and species selection of spring potato in Western Guizhou.
