Through site observation and indoor measurements in XieJiaji No.2 Coal Mine in Huainan and Luling Coal Mine in Huaibei, it is discovered that the fragmentation degree are different in different coal seams in same mini...Through site observation and indoor measurements in XieJiaji No.2 Coal Mine in Huainan and Luling Coal Mine in Huaibei, it is discovered that the fragmentation degree are different in different coal seams in same mining district and even in sublevels of the are coal seam,tbe coal mass structures exist much difference. By analyzing the relationship between the constitution of coal matters and the epigenesis breakage of coal. This paper points out that the internal factor which causes the diversity of the coal mass structure are from the diversity in the contents of telocollinite and desmocollinite in the vitrinite. The contenet of desmocollinite is higher than that of telocollinite in intact coal seam (sublevel) but the former is less than the later in breaking sublevel, the diversity of constituent content more affects the epigenetic fragmtation degree of coal seam. The content of desmocollinite proves lower than that of telocollinite in the broken coal seam. The new understanding has directing, and reference for the study of coal perology, coal mine gas geology and coal methane.展开更多
During the processes of methane adsorption and desorption,the internal structure of coal changes,accordingly leading to changes in electrical conductivity.In this paper,using low rank coal seams of the Yan'an Form...During the processes of methane adsorption and desorption,the internal structure of coal changes,accordingly leading to changes in electrical conductivity.In this paper,using low rank coal seams of the Yan'an Formation in the Dafbsi field as the research subject,the relationship between coal resistivity,methane adsorption quantity,and equilibrium pressure is analyzed through proximate analysis,mercury injection tests,low temperature liquid nitrogen adsorption tests,and coal resistivity measurements during methane adsorption and desorption.The results show that during the process of pressure rise and methane adsorption,the conductivity of coal increases,resulting from heat release from methane adsorption,coal matrix swelling and adsorbed water molecules replaced by methane,but the resistivity reduction gradually decreases.The relationship between coal resistivity and methane adsorption quantity and equilibrium pressure can be described by a quadratic function.During the processes of depressurization and desorption,the resistivity of coal rebounds slightly,due to decalescence of methane desorption,coal matrix shrinkage and water-gas displacement,and the relationship coincides with a linear function.Methane adsorption leads to irreversible changes in coal internal structure and enhances the coal conductivity,and resistivity can not be restored to the initial level even after methane desorption.The resistivity and reduction rate of durain are higher than those of vitrain,with relatively greater homogeneous pore throat structure and fewer charged particles in the double electric layer.In addition,moisture can enhance the conductivity of coal and makes it change more complexly during methane adsorption and desorption.展开更多
In terms of macrolithotypes and microlithotypes, the petrographic composition was determined on column samples of Permian Seam 2 and Carboniferous Seam 9(2) from the Xingtai Coalfield, China. The macrolithotypes are c...In terms of macrolithotypes and microlithotypes, the petrographic composition was determined on column samples of Permian Seam 2 and Carboniferous Seam 9(2) from the Xingtai Coalfield, China. The macrolithotypes are classified into bright coal (B), banded bright coal (BB), banded coal (BC),banded dull coal (BD), dull coal (D) and fibrous coal (F). The lithotypes are dominated by BD and D in Seam 2, and BB in Seam 9(2).Microlithotypes are dominated by inertite and durite in Seam 2 and by vitrite in Seam 9(2). Eight microlithotypes were selected as indicators of peat-forming environments. Two triangle diagrams were drawn based on the indicators in order to explicate the peat-forming environments of Permian Seam 2 and Carboniferous Seam 9(2). The results indicate that the peat of Carboniferous Seam 9(2) was formed dominantly in wet swamps, whereas tbe peat of Permian Seam 2 formed dominantly in dry and wet swamps. These results are agree with the regional geology, that is, the peat of Carboniferous Seam 9(2) was formed in a transition zone and the peat of Permian Seam 2 formed in an upper delta zone.The climate of the peat-forming time for Permian Seam 2 was drier than that for Carboniferous.展开更多
Sarvak Formation (Late Albian-Early Turonian) as main reservoir in the field is one of the carbonate units of Bangestan Group in Zagros Basin with average thickness of 640 m. This formation conformably overlays the Ka...Sarvak Formation (Late Albian-Early Turonian) as main reservoir in the field is one of the carbonate units of Bangestan Group in Zagros Basin with average thickness of 640 m. This formation conformably overlays the Kazhdumi Formation while the upper boundary is an erosional unconformity which is covered by Ilam Formation. There is a significant lateral and vertical heterogeneity in the reservoir layers that causes main challenge in reservoir characterization. In this paper, reservoir properties evaluation and construction of depositional model have been done based on lithotype study, sedimentary environment classification, petrophysical interpretations and SeisWorks. Five facies types (lithotypes) in the Sarvak Formation with particular rock properties are identified in 8 wells and 200 thin sections. The main facies association elements and relevant depositional settings have been interpreted by extracted Paleolog, facies and fossil association data which are related to depositional setting variations.展开更多
文摘Through site observation and indoor measurements in XieJiaji No.2 Coal Mine in Huainan and Luling Coal Mine in Huaibei, it is discovered that the fragmentation degree are different in different coal seams in same mining district and even in sublevels of the are coal seam,tbe coal mass structures exist much difference. By analyzing the relationship between the constitution of coal matters and the epigenesis breakage of coal. This paper points out that the internal factor which causes the diversity of the coal mass structure are from the diversity in the contents of telocollinite and desmocollinite in the vitrinite. The contenet of desmocollinite is higher than that of telocollinite in intact coal seam (sublevel) but the former is less than the later in breaking sublevel, the diversity of constituent content more affects the epigenetic fragmtation degree of coal seam. The content of desmocollinite proves lower than that of telocollinite in the broken coal seam. The new understanding has directing, and reference for the study of coal perology, coal mine gas geology and coal methane.
基金financially supported by the Independent Projects of the Key Lab. of Coal Resources Exploration and Comprehensive Utilization, Ministry of Land and Resources of China (grants No. KF2019-2, ZKF2018-1, KF2018-4, ZP2018-2)the Major National Science and Technology Special Projects (grant No. 2016ZX05042004)+3 种基金the Projects Funded by China Postdoctoral Science Foundation (grant No. 2019M653873XB)the Natural Science Foundation Research Projects of Shaanxi Province (grant No. 2019JQ-245)the Doctoral Research Starting Foundation of Xi’an University of Science and Technology (grant No. 2016QDJ041)the Research Projects of the Geological Research Institute for Coal Green Mining of Xi’an University of Science and Technology (grant No. MTy2019-04)
文摘During the processes of methane adsorption and desorption,the internal structure of coal changes,accordingly leading to changes in electrical conductivity.In this paper,using low rank coal seams of the Yan'an Formation in the Dafbsi field as the research subject,the relationship between coal resistivity,methane adsorption quantity,and equilibrium pressure is analyzed through proximate analysis,mercury injection tests,low temperature liquid nitrogen adsorption tests,and coal resistivity measurements during methane adsorption and desorption.The results show that during the process of pressure rise and methane adsorption,the conductivity of coal increases,resulting from heat release from methane adsorption,coal matrix swelling and adsorbed water molecules replaced by methane,but the resistivity reduction gradually decreases.The relationship between coal resistivity and methane adsorption quantity and equilibrium pressure can be described by a quadratic function.During the processes of depressurization and desorption,the resistivity of coal rebounds slightly,due to decalescence of methane desorption,coal matrix shrinkage and water-gas displacement,and the relationship coincides with a linear function.Methane adsorption leads to irreversible changes in coal internal structure and enhances the coal conductivity,and resistivity can not be restored to the initial level even after methane desorption.The resistivity and reduction rate of durain are higher than those of vitrain,with relatively greater homogeneous pore throat structure and fewer charged particles in the double electric layer.In addition,moisture can enhance the conductivity of coal and makes it change more complexly during methane adsorption and desorption.
文摘In terms of macrolithotypes and microlithotypes, the petrographic composition was determined on column samples of Permian Seam 2 and Carboniferous Seam 9(2) from the Xingtai Coalfield, China. The macrolithotypes are classified into bright coal (B), banded bright coal (BB), banded coal (BC),banded dull coal (BD), dull coal (D) and fibrous coal (F). The lithotypes are dominated by BD and D in Seam 2, and BB in Seam 9(2).Microlithotypes are dominated by inertite and durite in Seam 2 and by vitrite in Seam 9(2). Eight microlithotypes were selected as indicators of peat-forming environments. Two triangle diagrams were drawn based on the indicators in order to explicate the peat-forming environments of Permian Seam 2 and Carboniferous Seam 9(2). The results indicate that the peat of Carboniferous Seam 9(2) was formed dominantly in wet swamps, whereas tbe peat of Permian Seam 2 formed dominantly in dry and wet swamps. These results are agree with the regional geology, that is, the peat of Carboniferous Seam 9(2) was formed in a transition zone and the peat of Permian Seam 2 formed in an upper delta zone.The climate of the peat-forming time for Permian Seam 2 was drier than that for Carboniferous.
文摘Sarvak Formation (Late Albian-Early Turonian) as main reservoir in the field is one of the carbonate units of Bangestan Group in Zagros Basin with average thickness of 640 m. This formation conformably overlays the Kazhdumi Formation while the upper boundary is an erosional unconformity which is covered by Ilam Formation. There is a significant lateral and vertical heterogeneity in the reservoir layers that causes main challenge in reservoir characterization. In this paper, reservoir properties evaluation and construction of depositional model have been done based on lithotype study, sedimentary environment classification, petrophysical interpretations and SeisWorks. Five facies types (lithotypes) in the Sarvak Formation with particular rock properties are identified in 8 wells and 200 thin sections. The main facies association elements and relevant depositional settings have been interpreted by extracted Paleolog, facies and fossil association data which are related to depositional setting variations.
