Upper Ordovician-Lower Silurian Wufeng-Longmaxi Formation is the most developed strata of shale gas in southern China.Due to the complex sedimentary environment adjacent to the Kangdian Uplift,the favorable area for o...Upper Ordovician-Lower Silurian Wufeng-Longmaxi Formation is the most developed strata of shale gas in southern China.Due to the complex sedimentary environment adjacent to the Kangdian Uplift,the favorable area for organic-rich shale development is still undetermined.The authors,therefore,focus on the mechanism of accumulation of organic matter and the characterization of the sedimentary environment of the Wufeng-Longmaxi Shales to have a more complete understanding and new discovering of organic matter enrichment and favorable area in the marginal region around Sichuan Basin.Multiple methods were applied in this study,including thin section identification,scanning electron microscopy(SEM)observations and X-ray diffraction(XRD),and elemental analysis on outcrop samples.Five lithofacies have been defined according to the mineralogical and petrological analyses,including mudstone,bioclastic limestone,silty shale,dolomitic shale,and carbonaceous siliceous shale.The paleo-environments have been reconstructed and the organic enrichment mechanism has been identified as a reduced environment and high productivity.The Wufeng period is generally a suboxic environment and the early Longmaxi period is a reducing environment based on geochemical characterization.High dolomite content in the study area is accompanied by high TOC,which may potentially indicate the restricted anoxic environment formed by biological flourishing in shallower water.And for the area close to the Kangdian Uplift,the shale gas generation capability is comparatively favorable.The geochemical parameters implied that new favorable areas for shale gas exploration could be targeted,and more shale gas resources in the mountain-basin transitional zone might be identified in the future.展开更多
The oil-gas migration and accumulation in the Songliao Basin were analyzed in the view of fluid dynamics by the authors. The key point of fluid dynamics is hydrodynamics. Oil-gas migration and accumulation are related...The oil-gas migration and accumulation in the Songliao Basin were analyzed in the view of fluid dynamics by the authors. The key point of fluid dynamics is hydrodynamics. Oil-gas migration and accumulation are related closely with formation and evolution of hydrodynamic field. Based on abundant data, initial formation pressure and other parameters, such as water head were studied. They can be used to understand the present distribution of hydrodynamic field and its hydrochemical features. Generally, the hydrodynamic field in the basin is obviously asymmetrical. In its north and east part, there are the areas of centripetal flow caused by topographic relief when meteoric water permeate downwards. Its south part is an evaporation-concentration area. The central depression is an area of centrifugal flow driven by sediment compaction and its cross-formational flow area. Only at the basin margin and in the local uplifted and denudated area are the meteoric water permeating downwards areas. The centrifugal flow driven by sediment compaction is the main dynamic factor that induces oil-gas migration and accumulation and its formation period corresponding to the main stage of oil-gas migration and accumulation. Moreover, the evolution of hydrodynamic field has the cyclic property, which results in phased oil-gas migration by stages, and further dominates the terraced annular oil and gas distribution, concentric with their corresponding sags.展开更多
Geochronology of oil-gas accumulation (OGA) is a challenging subject of petroleum geology in multi-cycle superimposed basins.By K-Ar dating of authigenic illite (AI) and fluid inclusion (FI) analysis combined wi...Geochronology of oil-gas accumulation (OGA) is a challenging subject of petroleum geology in multi-cycle superimposed basins.By K-Ar dating of authigenic illite (AI) and fluid inclusion (FI) analysis combined with apatite fission track (AFT) thermal modeling,a case study of constraining the OGA times of the Permian reservoirs in northeast Ordos basin (NOB) has been conducted in this paper.AI dating of the Permian oil-gas-bearing sandstone core-samples shows a wide time domain of 178-108 Ma.The distribution of the AI ages presents 2-stage primary OGA processes in the Permian reservoirs,which developed in the time domains of 175-155 Ma and 145-115 Ma with 2-peak ages of 165 Ma and 130 Ma,respectively.The FI temperature peaks of the samples and their projected ages on the AFT thermal path not only present two groups with a low and a high peak temperatures in ranges of 90-78℃ and 125-118℃,respectively corresponding to 2-stage primary OGA processes of 162-153 Ma and 140-128 Ma in the Permian reservoirs,but also appear a medium temperature group with the peak of 98℃ in agreement with a secondary OGA process of c.~30 Ma in the Upper Permian reservoirs.The integrated analysis of the AI and FI ages and the tectono-thermal evolution reveals that the Permian reservoirs in the NOB experienced at least 2-stage primary OGA processes of 165-153 Ma and 140-128 Ma in agreement with the subsidence thermal process of the Mid-Early Jurassic and the tectono-thermal event of the Early Cretaceous.Then,the Upper Permian reservoirs further experienced at least 1-stage secondary OGA process of c.~30 Ma in coincidence with a critical tectonic conversion between the slow and the rapid uplift processes from the Late Cretaceous to Neogene.展开更多
Based on comprehensive analysis of tectonic and fault evolution, core, well logging, seismic, drilling, and production data, the reservoir space characteristic, distribution, origin of fault-karst carbonate reservoir ...Based on comprehensive analysis of tectonic and fault evolution, core, well logging, seismic, drilling, and production data, the reservoir space characteristic, distribution, origin of fault-karst carbonate reservoir in Yueman block of South Tahe area, Halahatang oilfield, Tarim Basin, were studied systematically. And the regular pattern of hydrocarbon accumulation and enrichment was analyzed systematically based on development practice of the reservoirs. The results show that fault-karst carbonate reservoirs are distributed in the form of "body by body" discontinuously, heterogeneously and irregularly, which are controlled by the development of faults. Three formation models of fault-karst carbonate reservoirs, namely, the models controlled by the main deep-large fault, the secondary fault and the secondary internal fault, are built. The hydrocarbon accumulation and enrichment of fault-karst carbonate reservoirs is controlled by the spatiotemporal matching relation between hydrocarbon generation period and fault activity, and the size and segmentation of fault. The study results can effectively guide the well deployment and help the efficient development of fault-karst carbonate reservoirs of South Tahe area, Halahatang oilfield.展开更多
The Lankao-Liaocheng Fractural Zone is a large-seade NNE-trending struetural zone in the North China Crustoblock. Dated from the Late Arehean-Early Proterozoie, it is stil1 active now. Its nature varied with time in i...The Lankao-Liaocheng Fractural Zone is a large-seade NNE-trending struetural zone in the North China Crustoblock. Dated from the Late Arehean-Early Proterozoie, it is stil1 active now. Its nature varied with time in its developing process. It has became a tensile ultralithospherie fraetural zone at present or in diwa residual-mobility period. Some cenozoic oil-gas-bearing basins are distributed along the fraetural zone which fomed an important oil-gas accumulating belt in the North China Ctustoblock.展开更多
In the framework of the two-continuum approach, using the matched asymptotic expansion method, the equations of a laminar boundary layer in mist flows with evaporating droplets were derived and solved. The similarity ...In the framework of the two-continuum approach, using the matched asymptotic expansion method, the equations of a laminar boundary layer in mist flows with evaporating droplets were derived and solved. The similarity criteria controlling the mist flows were determined. For the flow along a curvilinear surface, the forms of the boundary layer equations differ from the regimes of presence and absence of the droplet inertia deposition. The numerical results were presented for the vapor-droplet boundary layer in the neighborhood of a stagnation point of a hot blunt body. It is demonstrated that, due to evaporation, a droplet-free region develops near the wall inside the boundary layer. On the upper edge of this region, the droplet radius tends to zero and the droplet number density becomes much higher than that in the free stream. The combined effect of the droplet evaporation and accumulation results in a significant enhancement of the heat transfer on the surface even for small mass concentration of the droplets in the free stream.展开更多
基金jointly funded by the National Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(PLC20210104)China Geological Survey(DD20221661)China National Science and Technology Major Project“Test and Application of Shale Gas Exploration and Evaluation Technology(2016ZX05034004)”。
文摘Upper Ordovician-Lower Silurian Wufeng-Longmaxi Formation is the most developed strata of shale gas in southern China.Due to the complex sedimentary environment adjacent to the Kangdian Uplift,the favorable area for organic-rich shale development is still undetermined.The authors,therefore,focus on the mechanism of accumulation of organic matter and the characterization of the sedimentary environment of the Wufeng-Longmaxi Shales to have a more complete understanding and new discovering of organic matter enrichment and favorable area in the marginal region around Sichuan Basin.Multiple methods were applied in this study,including thin section identification,scanning electron microscopy(SEM)observations and X-ray diffraction(XRD),and elemental analysis on outcrop samples.Five lithofacies have been defined according to the mineralogical and petrological analyses,including mudstone,bioclastic limestone,silty shale,dolomitic shale,and carbonaceous siliceous shale.The paleo-environments have been reconstructed and the organic enrichment mechanism has been identified as a reduced environment and high productivity.The Wufeng period is generally a suboxic environment and the early Longmaxi period is a reducing environment based on geochemical characterization.High dolomite content in the study area is accompanied by high TOC,which may potentially indicate the restricted anoxic environment formed by biological flourishing in shallower water.And for the area close to the Kangdian Uplift,the shale gas generation capability is comparatively favorable.The geochemical parameters implied that new favorable areas for shale gas exploration could be targeted,and more shale gas resources in the mountain-basin transitional zone might be identified in the future.
文摘The oil-gas migration and accumulation in the Songliao Basin were analyzed in the view of fluid dynamics by the authors. The key point of fluid dynamics is hydrodynamics. Oil-gas migration and accumulation are related closely with formation and evolution of hydrodynamic field. Based on abundant data, initial formation pressure and other parameters, such as water head were studied. They can be used to understand the present distribution of hydrodynamic field and its hydrochemical features. Generally, the hydrodynamic field in the basin is obviously asymmetrical. In its north and east part, there are the areas of centripetal flow caused by topographic relief when meteoric water permeate downwards. Its south part is an evaporation-concentration area. The central depression is an area of centrifugal flow driven by sediment compaction and its cross-formational flow area. Only at the basin margin and in the local uplifted and denudated area are the meteoric water permeating downwards areas. The centrifugal flow driven by sediment compaction is the main dynamic factor that induces oil-gas migration and accumulation and its formation period corresponding to the main stage of oil-gas migration and accumulation. Moreover, the evolution of hydrodynamic field has the cyclic property, which results in phased oil-gas migration by stages, and further dominates the terraced annular oil and gas distribution, concentric with their corresponding sags.
基金supported by the National Basic Research Program of China (No.2003CB2146007)the Special Research Fund for the Doctoral Program of Colleges and Universities of the National Education Ministry of China (No. 20116101110006)+2 种基金the Key Project of Natural Science Basic Research Plan in Shaanxi Province of China (No.2012JZ5001)the Oil-gas Survey Project of China Geological Survey Bureau (1212011220761)the Preferred Foundation of Study Abroad Returnees of the Human Resources and Social Security of China
文摘Geochronology of oil-gas accumulation (OGA) is a challenging subject of petroleum geology in multi-cycle superimposed basins.By K-Ar dating of authigenic illite (AI) and fluid inclusion (FI) analysis combined with apatite fission track (AFT) thermal modeling,a case study of constraining the OGA times of the Permian reservoirs in northeast Ordos basin (NOB) has been conducted in this paper.AI dating of the Permian oil-gas-bearing sandstone core-samples shows a wide time domain of 178-108 Ma.The distribution of the AI ages presents 2-stage primary OGA processes in the Permian reservoirs,which developed in the time domains of 175-155 Ma and 145-115 Ma with 2-peak ages of 165 Ma and 130 Ma,respectively.The FI temperature peaks of the samples and their projected ages on the AFT thermal path not only present two groups with a low and a high peak temperatures in ranges of 90-78℃ and 125-118℃,respectively corresponding to 2-stage primary OGA processes of 162-153 Ma and 140-128 Ma in the Permian reservoirs,but also appear a medium temperature group with the peak of 98℃ in agreement with a secondary OGA process of c.~30 Ma in the Upper Permian reservoirs.The integrated analysis of the AI and FI ages and the tectono-thermal evolution reveals that the Permian reservoirs in the NOB experienced at least 2-stage primary OGA processes of 165-153 Ma and 140-128 Ma in agreement with the subsidence thermal process of the Mid-Early Jurassic and the tectono-thermal event of the Early Cretaceous.Then,the Upper Permian reservoirs further experienced at least 1-stage secondary OGA process of c.~30 Ma in coincidence with a critical tectonic conversion between the slow and the rapid uplift processes from the Late Cretaceous to Neogene.
基金Supported by the China National Sicence and Technology Project(2016ZX05004)
文摘Based on comprehensive analysis of tectonic and fault evolution, core, well logging, seismic, drilling, and production data, the reservoir space characteristic, distribution, origin of fault-karst carbonate reservoir in Yueman block of South Tahe area, Halahatang oilfield, Tarim Basin, were studied systematically. And the regular pattern of hydrocarbon accumulation and enrichment was analyzed systematically based on development practice of the reservoirs. The results show that fault-karst carbonate reservoirs are distributed in the form of "body by body" discontinuously, heterogeneously and irregularly, which are controlled by the development of faults. Three formation models of fault-karst carbonate reservoirs, namely, the models controlled by the main deep-large fault, the secondary fault and the secondary internal fault, are built. The hydrocarbon accumulation and enrichment of fault-karst carbonate reservoirs is controlled by the spatiotemporal matching relation between hydrocarbon generation period and fault activity, and the size and segmentation of fault. The study results can effectively guide the well deployment and help the efficient development of fault-karst carbonate reservoirs of South Tahe area, Halahatang oilfield.
文摘The Lankao-Liaocheng Fractural Zone is a large-seade NNE-trending struetural zone in the North China Crustoblock. Dated from the Late Arehean-Early Proterozoie, it is stil1 active now. Its nature varied with time in its developing process. It has became a tensile ultralithospherie fraetural zone at present or in diwa residual-mobility period. Some cenozoic oil-gas-bearing basins are distributed along the fraetural zone which fomed an important oil-gas accumulating belt in the North China Ctustoblock.
文摘In the framework of the two-continuum approach, using the matched asymptotic expansion method, the equations of a laminar boundary layer in mist flows with evaporating droplets were derived and solved. The similarity criteria controlling the mist flows were determined. For the flow along a curvilinear surface, the forms of the boundary layer equations differ from the regimes of presence and absence of the droplet inertia deposition. The numerical results were presented for the vapor-droplet boundary layer in the neighborhood of a stagnation point of a hot blunt body. It is demonstrated that, due to evaporation, a droplet-free region develops near the wall inside the boundary layer. On the upper edge of this region, the droplet radius tends to zero and the droplet number density becomes much higher than that in the free stream. The combined effect of the droplet evaporation and accumulation results in a significant enhancement of the heat transfer on the surface even for small mass concentration of the droplets in the free stream.