Shallow-water deltas are now a research focus of international sedimentology. Researchers have recently discovered that water depth is an important controlling factor for the development of shallow deltas, and that si...Shallow-water deltas are now a research focus of international sedimentology. Researchers have recently discovered that water depth is an important controlling factor for the development of shallow deltas, and that significant differences exist between shallow-water deltas and the traditional Gilbert deltas. The identification marks of shallow-water deltas are critical for better understanding sedimentary characteristics of these deltas. In continental basins, especially China＇s Mesozoic and Cenozoic continental basins, shallow-water deltas are widely developed. Thus, this work took the Songliao Basin as an example to analysis this kind of deltas.展开更多
Through the analysis of core descriptions, well-logs, seismic data, geochemical data and structural settings of the volcanic rock of the Yingcheng Formation in the Xujiaweizi fault depression, Songliao Basin, and the ...Through the analysis of core descriptions, well-logs, seismic data, geochemical data and structural settings of the volcanic rock of the Yingcheng Formation in the Xujiaweizi fault depression, Songliao Basin, and the geological section of the Yingcheng Formation in the southeast uplift area, this work determined the existence of volcanic weathering crust exists in the study area. The identification marks on the volcanic weathering crust can be recognized on the scale of core, logging, seismic, geochemistry, etc. In the study area, the structure of this crust is divided into clay layer, leached zone, fracture zone and host rocks, which are 5-118 m thick （averaging 27.5 m）. The lithology of the weathering crust includes basalt, andesite, rhyolite and volcanic breccia, and the lithofacies are igneous effusive and extrusive facies. The volcanic weathering crusts are clustered together in the Dashen zone and the middle of the Xuzhong zone, whereas in the Shengshen zone and other parts of the Xuzhong zone, they have a relatively scattered distribution. It is a major volcanic reservoir bed, which covers an area of 2104.16 km2. According to the geotectonic setting of the Songliao Basin, the formation process of the weathering crust is complete. Combining the macroscopic and microscopic features of the weathering crust of the Yingcheng Formation in Xujiaweizi with the logging and three-dimensional seismic sections, we established a developmental model of the paleo uplift and a developmental model of the slope belt that coexists with the sag on the Xujiaweizi volcanic weathering crust. In addition, the relationship between the volcanic weathering crust and the formation and distribution of the oil/gas reservoir is discussed.展开更多
Based on the geochemical characteristics of oil-cracking gas and kerogen-cracking gas revealed by simu-lation experiments and the chemical composition of natural gases in actual gas reservoirs,two kinds of natural gas...Based on the geochemical characteristics of oil-cracking gas and kerogen-cracking gas revealed by simu-lation experiments and the chemical composition of natural gases in actual gas reservoirs,two kinds of natural gases with different relationships between C_(2)/C_(3)and C_(1)/C_(2),C_(2)/C_(3)and C_(1)/C_(3),C_(2)/C_(3)and 100×C_(1)/(C_(1)-C5)were identified in the Tarim Basin,and proposed further by the authors.The relationship charts of C_(2)/C_(3)and C_(1)/C_(2),C_(2)/C_(3)and C_(1)/C_(3),C_(2)/C_(3)and 100×C_(1)/(C_(1)-C_(5))can be used to effectively distinguish oil-cracking gas from kerogen-cracking gas.Petro-leum geological analysis of the oil-cracking gas reservoirs showed that the distribution of oil-cracking gas is mostly related with deep-seated faults or faults with a large fault throw,and the burial depth of paleo-oil reservoir is rela-tively high;crude oil-cracking gas resources have been evaluated by using both forward and inversion methods.The plots of C_(2)/C_(3)vs.C_(1)/C_(2),C_(2)/C_(3)vs.C_(1)/C_(3),and C_(2)/C_(3)vs.100×C_(1)/(C_(1)-C_(5))were used to distinguish between oil-crack-ing gas and kerogen-cracking gas,and estimate the mixed ratios of the two kinds of natural gases in the main gas reservoirs of the platform area.展开更多
The Upper Sinian Dengying Fm is the focus of natural gas exploration in the central part of the Sichuan Basin (central Sichuan Basin) in recent years. Especially, epigenic karstification and its resulted reservoir-see...The Upper Sinian Dengying Fm is the focus of natural gas exploration in the central part of the Sichuan Basin (central Sichuan Basin) in recent years. Especially, epigenic karstification and its resulted reservoir-seepage spaces have always been the focal points in researches. Based on the petrographic characteristics of drilling cuttings and core samples, and through experimental analysis by using trace elements, isotopes, and cathodoluminescence, the Dengying Fm dolomite was demonstrated to have matrix recrystallized dolomite (MRD), filled saddle dolomite (FSD) (the mean homogenization temperature of inclusion: 178.5 °C, high concentrations of Fe & Mn, slightly positive 87Sr/86Sr value) and hydrothermal minerals combination (including sphalerite, galena, pyrite, and quartz, etc.). Thus, it was proposed that hydrothermal dolomite reservoir facies (HDRF) exist in the Dengying Fm dolomite, in other words, the dolomite reservoir is composed of hydrothermal dissolved pores, intercrystalline pores of hydrothermal origin, hydrothermal caverns and expanded fractures, and was formed due to the reworking of hydrothermal fluid on tight matrix dolomite. Identification marks are presented in terms of petrography and geochemistry so that hydrothermal dolomite reservoir facies can be effectively recognized and identified. It is concluded that the development of hydrothermal dolomite reservoir facies in this area are preliminary controlled by deep and large basement faults and the strength of hydrothermal fluids.展开更多
基金financially supported by the National Natural Science Foundation of China(grant No.41272133)
文摘Shallow-water deltas are now a research focus of international sedimentology. Researchers have recently discovered that water depth is an important controlling factor for the development of shallow deltas, and that significant differences exist between shallow-water deltas and the traditional Gilbert deltas. The identification marks of shallow-water deltas are critical for better understanding sedimentary characteristics of these deltas. In continental basins, especially China＇s Mesozoic and Cenozoic continental basins, shallow-water deltas are widely developed. Thus, this work took the Songliao Basin as an example to analysis this kind of deltas.
基金supported by the National Natural Science Fund Project(grant No.41430322)the National Basic Research Program of China(grant No.2009CB219306)the Open Fund of the State Key Laboratory Base of Unconventional Oil and Gas Accumulation and Exploitation,Northeast Petroleum University(grant No.2010DS670083-201301)
文摘Through the analysis of core descriptions, well-logs, seismic data, geochemical data and structural settings of the volcanic rock of the Yingcheng Formation in the Xujiaweizi fault depression, Songliao Basin, and the geological section of the Yingcheng Formation in the southeast uplift area, this work determined the existence of volcanic weathering crust exists in the study area. The identification marks on the volcanic weathering crust can be recognized on the scale of core, logging, seismic, geochemistry, etc. In the study area, the structure of this crust is divided into clay layer, leached zone, fracture zone and host rocks, which are 5-118 m thick （averaging 27.5 m）. The lithology of the weathering crust includes basalt, andesite, rhyolite and volcanic breccia, and the lithofacies are igneous effusive and extrusive facies. The volcanic weathering crusts are clustered together in the Dashen zone and the middle of the Xuzhong zone, whereas in the Shengshen zone and other parts of the Xuzhong zone, they have a relatively scattered distribution. It is a major volcanic reservoir bed, which covers an area of 2104.16 km2. According to the geotectonic setting of the Songliao Basin, the formation process of the weathering crust is complete. Combining the macroscopic and microscopic features of the weathering crust of the Yingcheng Formation in Xujiaweizi with the logging and three-dimensional seismic sections, we established a developmental model of the paleo uplift and a developmental model of the slope belt that coexists with the sag on the Xujiaweizi volcanic weathering crust. In addition, the relationship between the volcanic weathering crust and the formation and distribution of the oil/gas reservoir is discussed.
基金the National Natural Science Foundation of China(Grant No.40973041)
文摘Based on the geochemical characteristics of oil-cracking gas and kerogen-cracking gas revealed by simu-lation experiments and the chemical composition of natural gases in actual gas reservoirs,two kinds of natural gases with different relationships between C_(2)/C_(3)and C_(1)/C_(2),C_(2)/C_(3)and C_(1)/C_(3),C_(2)/C_(3)and 100×C_(1)/(C_(1)-C5)were identified in the Tarim Basin,and proposed further by the authors.The relationship charts of C_(2)/C_(3)and C_(1)/C_(2),C_(2)/C_(3)and C_(1)/C_(3),C_(2)/C_(3)and 100×C_(1)/(C_(1)-C_(5))can be used to effectively distinguish oil-cracking gas from kerogen-cracking gas.Petro-leum geological analysis of the oil-cracking gas reservoirs showed that the distribution of oil-cracking gas is mostly related with deep-seated faults or faults with a large fault throw,and the burial depth of paleo-oil reservoir is rela-tively high;crude oil-cracking gas resources have been evaluated by using both forward and inversion methods.The plots of C_(2)/C_(3)vs.C_(1)/C_(2),C_(2)/C_(3)vs.C_(1)/C_(3),and C_(2)/C_(3)vs.100×C_(1)/(C_(1)-C_(5))were used to distinguish between oil-crack-ing gas and kerogen-cracking gas,and estimate the mixed ratios of the two kinds of natural gases in the main gas reservoirs of the platform area.
基金Project supported by the National Major Science and Technology Project(No.2016ZX05015-003).
文摘The Upper Sinian Dengying Fm is the focus of natural gas exploration in the central part of the Sichuan Basin (central Sichuan Basin) in recent years. Especially, epigenic karstification and its resulted reservoir-seepage spaces have always been the focal points in researches. Based on the petrographic characteristics of drilling cuttings and core samples, and through experimental analysis by using trace elements, isotopes, and cathodoluminescence, the Dengying Fm dolomite was demonstrated to have matrix recrystallized dolomite (MRD), filled saddle dolomite (FSD) (the mean homogenization temperature of inclusion: 178.5 °C, high concentrations of Fe & Mn, slightly positive 87Sr/86Sr value) and hydrothermal minerals combination (including sphalerite, galena, pyrite, and quartz, etc.). Thus, it was proposed that hydrothermal dolomite reservoir facies (HDRF) exist in the Dengying Fm dolomite, in other words, the dolomite reservoir is composed of hydrothermal dissolved pores, intercrystalline pores of hydrothermal origin, hydrothermal caverns and expanded fractures, and was formed due to the reworking of hydrothermal fluid on tight matrix dolomite. Identification marks are presented in terms of petrography and geochemistry so that hydrothermal dolomite reservoir facies can be effectively recognized and identified. It is concluded that the development of hydrothermal dolomite reservoir facies in this area are preliminary controlled by deep and large basement faults and the strength of hydrothermal fluids.
