Sichuan Basin is a typical superimposed basin, which experienced multi-phase tectonic movements, meanwhile Sinian–Cambrian underwent complex hydrocarbon accumulation processes, causing exploration difficulties in the...Sichuan Basin is a typical superimposed basin, which experienced multi-phase tectonic movements, meanwhile Sinian–Cambrian underwent complex hydrocarbon accumulation processes, causing exploration difficulties in the past 60 years. Based on the microscopic evidence of fluid inclusions, combined with basin-modelling, this paper determines stages and time of hydrocarbon accumulation, reconstructs evolution of formation pressure and dynamic processes of hydrocarbon accumulation in Sinian Dengying Formation-Cambrian Longwangmiao Formation of Gaoshiti-Moxi structure. Three stages of inclusions are detected, including a stage of yellow-yellowgreen fluorescent oil inclusions, a stage of blue fluorescent oil-gas inclusions and a stage of non-fluorescent gas inclusions, reflecting the study area has experienced a series of complex hydrocarbon accumulation processes, such as formation of paleo-oil reservoirs, cracking of crude oil, formation of paleo-gas reservoirs and adjustment to present gas reservoirs, which occurred during 219–188, 192–146 and 168–0 Ma respectively. During the period of crude oil cracking, Dengying Formation-Longwangmiao Formation showed weak overpressure to overpressure characteristics, then after adjustment of paleo-gas reservoirs to present gas reservoirs, the pressure in Dengying Formation changed into overpressure but finally reduced to normal pressure system. However, due to excellent preservation conditions, the overpressure strength in Longwangmiao Formation only slightly decreased and was still kept to this day.展开更多
The multi-stage minerals filled in pore space were sequenced, and the charging stages of fluid and hydrocarbon were reconstructed based on the observation of drilling cores and thin sections, homogeneous temperature t...The multi-stage minerals filled in pore space were sequenced, and the charging stages of fluid and hydrocarbon were reconstructed based on the observation of drilling cores and thin sections, homogeneous temperature testing of fluid inclusions, Laser Raman composition analysis and isotope geochemical analysis. The Cambrian Longwangmiao Formation in the study area went through 5 stages of fluid charging, in which 3 stages, mid-late Triassic, early-mid Jurassic and early-mid Cretaceous, were related to oil and gas charging. Especially the oil and gas charging event in early-mid Cretaceous was the critical period of gas accumulation in the study area, and was recorded by methane gas inclusions in the late stage quartz fillings. The ^(40) Ar-^(39) Ar dating of the 3 rd stage methane inclusions shows that the natural gas charging of this stage was from 125.8±8.2 Ma. Analysis of Si, O isotopes and ^(87) Sr/^(86) Sr of the late stage quartz indicates that the fluid source of the quartz was formation water coming from long term evolution and concentration of meteoric water, but not from deep part or other sources, this also reflects that, in the critical charging period of natural gas, the Cambrian Longwangmiao Formation in Moxi structure had favorable conservation conditions for hydrocarbon accumulation, which was favorable for the formation of the Longwangmiao large natural gas pool.展开更多
By using core, thin section, well logging, seismic, well testing and other data, the reservoir grading evaluation parameters were selected, the classification criterion considering multiple factors for carbonate reser...By using core, thin section, well logging, seismic, well testing and other data, the reservoir grading evaluation parameters were selected, the classification criterion considering multiple factors for carbonate reservoirs in this area were established, and the main factors affecting the development of high quality reservoir were determined. By employing Formation MicroScanner Image(FMI) logging fracture-cavity recognition technology and reservoir seismic waveform classification technology, the spatial distribution of reservoirs of all grades were predicted. On the basis of identifying four types of reservoir space developed in the study area by mercury injection experiment, a classification criterion was established using four reservoir grading evaluation parameters, median throat radius, effective porosity and effective permeability of fracture-cavity development zone, relationship between fracture and dissolution pore development and assemblage, and the reservoirs in the study area were classified into grade I high quality reservoir of fracture and cavity type, grade II average reservoir of fracture and porosity type, grade Ⅲ poor reservoir of intergranular pore type. Based on the three main factors controlling the development of high quality reservoir, structural location, sedimentary facies and epigenesis, the distribution of the 3 grades reservoirs in each well area and formation were predicted using geophysical response and percolation characteristics. Follow-up drilling has confirmed that the classification evaluation standard and prediction methods established are effective.展开更多
This study aims to understand the particle size distribution and depositional styles of glacierassociated deposits in the Moxi basin in southwest China. Based on field surveys, 28 samples from glacier-associated depos...This study aims to understand the particle size distribution and depositional styles of glacierassociated deposits in the Moxi basin in southwest China. Based on field surveys, 28 samples from glacier-associated deposits(including glacial till,fluvioglacial, debris flow, river and lake deposits)were collected and tested in the laboratory. The results showed that the glacier-associated deposits can be differentiated based on particle gradation,particle size distribution and accumulated percentages. We evaluated the evolution of a former dammed lake in the Moxi basin based on glacierassociated deposits. The results of this study also indicated that the Moxi Platform was not formed by a single depositional process but is composed of both fluvioglacial and debris flow deposits. This research shows that the depositional style analysis is useful in identifying different glacier-associated deposits in high mountain regions. Moreover, the evaluation of the differences in particle sizes of the glacierassociated deposits is useful in reconstructing geohazard events in periglacial regions, and this information can help in identifying and reducing the potential risks associated with geo-hazards.展开更多
Debris flows are the main geological hazards in the Moxi basin, which locate on the eastern slope of the M.T Minya Konka, Sichuan province, southwestern of China. The location of 49 debris flow gullies have been ident...Debris flows are the main geological hazards in the Moxi basin, which locate on the eastern slope of the M.T Minya Konka, Sichuan province, southwestern of China. The location of 49 debris flow gullies have been identified and mapped from the 1:50000 scale through the extensive field survey across the Moxi basin. The historical events data were collected from documents and visit to local residents, and were used as the basis for frequency analysis. Anymore, topographic features of debris flow gullies have been calculated using GIS software. The analysis showed that 73.5% of the debris flow gullies are not randomly distributed but concentrated directly adjacent to the western side of Moxi fault, and only 26.5% are located to the eastern side. The numbers, frequency, catchments area, gully length, gully slope ratio of these debris flow gullies in Moxi basin were affected by the glaciations and geological activity. The results show potential activity of debris flow in Moxi basin is strong, this research is essential to debris flow hazards mitigation.展开更多
基于钻井、测井、实验分析及生产等资料,以磨溪气田嘉二气藏主力产层嘉二^(2)亚段B层(T_(1)j_(2)^(2B))白云岩储层为研究对象,利用流动单元来表征气藏白云岩储层非均质性,通过对比流动层带指数、孔喉半径(R_(35))及聚类分析的流动单元...基于钻井、测井、实验分析及生产等资料,以磨溪气田嘉二气藏主力产层嘉二^(2)亚段B层(T_(1)j_(2)^(2B))白云岩储层为研究对象,利用流动单元来表征气藏白云岩储层非均质性,通过对比流动层带指数、孔喉半径(R_(35))及聚类分析的流动单元划分方法,在取心井流动单元的研究基础上,利用多元回归的方式定量评价FZI(Flow Zone Index)值,未取心井通过fisher判别分析函数精细划分.从压汞参数与生产动态资料验证其流动单元划分合理性.研究结果表明:对于薄层的白云岩储层,采用流动层带指数法划分的流动单元为一组具有较好孔渗关系的岩石类型,R_(35)所划分的流动单元为一组具有相似孔喉半径(不同孔隙度有着相近的渗透率)的岩石类型,通过聚类方法,能将具有相似的孔隙结构的储层归位一类流动单元;流动层带指数的测井识别是流动单元划分的难点,机器学习、神经网络等算法对于精度具有较大提升,但需要大量数据,对于研究区,常规的线性回归方式成为了最佳的选择;流动单元预测结果与压汞参数、初期产能存在较强相关性,流动单元划分结果可靠,可为后续气藏的开发提供参考.展开更多
基金financially supported by the National Natural Science Foundation of China(No.41502134)the 973 Program of China(No.2012CB214805)+1 种基金the China Postdoctoral Science Foundation(No.2014M552327)the research grant from the Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education,China University of Geosciences(No.TPR-2014-02)
文摘Sichuan Basin is a typical superimposed basin, which experienced multi-phase tectonic movements, meanwhile Sinian–Cambrian underwent complex hydrocarbon accumulation processes, causing exploration difficulties in the past 60 years. Based on the microscopic evidence of fluid inclusions, combined with basin-modelling, this paper determines stages and time of hydrocarbon accumulation, reconstructs evolution of formation pressure and dynamic processes of hydrocarbon accumulation in Sinian Dengying Formation-Cambrian Longwangmiao Formation of Gaoshiti-Moxi structure. Three stages of inclusions are detected, including a stage of yellow-yellowgreen fluorescent oil inclusions, a stage of blue fluorescent oil-gas inclusions and a stage of non-fluorescent gas inclusions, reflecting the study area has experienced a series of complex hydrocarbon accumulation processes, such as formation of paleo-oil reservoirs, cracking of crude oil, formation of paleo-gas reservoirs and adjustment to present gas reservoirs, which occurred during 219–188, 192–146 and 168–0 Ma respectively. During the period of crude oil cracking, Dengying Formation-Longwangmiao Formation showed weak overpressure to overpressure characteristics, then after adjustment of paleo-gas reservoirs to present gas reservoirs, the pressure in Dengying Formation changed into overpressure but finally reduced to normal pressure system. However, due to excellent preservation conditions, the overpressure strength in Longwangmiao Formation only slightly decreased and was still kept to this day.
基金Supported by the National Natural Science Foundation of China(41572133,41372141)
文摘The multi-stage minerals filled in pore space were sequenced, and the charging stages of fluid and hydrocarbon were reconstructed based on the observation of drilling cores and thin sections, homogeneous temperature testing of fluid inclusions, Laser Raman composition analysis and isotope geochemical analysis. The Cambrian Longwangmiao Formation in the study area went through 5 stages of fluid charging, in which 3 stages, mid-late Triassic, early-mid Jurassic and early-mid Cretaceous, were related to oil and gas charging. Especially the oil and gas charging event in early-mid Cretaceous was the critical period of gas accumulation in the study area, and was recorded by methane gas inclusions in the late stage quartz fillings. The ^(40) Ar-^(39) Ar dating of the 3 rd stage methane inclusions shows that the natural gas charging of this stage was from 125.8±8.2 Ma. Analysis of Si, O isotopes and ^(87) Sr/^(86) Sr of the late stage quartz indicates that the fluid source of the quartz was formation water coming from long term evolution and concentration of meteoric water, but not from deep part or other sources, this also reflects that, in the critical charging period of natural gas, the Cambrian Longwangmiao Formation in Moxi structure had favorable conservation conditions for hydrocarbon accumulation, which was favorable for the formation of the Longwangmiao large natural gas pool.
基金Supported by CNPC Science and Technology Major Project(2016ZX052,2016ZX05015-003)
文摘By using core, thin section, well logging, seismic, well testing and other data, the reservoir grading evaluation parameters were selected, the classification criterion considering multiple factors for carbonate reservoirs in this area were established, and the main factors affecting the development of high quality reservoir were determined. By employing Formation MicroScanner Image(FMI) logging fracture-cavity recognition technology and reservoir seismic waveform classification technology, the spatial distribution of reservoirs of all grades were predicted. On the basis of identifying four types of reservoir space developed in the study area by mercury injection experiment, a classification criterion was established using four reservoir grading evaluation parameters, median throat radius, effective porosity and effective permeability of fracture-cavity development zone, relationship between fracture and dissolution pore development and assemblage, and the reservoirs in the study area were classified into grade I high quality reservoir of fracture and cavity type, grade II average reservoir of fracture and porosity type, grade Ⅲ poor reservoir of intergranular pore type. Based on the three main factors controlling the development of high quality reservoir, structural location, sedimentary facies and epigenesis, the distribution of the 3 grades reservoirs in each well area and formation were predicted using geophysical response and percolation characteristics. Follow-up drilling has confirmed that the classification evaluation standard and prediction methods established are effective.
基金funded by The China Geological Survey (Grant No. 12120113010200)Ministry of Science and Technology of the People’s Republic of China (Grant No. 2011FY110100-5)The National Natural Science Foundation of China (Grant No. 41101086)
文摘This study aims to understand the particle size distribution and depositional styles of glacierassociated deposits in the Moxi basin in southwest China. Based on field surveys, 28 samples from glacier-associated deposits(including glacial till,fluvioglacial, debris flow, river and lake deposits)were collected and tested in the laboratory. The results showed that the glacier-associated deposits can be differentiated based on particle gradation,particle size distribution and accumulated percentages. We evaluated the evolution of a former dammed lake in the Moxi basin based on glacierassociated deposits. The results of this study also indicated that the Moxi Platform was not formed by a single depositional process but is composed of both fluvioglacial and debris flow deposits. This research shows that the depositional style analysis is useful in identifying different glacier-associated deposits in high mountain regions. Moreover, the evaluation of the differences in particle sizes of the glacierassociated deposits is useful in reconstructing geohazard events in periglacial regions, and this information can help in identifying and reducing the potential risks associated with geo-hazards.
文摘Debris flows are the main geological hazards in the Moxi basin, which locate on the eastern slope of the M.T Minya Konka, Sichuan province, southwestern of China. The location of 49 debris flow gullies have been identified and mapped from the 1:50000 scale through the extensive field survey across the Moxi basin. The historical events data were collected from documents and visit to local residents, and were used as the basis for frequency analysis. Anymore, topographic features of debris flow gullies have been calculated using GIS software. The analysis showed that 73.5% of the debris flow gullies are not randomly distributed but concentrated directly adjacent to the western side of Moxi fault, and only 26.5% are located to the eastern side. The numbers, frequency, catchments area, gully length, gully slope ratio of these debris flow gullies in Moxi basin were affected by the glaciations and geological activity. The results show potential activity of debris flow in Moxi basin is strong, this research is essential to debris flow hazards mitigation.
文摘基于钻井、测井、实验分析及生产等资料,以磨溪气田嘉二气藏主力产层嘉二^(2)亚段B层(T_(1)j_(2)^(2B))白云岩储层为研究对象,利用流动单元来表征气藏白云岩储层非均质性,通过对比流动层带指数、孔喉半径(R_(35))及聚类分析的流动单元划分方法,在取心井流动单元的研究基础上,利用多元回归的方式定量评价FZI(Flow Zone Index)值,未取心井通过fisher判别分析函数精细划分.从压汞参数与生产动态资料验证其流动单元划分合理性.研究结果表明:对于薄层的白云岩储层,采用流动层带指数法划分的流动单元为一组具有较好孔渗关系的岩石类型,R_(35)所划分的流动单元为一组具有相似孔喉半径(不同孔隙度有着相近的渗透率)的岩石类型,通过聚类方法,能将具有相似的孔隙结构的储层归位一类流动单元;流动层带指数的测井识别是流动单元划分的难点,机器学习、神经网络等算法对于精度具有较大提升,但需要大量数据,对于研究区,常规的线性回归方式成为了最佳的选择;流动单元预测结果与压汞参数、初期产能存在较强相关性,流动单元划分结果可靠,可为后续气藏的开发提供参考.
