A systematic analysis of southwestern Ordos Basin's sedimentary characteristics,internal architectural element association styles and depositional model was illustrated through core statistics,well logging data an...A systematic analysis of southwestern Ordos Basin's sedimentary characteristics,internal architectural element association styles and depositional model was illustrated through core statistics,well logging data and outcrop observations in Chang 8 oil-bearing group.This analysis indicates that shallow water delta sediments dominated by a fluvial system is the primary sedimentary system of the Chang 8 oil-bearing group of the Yanchang Formation in southwestern Ordos Basin.Four microfacies with fine grain sizes are identified: distributary channels,sheet sandstone,mouth bar and interdistributary fines.According to the sandbody's spatial distribution and internal architecture,two types of sandbody architectural element associations are identified: amalgamated distributary channels and thin-layer lobate sandstone.In this sedimentary system,net-like distributary channels at the delta with a narrow ribbon shape compose the skeleton of the sandbody that extends further into the delta front and shades into contiguous lobate distribution sheet sandstone in the distal delta front.The mouth bar is largely absent in this system.By analyzing the palaeogeomorphology,the palaeostructure background,sedimentary characteristics,sedimentary facies types and spatial distribution of sedimentary facies during the Chang 8 period,a distinctive depositional model of the Chang 8 shallow water fluvial-dominated delta was established,which primarily consists of straight multi-phase amalgamated distributary channels in the delta plain,net-like distributary channels frequently diverting and converging in the proximal delta front,sheet sandstones with dispersing contiguous lobate shapes in the distal delta front,and prodelta or shallow lake mudstones.展开更多
探讨鄂尔多斯盆地镇原地区油气充注特征与油藏主控因素,以及油气聚集规律与成藏模式。运用成藏动力学,以典型油气藏或出油点解剖为基础,以流体来源及其流动样式为核心,采用精细油源对比、流体包裹体技术和油气运移路径示踪技术等方法。...探讨鄂尔多斯盆地镇原地区油气充注特征与油藏主控因素,以及油气聚集规律与成藏模式。运用成藏动力学,以典型油气藏或出油点解剖为基础,以流体来源及其流动样式为核心,采用精细油源对比、流体包裹体技术和油气运移路径示踪技术等方法。结果表明长8油层组为岩性或构造-岩性油藏,油气主要来源于长7段优质烃源岩;主要存在2期原油连续充注过程(±130 Ma B.P.和±105 Ma B.P.),第二期为主充注期;流体存在明显的从上至下的垂向运移指向,进一步证实"上生下储、高压驱动、裂缝与砂体输导、多点充注、近源成藏"的模式特征。展开更多
基金Project(SQ2013CB021013)supported by the National Key Basic Research Program of ChinaProject(41002045)supported by the National Natural Science Foundation of China
文摘A systematic analysis of southwestern Ordos Basin's sedimentary characteristics,internal architectural element association styles and depositional model was illustrated through core statistics,well logging data and outcrop observations in Chang 8 oil-bearing group.This analysis indicates that shallow water delta sediments dominated by a fluvial system is the primary sedimentary system of the Chang 8 oil-bearing group of the Yanchang Formation in southwestern Ordos Basin.Four microfacies with fine grain sizes are identified: distributary channels,sheet sandstone,mouth bar and interdistributary fines.According to the sandbody's spatial distribution and internal architecture,two types of sandbody architectural element associations are identified: amalgamated distributary channels and thin-layer lobate sandstone.In this sedimentary system,net-like distributary channels at the delta with a narrow ribbon shape compose the skeleton of the sandbody that extends further into the delta front and shades into contiguous lobate distribution sheet sandstone in the distal delta front.The mouth bar is largely absent in this system.By analyzing the palaeogeomorphology,the palaeostructure background,sedimentary characteristics,sedimentary facies types and spatial distribution of sedimentary facies during the Chang 8 period,a distinctive depositional model of the Chang 8 shallow water fluvial-dominated delta was established,which primarily consists of straight multi-phase amalgamated distributary channels in the delta plain,net-like distributary channels frequently diverting and converging in the proximal delta front,sheet sandstones with dispersing contiguous lobate shapes in the distal delta front,and prodelta or shallow lake mudstones.
文摘探讨鄂尔多斯盆地镇原地区油气充注特征与油藏主控因素,以及油气聚集规律与成藏模式。运用成藏动力学,以典型油气藏或出油点解剖为基础,以流体来源及其流动样式为核心,采用精细油源对比、流体包裹体技术和油气运移路径示踪技术等方法。结果表明长8油层组为岩性或构造-岩性油藏,油气主要来源于长7段优质烃源岩;主要存在2期原油连续充注过程(±130 Ma B.P.和±105 Ma B.P.),第二期为主充注期;流体存在明显的从上至下的垂向运移指向,进一步证实"上生下储、高压驱动、裂缝与砂体输导、多点充注、近源成藏"的模式特征。
