| 鄂尔多斯盆地西南地区上三叠统延长组沉积相及石油地质意义 |
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| 引用本文： | 付金华,郭正权,邓秀芹.鄂尔多斯盆地西南地区上三叠统延长组沉积相及石油地质意义[J].古地理学报,2005,7(1):34-44. |
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| 作者姓名： | 付金华 郭正权 邓秀芹 |
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| 作者单位： | 1. 西北大学地质系 710069 ;
2.长庆油田公司勘探开发研究院 710021 |
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| 摘 要： | 鄂尔多斯盆地三叠系延长组主要发育东北和西南两大沉积体系，东北的河流三角洲体系已为大量的勘探研究资料所证实，而西南体系因受勘探程度限制,目前研究不够。本文通过最新钻探成果，结合盆地西南部露头资料，确立盆地西南地区三叠系延长组为冲积扇-扇三角洲沉积体系，发育冲积扇、扇三角洲、湖泊（浊积）相。冲积扇以西南缘平凉崆峒山和汭水河剖面为代表，扇三角洲及湖泊（浊积）相为区内钻井剖面所证实。长6-长8为区内主力油层组，地层保存完整，钻探程度相对较高。扇三角洲前缘砂体类型以水下分流河道为主,局部发育河口坝,浊积体以厚层块状为主。长8亚期为扇三角洲前缘亚相最发育期，横向形成自西南向东北延伸的三支前缘砂体带，是石油聚集的重要区带；长7亚期随着湖盆沉降，周边抬升强烈，湖岸较陡，大量发育浊积体系；长6亚期湖退导致扇三角洲再次发育，但规模较长8亚期弱。扇三角洲前缘砂体单层厚度大,砂岩粒度较粗,颗粒分选及物性好,是石油富集的最有利相带。
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| 关 键 词： | 鄂尔多斯盆地 上三叠统 沉积相 冲积扇 扇三角洲 浊积 |
| 文章编号： | 1671-1505(2005)01-0034-11 |
| 修稿时间： | 2004年5月13日 |
Sedimentary facies of the Yanchang Formation of Upper Triassic and petroleum geological implication in southwestern Ordos Basin |
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| Fu Jinhua,Guo Zhengquan,Deng Xiuqin.Sedimentary facies of the Yanchang Formation of Upper Triassic and petroleum geological implication in southwestern Ordos Basin[J].Journal of Palaeogeography,2005,7(1):34-44. |
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| Authors: | Fu Jinhua Guo Zhengquan Deng Xiuqin |
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| Institution: | 1.Department of Geology, Northwest University, Xi’an 710069, Shaanxi;2.Research Institute of Petroleum Exploration and Development, Changqing Oilfield Company, PetroChina Xi’an 710021, Shaanxi |
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| Abstract: | In the Yanchang Formation of Triassic in the Ordos Basin mainly two sedimentary systems are developed:the northeastern and southwestern systems.It has been proved that the northeastern sedimentary system is a river delta system through abundant research data.However,the southwestern system is little studied as there has been only limited efforts in exploration.Based on the latest drilling and outcrop data,it has been concluded that the southwestern sedimentary system in the Ordos Basin is an alluvial fan-fan delta system and the alluvial fan,fan delta and lake facies or turbidite facies were developed.The alluvial fan is typical in the sections of Pingliang Kongdongshan and Ruishuihe River.The fan delta and lake facies or turbidite facies are proved by observation on the drilling sections in the study area.The main reservoirs include the intervals Chang 6 to Chang 8 and the strata are preserved integration with relatively high intensity of drilling efforts.The subaqueous distributary channel is the main type of the fan delta front while the channel mouth bar is developed locally.The turbidite sandstone is mainly thick-bedded.Fan delta front subfacies was best developed during the Chang 8 Subage.Three delta front sandbody belts are formed from southwest to northeast and they are the important areas where hydrocarbon accumulates.The turbidite system was well developed in the Chang 7 Subage because the lake basin subsided,the periphery was uplifted strongly and the lakeshore was very steep.The fan delta was developed again because the lake regression occurred during the Chang 6 Subage,but the scale was smaller than that of the Chang 8 Subage.The fan delta front sandbody is the most advantageous zone of petroleum accumulation because of its great thickness,coarse grainsize,well sorting and good physical properties. |
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| Keywords: | Ordos Basin Upper Triassic sedimentary facies alluvial fan fan delta turbidite |
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