致密碎屑岩储层“甜点”形成及保持机理——以鄂尔多斯盆地西南部镇泾地区延长组长8油层组为例

doi:10.11743/ogg20150601

摘要/Abstract

摘要： 中西部盆地碎屑岩普遍致密化、储层“甜点”预测难度大是制约油气发现的重要因素。为探索储层致密化及“甜点”形成和保持机理，通过岩心观察、铸体、荧光、包裹体、阴极发光等薄片鉴定、粒度分析、压汞和覆压孔渗测试、扫描电镜和能谱分析等沉积、岩石和地球化学综合研究，根据成因类型，将鄂尔多斯盆地西南部镇泾地区延长组长8油层组“甜点”划分为原生型、次生型两大类，认为早期绿泥石膜的发育适度抑制了后期的成岩改造，是原生型“甜点”得以形成、保持的重要因素。对于次生型“甜点”，各类溶蚀孔和微裂缝为其主要孔隙空间，可进一步划分为溶蚀型“甜点”和裂缝型“甜点”，并证实了各类溶蚀、破裂等建设性成岩作用是形成次生型“甜点”的关键因素。研究认为，早期油气充注可有效地抑制后期胶结作用的发生，多期次的成岩交替过程使“甜点”形成-保持(或失效)。纵向上，单砂体的去致密化作用始自原生孔隙保存相对较好的高渗层或裂缝与溶蚀作用较强的叠合部位，并逐渐向外推进。平面上，砂体的去致密化有着类似的特点，顺沿砂体，储层“甜点”呈现“竹节状”分布的特点。

关键词: “甜点”发育模型, 成岩作用, 碎屑岩, 致密储层, 延长组, 鄂尔多斯盆地

Abstract: Densification of clastic reservoirs and difficulties in predicting their sweet spots constrain petroleum discovery in basins in central and western China.In order to investigate the mechanisms of reservoir densification and formation and preservation of sweet spots,a comprehensive study of sedimentology,petrology,and geochemstry were performed by using various methods,including core observation,microscopic observation of casting thin section and under fluorescence and cathode luminescence,fluid inclusion analysis,particle size analysis,mercury injection and permeability tests under overburden pressure,scanning electron microscopic analysis and so on.According to the generic types,sweet spots of the Chang 8 oil layer of Yanchang Formation in Zhenjing area, southwest Ordos Basin,are divided into a primary type and a secondary type.Early developments of chlorite films moderately inhibited later diagenesis processes,which is the main factor contributing to the formation and preservation of the primary sweet spot.The secondary type can be subdivided into a dissolution-type and a fracture-type according to their major pore space being dissolution pores or microfractures.The key factor determining the formation of the secondary sweet spot is constructive diagenesis.It can be concluded that the early charging of hydrocarbons effectively inhibited later cementation,and the multiphase diagenesis resulted the formation and preservation(or lost)of sweet spots.In vertical sections,individual sand body de-densification started from layers of relative high permeability,or areas of fracture and dissolution superimposing,and propagated outwards progressively.In planar view,sand body de-densification shows similar features,the sweet spots distribute in “bamboo-like” shape along the sand body.

Key words: sweet spot development model, diagenesis, clastic rock, tight reservoin, Yanchang Formation, Ordos Basin

中图分类号:

TE122.2

刘春燕. 致密碎屑岩储层“甜点”形成及保持机理——以鄂尔多斯盆地西南部镇泾地区延长组长8油层组为例[J]. 石油与天然气地质, 2015, 36(6): 873-879. doi: 10.11743/ogg20150601 Liu Chunyan. Formation and preservation mechanism of sweet spot in tight clastic reservoirs —A case study of Chang 8 oil layer of Yanchang Formation in Zhenjing area, southwest Ordos Basin[J]. Oil & Gas Geology, 2015, 36(6): 873-879. doi: 10.11743/ogg20150601

参考文献

[1] Liu Chunyan,Zheng Herong,Hu Zongquan,et al.Characteristics of carbonate cementation in clastic rocks from the Chang 6 Sandbody of Yanchang Formation,Southern Ordos Basin[J].Science in China,2012,55(1):58-66.
[2] 邵晓岩,田景春,樊勇杰,等.鄂尔多斯盆地马坊地区延长组长8油层组油藏特征与富集规律[J].石油与天然气地质,2015,36(2):203-208. Shao Xiaoyan,Tian Jingchun,Fan Yongjie,et al.Characteristics and accumulation pattern of oil reservoirs in the 8th member of the Yangchang Formation in Mafang area,Ordos Basin[J].Oil & Gas Geology,2015,36(2):203-208.
[3] 祝海华,钟大康,张亚雄,等.川南地区三叠系须家河组致密砂岩孔隙类型及物性控制因素[J].石油与天然气地质,2014,35(1):65-76. Zhu Haihua,Zhong Dakang,Zhang Yaxiong,et al.Pore types and controlling factors on porosity and permeability of Upper Triassic Xujiahe tight sandstone reservoir in Southern Sichuan Basin[J].Oil & Gas Geology,2014,35(1):65-76.
[4] 张兴良,田景春,王峰,等.致密砂岩储层成岩作用特征与孔隙演化定量评价——以鄂尔多斯盆地高桥地区二叠系下石盒子组盒8段为例[J].石油与天然气地质,2014,35(2):212-217. Zhang Xingliang,Tian Jingchun,Wang Feng,et al.Diagenetic characteristics and quantitative porosity estimation of tight sandstone reservoirs:a case from the 8th Member of Permian Xiashihezi Formation in the Gaoqiao region,Ordos Basin[J].Oil & Gas Geology,2014,35(2):212-217.
[5] Gregory B,Roger S,Jean-pierre S,et al.The importance of the degree of cataclasis in shear bands for fluid flow in porous sandstone,Provence,France[J].AAPG Bulletin,2012,96(11):2167-2186.
[6] Trevor M S,Nicholas B H,Crawford W E.Diagenesis of a tight gas sand reservoir:Upper Cretaceous Mesaverde Group,Piceance Basin,Colorado[J].Marine and Petroleum Geology,2013,40(6):48-68.
[7] 林小兵,刘莉萍,田景春,等.川西坳陷中部须家河组五段致密砂岩储层特征及主控因素[J].石油与天然气地质,2014,35(2):224-230. Lin Xiaobing,Liu Liping,Tian Jingchun,et al.Characteristics and controlling factors of tight sandstone reservoirs in the 5th member of Xujiahe Formation in the central of western Sichuan Depression[J].Oil & Gas Geology,2014,35(2):224-230.
[8] 肖开华,李宏涛,贾爽.川东北元坝地区须三段钙屑砂岩储层特征及控气因素[J].石油与天然气地质,2014,35(5):654-660. Xiao Kaihua,Li Hongtao,Jia Shuang.Characteristics of calcarenaceous sandstone reservoirs and gas accumulation control factors of the 3rd Member of Xujiahe Formation in Yuanba area,Northeast Sichuan Basin[J].Oil & Gas Geology,2014,35(5):654-660.
[9] 王瑞飞,孙卫.鄂尔多斯盆地姬塬油田上三叠统延长组超低渗透砂岩储层微裂缝研究[J].地质论评,2009,55(3):444-448. Wang Ruifei,Sun Wei.A study on micro cracks in supper-Low permeability sandstone reservoir of the Upper Triassic Yanchang Formation in the Ordos Basin[J].Geological Review,2009,55(3):444-448.
[10] 罗静兰,刘小洪,林潼,等.成岩作用与油气侵位对鄂尔多斯盆地延长组砂岩储层物性的影响[J].地质学报,2006,80(5):664-673. Luo Jinglan,Liu Xiaohong,Lin Tong,et al.Impact of diagenesis and hydrocarbon emplacement on sandstone reservoir quality of the Yanchang Formation (Upper Triassic) in the Ordos Basin[J].Acta Geologica Sinica,2006,80(5):664-673.
[11] 公言杰,柳少波,刘可禹,等.致密油充注过程中的储层润湿性变化对含油性影响[J].石油实验地质,2015,37(4):423-429. Gong Yanjie,Liu Shaobo,Liu Keyu,et al.Influence of reservoir wettability changes on oil-bearing features during tight oil accumulation[J].Petroleum Geology & Experiment,2015,37(4):423-429.
[12] 葛云锦,陈勇,周瑶琪.不同成岩条件下油气充注对碳酸盐岩成岩作用的影响[J].中国石油大学学报(自然科学版),2009,33(1):18-27. Ge Yunjin,Chen Yong,Zhou Yaoqi,et.al.Effects of hydrocarbon emplacement on diagenesis of carbonatite in different conditions[J].Journal of China University of Petroleum,2009,33(1):18-27.
[13] 王峰,陈蓉,田景春,等.鄂尔多斯盆地陇东地区长4+5油层组致密砂岩储层成岩作用及成岩相[J].石油与天然气地质,2014,35(2):199-206. Wang Feng,Chen Rong,Tian Jingchun,et al.Diagenesis and diagenetic facies of the Chang 4+5 tight sandstone reservoirs in Longdong area,Ordos Basin[J].Oil & Gas Geology,2014,35(2):199-206.
[14] Khalid A.Illitization of smectite in sandstones:the Permian Unayzah reservoir,Saudi Arabia[J].Arab Journal Science English,2014,39(6):407-412.
[15] 洪雪,周卓明,刘福春.松辽盆地彰武断陷九佛堂组碎屑岩储层特征研究[J].石油实验地质,2015,37(4):445-451. Hong Xue,Zhou Zhuoming,Liu Fuchun.Characteristics of clastic rock reservoirs in Jiufotang Formation,Zhangwu Depression,Songliao Basin[J].Petroleum Geology & Experiment,2015,37(4):445-451.
[16] 田景春,刘伟伟,王峰,等.鄂尔多斯盆地高桥地区上古生界致密砂岩储层非均质性特征[J].石油与天然气地质,2014,35(2):183-189. Tian Jingchun,Liu Weiwei,Wang Feng,et al.Heterogeneity of the Paleozoic tight sandstone reservoirs in Gaoqiao Area of Ordos Basin[J].Oil & Gas Geology,2014,35(2):183-189.
[17] 吴建国,刘大锰,姚艳斌.鄂尔多斯盆地渭北地区页岩纳米孔隙发育特征及其控制因素[J].石油与天然气地质,2014,35(4):542-550. Wu Jianguo,Liu Dameng,Yao Yanbin.Sedimentary characteristics of the Cretaceous Denglouku Formation in the southeast uplift of the southern Songliao Basin[J].Oil & Gas Geology,2014,35(4):542-550.
[18] 吕正祥,刘四兵.川西须家河组超致密砂岩成岩作用与相对优质储层形成机制[J].岩石学报,2009,25(10):2373-2383. Lv Zhengxiang,Liu Sibing.Ultra-tight sandstone diagenesis and mechanism for the formation of relatively high-quality reservoir of Xujiahe Group in western Sichuan[J].Acta Petrologica Sinica,2009,25(10):2373-2383.
[19] 刘春燕,郑和荣,胡宗全,等.碎屑岩中的碳酸盐胶结特征[J].中国科学,2012,55(11):58-66. Liu Chunyan,Zheng Herong,Hu Zongquan,et.al.Characteristics of carbonate cementation in clastic rocks from the Chang 6 sandbody of Yanchang Formation,southern Ordos Basin[J].Science China,2012,55(11):58-66.
[20] Zeng L B,Tang X M,Wang T C,et.al.The influence of fracture cements in tight Paleogene saline lacustrine carbonate reservoirs,western Qaidam Basinetin,northwest China[J].AAPG Bulletin,2012,96(11):2003-2017.