混积型页岩油储层甜点体特征及平面分布——以吉木萨尔凹陷芦草沟组为例

Characteristics and planar distribution of sweet spots in mixed-sedimentary shale oil reservoirs: a case study of the Lucaogou Formation in the Jimsar Sag

摘要

以准噶尔盆地吉木萨尔凹陷芦草沟组为例,利用岩心和测井资料,采用铸体薄片、X射线衍射、扫描电镜、纳米CT、高压压汞及氮气吸附等实验方法,分析甜点体储层岩石学特征、物性特征、混合沉积及差异成岩特征,划分甜点段沉积微相和成岩相类型,探讨甜点体主控因素并预测甜点体平面分布。结果表明:吉木萨尔凹陷芦草沟组甜点体主要由白云质粉砂岩、凝灰质粉砂岩及粉砂质白云岩等组成,属于超低-特低孔、超低渗储层;孔隙类型以粒内溶孔和粒间溶孔为主,主要为亚微米孔隙,孔喉连通性较好,孔隙形态主要为板状平行狭缝孔和半封闭楔形孔。甜点体的形成受沉积、成岩作用控制,陆源碎屑组分是影响甜点体发育的主控因素。砂质坝、砂质滩等微相主要发育陆源主导型混积岩,粒度较粗,颗粒分选好,杂基含量低,富集长石、凝灰质等易溶组分;抗压实作用强,后期经历较强的溶蚀作用,形成凝灰质-长石溶蚀相、混合胶结-溶蚀孔相和绿泥石薄膜-粒间孔相等优势成岩相。优势沉积微相与优质成岩相的叠合区为甜点体的有利发育区。该结果为准噶尔盆地混积型页岩油目标优选提供支持。

Abstract

The Permian Lucaogou Formation in the Jimsar Sag, Junggar Basin, was investigated using core and well-log data, together with cast thin-section petrography, X-ray diffraction, scanning electron microscopy, nano-CT, high-pressure mercury intrusion, and nitrogen adsorption analyses. The petrological characteristics, reservoir properties, mixed-sedimentary features, and differential diagenesis of the sweet spot reservoirs were characterized. Sedimentary microfacies and diagenetic facies within the sweet spot intervals were identified, the controlling factors of sweet spot development were evaluated, and the planar distribution of the sweet spots was predicted. The results indicate that the sweet spot reservoirs in the Lucaogou Formation are mainly composed of dolomitic siltstone, tuffaceous siltstone, and silty dolostone, and are characterized by ultra-low to very low porosity and ultra-low permeability. The pore system is dominated by intragranular and intergranular dissolution pores, with submicron pores being the most abundant. The pore-throat networks are relatively well connected, and the pores are mainly plate-like parallel slit-shaped pores and semi-closed wedge-shaped pores. Sweet spot development is jointly controlled by depositional processes and diagenetic modification, among which terrigenous clastic input is the primary controlling factor. Sandy-bar and sandy-flat microfacies are dominated by siliciclastic-rich mixed sedimentary rocks characterized by relatively coarse grain size, good sorting, low matrix content, and abundant soluble components, including feldspar and tuffaceous material. These rocks have relatively high resistance to mechanical compaction and subsequently underwent strong dissolution, resulting in the development of favorable diagenetic facies, including tuffaceous-feldspar dissolution facies, mixed cementation-dissolution-pore facies, and chlorite-coating-intergranular-pore facies. Favorable zones for sweet spot development occur where favorable sedimentary microfacies overlap with favorable diagenetic facies. These results provide a geological basis for target selection in mixed-sedimentary shale oil exploration in the Junggar Basin.

关键词

混积型页岩油 / 甜点体 / 储层质量 / 平面分布 / 芦草沟组 / 吉木萨尔凹陷 / 准噶尔盆地

Key words

mixed-sedimentary shale oil / sweet spots / reservoir quality / planar distribution / Lucaogou Formation / Jimsar Sag / Junggar Basin

参考文献

[1] 邹才能, 潘松圻, 荆振华, 等 . 页岩油气革命及影响[J]. 石油学报, 2020, 41(1): 1-12.

[2] Zou Caineng, Pan Songqi, Jing Zhenhua, et al. Shale oil and gas revolution and its impact[J]. Acta Petrolei Sinica, 2020, 41(1): 1-12.

[3] 杨智, 侯连华, 林森虎, 等 . 吉木萨尔凹陷芦草沟组致密油、页岩油地质特征与勘探潜力[J]. 中国石油勘探, 2018, 23(4): 76-85.

[4] Yang Zhi, Hou Lianhua, Lin Senhu, et al. Geologic characteristics and exploration potential of tight oil and shale oil in Lucaogou Formation in Jimsar Sag[J]. China Petroleum Exploration, 2018, 23(4): 76-85.

[5] 杨智, 侯连华, 陶士振, 等 . 致密油与页岩油形成条件与“甜点区”评价[J]. 石油勘探与开发, 2015, 42(5): 555-565.

[6] Yang Zhi, Hou Lianhua, Tao Shizhen, et al. Formation conditions and “sweet spot” evaluation of tight oil and shale oil[J]. Petroleum Exploration and Development, 2015, 42(5): 555-565.

[7] Mount J F . Mixing of siliciclastic and carbonate sediments in shallow shelf environments[J]. Geology, 1984, 12(7): 432-435.

[8] Garcia-Hidalgo J F, Gil J, Segura M, et al. Internal anatomy of a mixed siliciclastic-carbonate platform: the Late Cenomanian-Mid Turonian at the southern margin of the Spanish Central System[J]. Sedimentology, 2007, 54(6): 1245-1271.

[9] Mount J F . Mixed siliciclastic and carbonate sediments: a proposed first-order textural and compositional classification[J]. Sedimentology, 1985, 32(3): 435-442.

[10] 张雄华 . 混积岩的分类和成因[J]. 地质科技情报, 2000, 19(4): 31-34.

[11] Zhang Xionghua . Classification and origin of mixosedimentite[J]. Geological Science and Technology Information, 2000, 19(4): 31-34.

[12] 马克, 侯加根, 刘钰铭, 等 . 吉木萨尔凹陷二叠系芦草沟组咸化湖混合沉积模式[J]. 石油学报, 2017, 38(6): 636-648.

[13] Ma Ke, Hou Jiagen, Liu Yuming, et al. The sedimentary model of saline lacustrine mixed sedimentation in Permian Lucaogou Formation, Jimsar Sag[J]. Acta Petrolei Sinica, 2017, 38(6): 636-648.

[14] 冯进来, 胡凯, 曹剑, 等 . 陆源碎屑与碳酸盐混积岩及其油气地质意义[J]. 高校地质学报, 2011, 17(2): 297-307.

[15] Feng Jinlai, Hu Kai, Cao Jian, et al. A review on mixed rocks of terrigenous clastics and carbonates and their petroleum-gas geological significance[J]. Journal of Geology of Universities, 2011, 17(2): 297-307.

[16] 覃建华, 高儇博, 彭寿昌, 等 . 准噶尔盆地吉木萨尔凹陷页岩油地球化学特征及油-源对比[J]. 东北石油大学学报, 2021, 45(1): 1-10.

[17] Qin Jianhua, Gao Xuanbo, Peng Shouchang, et al. Geochemical characteristics and oil-source correlation of shale oil in Jimsar Sag, Junggar Basin, China[J]. Journal of Northeast Petroleum University, 2021, 45(1): 1-10.

[18] 李映艳, 邓远, 徐田录, 等 . 吉木萨尔凹陷页岩油赋存特征及含油下限[J]. 东北石油大学学报, 2022, 46(6): 52-62.

[19] Li Yingyan, Deng Yuan, Xu Tianlu, et al. Occurrence characteristics of shale oil and lower-limit of oil-bearing in Jimsar Sag[J]. Journal of Northeast Petroleum University, 2022, 46(6): 52-62.

[20] 王小军, 杨智峰, 郭旭光, 等 . 准噶尔盆地吉木萨尔凹陷页岩油勘探实践与展望[J]. 新疆石油地质, 2019, 40(4): 402-413.

[21] Wang Xiaojun, Yang Zhifeng, Guo Xuguang, et al. Practices and prospects of shale oil exploration in Jimsar Sag of Junggar Basin[J]. Xinjiang Petroleum Geology, 2019, 40(4): 402-413.

[22] 匡立春, 胡文瑄, 王绪龙, 等 . 吉木萨尔凹陷芦草沟组致密油储层初步研究:岩性与孔隙特征分析[J]. 高校地质学报, 2013, 19(3): 529-535.

[23] Kuang Lichun, Hu Wenxuan, Wang Xulong, et al. Research of the tight oil reservoir in the Lucaogou Formation in Jimusar Sag: analysis of lithology and porosity characteristics[J]. Journal of Geology of Universities, 2013, 19(3): 529-535.

[24] 张治恒, 田继军, 韩长城, 等 . 吉木萨尔凹陷芦草沟组储层特征及主控因素[J]. 岩性油气藏, 2021, 33(2): 116-126.

[25] Zhang Zhiheng, Tian Jijun, Han Changcheng, et al. Reservoir characteristics and main controlling factors of Lucaogou Formation in Jimsar Sag, Jungger Basin[J]. Lithologic Reservoirs, 2021, 33(2): 116-126.

[26] 邵雨, 杨勇强, 万敏, 等 . 吉木萨尔凹陷二叠系芦草沟组沉积特征及沉积相演化[J]. 新疆石油地质, 2015, 36(6): 635-641.

[27] Shao Yu, Yang Yongqiang, Wan Min, et al. Sedimentary characteristic and facies evolution of Permian Lucaogou Formation in Jimsar Sag, Junggar Basin[J]. Xinjiang Petroleum Geology, 2015, 36(6): 635-641.

[28] 张亚奇, 马世忠, 高阳, 等 . 吉木萨尔凹陷芦草沟组致密油储层沉积相分析[J]. 沉积学报, 2017, 35(2): 358-370.

[29] Zhang Yaqi, Ma Shizhong, Gao Yang, et al. Depositional facies analysis on tight reservoir of Lucaogou Formation in Jimsar Sag, Junggar Basin[J]. Acta Sedimentologica Sinica, 2017, 35(2): 358-370.

[30] 操应长, 朱宁, 张少敏, 等 . 准噶尔盆地吉木萨尔凹陷二叠系芦草沟组致密油储层成岩作用与储集空间特征[J]. 地球科学与环境学报, 2019, 41(3): 253-266.

[31] Cao Yingchang, Zhu Ning, Zhang Shaomin, et al. Diagenesis and reserving space characteristics of tight oil reservoirs of Permian Lucaogou Formation in Jimusar Sag of Junggar Basin, China[J]. Journal of Earth Sciences and Environment, 2019, 41(3): 253-266.

[32] 董岩, 徐东升, 钱根葆, 等 . 吉木萨尔页岩油“甜点”预测方法[J]. 特种油气藏, 2020, 27(3): 54-59.

[33] Dong Yan, Xu Dongsheng, Qian Genbao, et al. Shale oil “sweet-spot” prediction in Jimusar Sag[J]. Special Oil & Gas Reservoirs, 2020, 27(3): 54-59.

[34] 贾曙光, 王军, 王玲玲, 等 . 吉木萨尔凹陷芦草沟组页岩油甜点地震预测方法[J]. 新疆石油地质, 2020, 41(5): 535-541.

[35] Jia Shuguang, Wang Jun, Wang Lingling, et al. Seismic prediction methods of shale oil sweet spots in Lucaogou Formation of Jimsar Sag[J]. Xinjiang Petroleum Geology, 2020, 41(5): 535-541.

[36] 王正和, 周继兵, 余谦, 等 . 准噶尔盆地南缘芦草沟组碳质细粒沉积岩地球化学特征及地质背景[J]. 东北石油大学学报, 2018, 42(1): 86-95.

[37] Wang Zhenghe, Zhou Jibing, Yu Qian, et al. Geochemistry and its geological background of the carbonaceous fine-grained sedimentary rocks in Lucaogou Formation, Southern Junggar Basin, NW China[J]. Journal of Northeast Petroleum University, 2018, 42(1): 86-95.

[38] 曲长胜, 邱隆伟, 杨勇强, 等 . 吉木萨尔凹陷芦草沟组碳酸盐岩碳氧同位素特征及其古湖泊学意义[J]. 地质学报, 2017, 91(3): 605-616.

[39] Qu Changsheng, Qiu Longwei, Yang Yongqiang, et al. Carbon and oxygen isotope compositions of carbonatic rock from Permian Lucaogou Formation in the Jimsar Sag, NW China and their paleolimnological significance[J]. Acta Geologica Sinica, 2017, 91(3): 605-616.

[40] 周新锐, 王喜鑫, 李少华, 等 . 陆相混积型页岩储集层孔隙结构特征及其控制因素[J]. 新疆石油地质, 2023, 44(4): 411-420.

[41] Zhou Xinrui, Wang Xixin, Li Shaohua, et al. Pore structure characteristics and controlling factors of continental mixed shale reservoirs[J]. Xinjiang Petroleum Geology, 2023, 44(4): 411-420.

[42] 张少敏, 操应长, 朱如凯, 等 . 湖相细粒混合沉积岩岩石类型划分:以准噶尔盆地吉木萨尔凹陷二叠系芦草沟组为例[J]. 地学前缘, 2018, 25(4): 198-209.

[43] Zhang Shaomin, Cao Yingchang, Zhu Rukai, et al. Lithofacies classification of fine-grained mixed sedimentary rocks in the Permian Lucaogou Formation, Jimsar Sag, Junggar Basin[J]. Earth Science Frontiers, 2018, 25(4): 198-209.

[44] 赵迪斐, 郭英海, 解徳录, 等 . 基于低温氮吸附实验的页岩储层孔隙分形特征[J]. 东北石油大学学报, 2014, 38(6): 100-108.

[45] Zhao Difei, Guo Yinghai, Xie Delu, et al. Fractal characteristics of shale reservoir pores based on nitrogen adsorption[J]. Journal of Northeast Petroleum University, 2014, 38(6): 100-108.

[46] 孙乐, 王志章, 于兴河, 等 . 高精度CT成像技术在致密油储层孔隙结构研究中的应用:以准噶尔盆地玛湖西斜坡风城组为例[J]. 东北石油大学学报, 2016, 40(6): 26-34.

[47] Sun Le, Wang Zhizhang, Yu Xinghe, et al. Application of high resolution CT image technology to the research of pore structure of tight oil reservoir: a case study of the Fengcheng Formation on the Mahu west slope in Junggar Basin[J]. Journal of Northeast Petroleum University, 2016, 40(6): 26-34.

[48] 程泽虎, 李文浩, 薛海涛, 等 . 基于高压压汞技术和分形理论的致密砂岩储层分级评价标准[J]. 东北石油大学学报, 2019, 43(1): 50-59.

[49] Cheng Zehu, Li Wenhao, Xue Haitao, et al. Grading evaluation criteria of tight sandstone reservoir based on high pressure mercury injection technology and fractal theory[J]. Journal of Northeast Petroleum University, 2019, 43(1): 50-59.

[50] Lu C, Wang X, Ma S, et al. The classification and evaluation of an interlayer shale oil reservoir based on the fractal characteristics of pore systems: a case study in the HSN Area, China[J]. Fractal and Fractional, 2024, 8(3): 167.

[51] Thommes M, Kaneko K, Neimark A V, et al. Physisorption of gases, with special reference to the evaluation of surface area and pore size distribution (IUPAC Technical Report)[J]. Pure and Applied Chemistry, 2015, 87(9/10): 1051-1069.

[52] 李书琴 . 吉木萨尔凹陷芦草沟组混积岩沉积微相及微环境研究[D]. 武汉: 长江大学, 2020: 35-36.

[53] Li Shuqin . Study on the mixed rock microenvironment of Lucaogou Formation in Jimusar Depression[D]. Wuhan: Yangtze University, 2020: 35-36.

[54] 朱柏宇, 印森林, 郭海平, 等 . 陆相混合细粒岩沉积微相及其对甜点的控制作用:以吉木萨尔凹陷芦草沟组为例[J]. 沉积学报, 2024, 42(3): 839-856.

[55] Zhu Baiyu, Yin Senlin, Guo Haiping, et al. Continental sedimentary microfacies distribution of mixed fine-grained rocks and its controlling effect on sweet spots[J]. Acta Sedimentologica Sinica, 2024, 42(3): 839-856.

[56] 付林圃, 王喜鑫, 麻书玮, 等 . 合水南地区长7段夹层型页岩油储层孔隙结构特征及主控因素[J]. 东北石油大学学报, 2025, 49(1): 77-90.

[57] Fu Linpu, Wang Xixin, Ma Shuwei, et al. Pore structure characteristics and main controlling factors of interbedded shale oil reservoirs of Chang 7 Member in South Heshui Area[J]. Journal of Northeast Petroleum University, 2025, 49(1): 77-90.

[58] Beard D C, Weyl P K . Influence of texture on porosity and permeability of unconsolidated sand[J]. AAPG Bulletin, 1973, 57(2): 349-369.

[59] 柳忠泉, 曾治平, 田继军, 等 . 吉木萨尔凹陷二叠系芦草沟组“甜点”成因与分布预测[J]. 岩性油气藏, 2022, 34(3): 15-28.

[60] Liu Zhongquan, Zeng Zhiping, Tian Jijun, et al. Genesis and distribution prediction of sweet spots of Permian Lucaogou Formation in Jimsar Sag[J]. Lithologic Reservoirs, 2022, 34(3): 15-28.

基金资助

中国石油科技创新基金项目(2021DQ02-0106)