Formation mechanism of favorable reservoirs in red beds in lower submember of fourth member of Shahejie Formation, Bonan Subsag, Jiyang Depression, Bohai Bay Basin
-
摘要: 渤海湾盆地济阳坳陷渤南洼陷沙四下亚段红层经历了较长时期的沉积和成岩改造作用,原生孔隙保留机制、次生孔隙演化规律不清,制约着勘探进展。运用岩心观察、铸体薄片鉴定及扫描电镜分析等技术手段,在储层特征分析基础上,开展了红层有利储层受控因素分析,总结了有利储层成因机制,预测了有利储层分布。该区沙四下亚段红层沉积存在冲积扇-辫状河-辫状河三角洲-湖泊和扇三角洲-湖泊2大沉积体系;砂岩类型以岩屑长石砂岩为主,储集空间由残留原生孔隙、次生溶蚀孔隙及裂缝构成,储层物性较差,属于特低孔特低渗储层。储层在机械压实作用以及碱、酸流体的交替影响下,储集空间经历了原生孔隙保留、次生孔隙形成及储层致密化3个阶段;埋深与有利相带决定原生孔隙保存程度,有机酸、上覆地层异常高压与断裂展布决定次生孔隙发育程度。原生孔隙发育的有利储层类型为3 000 m以浅的冲积扇扇端储集体,分布于南部盆缘,呈裙带状展布;次生孔隙发育的有利储层类型为沙四上亚段压力系数大于1.2且沙四下亚段断裂体系发育的辫状河和辫状河三角洲储集体,分布在洼陷带,呈带状、叠合连片状展布。Abstract: The red beds in the lower submember of the fourth member of Shahejie Formation (Es4) in the Bonan Subsag of the Jiyang Depression of the Bohai Bay Basin have undergone a long period of sedimentation and diagenesis. The mechanism of primary pore retention and the evolution constraints of secondary pores are not clear, which restricts exploration progress. The controlling factors of favorable reservoirs in the red beds were analyzed by means of core observation, casting thin section identification and scanning electron microscopy and combined with reservoir characteristics analysis. The formation mechanism of the favorable reservoirs was summarized, and their distribution was also predicted. There are two major sedimentary systems in the red bed sediments of the lower Es4 submember of Bonan Subsag, including alluvial fan-braided river-braided river delta-lake and fan delta-lake. Sandstones are mainly lithic feldspars. Reservoir porosity is composed of residual primary pores, secondary dissolution pores and fractures. Reservoir physical properties are poor. The reservoir belongs to the category of ultra-low porosity and ultra-low permeability. Under the influence of mechanical compaction and the alternation of alkali and acid fluids, the reservoir porosity in the study area experienced three stages: primary pore retention, secondary pore formation and reservoir densification. Burial depth and favorable facies zones determine the preservation degree of primary pores, while organic acid, abnormally high pressure in overlying strata and fracture distribution determine the degree of secondary pore development. The favorable reservoirs with primary pore development are fan-terminal reservoirs of alluvial fan buried less than 3 000 m, which are distributed as belts on the southern basin margin. The favorable reservoirs with secondary pore development are braided river and braided river delta reservoirs with pressure coefficient greater than 1.2 in the upper submember of Es4 and fault system develop in the lower submember of Es4, which are distributed in sag zones and show strip-like and overlapping sheet distribution.
-
Key words:
- favorable reservoir /
- formation mechanism /
- red bed /
- lower Es4 submember /
- Bonan Subsag /
- Jiyang Depression /
- Bohai Bay Basin
-
图 4 渤海湾盆地济阳坳陷渤南洼陷沙四下亚段红层储集空间类型及成岩现象
a.原生孔隙发育,孔隙空间被黑色有机质充填,义193,2 941.41 m,单偏光;b.颗粒之间残留原生孔隙,孔隙被黑色有机质充填,罗10,2 438.21 m,单偏光;c.石英(Q)次生加大发育,加大边充填一部分粒间孔隙,残留粒间孔隙被黑色有机质充填,义193,2 941.49 m,单偏光;d.石英(Q)次生加大明显,残留粒间孔隙被黑色有机质充填,义193,2 942.61 m,单偏光;e.颗粒边缘存在绿泥石胶结,胶结物占据一部分孔隙空间,残留一部分粒间孔隙,孔隙被黑色有机质充填,义160井,3 080.65 m,单偏光;f.岩屑溶蚀形成粒内孔隙、红色方解石胶结物(Cc)溶蚀形成粒间孔隙、颗粒边缘存在粒缘缝,罗358,2 779.61 m,单偏光;g.红色方解石胶结物(Cc)溶蚀形成晶间孔隙、岩屑溶蚀形成粒内孔隙,新义深9,3 792 m,单偏光;h.长石(F)溶蚀形成粒间、粒内孔隙,罗斜153,3 856 m,单偏光;i.长石、岩屑溶蚀形成粒间孔隙,罗斜153,3 853.8 m,单偏光;j.破裂缝发育,新义深9,3 795.97 m,单偏光;k.红色方解石胶结物(Cc)充填粒间孔隙,义130,2 333.76 m,单偏光;l.红色方解石胶结物(Cc)充填粒间孔隙和粒内孔隙,新渤深1,3 753.87 m,单偏光;m.长石溶蚀后形成铸模孔,后被红色方解石胶结物(Cc)充填,残留部分粒间孔隙(蓝色铸体),罗斜153,3 855.3 m,单偏光;n.长石溶蚀形成铸模孔,后被红色方解石胶结物(Cc)充填,岩屑溶蚀形成粒内孔隙,孔隙被黑色有机质充填,义292,4 639.24 m,单偏光;o.石英次生(Q)加大明显,加大部分占据孔隙空间,罗斜153,3 855.3 m,单偏光;p.长石、岩屑溶蚀后形成粒内孔隙,后被紫色铁方解石胶结物(Ank)充填,颗粒致密,呈凹凸接触,义292,4 639.24 m,单偏光
Figure 4. Pore types and diagenesis of red beds in lower Es4 submember in Bonan Subsag, Jiyang Depression, Bohai Bay Basin
表 1 渤海湾盆地济阳坳陷渤南洼陷沙四下亚段不同沉积相类型物性数据
Table 1. Physical properties of different sedimentary facies in lower Es4 submember in Bonan Subsag, Jiyang Depression, Bohai Bay Basin
沉积相 孔隙度/% 渗透率/10-3 μm2 最小值 最大值 均值 最小值 最大值 均值 冲积扇 2.09 25.80 11.81 0.03 131.00 9.54 辫状河 0.05 18.73 8.16 0.05 169.26 7.21 辫状河三角洲 3.39 14.12 7.94 0.07 10.74 2.26 扇三角洲 0.43 9.10 3.55 0.01 1.07 0.18 -
[1] 李廷勇, 王建力. 中国的红层及发育的地貌类型[J]. 四川师范大学学报(自然科学版), 2002, 25(4): 427-431. https://www.cnki.com.cn/Article/CJFDTOTAL-SCSD200204028.htmLI Tingyong, WANG Jianli. Chinese red beds and developing landforms[J]. Journal of Sichuan Normal University (Natural Science), 2002, 25(4): 427-431. https://www.cnki.com.cn/Article/CJFDTOTAL-SCSD200204028.htm [2] 谭先锋, 蒋艳霞, 田景春, 等. 济阳坳陷古近系孔店组层序界面特征及时空属性[J]. 石油实验地质, 2014, 36(2): 136-143. doi: 10.11781/sysydz201402136TAN Xianfeng, JIANG Yanxia, TIAN Jingchun, et al. Sequence interface characteristics and spatial and temporal properties of Kongdian Formation of Paleogene in Jiyang Depression[J]. Petroleum Geology & Experiment, 2014, 36(2): 136-143. doi: 10.11781/sysydz201402136 [3] 李继岩. 渤海湾盆地东营凹陷东段红层储层成岩环境时空演化及成岩孔隙演化[J]. 石油与天然气地质, 2017, 38(1): 90-97. https://www.cnki.com.cn/Article/CJFDTOTAL-SYYT201701011.htmLI Jiyan. Temporal-spatial evolution of diagenetic environment and diagenesis pore evolutionary process of red beds in the eastern Dongying Sag, Bohai Bay Basin[J]. Oil & Gas Geology, 2017, 38(1): 90-97. https://www.cnki.com.cn/Article/CJFDTOTAL-SYYT201701011.htm [4] 董大伟, 李继岩, 王晓蕾, 等. 渤海湾盆地东营凹陷东部孔店组红层储层特征及控制因素[J]. 中国石油大学学报(自然科学版), 2017, 41(5): 20-29. https://www.cnki.com.cn/Article/CJFDTOTAL-SYDX201705003.htmDONG Dawei, LI Jiyan, WANG Xiaolei, et al. Reservoir characteristics and controlling factors of red bed of Kongdian Formation in eastern Dongying Depression, Bohai Bay Basin[J]. Journal of China University of Petroleum, 2017, 41(5): 20-29. https://www.cnki.com.cn/Article/CJFDTOTAL-SYDX201705003.htm [5] 牛栓文, 李继岩. 东营凹陷东段始新统红层储层多重成岩环境及演化模式[J]. 石油与天然气地质, 2014, 35(5): 661-669. https://www.cnki.com.cn/Article/CJFDTOTAL-SYYT201405013.htmNIU Shuanwen, LI Jiyan. Multiple diagenetic environments and evolutionary patterns of the Eocene red beds in the eastern Dongying Sag[J]. Oil & Gas Geology, 2014, 35(5): 661-669. https://www.cnki.com.cn/Article/CJFDTOTAL-SYYT201405013.htm [6] 李继岩, 宋国奇, 王晓蕾, 等. 不同沉积环境形成的储层成岩差异性研究: 以东营凹陷王家岗地区红层与博兴洼陷灰层滩坝为例[J]. 天然气地球科学, 2015, 26(2): 269-276. https://www.cnki.com.cn/Article/CJFDTOTAL-TDKX201502012.htmLI Jiyan, SONG Guoqi, WANG Xiaolei, et al. Study on the diffe-rences of diagenetic evolution under different sedimentary environment: take an example of the red-beds of Wangjiagang, Dongying Sag and Oligocene gray-beds beach-bar of Boxing Sag[J]. Natural Gas Geoscience, 2015, 26(2): 269-276. https://www.cnki.com.cn/Article/CJFDTOTAL-TDKX201502012.htm [7] 余义川, 德勒恰提·加娜塔依, 陈春勇, 等. 济阳坳陷博兴洼陷南部孔店组储层特征[J]. 煤炭技术, 2017, 36(11): 114-115. https://www.cnki.com.cn/Article/CJFDTOTAL-MTJS201711044.htmYU Yichuan, JANNEY D, CHEN Chunyong, et al. Reservoir characteristics of Kongdian Formation in southern Boxing Sag of Jiyang Depression[J]. Coal Technology, 2017, 36(11): 114-115. https://www.cnki.com.cn/Article/CJFDTOTAL-MTJS201711044.htm [8] 刘鹏. 渤南洼陷沙四上亚段沉积储层特征及其对油气成藏的影响[D]. 青岛: 中国石油大学(华东), 2014.LIU Peng. The characteristics of depositional reservoirs and their effects on hydrocarbon accumulation in the upper part of the fourth member of Shahejie Formation in Bonan Sag[D]. Qing-dao: China University of Petroleum (East China), 2014. [9] 宋国奇, 刘华, 蒋有录, 等. 沾化凹陷渤南洼陷沙河街组原油成因类型及分布特征[J]. 石油实验地质, 2014, 36(1): 33-38, 45. doi: 10.11781/sysydz201401033SONG Guoqi, LIU Hua, JIANG Youlu, et al. Genetic types and distribution characteristics of crude oils from Shahejie Formation in Bonan Subsag, Zhanhua Sag, Jiyang Depression[J]. Petro-leum Geology & Experiment, 2014, 36(1): 33-38, 45. doi: 10.11781/sysydz201401033 [10] 刘军锷. 济阳坳陷渤南洼陷沙四下亚段红层沉积特征及其油气富集规律[D]. 武汉: 中国地质大学(武汉), 2014.LIU June. Petroleum accumulation and sediment features of red beds in the lower Es4 of Bonan Sag, the Jiyang Depression[D]. Wuhan: China University of Geosciences (Wuhan), 2014. [11] 张志全. 渤南洼陷沙四段下亚段沉积相识别[J]. 河南石油, 2003, 17(4): 22-25. https://www.cnki.com.cn/Article/CJFDTOTAL-SYHN200304008.htmZHANG Zhiquan. Identification of sedimentary facies of the lower Ⅳ interval of the Shahejie Formation in Bonan Sag[J]. Henan Petroleum, 2003, 17(4): 22-25. https://www.cnki.com.cn/Article/CJFDTOTAL-SYHN200304008.htm [12] 王真. 渤南洼陷沙四下亚段沉积体系研究[D]. 青岛: 中国石油大学(华东), 2013.WANG Zhen. The sedimentary system study in the Lower Fourth Member of Shahejie Formation in the Bonan Subsag[D]. Qing-dao: China University of Petroleum (East China), 2013. [13] 陈阳, 张扬, 朱正杰, 等. 济阳坳陷渤南洼陷沙四下亚段沉积序列及石油地质意义[J]. 中国石油勘探, 2019, 24(3): 313-322. https://www.cnki.com.cn/Article/CJFDTOTAL-KTSY201903004.htmCHEN Yang, ZHANG Yang, ZHU Zhengjie, et al. Early sedimentary sequence and petroleum geological significance of faulted basins: a case study on the lower Es4 in Bonan Sag, Jiyang Depression[J]. China Petroleum Exploration, 2019, 24(3): 313-322. https://www.cnki.com.cn/Article/CJFDTOTAL-KTSY201903004.htm [14] 李文浩, 张枝焕, 昝灵, 等. 渤南洼陷北部陡坡带沙河街组砂砾岩有效储层物性下限及其主控因素[J]. 石油与天然气地质, 2012, 33(5): 766-777. https://www.cnki.com.cn/Article/CJFDTOTAL-SYYT201205015.htmLI Wenhao, ZHANG Zhihuan, ZAN Ling, et al. Lower limits of physical properties and their controlling factors of effective coarse-grained clastic reservoirs in the Shahejie Formation on northern steep slope of Bonan Subsag, the Bohai Bay Basin[J]. Oil & Gas Geology, 2012, 33(5): 766-777. https://www.cnki.com.cn/Article/CJFDTOTAL-SYYT201205015.htm [15] 邱桂强. 东营凹陷古近系成岩层序特征与储集差异性分析[J]. 沉积学报, 2007, 25(6): 915-922. https://www.cnki.com.cn/Article/CJFDTOTAL-CJXB200706015.htmQIU Guiqiang. Analysis on Lower Tertiary diagenetic sequence characteristics and their differences of reservoirs in Dongying Sag[J]. Acta Sedimentologica Sinica, 2007, 25(6): 915-922. https://www.cnki.com.cn/Article/CJFDTOTAL-CJXB200706015.htm [16] 吴富强, 李后蜀, 胡雪, 等. 沾化凹陷渤南洼陷沙四段成岩史恢复及成岩模式建立[J]. 油气地质与采收率, 2001, 8(6): 1-4. https://www.cnki.com.cn/Article/CJFDTOTAL-YQCS200106000.htmWU Fuqiang, LI Houshu, HU Xue, et al. Diagenetic history of Es4 in Bonan Subsag of Zhanhua Sag and establishment of diagenetic model[J]. Petroleum Geology and Recovery Efficiency, 2001, 8(6): 1-4. https://www.cnki.com.cn/Article/CJFDTOTAL-YQCS200106000.htm [17] 陈永峤, 于兴河, 周新桂, 等. 东营凹陷各构造区带下第三系成岩演化与次生孔隙发育规律研究[J]. 天然气地球科学, 2004, 15(1): 68-74. https://www.cnki.com.cn/Article/CJFDTOTAL-TDKX200401013.htmCHEN Yongqiao, YU Xinghe, ZHOU Xingui, et al. Research on diagenetic evolution succession and occurrence of secondary porosity of Lower Tertiary in different structural belt of Dongying Depression[J]. Natural Gas Geoscience, 2004, 15(1): 68-74. https://www.cnki.com.cn/Article/CJFDTOTAL-TDKX200401013.htm [18] 宋国奇, 刘鹏, 刘雅利. 渤南洼陷沙河街组四段下亚段成岩作用与储层孔隙演化[J]. 沉积学报, 2014, 32(5): 941-948. https://www.cnki.com.cn/Article/CJFDTOTAL-CJXB201405017.htmSONG Guoqi, LIU Peng, LIU Yali. Diagenesis and reservoir porosity evolution of the lower section of the 4th member of Shahejie Formation in Bonan Sag[J]. Acta Sedimentologica Sinica, 2014, 32(5): 941-948. https://www.cnki.com.cn/Article/CJFDTOTAL-CJXB201405017.htm [19] 葸克来, 操应长, 赵贤正, 等. 霸县凹陷古近系中深层有效储层成因机制[J]. 天然气地球科学, 2014, 25(8): 1144-1155. https://www.cnki.com.cn/Article/CJFDTOTAL-TDKX201408004.htmXI Kelai, CAO Yingchang, ZHAO Xianzheng, et al. Genetic mechanism of Paleogene middle-deep effective reservoirs in Baxian Sag[J]. Natural Gas Geoscience, 2014, 25(8): 1144-1155. https://www.cnki.com.cn/Article/CJFDTOTAL-TDKX201408004.htm [20] 宋磊, 宁正福, 孙一丹, 等. 联合压汞法表征致密油储层孔隙结构[J]. 石油实验地质, 2017, 39(5): 700-705. doi: 10.11781/sysydz201705700SONG Lei, NING Zhengfu, SUN Yidan, et al. Pore structure characterization of tight oil reservoirs by a combined mercury method[J]. Petroleum Geology & Experiment, 2017, 39(5): 700-705. doi: 10.11781/sysydz201705700 [21] 曹忠祥, 张宇, 蔡攀, 等. 济阳坳陷精细勘探新成果与启示[J]. 中国石油勘探, 2016, 21(3): 14-23. https://www.cnki.com.cn/Article/CJFDTOTAL-KTSY201603002.htmCAO Zhongxiang, ZHANG Yu, CAI Pan, et al. New achievements and recognitions of fine exploration in Jiyang Depression[J]. China Petroleum Exploration, 2016, 21(3): 14-23. https://www.cnki.com.cn/Article/CJFDTOTAL-KTSY201603002.htm [22] 梁金萍, 国景星, 于洪洲. 冲积—河流相层序地层模式探讨及其在济阳坳陷的应用[J]. 油气地质与采收率, 2005, 12(1): 15-17. https://www.cnki.com.cn/Article/CJFDTOTAL-YQCS200501006.htmLIANG Jinping, GUO Jingxing, YU Hongzhou. Discussion on the stratigraphic model in alluvial-fluvial facies sequence and its application in Jiyang Depression[J]. Petroleum Geology and Recovery Efficiency, 2005, 12(1): 15-17. https://www.cnki.com.cn/Article/CJFDTOTAL-YQCS200501006.htm [23] 姜超. 断陷湖盆斜坡带重力流砂体沉积特征及沉积模式: 以沾化凹陷渤南洼陷南部斜坡带沙三段为例[J]. 油气地质与采收率, 2018, 25(1): 6-13. https://www.cnki.com.cn/Article/CJFDTOTAL-YQCS201801002.htmJIANG Chao. Characteristics and model of gravity flow sand body deposition in the slope zone of rifted lacustrine basin: a case study from the Sha3 member in the south slope zone of Bonan Sag, Zhanhua Depression[J]. Petroleum Geology and Recovery Efficiency, 2018, 25(1): 6-13. https://www.cnki.com.cn/Article/CJFDTOTAL-YQCS201801002.htm [24] 朱筱敏, 米立军, 钟大康, 等. 济阳坳陷古近系成岩作用及其对储层质量的影响[J]. 古地理学报, 2006, 8(3): 295-305. https://www.cnki.com.cn/Article/CJFDTOTAL-GDLX200603002.htmZHU Xiaomin, MI Lijun, ZHONG Dakang, et al. Paleogene diage-nesis and its control on reservoir quality in Jiyang Depression[J]. Journal of Palaeogeography, 2006, 8(3): 295-305. https://www.cnki.com.cn/Article/CJFDTOTAL-GDLX200603002.htm [25] 孟昱璋, 刘鹏. 济阳坳陷渤南洼陷沙四上亚段碎屑岩成岩作用及其孔隙演化[J]. 中国石油勘探, 2015, 20(6): 14-21. https://www.cnki.com.cn/Article/CJFDTOTAL-KTSY201506002.htmMENG Yuzhang, LIU Peng. Diagenesis and porous development of clastic rock in upper part of 4th member of Shahejie Formation in Bonan Sag of Jiyang Depression[J]. China Petroleum Exploration, 2015, 20(6): 14-21. https://www.cnki.com.cn/Article/CJFDTOTAL-KTSY201506002.htm [26] 吕明才, 张立强, 史文东, 等. 东营凹陷南斜坡孔店组冲积体系碎屑岩储层特征及评价[J]. 西安石油大学学报(自然科学版), 2004, 19(6): 5-9. https://www.cnki.com.cn/Article/CJFDTOTAL-XASY200406001.htmLV Mingcai, ZHANG Liqiang, SHI Wendong, et al. Characteristics and evaluation of the clastic reservoirs in Kongdian Member in the southern slope belt of Dongying Sag[J]. Journal of Xi'an Shiyou University (Natural Science Edition), 2004, 19(6): 5-9. https://www.cnki.com.cn/Article/CJFDTOTAL-XASY200406001.htm