Formation Process and Distribution of Laumontite in Yanchang 3 Reservoir of Fuxian Exploration Area in North Shaanxi Province and the Controls of the High Quality Reservoirs
-
摘要: 鄂尔多斯盆地东南富县探区延长组长3油层组广泛发育浊沸石胶结作用,其主要成因是富县探区长3油层斜长石含量高,与碱性富钠的孔隙水相互反应形成浊沸石胶结物,包体测温表明,形成温度主要在85~100℃之间,对应于早期成岩的晚期;浊沸石发育受地下流体活动的控制,多发育在三角洲平原及前缘相互叠置的分流河道复合砂体;在晚成岩早期,有机质脱羟作用形成有机酸对浊沸石溶蚀,形成大量次生孔隙.在富县探区东部地区,浊沸石沉淀与溶解总体效应造成孔隙度的增加;而在西部地区,由于浊沸石胶结物含量较小,后期的溶蚀作用不明显,其综合效应是造成孔隙降低.浊沸石溶蚀次生孔隙的发育是控制富县探区延长组长3油层优质储层的主控因素.Abstract: The degree of laumontites development and the status of laumontites dissolution are important indexes for the prediction of potential sedimentary belt in extra-low permeability formations of Yanchang group in Ordos basin. Laumontite is not only distributed in the deep reservoir such as Chang 6 of the northeast Ordos basin, but also extensively distributed in the shallow reservoir such as Chang 3 of Fuxian exploration area in the southeast basin. The main reason is that the Chang 3 reservoir of Fuxian exploration area has a great quantity of plagioclase. In the later period of early diagenetic stage, laumontite and the alkaline pore water which was rich in Na were interactional, and the laumontite cement was formed. Through measuring inclusions in laumontite, we find out that its forming temperature is between 85-100℃. The development of laumontite was controlled by sedimentary micro-facies and the sequences stacked of sandbody, and it was mostly distributed in the delta plain and delta front stacked of the distributary channels compound sandbody. In the early period of later diagenetic stage, laumontite were dissolved by organic acid which was generated in decarboxylation of kerogen, and a great quantity of secondary pores were formed. The total effect of the laumontites sedimentation and dissolution led to the increased porosity in the Fuxian exploration east area and the reduced porosity in the west area. The development of laumontite dissoluted secondary pore was the main control factor of the high quality reservoirs in Yanchang Formation of Fuxian exploration area.
-
Key words:
- laumontite /
- Yanchang Formation /
- high quality reservoirs /
- petroleum geology /
- Fuxian exploration area
-
图 1 陕北斜坡南部延长组长3沉积体系分布(据柳益群等,1997)
Fig. 1. Distribution of deposition system in Chang 3 reservoir of Yanchang Formation in the south of Shanbei slope
表 1 长3储层自生矿物电子探针分析数据
Table 1. Data of authigenic mineral in Chang 3 reservoir (analyzed by electronic microscope)
序号 井号/样号 氧化物含量(%) 矿物名称 Na2O MgO Al2O3 SiO2 K2O CaO TiO2 MnO FeO 总量 10 zf48-9 0.074 0.046 19.665 58.181 0.163 9.812 0.013 0.000 0.431 88.385 浊沸石 11 zf47-33 0.198 0.034 19.657 55.076 0.172 9.368 0.000 0.163 84.668 12 zf47-56 0.013 0.078 21.980 48.980 0.000 10.320 0.055 0.064 0.321 81.811 13 zfq31-54 0.008 0.007 17.120 58.980 0.022 10.340 0.000 0.065 0.147 86.689 14 zfq8-3-101 0.235 0.043 16.980 58.210 0.000 9.980 0.024 0.000 0.089 85.561 15 zfq45-73 0.054 0.015 20.890 57.760 0.016 10.022 0.001 0.130 0.154 89.042 表 2 长3段地层水分析数据
Table 2. Analytic data of stratum water in Chang 3
区块 井号 层位 试油结论 地层水离子含量(mg/L) 水型 pH值 K++Na+ Ca2+ Mg2+ Cl- SO42- HCO3- CO32- 总矿化度 中富43井区 中富43 T3c3 油水同层 6125 4849 74 17736 470 259 29513 CaCl2 5 中富43-6 T3c3 油水同层 5608 4967 89 16532 1401 212 16824 CaCl2 5 中富43-19 T3c3 油水同层 6247 4552 86 19309 510 237 30941 CaCl2 6 中富47井区 中富47 T3c3 油水同层 46813 CaCl2 6 中富49 T3c3 油水同层 6665 4408 104 17400 1115 259 29951 CaCl2 5 表 3 浊沸石沉淀与溶解对孔隙影响评价
Table 3. Estimate of the influence of the laumontites sedimentation and dissolution on porosity
区块 井号 平均浊沸石含量(%) 平均浊沸石溶孔(%) 平均原始浊沸石含量(%) 平均浊沸石溶蚀率(%) 平均孔隙度净增加值(%) 样品数 中富43 zf43 3.41 2.03 5.44 37.31 21 8 zf47 2.45 3.02 5.47 55.21 15 7 zfq8-3 5.30 2.57 7.87 32.66 25 9 zfq15-3 3.23 1.90 5.13 37.04 35 11 中陕18 zsh18 0.90 0.21 1.11 18.92 -48 5 表 4 长3油层组储层砂岩次生孔隙构成统计
Table 4. Secondary pore in Chang 3 reservoir sandstone
层位 样品数 项目(%) 面孔率 粒间孔 浊沸石溶孔 长石溶孔 岩屑溶孔 碳酸盐溶孔 杂基溶孔 晶间孔 长3 83 最大值 11.80 9.50 4.50 4.00 2.00 0.50 0.15 0.25 最小值 4.50 2.00 0.30 0.05 0.10 0.01 0.01 0.01 平均值 7.90 3.67 2.83 0.82 0.33 0.17 0.03 0.05 对次生孔隙贡献率 66.90 19.39 7.80 4.02 0.71 1.18 占总孔隙 46.46 35.82 10.38 4.18 2.15 0.38 0.63 -
[1] Guo, Y.Q., 2006. Research on reservoir micro-characteristic of Yangchang Formation in Fuxian exploration area of the Ordos basin [Dissertation]. Northwest University, Xiẚn (in Chinese). [2] Liu, Y.Q., Li, W.H., Feng, Q., 1997. Palaeotemperatures and diagenetic stage of the Upper Triassic oil sandatones in the eastern Ordos basin. Acta Geologica Sinica, 71(1): 65-74 (in Chinese with English abstract). http://www.cnki.com.cn/Article/CJFDTotal-DZXW199703007.htm [3] Luo, J.L., Zhang, X.L., Moras, S., et al., 2001. The reconstruction of the stream-lake-delta facies sands diagenesis and the effect for the evolution of the quality of reservoirs—taking the sand of Jurassic-Upper Triassic in Yangchang oil area as an example. Science in China (Ser. D), 31(12): 1006-1016 (in Chinese). [4] Surdam, R.C., Crossey, L.J., Hagen, E.S., et al., 1989. Organic-inorganic interaction and sandstone diagenesis. AAPG Bulletin, 78(1): 1-23. http://www.researchgate.net/profile/Laura_Crossey/publication/237072808_Organic-inorganic_interactions_and_Sandstone_diagenesis/links/5c0d5472a6fdcc494fe87bd7/Organic-inorganic-interactions-and-Sandstone-diagenesis.pdf [5] Surdam, R.C., Crossey, L.J., Lahamn, R., 1984. Mineral oxidants and porosity enhancement. AAPG Bulletin, 68: 532. doi: 10.1306/ad46123c-16f7-11d7-8645000102c1865d [6] Wei, Z.Y., Yao, G.Q., He, S., 2008. Diagenetic evolution and mode in the Chaluhe faulted depression reservoir Yitong craben. Earth Science—Journal of China University of Geosciences, 33(2): 227-232 (in Chinese with English abstract). doi: 10.3799/dqkx.2008.030 [7] Xie, Y., 2002. Sequence stratigraphy and hydrocarbon reservoirs of the Upper Triassic Yangchang Formation in the Fuxian prospect area of the Ordos basin [Dissertation]. Chengdu University of Technology, Chengdu (in Chinese). [8] Yang, H., Fu, J.H., Yu, J., 2003. Oil reservoir enrichment patterns of large delta systems and application of exploration techniques in Shanbei area. Acta Petrolei Sinica, 24(3): 6-10 (in Chinese with English abstract). http://www.researchgate.net/publication/293207100_Oil_reservoir_enrichment_patterns_of_large_delta_systems_and_application_of_exploration_techniques_in_Shanbei_area [9] Yang, J.J., 2002. The tectonic evolvement and oil-gas distribution Pattern of Ordos basin. Petroleum Industry Press, Beijing (in Chinese). [10] Yang, X.P., Qiu, Z.N., 2002. Formation process and distribution of laumontite in Yanchang Formation (Upper Triassic) of Ordos basin. Acta Sedimentologica Sinica, 20(4): 628-632 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-CJXB200204014.htm [11] Yang, X.P., Zhang, B.M., Lei, Z.Y., et al., 2006. Formation and distribution of laumonitede cement in petroliferous basin and its significance for oil-gas exploration. China Petroleum Exploration, 11(2): 33-38 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-KTSY200602006.htm [12] Zhu, G.H., 1985. Formation of lomonitic sand bodies with secondary porosity and their relationship with hydrocarbons. Acta Petrolei Sinica, 6(1): 1-8 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-SYXB198501000.htm [13] 郭艳琴, 2006. 富县探区延长组储层微观特征研究[博士学位论文]. 西安: 西北大学. [14] 柳益群, 李文厚, 冯乔, 1997. 鄂尔多斯盆地东部上三叠统含油砂岩的古地温及成岩阶段. 地质学报, 71(1): 65-74. https://www.cnki.com.cn/Article/CJFDTOTAL-DZXE199701007.htm [15] 罗静兰, 张晓莉, Morad, S., 等, 2001. 河流-湖泊三角洲相砂岩成岩作用的重建及其对储层物性演化的影响——以延长油区侏罗系-上三叠统砂岩为例. 中国科学(D辑), 31(12): 1006-1016. https://www.cnki.com.cn/Article/CJFDTOTAL-JDXK200112005.htm [16] 魏忠元, 姚光庆, 何生, 2008. 伊通地堑岔路河断陷储层成岩演化史与成岩模式. 地球科学——中国地质大学学报, 33(2): 227-232. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX200802011.htm [17] 谢渊, 2002. 鄂尔多斯盆地富县探区上三叠统延长组层序地层与储层研究[博士学位论文]. 成都: 成都理工大学. [18] 杨华, 付金华, 喻建, 2003. 陕北地区大型三角洲油藏富集规律及勘探技术应用. 石油学报, 24(3): 6-10. https://www.cnki.com.cn/Article/CJFDTOTAL-SYXB200303001.htm [19] 杨俊杰, 2002. 鄂尔多斯盆地构造演化与油气分布规律. 北京: 石油工业出版社. [20] 杨晓萍, 裘择楠, 2002. 鄂尔多斯盆地上三叠统延长组浊沸石的形成机理、分布规律与油气关系. 沉积学报, 20(4): 628-632. doi: 10.3969/j.issn.1000-0550.2002.04.015 [21] 杨晓萍, 张宝民, 雷振宇, 等, 2006. 含油气盆地中浊沸石的形成与分布及其对油气勘探的意义. 中国石油勘探, 11(2): 33-38. https://www.cnki.com.cn/Article/CJFDTOTAL-KTSY200602006.htm [22] 朱国华, 1985. 陕北浊沸石次生孔隙砂体的形成与油气的关系. 石油学报, 6(1): 1-8. https://www.cnki.com.cn/Article/CJFDTOTAL-SYXB198501000.htm