Genetic mechanism of inner reservoirs of Yingshan Formation of Middle-Lower Ordovician in Tahe Oil Field, Tarim Basin
-
摘要: 塔里木盆地塔河油田中下奥陶统顶部风化壳缝洞型储集体是主力产层,在其下部依然发育规模性储集体,为探讨这套储集体的成因机理,在A井区开展了碳氧同位素、锶同位素、稀土元素和阴极发光等分析测试工作。洞穴和构造裂缝方解石的δ18O和δ13C值明显比灰岩背景值偏负,具有δ18O不变而δ13C可变的趋势,δ18OPDB均值为-14.74‰,为脱气作用形成的大气水方解石线。洞穴和构造裂缝方解石的87Sr/86Sr比值介于0.709 622~0.709 968之间,明显高于背景值,主要受壳源锶的影响;稀土元素中Ce和Eu元素无正异常,表明缺乏热液流体的参与。洞穴和构造裂缝方解石胶结物主要发橘黄色和暗棕色光,代表的是弱氧化—弱还原环境。研究认为,A井区中下奥陶统鹰山组缝洞储集体形成于海西早期大气淡水深部缓流带环境,该岩溶环境具有承压、水流缓慢、不受排水基准面控制的特点。Abstract: The fracture-cave reservoirs of weathering crust on the top of Middle-Lower Ordovician in the Tahe Oil Field of Tarim Basin are the major production layer, and large scale reservoirs are also developed underneath the reservoirs. In order to discuss the genetic mechanism of formation of these reservoirs, carbon and oxygen isotope, strontium isotope, rare earth elements and cathodoluminescence were tested in the well A area. The δ18O and δ13C values of calcite in caves and structural fractures are obviously negative than those in limestone background. The mean value of δ18OPDB is -14.74‰, showing a trend of constant δ18O and variable δ13C, which are the calcite lines of atmospheric water formed by degassing. The 87Sr/86Sr ratios of calcites from caves and structures range from 0.709 622 to 0.709 968, which are obviously higher than the background values, and are mainly affected by crustal strontium. There are no positive anomalies in Ce and Eu elements, indicating that there is no hydrothermal fluid involved. The cathodoluminescence of calcites are mainly orange and dark brown, which represents weak oxidation-reduction environment. The results showed that the fracture-cave reservoirs of the Midde-Lower Ordovician Yingshan Formation in the well A area were formed in the deep slow flow zone of atmospheric water during the Early Hercynian, showing the characteristics of pressure bearing, slow flow and not controlled by the karst drainage base level.
-
图 7 塔里木盆地塔河油田构造裂缝和洞穴方解石阴极发光特征
a.B井,6 283.41 m,构造裂缝方解石发橘黄色光,上为单偏光照片,下为阴极发光照片,下同;b.B井,6 283.41 m,洞穴巨晶方解石发橘黄色光;c.A井,6 105.5 m,洞穴巨晶方解石发暗棕色光;d.A井,6 105.8 m,洞穴巨晶方解石发橘黄色光;e.A井,6 115.6 m,构造裂缝方解石发暗棕色光、暗橘黄色光和亮黄色光
Figure 7. Characteristics of cathodoluminescence of calcites of tectonic fissures and caves in Tahe Oil Field, Tarim Basin
表 1 塔里木盆地塔河油田测试样品碳、氧、锶同位素组成
Table 1. Carbon, oxygen and strontium isotopic compositions of test samples in Tahe Oil Field, Tarim Basin
井号 深度/m 产状 δ13CPDB/‰ δ18OPDB/‰ 87Sr/86Sr A井 6 100.15 洞穴巨晶方解石 -1.5 -16.2 0.709 622 6 100.20 洞穴巨晶方解石 -2.4 -13.8 0.709 657 6 106.10 洞穴巨晶方解石 -1.5 -15.5 0.709 641 6 106.80 洞穴巨晶方解石 -1.0 -15.4 0.709 663 6 115.60 构造裂缝方解石 -1.4 -14.2 0.709 777 6 115.60 云质灰岩 -1.4 -9.5 0.708 960 B井 6 284.10 构造裂缝方解石 -0.4 -13.8 0.709 868 6 284.80 洞穴巨晶方解石 -2.2 -14.3 0.709 968 表 2 塔里木盆地塔河油田测试样品稀土元素组成
Table 2. REE compositions of test samples in Tahe Oil Field, Tarim Basin
10-6 井号 深度/m La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu ∑REE A井 6 100.15 0.397 0.920 0.105 0.423 0.075 0.009 0.051 0.011 0.067 0.016 0.042 0.002 0.028 0.003 2.149 6 100.20 0.386 0.542 0.067 0.301 0.060 0.015 0.114 0.017 0.154 0.022 0.071 0.005 0.025 0.004 1.783 6 106.10 0.457 1.020 0.121 0.439 0.081 0.013 0.174 0.013 0.045 0.006 0.030 0.004 0.045 0.003 2.451 6 106.80 2.590 4.680 0.507 2.000 0.399 0.089 0.441 0.086 0.483 0.106 0.269 0.049 0.221 0.034 11.954 6 115.60 0.842 1.710 0.189 0.729 0.119 0.028 0.146 0.033 0.12 0.025 0.063 0.006 0.091 0.007 4.108 6 115.60 1.040 2.010 0.203 0.831 0.146 0.028 0.165 0.014 0.156 0.032 0.076 0.018 0.068 0.007 4.794 B井 6 284.10 0.613 0.868 0.127 0.575 0.110 0.024 0.132 0.021 0.131 0.027 0.081 0.010 0.059 0.008 2.786 6 284.80 4.450 8.120 1.00 4.340 0.841 0.199 0.871 0.157 0.820 0.149 0.438 0.068 0.402 0.057 21.912 TP28 6 738.38 0.897 1.530 0.184 0.713 0.136 0.029 0.123 0.023 0.136 0.027 0.079 0.013 0.085 0.015 3.990 6 742.98 0.615 0.989 0.118 0.444 0.085 0.028 0.087 0.017 0.088 0.021 0.065 0.007 0.069 0.012 2.645 6 745.01 0.870 1.560 0.167 0.649 0.101 0.034 0.118 0.018 0.112 0.023 0.074 0.012 0.079 0.014 3.831 注:样品产状同表 1。 -
[1] 赵文智, 胡素云, 刘伟, 等. 再论中国陆上深层海相碳酸盐岩油气地质特征与勘探前景[J]. 天然气工业, 2014, 34(4): 1-9. https://www.cnki.com.cn/Article/CJFDTOTAL-TRQG201404002.htmZHAO Wenzhi, HU Suyun, LIU Wei, et al. Petroleum geological features and exploration prospect in deep marine carbonate strata onshore China: a further discussion[J]. Natural Gas Industry, 2014, 34(4): 1-9. https://www.cnki.com.cn/Article/CJFDTOTAL-TRQG201404002.htm [2] 何治亮, 张军涛, 丁茜, 等. 深层-超深层优质碳酸盐岩储层形成控制因素[J]. 石油与天然气地质, 2017, 38(4): 633-644. https://www.cnki.com.cn/Article/CJFDTOTAL-SYYT201704001.htmHE Zhiliang, ZHANG Juntao, DING Qian, et al. Factors controlling the formation of high-quality deep to ultra-deep carbonate reservoirs[J]. Oil & Gas Geology, 2017, 38(4): 633-644. https://www.cnki.com.cn/Article/CJFDTOTAL-SYYT201704001.htm [3] 马永生, 何治亮, 赵培荣, 等. 深层-超深层碳酸盐岩储层形成机理新进展[J]. 石油学报, 2019, 40(12): 1415-1425. doi: 10.7623/syxb201912001MA Yongsheng, HE Zhiliang, ZHAO Peirong, et al. A new progress in formation mechanism of deep and ultra-deep carbonate reservoir[J]. Acta Petrolei Sinica, 2019, 40(12): 1415-1425. doi: 10.7623/syxb201912001 [4] 刘存革, 张钰, 吕海涛. 塔河油田中-下奥陶统古岩溶洞穴巨晶方解石成因及演化[J]. 地质科技情报, 2008, 27(4): 33-38. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ200804007.htmLIU Cunge, ZHANG Yu, LV Haitao. Genesis and evolution of gigantic calcites in paleokarstic caves of Middle-Lower Ordovician in Tahe oilfield[J]. Geological Science and Technology Information, 2008, 27(4): 33-38. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ200804007.htm [5] 余智超, 王志章, 魏荷花, 等. 塔河油田缝洞型油藏不同成因岩溶储集体表征[J]. 油气地质与采收率, 2019, 26(6): 53-61. https://www.cnki.com.cn/Article/CJFDTOTAL-YQCS201906007.htmYU Zhichao, WANG Zhizhang, WEI Hehua, et al. Characterization of fracture-cave karst reservoirs with different genesis in Tahe Oilfield[J]. Petroleum Geology and Recovery Efficiency, 2019, 26(6): 53-61. https://www.cnki.com.cn/Article/CJFDTOTAL-YQCS201906007.htm [6] 鲁新便, 杨敏, 汪彦, 等. 塔里木盆地北部"层控"与"断控"型油藏特征: 以塔河油田奥陶系油藏为例[J]. 石油实验地质, 2018, 40(4): 461-469. doi: 10.11781/sysydz201804461LU Xinbian, YANG Min, WANG Yan, et al. Geological characteristics of '-bound' and '-controlled' reservoirs in the northern Tarim Basin: taking the Ordovician reservoirs in the Tahe Oil Field as an example[J]. Petroleum Geology & Experiment, 2018, 40(4): 461-469. doi: 10.11781/sysydz201804461 [7] 张娟, 鲍典, 杨敏, 等. 塔河油田西部古暗河缝洞结构特征及控制因素[J]. 油气地质与采收率, 2018, 25(4): 33-39. https://www.cnki.com.cn/Article/CJFDTOTAL-YQCS201804006.htmZHANG Juan, BAO Dian, YANG Min, et al. Analysis on fracture-cave structure characteristics and its controlling factor of Palaeo-subterranean rivers in the western Tahe Oilfield[J]. Petroleum Geology and Recovery Efficiency, 2018, 25(4): 33-39. https://www.cnki.com.cn/Article/CJFDTOTAL-YQCS201804006.htm [8] 刘永立, 罗明霞, 夏永涛, 等. 塔河油田塔深3井区奥陶系深层油气成藏的地球化学证据[J]. 石油实验地质, 2017, 39(3): 377-382. doi: 10.11781/sysydz201703377LIU Yongli, LUO Mingxia, XIA Yongtao, et al. Geochemical evidence for hydrocarbon accumulation in deep Ordovician in TS3 well block, Tahe oil field[J]. Petroleum Geology & Experiment, 2017, 39(3): 377-382. doi: 10.11781/sysydz201703377 [9] 巫波, 荣元帅, 张晓. 塔河油田中深部缝洞体油藏控制因素分析[J]. 特种油气藏, 2014, 21(2): 115-118. https://www.cnki.com.cn/Article/CJFDTOTAL-TZCZ201402026.htmWU Bo, RONG Yuanshuai, ZHANG Xiao. Analysis of controlling factors over the medium-deep fracture-cavern type oil reservoir in the Tahe oilfield[J]. Special Oil & Gas Reservoirs, 2014, 21(2): 115-118. https://www.cnki.com.cn/Article/CJFDTOTAL-TZCZ201402026.htm [10] 宋倩, 马青, 董旭江, 等. 塔里木盆地北部地区奥陶系层序地层格架与沉积演化[J]. 古地理学报, 2016, 18(5): 731-742. https://www.cnki.com.cn/Article/CJFDTOTAL-GDLX201605004.htmSONG Qian, MA Qing, DONG Xujiang, et al. Sequence stratigraphic framework and sedimentary evolution of the Ordovician in northern Tarim Basin[J]. Journal of Palaeogeography, 2016, 18(5): 731-742. https://www.cnki.com.cn/Article/CJFDTOTAL-GDLX201605004.htm [11] LIU Cunge, LI Guorong, WANG Dawei, et al. Middle-Upper Ordovician (Darriwilian-Early Katian) positive carbon isotope excursions in the northern Tarim Basin, Northwest China: implications for stratigraphic correlation and paleoclimate[J]. Journal of Earth Science, 2016, 27(2): 317-328. [12] 刘存革, 李国蓉, 张一伟, 等. 锶同位素在古岩溶研究中的应用: 以塔河油田奥陶系为例[J]. 地质学报, 2007, 81(10): 1398-1406. https://www.cnki.com.cn/Article/CJFDTOTAL-DZXE200710011.htmLIU Cunge, LI Guorong, ZHANG Yiwei, et al. Application of strontium isotope to the study of paleokarst: an case from Ordovician in the Tahe oilfield, Tarim Basin[J]. Acta Geologica Sinica, 2007, 81(10): 1398-1406. https://www.cnki.com.cn/Article/CJFDTOTAL-DZXE200710011.htm [13] LOHMANN K C. Geochemical patterns of meteoric diagenetic systems and their application to studies of paleokarst[M]//JAMES N P, CHOQUETTE P W. Paleokarst. New York: Springer-Verlag, 1988. [14] BANNER J L. Radiogenic isotopics: systematics and applications to earth surface processes and chemical stratigraphy[J]. Earth-Science Reviews, 2004, 65(3/4): 141-194. [15] MCARTHUR J M, HOWARTH R J, BAILEY T R. Strontium isotope stratigraphy: LOWESS vension 3: best fit to the marine Sr-isotope curve for 0-509 Ma and accompanying look-up table for deriving numerical age[J]. The Journal Geology, 2001, 109(2): 155-170. [16] 赵伦山, 张本仁. 地球化学[M]. 北京: 地质出版社, 1988.ZHAO Lunshan, ZHANG Benren. Geochemistry[M]. Beijing: Geological Publishing House, 1988. [17] 王小林, 金之钧, 胡文瑄, 等. 塔里木盆地下古生界白云石微区REE配分特征及其成因研究[J]. 中国科学(D缉 地球科学), 2009, 39(6): 721-733. https://www.cnki.com.cn/Article/CJFDTOTAL-JDXK200906004.htmWANG Xiaolin, JIN Zhijun, HU Wenxuan, et al. Using in situ REE analysis to study the origin and diagenesis of dolomite of Lower Paleozoic, Tarim Basin[J]. Science in China(Series D Earth Sciences), 2009, 52(5): 681-693. https://www.cnki.com.cn/Article/CJFDTOTAL-JDXK200906004.htm [18] 强子同. 碳酸盐岩储层地质学[M]. 东营: 石油大学出版社, 1998: 107-322.QIANG Zitong. Carbonate reservoir geology[M]. Dongying: China University of Petroleum Press, 1998: 107-322. [19] 徐国强, 李国蓉, 刘树根, 等. 塔里木盆地早海西期多期次风化壳岩溶洞穴层[J]. 地质学报, 2005, 79(4): 557-568. https://www.cnki.com.cn/Article/CJFDTOTAL-DZXE200504018.htmXU Guoqiang, LI Guorong, LIU Shugen, et al. Multiple karst cave horizons in the Early Hercynian weathering crust in the Tarim Basin[J]. Acta Geologica Sinica, 2005, 79(4): 557-568. https://www.cnki.com.cn/Article/CJFDTOTAL-DZXE200504018.htm [20] 张宝民, 刘静江. 中国岩溶储集层分类与特征及相关的理论问题[J]. 石油勘探与开发, 2009, 36(1): 12-29. https://www.cnki.com.cn/Article/CJFDTOTAL-SKYK200901004.htmZHANG Baomin, LIU Jingjiang. Classification and characteristics of karst reservoirs in China and related theories[J]. Petroleum Exploration & Development, 2009, 36(1): 12-29. https://www.cnki.com.cn/Article/CJFDTOTAL-SKYK200901004.htm [21] 何宇彬. 试论均匀状厚层灰岩水动力剖面及实际意义[J]. 中国岩溶, 1991, 10(1): 1-12. https://www.cnki.com.cn/Article/CJFDTOTAL-ZGYR199101000.htmHE Yubin. Hydrodynamic section of thick homogeneous limestone and its practical significance[J]. Carsologica Sinica, 1991, 10(1): 1-12. https://www.cnki.com.cn/Article/CJFDTOTAL-ZGYR199101000.htm