Pattern of Vertical Fracture Development Controlled by Mechanical Stratigraphy in Carbonate Layer in Xikeer Outcrop Area of Xinjiang Autonomous Region
-
摘要: 为研究裂缝力学层控发育模式, 进而实现对裂缝型油气藏碳酸盐岩层系裂缝发育特征有效预测, 通过对新疆西克尔露头区地层产状平缓奥陶系碳酸盐岩层系3个野外露头剖面(21号剖面(39°50'17.34″N, 77°28'36.12″E)、32号剖面(39°50'18.18″N, 77°28'25.62″E)以及43号剖面(39°50'10.88″N, 77°28'26.1″E))垂向裂缝生长特征的统计分析, 结合沉积旋回的划分结果, 揭示了不同剖面力学界面的分布特征以及力学单元控制下各剖面的裂缝密度.结果表明, 21号剖面的平均裂缝密度为7.1条/m, 远大于32号剖面的2.2条/m以及43号剖面的2.9条/m.分别从岩性特征、力学单元厚度以及应力状态等方面探讨其对于3条剖面裂缝密度差异分布的影响与控制.碳酸盐岩层系裂缝的密度随灰岩中泥晶含量的增加而递增, 颗粒灰岩中裂缝的密度明显低于泥晶灰岩; 受压力影作用的影响, 力学单元的厚度与裂缝的密度呈负相关, 力学单元越厚则裂缝密度越低.43号剖面与32号剖面的裂缝饱和度均大于0.8, 接近裂缝饱和状态; 而裂缝平均密度最大的21号剖面其裂缝饱和度仅为0.6, 为不饱和状态, 裂缝的平均密度与其饱和度值呈负相关.Abstract: It is supposed that we can effectively predict the fracture density in carbonate layer by studying the pattern of vertical fracture development controlled by mechanical stratigraphy. The latitude of stratum is smooth in Ordovician carbonate in Xikeer outcrop area of Xinjiang autonomous region. Opening-mode fractures (joints) that are perpendicular to bedding are typically controlled by mechanical stratigraphy. After computing amounts and analyzing characteristics of vertical fractures in combination with the results of dividing sedimentary cycle in stratum section of Number 21 (latitude 39°50'17.34″N, longitude 77°28'36.12″E), number 32 (latitude 39°50'18.18″N, longitude 77°28'25.62″E) and number 43 (latitude 39°50'10.88″N, longitude 77°28'26.1″E) in researching outcrop area, we identify the distribution characteristics of different mechanical interfaces and based on which we calculate the fracture density controlled by different mechanical units in each section. The average of fracture density of section 21 is 7.1 per meter which is larger than 2.9 per meter of section 43 and 2.2 per meter of section 32. At the same time, we study the dominating factors of fracture density differences in different section from lithological characteristics, thickness of mechanical unit and stress state. It shows that fracture density increases as the content of mudstone is higher in limestone in carbonate stratigraphy and fracture density is sharply lower in grain limestone than that in mudstone. On the other hand, because of the influence of stress shadow, the thickness of mechanical unit has negative correlation with fracture density: the thicker the mechanical unit is, the less the fracture density is. Fracture saturation in section 43 and section 32 is larger than 0.8, which shows they have approached fracture saturated state. However, the section 21 that has the largest fracture density is of unsaturated state, with a fracture saturation of mere 0.6. Therefore, the average fracture has negative correlation with fracture saturation.
-
图 1 力学单元及力学界面示意(Underwood et al., 2003)
Fig. 1. The mechanical unit and mechanical interface
图 3 力学界面与非力学界面上的裂缝节点差异
Fig. 3. The difference of the fracture tip's numbers between mechanical interface and non-mechanical interface
图 4 野外剖面裂缝发育模式
a.21号点剖面裂缝发育模式；b.32号点剖面裂缝发育模式；c.43号点剖面裂缝发育模式
Fig. 4. The pattern of the fracture development
图 5 西克尔地区鹰山组地层剖面镜下岩性照片
a.21号剖面中发育的纹层状鸟眼构造的泥晶灰岩；b.21号剖面发育的粉砂屑泥晶灰岩；c.32号剖面中发育泥晶砂屑灰岩；d.32号剖面亮晶砂屑灰岩；e.43号剖面中发育砂屑泥晶灰岩；f.43号剖面中发育的泥晶砂屑灰岩(可见藻类和生物碎屑壳体)
Fig. 5. Photos of the rock sample from Yingshan Fromation under the microscope in Xikeer area
-
[1] Atkinson, T.C., 1977. Diffuse flow and conduit flow in limestone terrain in the Mendip Hills, Somerset (Great Britain). Journal of Hydrology, 35(1-2): 93-110. doi: 10.1016/0022-1694(77)90079-8 [2] Bai, T., Pollard, D.D., 2000a. Fracture spacing in layered rocks: a new explanation based on the stress transition. Journal of Structural Geology, 22(1): 43-57. doi: 10.1016/S0191-8141(99)00137-6 [3] Bai, T., Pollard, D.D., 2000b. Closely spaced fractures in layered rocks: initiation mechanism and propagation kinematics. Journal of Structural Geology, 22(10): 1409-1425. doi: 10.1016/S0191-8141(00)00062-6 [4] Bai, T., Pollard, D.D., Gao, H.J., 2000. Spacing of edge fractures in layered materials. International Journal of Fracture, 103(4): 373-395. doi: 10.1023/A:1007659406011 [5] Becker, A., Gross, M.R., 1996. Mechanisms for joint saturation in mechanically layered rocks: an example from southern Israel. Tectonophysics, 257(2-4): 223-237. doi: 10.1016/0040-1951(95)00142-5 [6] Cooke, M.L., Simo, J.A., Underwood, C.A., et al., 2006. Mechanical stratigraphic controls on fracture patterns within carbonates and implications for groundwater flow. Sedimentary Geology, 184(3-4): 225-239. doi: 10.1016/j.sedgeo.2005.11.004 [7] Cooke, M.L., Underwood, C.A., 2001. Fracture termination and step-over at bedding interfaces due to frictional slip and interface opening. Journal of Structural Geology, 23(2-3): 223-238. doi: 10.1016/S0191-8141(00)00092-4 [8] Corbett, K.P., Friedman, M., Spang, J., 1987. Fracture development and mechanical stratigraphy of Austin Chalk, Texas. AAPG Bulletin, 71(1): 17-28. doi: 10.1306/94886D35-1704-11D7-8645000102C1865D [9] Engelder, T., Gross, M.R., Pinkerton, P., 1997. An analysis of joint development in thick sandstone beds of the Elk basin anticline, Montana-Wyoming. In: Hoak, T., Klawitter, A., Blomquist, P., eds., Fractured reservoirs characterization and modeling guidebook. Rocky Mountain Association of Geologists, Denver, Colorado, 1-18. [10] Eyssautier-Chuine, S., Odonne, F., Massonnat, G., 2002. Control of bioclast abundance on natural joint density in carbonate rocks: data from Oman, Provence and Languedoc (France). Terra Nova, 14(3): 198-204. doi: 10.1046/j.1365-3121.2002.00411.x [11] Friedman, M., Kwon, O., French, V.L., 1994. Containment of natural fractures in brittle beds of the Austin Chalk, rock mechanics, models and measurements challenges from industry. In: Nelson, P.P., Laubach, S.E., eds., Proceedings of the 1st North American Rock Mechanics Symposium. Balkema, Texas, Austin, 833-840. [12] Gross, M.R., 1993. The origin and spacing of cross joints: example from the Monterey Formation, Santa Barbara Coastline, California. Journal of Structural Geology, 15(6): 737-751. doi: 10.1016/0191-8141(93)90059-J [13] Gross, M.R., Fischer, M.P., Engelder, T., et al., 1995. Factors controlling joint spacing in interbedded sedimentary rocks: integrating numerical models with field observations from the Monterey Formation, USA. In: Ameen, M.S., ed., Fractography: fracture topography as a tool in fracture mechanics and stress analysis. Geological Society Special Publication, London, 92: 215-233. doi: 10.1144/1995.092.01.12 [14] Hanks, C.L., Lorenz, J., Teufel, L., et al., 1997. Lithologic and structural controls on natural fracture distribution and behavior within the Lisburne Group, northeastern Brooks Range and North Slope subsurface, Alaska. AAPG Bulletin, 81(10): 1700-1720. http://www.researchgate.net/publication/308485684_Lithologic_and_Structural_Controls_on_Natural_Fracture_Distribution_and_Behavior_Within_the_Lisburne_Group_Northeastern_Brooks_Range_and_North_Slope_Subsurface_Alaska [15] Harris, J.F., Taylor, G.L., 1960. Relation of deformational fractures in sedimentary rocks to regional and local structure. AAPG Bulletin, 44(12): 1853-1873. doi: 10.1306/0BDA6257-16BD-11D7-8645000102C1865D [16] Hennings, P.H., Olson, J.E., Thompson, L.B., 2000. Combining outcrop data and three-dimensional structural models to characterize fractured reservoirs: an example from Wyoming. AAPG Bulletin, 84(6): 830-849. doi: 10.1306/A967340A-1738-11A7-8645000102A1865D [17] Hillis, R.R., 1998. The influence of fracture stiffness and the in situ stress field on the closure of natural fractures. Petroleum Geoscience, 4(1): 57-65. doi: 10.1144/petgeo.4.1.57 [18] Hobbs, D.W., 1967. The formation of tension joints in sedimentary rocks, an explanation. Geological Magazine, 104(6): 550-556. doi: 10.1017/s0016756800050226 [19] Huang, G.Y., Lu, S.F., Yang, F.P., 2003. Application of curvature method to fissure forecast of the Yingcheng Formation stratum of Xujiaweizi fault depression. Journal of Daqing Petroleum Institute, 27(4): 9-11 (in Chinese with English abstract). http://www.cqvip.com/main/zcps.aspx?c=1&id=8707244 [20] Huang, Q., Angelier, J., 1989. Fracture spacing and its relation to bed thickness. Geological Magazine, 126(4): 355-362. doi: 10.1017/s0016756800006555 [21] Ladeira, F.L., Price, N.J., 1981. Relationship between fracture spacing and bed thickness. Journal of Structural Geology, 3(2): 179-183. doi: 10.1016/0191-8141(81)90013-4 [22] Laubach, S.E., 2003. Practical approaches to identifying sealed and open fractures. AAPG Bulletin, 87(4): 561-579. doi: 10.1306/11060201106 [23] Lézin, C., Odonne, F., Massonnat, G.J., et al., 2009. Dependence of joint spacing on rock properties in carbonate strata. AAPG Bulletin, 93(2): 271-290. doi: 10.1306/09150808023 [24] Li, Z.Y., Zeng, Z.X., Luo, W.Q., 2004. Curvature analysis and fracture estimating of folds—a case study of Wangchang fold in Jianghan basin. Journal of Jilin University (Earth Science Edition), 34(4): 517-521 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTotal-CCDZ200404005.htm [25] Ma, D.M., Chen, J.L., Zeng, C.M., et al., 2007. Structural deformation characteristics of the Kalpin thrust belt on the Northwestern margin of the Tarim basin. Journal of Geomechanics, 13(4): 340-347 (in Chinese with English abstract). http://www.cqvip.com/QK/98414X/2007004/26597623.html [26] Masaferro, J.L., Bulnes, M., Poblet, J., et al., 2003. Kinematic evolution and fracture prediction of the Valle Morado structure inferred from 3-D seismic data, Salta Province, Northwest Argentina. AAPG Bulletin, 87(7): 1083-1104. doi: 10.1306/02070301102 [27] McQuillan, H., 1973. Small-scale fracture density in Amari Formation of Southwest Iran and its relation to bed thickness and structural setting. AAPG Bulletin, 57(12): 2367-2385. http://aapgbull.geoscienceworld.org/content/57/12/2367 [28] Murray, G.H., 1968. Quantitative fracture study—sanish pool, Mckenzie county, North Dakota. AAPG Bulletin, 52(1): 57-65. http://www.researchgate.net/publication/270483544_Quantitative_Fracture_Study--Sanish_Pool_McKenzie_County_North_Dakota_ABSTRACT [29] Nelson, R.A., Co, A.P., 1982. An approach to evaluating fractured reservoirs. Journal of Petroleum Technology, 34(9): 2167-2177. doi: 10.2118/10331-PA [30] Pollard, D.D., Segall, P., 1987. Theoretical displacements and stresses near fractures in rock: with applications to faults, joints, veins, dikes, and solution surfaces. In: Atkinson, B.K., ed., Fracture mechanics of rock. Academic Press, London, 277-349. [31] Rijken, P., Cooke, M.L., 2001. Role of shale thickness on vertical connectivity of fractures application of crack-bridging theory to the Austin Chalk, Texas. Tectonophysics, 337(1-2): 117-133. doi: 10.1016/S0040-1951(01)00107-X [32] Stauffer, M.R., Gendzwill, D.J., 1987. Fractures in the Northern Plains, stream patterns, and the Midcontinent stress field. Canadian Journal of Earth Sciences, 24(6): 1086-1097. doi: 10.1139/e87-106 [33] Sun, S.R., 2003. Application comparison of two curvature methods for predicating reservoir fractures. Geological Science and Technology Information, 22(4): 71-74 (in Chinese with English abstract). http://d.wanfangdata.com.cn/periodical/dzkjqb200304013 [34] Teufel, L.W., Clark, J.A., 1984. Hydraulic fracture propagation in layered rock: experimental studies of fracture containment. Society of Petroleum Engineers Journal, 24(1): 19-32. doi: 10.2118/9878-PA [35] Underwood, C.A., Cooke, M.L., Simo, J.A., et al., 2003. Stratigraphic controls on vertical fracture patterns in Silurian dolomite, northeastern Wisconsin. AAPG Bulletin, 87(1): 121-142. doi: 10.1306/072902870121 [36] Vermilye, J.M., Scholz, C.H., 1995. Relation between vein length and aperture. Journal of Structural Geology, 17(3): 423-434. doi: 10.1016/0191-8141(94)00058-8 [37] Wall, B.R.G., Girbacea, R., Mesonjesi, A., et al., 2006. Evolution of fracture and fault-controlled fluid pathways in carbonates of the Albanides fold-thrust belt. AAPG Bulletin, 90(8): 1227-1249. doi: 10.1306/03280604014 [38] Wiltschko, D.V., Medwedeff, D.A., Millson, H.E., 1985. Distribution and mechanisms of strain within rocks on the northwest ramp of Pine Mountain block, southern Appalachian foreland: a field test of theory. Geological Society of America Bulletin, 96(4): 426-435. doi: 10.1130/0016-7606(1985)96<426:DAMOSW>2.0.CO;2 [39] Wu, H., Pollard, D.D., 1995. An experimental study of the relationship between joint spacing and layer thickness. Journal of Structural Geology, 17(6): 887-905. doi: 10.1016/0191-8141(94)00099-l [40] Yang, G., Guo, H., 2003. Superposed relationship between Kalping thrust belt and Bachu uplift, Northwest Tarim. Uranium Geology, 19(1): 1-7(in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-YKDZ200301000.htm [41] Zhang, C., Zheng, D.M., Li, J.H., 2001. Attribute of Paleozoic structures and its evolution characteristics in Keping fault-uplift. Oil & Gas Geology, 22(4): 315-318 (in Chinese with English abstract). http://d.wanfangdata.com.cn/Periodical_syytrqdz200104006.aspx [42] 黄光玉, 卢双舫, 杨峰平, 2003. 曲率法在松辽盆地徐家围子断陷营城组地层裂缝预测中的应用. 大庆石油学院学报, 27(4): 9-11. https://www.cnki.com.cn/Article/CJFDTOTAL-DQSY200304002.htm [43] 李志勇, 曾佐勋, 罗文强, 2004. 褶皱构造的曲率分析及其裂缝估算——以江汉盆地王场褶皱为例. 吉林大学学报(地球科学版), 34(4): 517-521. https://www.cnki.com.cn/Article/CJFDTOTAL-CCDZ200404005.htm [44] 马德明, 陈江力, 曾昌民, 等, 2007. 塔里木盆地西北缘柯坪冲断带的构造变形特征. 地质力学学报, 13(4): 340-347. doi: 10.3969/j.issn.1006-6616.2007.04.007 [45] 孙尚如, 2003. 预测储层裂缝的两种曲率方法应用比较. 地质科技情报, 22(4): 71-74. doi: 10.3969/j.issn.1000-7849.2003.04.013 [46] 杨庚, 郭华, 2003. 塔里木盆地西北缘柯坪逆冲构造带与巴楚隆起的叠加关系. 铀矿地质, 19(1): 1-7. https://www.cnki.com.cn/Article/CJFDTOTAL-YKDZ200301000.htm [47] 张臣, 郑多明, 李江海, 2001. 柯坪断隆古生代的构造属性及其演化特征. 石油与天然气地质, 22(4): 315-318. https://www.cnki.com.cn/Article/CJFDTOTAL-SYYT200104005.htm -
下载:
点击查看大图
图(6)
计量
- 文章访问数: 184
- HTML全文浏览量: 133
- PDF下载量: 4
- 被引次数: 0
