Application of the improved seismic AVAZ inversion method for fracture characterization of a tight sandstone gas reservoir in the Ordos Basin
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摘要: 致密砂岩气储层具有低孔、低渗的特征,裂缝的存在可以提高储层的渗透率,同时裂缝是油气重要的储存空间和运移通道,裂缝发育也有利于水力压裂过程中裂缝网络的形成,裂缝预测可为致密砂岩气储层的开发和部署提供重要依据. 地震振幅随方位角的变化可以提供储层中垂直裂缝的信息,本文针对HTI介质提出了一种改进的方位振幅差异反演方法,并结合岩石物理理论预测表征裂缝性质的裂缝弱度参数. 常规的反演方法一般同时反演弹性参数和裂缝参数,改进的方位振幅差异方法引入一个参考方位,构建消除各向同性背景的方位振幅差异道集,仅反演与各向异性项相关的裂缝弱度参数,充分利用方位各向异性响应,提高裂缝识别的敏感性与裂缝参数反演的准确性. 实际数据应用表明,方位振幅差异反演方法对裂缝参数预测的敏感性较常规方法有所提高,预测的裂缝弱度与测井渗透率曲线相吻合,并且与致密砂岩气储层产气性具有明显的相关性. 因此,利用方位振幅差异方法预测裂缝分布及其发育程度可为致密砂岩储层含气有利区的识别与开发提供可靠的指标.Abstract: A tight sandstone gas reservoir is characterized by low porosity and permeability. The existence of fractures can improve the permeability of the reservoir, and fractures are a vital storage space and migration channel of oil and gas. The development of fractures is also conducive to forming a fracture network during hydraulic fracturing. The prediction of fractures can provide an essential basis for developing tight sandstone gas reservoirs. The variation of seismic amplitude with azimuth can provide information on vertical fractures in the reservoir. This study proposed an improved inversion method of azimuth amplitude difference for the HTI (transversely isotropy with a horizontal axis) medium and combined with the rock physical theory, predicted fracture weakness parameter, characterizing the fracture properties. Conventional inversion methods invert elastic and fracture parameters simultaneously. The improved azimuth amplitude difference method introduces a reference azimuth, builds the track set of azimuth amplitude difference to eliminate the isotropic background, and inverts only the fracture weakness parameters related to the anisotropic terms. Using the only azimuth anisotropic response, the sensitivity of fracture identification and the accuracy of fracture parameter inversion are improved. The application of the field data shows that the sensitivity of the proposed inversion method to the prediction of fracture parameters is improved compared with the conventional inversion method, and the predicted fracture weakness is consistent with the permeability well logs and has a significant correlation with the gas production of tight sandstone gas reservoirs. Therefore, the prediction of fracture distribution and development degree based on the proposed method can provide a reliable indicator for the identification and development of gas-bearing favorable areas in tight sandstone reservoirs.
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图 12 利用地震方位振幅差异ΔRpp反演方法计算井A、B和C(a)法向裂缝弱度和(b)切向裂缝弱度剖面图. 图中曲线为三口井的渗透率测井数据
Figure 12. Cross-section of normal (a) and tangential (b) fracture weakness for wells A, B, and C, calculated by the seismic azimuthal amplitude differences ΔRpp inversion method. The curves are the permeability logs of the three wells
表 1 HTI介质模型参数
Table 1. Model parameters of HTI media
VP/
(km·s−1)VS/
(km·s−1)ρ/
(g·cm−3)V′P/
( km·s−1)V′S/
( km·s−1)ρ′/
(g·cm−3)φ/% 模型1 4.60 2.60 2.46 0.62 0 0.065 0.05 模型2 4.60 2.60 2.46 1.5 0 1.0 0.05 表 2 双层介质模型参数
Table 2. Model parameters of the double-layer medium
VP /(km·s−1) VS /(km·s−1) ρ /(g·cm−3) ΔN ΔT ISO 3.90 2.30 2.46 0 0 HTI 4.60 2.60 2.46 0.3 0.1 -
[1] Anees A, Shi W Z, Ashraf U, et al. 2019. Channel identification using 3D seismic attributes and well logging in lower Shihezi Formation of Hangjinqi area, northern Ordos Basin, China[J]. Journal of Applied Geophysics, 163: 139-150. doi: 10.1016/j.jappgeo.2019.02.015 [2] Bachrach R, Sengupta M, Salama A, et al. 2009. Reconstruction of the layer anisotropic elastic parameters and high-resolution fracture characterization from P-wave data: a case study using seismic inversion and Bayesian rock physics parameter estimation[J]. Geophysical Prospecting, 57(2): 253-262. doi: 10.1111/j.1365-2478.2008.00768.x [3] Bakulin A, Grechka V, Tsvankin I. 2000. Estimation of fracture parameters from reflection seismic data—Part I: HTI model due to a single fracture set[J]. Geophysics, 65(6): 1788-1802. doi: 10.1190/1.1444863 [4] Barone A, Sen M K. 2018. A new Fourier azimuthal amplitude variation fracture characterization method: Case study in the Haynesville Shale[J]. Geophysics, 83(1): WA101-WA120. doi: 10.1190/geo2017-0030.1 [5] 陈祥忠, 王斌. 2021. 基于岩石物理模型的裂缝型储层AVOA反演方法[J]. 吉林大学学报(地球科学版), 51(1): 266-276Chen X Z, Wang B. 2021. AVOA inversion method of fractured reservoir based on petrophysical model[J]. Journal of Jilin University (Earth Science Edition), 51 (1): 266-276 (in Chinese). [6] Downton J, Gray D. 2006. AVAZ parameter uncertainty estimation[J]. SEG Technical Program Expanded Abstracts, 25(1): 234-238. [7] Downton J, Roure B. 2015. Interpreting azimuthal Fourier coefficients for anisotropic and fracture parameters[J]. Interpretation, 3(3): ST9-ST27. doi: 10.1190/INT-2014-0235.1 [8] 傅宁, 杨树春, 贺清, 等. 2016. 鄂尔多斯盆地东缘临兴-神府区块致密砂岩气高效成藏条件[J]. 石油学报, 37(增刊1): 111-120Fu N, Yang S C, He Q, et al. 2016. High-efficiency reservoir formation conditions of tight sandstone gas in Linxing-Shenfu blocks on the east margin of Ordos Basin[J]. Acta Petrolei Sihica, 37(Sup. 1): 111-120 (in Chinese). [9] Guo Z Q, Zhao D Y, Liu C. 2022. Gas prediction using an improved seismic dispersion attribute inversion for tight sandstone gas reservoirs in the Ordos Basin, China[J]. Journal of Natural Gas Science and Engineering, 101: 104499. doi: 10.1016/j.jngse.2022.104499 [10] Guo Z Q, Qin X Y, Liu C. 2023. Pore and microfracture characterization in tight gas sandstone reservoirs with a new rock-physics-based seismic attribute[J]. Remote Sensing, 15(2): 289. doi: 10.3390/rs15020289 [11] 胡艳飞, 孔庆莹. 2022. 鄂尔多斯盆地西南部长8油层储层主控因素及分布规律[J]. 吉林大学学报(地球科学版), 52(4): 1078-1090Hu Y F, Kong Q Y. 2022. Main controlling factors and distribution laws of reservoirs in the Chang 8 oil layer in the southwestern Ordos Basin[J]. Journal of Jilin University (Earth Science Edition), 52(4): 1078-1090 (in Chinese). [12] Hudson J A. 1988. Seismic wave propagation through material containing partially saturated cracks[J]. Geophysical Journal, 92: 33-37. doi: 10.1111/j.1365-246X.1988.tb01118.x [13] Ikelle L T. 1996. Amplitude Variations with Azimuths (AVAZ) Inversion Based on Linearized Inversion of Common Azimuth Sections[M]// Seismic Anisotropy. Society of Exploration Geophysicists, 601-644. [14] Ikelle L T. 1997. Parameterization of AVAZ (Amplitude Variation with Azimuth) inversion[J]. Journal of Seismic Exploration, 6(1): 19-34. [15] 贾承造, 郑民, 张永峰. 2012. 中国非常规油气资源与勘探开发前景[J]. 石油勘探与开发, 39(2): 129 -136.Jia C Z, Zheng M, Zhang Y F. 2012. Unconventional hydrocarbon resources and exploration prospects in China[J]. Petroleum Exploration and Development, 39(2): 129- 136 (in Chinese). [16] Jin H, Liu C, Guo Z Q, et al. 2021. Rock physical modeling and seismic dispersion attribute inversion for the characterization of a tight gas sandstone reservoir[J]. Frontiers in Earth Science, 9: 641651. doi: 10.3389/feart.2021.641651 [17] 康立明, 任战利, 张林, 等. 2020. 鄂尔多斯盆地Y区块长6致密油层裂缝特征[J]. 吉林大学学报(地球科学版), 50(4): 979-990Kang L M, Ren Z L, Zhang L, et al. 2020. Fracture characteristics of Chang 6 tight oil reservoir in Block Y in Ordos Basin[J]. Journal of Jilin University (Earth Science Edition), 50 (4): 979-990 (in Chinese). [18] 李剑, 魏国齐, 谢增业, 等. 2013. 中国致密砂岩大气田成藏机理与主控因素——以鄂尔多斯盆地和四川盆地为例[J]. 石油学报, 34(1): 14-28Li J, Wei G Q, Xie Z Y, et al. 2013. Accumulation mechanism and main controlling factors of large tight sandstone gas fields in China: Cases study on Ordos Basin and Sichuan Basin[J]. Acta Petrolei Sinica, 34(1): 14-28 (in Chinese). [19] Li Y, Tang D Z, Wu P, et al. 2016. Continuous unconventional natural gas accumulations of Carboniferous-Permian coal-bearing strata in the Linxing area, northeastern Ordos basin, China[J]. Journal of Natural Gas Science and Engineering, 36: 314-327. doi: 10.1016/j.jngse.2016.10.037 [20] 林玉祥, 余志勇, 刘冬. 2021. 临兴地区致密砂岩气藏形成机理与成藏模式[J]. 地质与勘探, 57(1): 210-221 doi: 10.12134/j.dzykt.2021.01.020Lin Y X, Yu Z Y, Liu D. 2021. Formation mechanism and model of tight sandstone gas reservoirs in the Linxing area of Ordos Basin[J]. Geology and Exploration, 57(1): 210-221 (in Chinese). doi: 10.12134/j.dzykt.2021.01.020 [21] 刘财, 刘宇巍, 冯暄, 等. 2013. 基于方位相交的纵波AVA数据运用SVD反演HTI介质裂缝密度[J]. 吉林大学学报(地球科学版), 43(5): 1655-1662Liu C, Liu Y W, Feng X, et al. 2013. Invert crack Density of HTI media by using SVD based on PP-Wave AVA data from crossing seismic survey lines[J]. Journal of Jilin University (Earth Science Edition), 43(5): 1655-1662 (in Chinese). [22] 刘玲, 汤达祯, 王烽. 2019a. 鄂尔多斯盆地临兴区块太原组致密砂岩黏土矿物特征及其对储层物性的影响[J]. 油气地质与采收率, 26(6): 28-35 doi: 10.13673/j.cnki.cn37-1359/te.2019.06.004Liu L, Tang D Z, Wang F. 2019a. Clay minerals characteristics of tight sandstone and its impact on reservoir physical properties in Taiyuan Formation of Block Linxing in Ordos Basin[J]. Petroleum Geology and Recovery Efficiency, 26(6): 28-35 (in Chinese). doi: 10.13673/j.cnki.cn37-1359/te.2019.06.004 [23] 刘玲, 汤达祯, 许浩. 2019b. 临兴上古生界致密储层裂缝发育特征及对致密气富集影响[J]. 高校地质学报, 25(3): 457-465.Liu L, Tang D Z, Xu H. 2019b. Development of fractures and its effects on gas accumulation in the Upper Paleozoic tight sandstone reservoirs of the Linxing Block[J]. Geological Journal of China Universities, 25(3): 457-465 (in Chinese). [24] 刘鹏, 王伟锋, 孟蕾, 等. 2016. 鄂尔多斯盆地上古生界煤层气与致密气联合优选区评价[J]. 吉林大学学报(地球科学版), 46(3): 692-701.Liu P, Wang W F, Meng L, et al. 2016. Joint optimization of coal-bed methane and tight gas in the Upper Paleozoic of the Ordos Basin[J]. Journal of Jilin University (Earth Science Edition), 46(3): 692-701 (in Chinese). [25] 刘喜杰, 马遵敬, 韩冬, 等. 2018. 鄂尔多斯盆地东缘临兴区块致密砂岩优质储层形成的主控因素[J]. 天然气地球科学, 29(4): 481-490Liu X J, Ma Z J, Han D, et al. 2018. Research on the main factors of high-quality tight sandstone reservoir in Linxing block, Ordos Basin[J]. Natural Gas Geoscience, 29(4): 481-490 (in Chinese). [26] 刘新社, 任德生, 候云东, 等. 2017. 鄂尔多斯盆地天环坳陷北段上古生界裂缝特征及对气水分布的影响[J]. 地质力学学报, 23(5): 646-653 doi: 10.3969/j.issn.1006-6616.2017.05.002Liu X S, Ren D S, Hou Y D, et al. 2017. Fracture characteristics of Upper Paleozoic and its influence on gas and water distribution on the northern section of the Tianhuan depression, Ordos Basin[J]. Journal of Geomechanics, 23(5): 646-653 (in Chinese). doi: 10.3969/j.issn.1006-6616.2017.05.002 [27] 罗腾, 冯暄, 郭智奇, 等. 2019. 基于模拟退火粒子群优化算法的裂缝型储层各向异性参数地震反演[J]. 吉林大学学报(地球科学版), 49(5): 1466-1476Luo T, Feng X, Guo Z Q, et al. 2019. Seismic inversion of anisotropy parameters of fractured reservoirs by simulated annealing and particle swarm optimization[J]. Journal of Jilin University (Earth Science Edition), 49 (5): 1466-1476 (in Chinese). [28] 潘新朋, 张广智, 印兴耀. 2018. 岩石物理驱动的储层裂缝参数与物性参数概率地震反演方法[J]. 地球物理学报, 61(2): 683-696 doi: 10.6038/cjg2018K0759Pan X P, Zhang G Z, Yin X Y. 2018. Probabilistic seismic inversion for reservoir fracture and petrophysical parameters driven by rock-physics models[J]. Chinese Journal of Geophysics, 61(2): 683-696 (in Chinese). doi: 10.6038/cjg2018K0759 [29] 潘新朋, 张广智. 2019. 裂缝-孔隙型含气储层流体与裂缝参数贝叶斯地震反演方法[J]. 中国科学: 地球科学, 49(5): 796-810Pan X P, Zhang G Z. 2019. Bayesian seismic inversion for estimating fluid content and fracture parameters in a gas-saturated fractured porous reservoir[J]. Science China Earth Sciences, 49(5): 796-810 (in Chinese). [30] Rüger A. 1998. Variation of P-wave reflectivity with offset and azimuth in anisotropic media[J]. Geophysics, 63(3): 935-947. doi: 10.1190/1.1444405 [31] Sayers C M, Dean S. 2001. Azimuth-dependent AVO in reservoirs containing non-orthogonal fracture sets[J]. Geophysical Prospecting, 49(1): 100-106. doi: 10.1046/j.1365-2478.2001.00236.x [32] Schoenberg M, Douma J. 1988. Elastic wave propagation in media with parallel fractures and aligned cracks[J]. Geophysical Prospecting, 36(6): 571-590. doi: 10.1111/j.1365-2478.1988.tb02181.x [33] Schoenberg M, Protazio J. 1992. ’Zoeppritz’ rationalized and generalized to anisotropy[J]. Journal of Seismic Exploration, 1(2): 125-144. [34] Schoenberg M, Sayers C M. 1995. Seismic anisotropy of fractured rock[J]. Geophysics, 60(1): 204-211. doi: 10.1190/1.1443748 [35] Shaw R K, Sen M K. 2006. Use of AVOA data to estimate fluid indicator in a vertically fractured medium[J]. Geophysics, 71(3): C15-C24. doi: 10.1190/1.2194896 [36] Thomsen L. 1986. Weak elastic anisotropy[J]. Geophysics, 51(10): 1954-1966. doi: 10.1190/1.1442051 [37] 魏志鹏, 施瑞生, 王辉. 2021. 鄂尔多斯盆地L区块石盒子组4段致密砂岩气藏地质—工程甜点预测与评价[J]. 天然气勘探与开发, 44(4): 107-114Wei Z P, Shi R S, Wang H. 2021. Prediction and evaluation on geological and engineering sweet spots: Examples from H4 tight sandstone reservoirs, L block, Ordos Basin[J]. Natural Gas Exploration and Development, 44(4): 107-114 (in Chinese). [38] 谢英刚, 孟尚志, 高丽军, 等. 2015. 临兴地区深部煤层气及致密砂岩气资源潜力评价[J]. 煤炭科学技术, 43(2): 21-24, 28 doi: 10.13199/j.cnki.cst.2015.02.005Xie Y G, Meng S Z, Gao L J, et al. 2015. Assessments on potential resources of deep coaled methane and compact sand-stone gas in Linxing area[J]. Coal Science and Technology, 43(2): 21-24, 28 (in Chinese). doi: 10.13199/j.cnki.cst.2015.02.005 [39] 杨华, 付金华, 刘新社, 等. 2012. 鄂尔多斯盆地上古生界致密气成藏条件与勘探开发[J]. 石油勘探与开发, 39(3): 295-303 doi: 10.1016/S1876-3804(12)60045-7Yang H, Fu J H, Liu X S, et al. 2012. Accumulation condition sand exploration and development of tight gas in the Upper Paleozoic of the Ordos Basin[J]. Petroleum Exploration and Development, 39(3): 295-303 (in Chinese). doi: 10.1016/S1876-3804(12)60045-7 [40] 杨华, 王大兴, 张盟勃, 等. 2017. 鄂尔多斯盆地致密气储集层孔隙流体地震预测方法[J]. 石油勘探与开发, 44(4): 513-520 doi: 10.11698/PED.2017.04.04Yang H, Wang D X, Zhang M B, et al. 2017. Seismic prediction method of pore fluid in tight gas reservoirs, Ordos Basin, NW China[J]. Petroleum Exploration and Development, 44(4): 513-520 (in Chinese). doi: 10.11698/PED.2017.04.04 [41] Yin S, Han C, Wu Z H, et al. 2019. Developmental characteristics, influencing factors and prediction of fractures for a tight gas sandstone in a gentle structural area of the Ordos Basin, China[J]. Journal of Natural Gas Science and Engineering, 72: 103032. doi: 10.1016/j.jngse.2019.103032 [42] Yin S, Tian T, Wu Z H. 2020. Developmental characteristics and distribution law of fractures in a tight sandstone reservoir in a low-amplitude tectonic zone, eastern Ordos Basin, China[J]. Geological Journal, 55: 1546–1562. doi: 10.1002/gj.3521 [43] 赵靖舟, 付金华, 姚泾利, 等. 2012. 鄂尔多斯盆地准连续型致密砂岩大气田成藏模式[J]. 石油学报, 33(S1): 37-48 doi: 10.7623/syxb2012S1006Zhao J Z, Fu J H, Yao J L, et al. 2012. Quasi-continuous accumulation model of large tight sandstone gas field in Ordos Basin[J]. Acta Petrolei Sinica, 33(S1): 37-48 (in Chinese). doi: 10.7623/syxb2012S1006 [44] 郑定业, 庞雄奇, 姜福杰, 等. 2020. 鄂尔多斯盆地临兴地区上古生界致密气成藏特征及物理模拟[J]. 石油与天然气地质, 41(4): 744-754 doi: 10.11743/ogg20200408Zheng D Y, Pang X Q, Jiang F J, et al. 2020. Characteristics and physical simulation of the Upper Paleozoic tight gas accumulation in Linxing area, Ordos Basin[J]. Oil and Gas Geology, 41(4): 744-754 (in Chinese). doi: 10.11743/ogg20200408 [45] Zong Z Y, Ji L X. 2021. Model parameterization and amplitude variation with angle and azimuthal inversion in orthotropic media[J]. Geophysics, 86(1): R1-R14. [46] Zou C N, Zhai G M, Zhang G Y, et al. 2015. Formation, distribution, potential and prediction of global conventional and unconventional hydrocarbon resources[J]. Petroleum Exploration and Development, 42 (1): 14-28. doi: 10.1016/S1876-3804(15)60002-7 -