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Application of the AVO gradient-based spectral bluing technique in the characterization of thin sandstones in moderately deep strata |
LIU Qing-Wen( ), LI Jian, QIN De-Wen |
Shanghai Branch of CNOOC Co. Ltd.,Shanghai 200030,China |
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Abstract The conventional spectral bluing technique is mainly utilized for post-stack seismic frequency expansion.It is applicable to the shallow strata where sandstones and mudstones can be effectively identified based on the wave impedance of logs.However,this technique has many limitations for the impedance aliasing zones of moderately deep strata.The amplitude versus offset (AVO) gradient reflects the change in the relative reflection coefficient with offset and is positively correlated with the rate of change in Poisson's ratio,which can distinguish between sandstones and mudstones in moderately deep strata.Through forward modeling,this study first proved the reliability and stability of the AVO gradient in identifying the top interface of sandstones in moderately deep strata according to the changes in parameters such as lithologic association,physical properties,and fluids.Furthermore,to improve the characterization precision of thin sandstone interbeds in moderately deep strata,this study proposed a AVO gradient-based spectral bluing for seismic frequency expansion.The model tests and practical applications show that the spectral bluing based on AVO gradient can directly identify the information on reservoir interfaces and simplify the multi-parameter lithology prediction method based on CRP gathers or partial angle stack data.Moreover,the new technique proposed in this study can effectively characterize the thin sandstones in deeply buried strata in the XH sag and provides a reference for high-resolution seismic processing of moderately deep strata.
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Received: 14 June 2022
Published: 27 April 2023
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AVO characteristic curves of four types of sandstone
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| 纵波速度/ (m·s-1) | 横波速度/ (m·s-1) | 密度/ (g·cm-3) | 纵波阻抗/ (g·cm-3·m·s-1) | Ⅰ类砂岩 | 5300 | 3050 | 2.55 | 13515 | Ⅱ类a型砂岩 | 4700 | 2800 | 2.49 | 11703 | Ⅱ类b型砂岩 | 4300 | 2610 | 2.47 | 10621 | 三类砂岩 | 3850 | 2600 | 2.40 | 9240 | 上覆介质 | 4150 | 2220 | 2.65 | 10997.5 |
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Sandstone’s elastic parameters of four AVO types
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Eleven types of lithological association in the target area
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岩相 | 纵波速度/(m·s-1) | 横波速度/(m·s-1) | 密度/(g·cm-3) | 纵波阻抗/(m·s-1·g·cm-3) | Vp/Vs | 泥岩 | 3920 | 2130 | 2.64 | 10349 | 1.84 | 煤层 | 3100 | 1615 | 1.94 | 6014 | 1.92 | 气层 | 4000 | 2469 | 2.40 | 9600 | 1.62 | 水层 | 4140 | 2437 | 2.42 | 10018 | 1.70 |
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Elastic parameters of different lithology in the target area
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Forward modeling of different lithological associations in gas case a—normal post-stack seismic;b—AVO gradient
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Forward modeling of different lithological associations in water case a—normal post-stack seismic;b—AVO gradient
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Forward modeling based on reservoir porosity change a—normal post-stack seismic change of different porosity;b—AVO gradient change of different porosity
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Analysis of pre-stack AVO gradient spectral bluing for well A-1 a—raw AVO gradient;b—90°phase shift of raw AVO gradient;c—spectral bluing AVO gradient;d—90°phase shift of spectral bluing AVO gradient
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P8 sandstone distribution of well A-1 and A-1S
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Normal post-stack seismic(a) and AVO gradient(b) through exploration wells
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Process of spectrum bluing operator calculation a—calculation of well-log’s reflection spectrum;b—calculation of AVO gradient spectrum;c—calculation of bluing operator;d—bluing operator in the time domain
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AVO gradient section based on spectral bluing technique through exploration wells
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Lithology prediction comparison before(a) and after(b) AVO gradient spectral bluing
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[1] |
李庆忠. 走向精确勘探的道路——高分辨率地震勘探系统工程剖析[M]. 北京: 石油工业出版社, 1994.
|
[1] |
Li Q Z. The way to obtain a better resolution in seismic prospecting:A systematical analysis of high resolution seismic exploration[M]. Beijing: Petroleum Industry Press, 1994.
|
[2] |
刁瑞. 提高地震分辨率处理效果定量评价方法研究[J]. 物探与化探, 2020, 44(2):381-387.
|
[2] |
Diao R. The quantitative evaluation method of seismic high resolution processing effect[J]. Geophysical and Geochemical Exploration, 2020, 44(2):381-387.
|
[3] |
陈传仁, 周熙蘘. 小波谱白化方法提高地震资料的分辨率[J]. 石油地球物理勘探, 2000, 35(6):703-709.
|
[3] |
Chen C R, Zhou X X. Improving resolution of seismic data using wavelet spectrum whitening[J]. OGP, 2000, 35(6):703-709.
|
[4] |
孙学凯, 孙赞东, 谢会文, 等. 非稳态地震稀疏反褶积[J]. 石油地球物理勘探, 2015, 50(2):260-266.
|
[4] |
Sun X K, Sun Z D, Xie H W, et al. A nonstationary perspective on sparse deconvolution[J]. OGP, 2015, 50(2):260-266.
|
[5] |
邓儒炳, 阎建国, 陈琪, 等. 一种基于连续补偿函数的时变增益限反Q滤波方法[J]. 物探与化探, 2021, 45(3):702-711.
|
[5] |
Deng R B, Yan J G, Chen Q, et al. A new time-varying gain limits inverse Q filtering with the continuous compensation function[J]. Geophysical and Geochemical Exploration, 2021, 45(3):702-711.
|
[6] |
Braga I L S, Moraes F S. High resolution gathers by inverse Q filtering in the wavelet domain[J]. Geophysics, 2013, 78(2):53-61.
|
[7] |
徐倩茹, 孙成禹, 乔志浩, 等. 基于Gabor变换的地震资料高分辨率处理方法研究[J]. 断块油气田, 2016, 23(4):460-464.
|
[7] |
Xu Q R, Sun C Y, Qiao Z H, et al. High-resolution processing method of seismic data based on Gabor transform[J]. Fault-Block Oil & Gas Field, 2016, 23(4):460-464.
|
[8] |
Blache-Fraser G. Increasing seismic resolution using spectral blueing and colored inversion:Cannonball field,Trinidad[C]// SEG Technical Program Expanded Abstracts, 2004, 23:2586.
|
[9] |
Neep J P. Time-variant colored inversion and spectral blueing[C]// Eage Conference & Exhibition Incorporating Spe Europec, 2014.
|
[10] |
杨瑞召, 赵争光, 马彦龙, 等. 利用谱蓝化和有色反演分辨薄煤层[J]. 天然气地球科学, 2013, 24(1):156-161.
|
[10] |
Yang R Z, Zhao Z G, Ma Y L, et al. Thin coal bed resolution by using seismic spectral blueing and colored inversion[J]. Nature Gas Geoscience, 2013, 24(1):156-161.
|
[11] |
陈文雄. 渤海西南部新近系超薄储层定量预测技术研究与应用[J]. 地球物理学进展, 2019, 34(2):694-701.
|
[11] |
Chen W X. Research and application of quantitative prediction technique for ultrathin reservoir in the neogene of southwestern Bohai sea[J]. Progress in Geophysics, 2019, 34(2):694-701.
|
[12] |
杨培杰. 复数域约束最小二乘拓频[J]. 石油地球物理勘探, 2021, 56(6):1244-1253.
|
[12] |
Yang P J. Constrained complex-domain least-squares spectrum blueing[J]. OGP, 2021, 56(6):1244-1253.
|
[13] |
Kazemeini S H, Can Y, Juhlin C, et al. Enhancing seismic data resolution using the prestack blueing technique:An example from the Ketzin CO2 injection site,Germany[J]. Geophysics, 2010, 75(6):101-110.
|
[14] |
李贤兵, 赵俊杰, 晋剑利, 等. 叠前谱蓝化提频技术在乍得Baob油田储层预测中的应用[J]. 石油地球物理勘探, 2020, 55(6):1343-1348.
|
[14] |
Li X B, Zhao J J, Jin J L, et al. Pre-stack spectrum blueing frequency increasing technique:A case study on reservoir prediction in Chad Baob Oilfield[J]. OGP, 2020, 55(6):1343-1348.
|
[15] |
Shuey R T. A simplification of Zoeppritz equations[J]. Geophysics, 1985, 50(9):609-614.
|
[16] |
Rutherford S R, Williams R H. Amplitude-versus-offset variations in gas sands[J]. Geophysics, 1989, 54(6):680-688.
|
[17] |
Castagna J P, Swan H W, Foster D J. Framework for AVO gradient and intercept interpretation[J]. Geophysics, 1998, 63(3):948-956.
|
[18] |
王迪, 张益明, 刘志斌, 等. AVO定量解释模板在LX地区致密气“甜点”预测中的应用[J]. 石油物探, 2020, 59(6):936-948.
|
[18] |
Wang D, Zhang Y M, Liu Z B, et al. Application of an AVO template to identify sweet spots in a tight sandstone reservoir in the LX area[J]. Geophysical Prospecting for Petroleum, 2022, 59(6):936-948.
|
[19] |
付琛, 廖键, 陈殿远, 等. 根据AVO相对变化识别流体的新方法[J]. 中国海上油气, 2021, 33(5):62-72.
|
[19] |
Fu C, Liao J, Chen D Y, et al. A new method for fluid identification based on relative changes in AVO[J]. China Offshore Oil and Gas, 2021, 33(5):62-72.
|
[20] |
刘力辉, 李建海, 杨晓, 等. 叠前AVO属性的地震岩性学探索与实践研究[J]. 石油物探, 2013, 52(3):247-252.
|
[20] |
Liu L H, Li J H, Yang X, et al. Exploration and practical study of pre-stack AVO property on seismic lithology[J]. Geophysical Prospecting for Petroleum, 2013, 52(3):247-252.
|
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