﻿ 叠前道集优化处理技术及其应用
 西南石油大学学报(自然科学版)  2017, Vol. 39 Issue (6): 55-62

"油气藏地质及开发工程"国家重点实验室 成都理工大学, 四川 成都 610059

Prestack Gather Optimization Technique and Application
XIONG Xiaojun , JIAN Shikai, LI Xiang, LIU Yang
State Key Laboratory of Oil & Gas Reservoir Geology and Exploitation, Chengdu University of Technology, Chengdu, Sichuan 610059, China
Abstract: This research presents an optimization technique involving the combination of prestack gather "noise suppression-equalization-reduction" with the improvement of the AVO (Amplitude variation with offset) analysis accuracy as the starting point. First, the characteristics of the effective and interference waves of the target formation of the prestack gather were analyzed; next, random noise from the target formation was removed using a fourth-order polynomial fit; then, the phase-axis target formation gathers were equalized using non-surface-consistent residual static correction. Finally, the effective incidence angle selection range for the target formation was optimized to reduce big-offset, stretched or distorted gathers. The practical application in some areas of the Bohai Sea shows that the signal-to-noise ratio between the optimized gathers and stacked profile improved significantly. Moreover, the AVO-curve characteristics of the target formation became more apparent and the obtained AVO-characteristics prediction results conformed more closely with the actual drilling conditions.
Key words: prestack gather     optimization     layer flattening     stacked profile     AVO analysis

1 叠前道集优化处理技术 1.1 叠前道集分析

 图1 叠前道集 Fig. 1 Pre-stack gathers

1.2 叠前道集优化处理 1.2.1 道集去噪处理方法

(1) 基于AVO曲线拟合，通过四阶多项式拟合叠前某个道集中某一时刻的道集数据采样点，得到拟合曲线；

(2) 选择初始参数，将拟合曲线上下移动，对比同一时刻的道集数据采样点值，将上下移动值之外的值去除，用拟合值代替(见图 2)；

 图2 拟合去噪示意图 Fig. 2 Schematic diagram of fitting to noise

(3) 检验拟合的AVO曲线，是否与正演道集的AVO曲线趋势一致；

(4) 调整参数值大小，重复步骤(2)和步骤(3)，输出去噪后道集。

1.2.2 道集拉平处理方法

(1) 将一定角度或偏移距内道集进行叠加作为初始道$\vec{x}$

(2) 在一定时窗(T)内，分别计算各道$\vec{y_{J}}$与初始道$\vec{x}$的相关系数$r_j$

 ${{r}_{j}}=\dfrac{\sum\nolimits_{i=1}^{n}{({{x}_{i}}-\bar{x})({{y}_{i}}-\bar{y})}}{\sqrt{\sum\nolimits_{i=1}^{n}{{{({{x}_{i}}-\bar{x})}^{2}}*\sum\nolimits_{i=1}^{n}{{{({{y}_{i}}-\bar{y})}^{2}}}}}}$ (1)

(3) 选择相关系数最大的一道(k)作为模型道；

(4) 从k道开始，依次在指定可移动时窗(t)范围内(即T-tT+t)，以时窗T滑动求取其与相邻道的相关系数；

(5) 将相关系数最大的滑动数作为当前的剩余时差，在指定时间段(t)内，各道减去剩余时差之后，输出拉平道集。

 图3 去噪拉平前后叠前道集对比 Fig. 3 Before and after flattened and denoised comparison of pre-stack gathers
1.2.3 道集切除处理方法

 图4 切除前后叠前道集对比 Fig. 4 Before and after removed comparison of pre-stack gathers
2 应用效果

2.1 目的层段AVO曲线对比

 图5 优化前后AVO曲线对比 Fig. 5 Before and after optimization processing comparison of AVO curves
2.2 叠加剖面对比

 图6 优化前后叠加剖面对比 Fig. 6 Before and after optimization processing comparison of superposition profile
2.3 AVO属性平面对比

 图7 PG属性对比 Fig. 7 Comparison of PG properties

3 结论

(1) 常规处理后的叠前道集若直接用于AVO分析，其结果常不能满足要求。因此，提出了一种针对叠前道集的“去噪$\rightarrow$拉平$\rightarrow$切除”组合的优化处理技术。

(2) 针对工区叠前道集存在的问题，先采用多项式拟合去噪方法消除目的层段的随机噪声，再采用非地表一致性剩余静校正方法对目的层段的道集同相轴进行拉平处理，最后，优选目的层段的有效入射角度范围对大偏移距拉伸畸变的道集进行切除，从而得到品质较好的道集资料。

(3) 优化处理有助于提高AVO计算精度，也反映了优化处理及各种方法有机组合的重要性，比仅使用单一方法效果更佳，同时验证了“去噪$\rightarrow$拉平$\rightarrow$切除”组合优化处理技术的有效性。

 [1] 贾承造, 赵文智, 邹才能, 等. 岩性地层油气藏地质理论与勘探技术[M]. 北京: 石油工业出版社, 2008. JIA Chengzao, ZHAO Wenzhi, ZOU Caineng, et al. Geological theory and exploration technology of lithologic stratigraphic oil and gas reservoir[M]. Beijing: Petroleum Industry Press, 2008. [2] 邹贤军. JSB地区叠前反演道集优化处理[J]. 内蒙古石油化工, 2015(7): 32–35. ZOU Xianjun. Gather conditioning for prestack inversion in JSB area[J]. Inner Mongolia Petrochemical Industry, 2015(7): 32–35. [3] 鲍熙杰. 叠前AVA同时反演的道集优化处理及应用效果[J]. 断块油气田, 2013, 20(3): 283–285. BAO Xijie. Gather optimal processing and application effect of prestack AVA instantaneous inversion[J]. FaultBlock Oil & Gas Field, 2013, 20(3): 283–285. doi: 10.6056/dkyqt201303003 [4] 张津海, 张远银, 孙赞东. 道集品质对叠前AVO/AVA同时反演的影响[J]. 石油地球物理勘探, 2012, 47(1): 68–73. ZHANG Jinhai, ZHANG Yuanyin, SUN Zandong. The effects of seismic data conditioning on pre-stack AVO/AVA simultaneous inversion[J]. Oil Geophysical Prospecting, 2012, 47(1): 68–73. [5] 熊定钰, 钱忠平, 赵波. 拟合AVO属性反演[J]. 石油地球物理勘探, 2005, 40(6): 646–651. XIONG Dingyu, QIAN Zhongping, ZHAO Bo. Inversion of fitted AVO attributes[J]. Oil Geophysical Prospecting, 2005, 40(6): 646–651. doi: 10.13810/j.cnki.issn.1000-7210.2005.06.007 [6] 张雅君, 侯斌, 陈岭. 叠前地震反演道集数据的预处理[J]. 复杂油气藏, 2014, 7(1): 35–37. ZHANG Yajun, HOU Bin, CHEN Ling. The gather data preprocessing of prestack seismic inversion[J]. Complex Hydrocarbon Reservoirs, 2014, 7(1): 35–37. doi: 10.3969/j.issn.1674-4667.2014.01.012 [7] 吴常玉, 王棣, 王立歆, 等. 叠前预处理技术[J]. 石油地球物理勘探, 2007, 42(1): 34–37. WU Changyu, WANG Di, WANG Lixin, et al. Prestack preprocessing technology[J]. Oil Geophysical Prospecting, 2007, 42(1): 34–37. doi: 10.13810/j.cnki.issn.10007210.2007.01.007 [8] 程玉坤, 冉建斌, 肖伟. 基于CRP道集的叠前处理技术及应用[J]. 勘探地球物理学进展, 2008, 31(1): 38–43. CHENG Yukun, RAN Jianbin, XIAO Wei. CRP gather based prestack data processing and its application[J]. Progress in Exploration Geophysics, 2008, 31(1): 38–43. [9] 刘素芹, 何旭莉, 何潮观, 等. 叠前深度偏移及应用研究[J]. 西南石油大学学报(自然科学版), 2009, 31(4): 35–37. LIU Suqin, HE Xuli, HE Chaoguan, et al. Study on prestack depth migration and the application[J]. Journal of Southwest Petroleum University (Science & Technology Edition), 2009, 31(4): 35–37. doi: 10.3863/j.issn.1674-5086.2009.04.007 [10] 张征, 狄帮让, 胡英, 等. CRP道集叠前精细处理技术应用[J]. 科技导报, 2012, 30(27): 35–40. ZHANG Zheng, DI Bangrang, HU Ying, et al. Application of pre-stack detailed process technique on CRP traces gather[J]. Science & Technology Review, 2012, 30(27): 35–40. doi: 10.3981/j.issn.1000-7857.2012.27.004 [11] 许自龙, 孟繁举, 唐勇, 等. 叠前反演数据优化处理技术[J]. 石油物探, 2014, 53(4): 404–411. XU Zilong, MENG Fanju, TANG Yong, et al. Seismic data optimization processing techniques for pre-stack inversion[J]. Geophysical Prospecting for Petroleum, 2014, 53(4): 404–411. doi: 10.3969/j.issn.1000-1441.2014.04.005 [12] 许璐, 刘志成, 王小青, 等. 基于结构中值滤波的CRP道集优化处理技术[J]. 地球物理学进展, 2015, 30(4): 1804–1810. XU Lu, LIU Zhicheng, WANG Xiaoqing, et al. Optimization technology based on structure median filter for CRP gathers[J]. Progress in Geophysics, 2015, 30(4): 1804–1810. doi: 10.6038/pg20150438 [13] 周鹏, 张益明, 刘志斌, 等. 地震道集优化方法及应用[J]. 石油地球物理勘探, 2016, 51(2): 232–237. ZHOU Peng, ZHANG Yiming, LIU Zhibin, et al. Seismic gather optimization[J]. Oil Geophysical Prospecting, 2016, 51(2): 232–237. [14] HINKLEY D, BEAR G W, DAWSON C. Prestack gather flattening for AVO[C]//SEG Technical Program Expanded Abstracts. 1999:271-273. doi:10.1190/1.1839719 [15] CANNING A. Some practical aspects of amplitude recovery before AVO and inversion[C]//SEG Technical Program Expanded Abstracts. 2010:393-397. doi:10.1190/1.3513672 [16] 刘力辉, 杨晓, 丁燕, 等. 基于岩性预测的CRP道集优化处理[J]. 石油物探, 2013, 52(5): 483–488. LIU Lihui, YANG Xiao, DING Yan, et al. CRP Gather optimization processing based on lithological prediction[J]. Geophysical Prospecting for Petroleum, 2013, 52(5): 483–488. doi: 10.3969/j.issn.1000-1441.2013.05.006 [17] 应明雄, 陈殿远, 刘建英, 等. 琼东南盆地LS区近道地震反射性质研究及意义[J]. 西南石油大学学报(自然科学版), 2016, 38(3): 46–54. YING Mingxiong, CHEN Dianyuan, LIU Jianying, et al. The nature and significanceof shortcut seismic reflection in the LS Area in Qiongdongnan Basin[J]. Journal of Southwest Petroleum University (Science & Technology Edition), 2016, 38(3): 46–54. doi: 10.11885/j.issn.16745086.2014.09.18.08 [18] 康冶, 于承业, 贾卧, 等. f-x域去噪方法研究[J]. 石油地球物理勘探, 2003, 38(2): 136–138. KANG Ye, YU Chengye, JIA Wo, et al. Study on noisesuppression method in f-x domain[J]. Oil Geophysical Prospecting, 2003, 38(2): 136–138. doi: 10.13810/j.cnki.issn.1000-7210.2003.02.006 [19] 钟伟, 杨宝俊, 张智. 多项式拟合技术在强噪声地震资料中的应用研究[J]. 地球物理学进展, 2006, 21(1): 184–189. ZHONG Wei, YANG Baojun, ZHANG Zhi. Research on application of polynomial fitting technique in highly noisy seismic data[J]. Progress in Geophysics, 2006, 21(1): 184–189. doi: 10.3969/j.issn.1004-2903.2006.01.027 [20] 陈辉, 贺玉山, 李录明, 等. 基于保幅延拓算子的共成像点道集敏感性分析[J]. 西南石油大学学报(自然科学版), 2010, 32(3): 35–40. CHEN Hui, HE Yushan, LI Luming, et al. Sensitivity analysis of common mage gathers based on preserved amplitude continuation operator[J]. Journal of Southwest Petroleum University (Science & Technology Edition), 2010, 32(3): 35–40. doi: 10.3863/j.issn.1674-5086.2010.03.007 [21] 荆雅莉. 叠前道集优化处理在浅层气预测中的应用[J]. 断块油气田, 2015, 22(6): 717–721. JING Yali. Application of prestack gather optimization preprocessing to prediction of shallow gas[J]. Fault-Block Oil & Gas Field, 2015, 22(6): 717–721. doi: 10.6056/dkyqt201506008 [22] 刘仕友, 周家雄, 孙万元, 等. 基于优化处理的宽角度道集密度反演及应用[J]. 物探与化探, 2016, 40(2): 417–422. LIU Shiyou, ZHOU Jiaxiong, SUN Wanyuan, et al. The density inversion based on optimized wide-angle gathers and its application[J]. Geophysical and Geochemical Exploration, 2016, 40(2): 417–422. doi: 10.11720/wtyht.2016.2.30 [23] 陈春燕, 晋达, 董秀伟. 叠前道集质量优化方法研究[J]. 中国石油和化工标准与质量, 2014(9): 63. CHEN Chunyan, JIN Da, DONG Xiuwei. Research about quality optimization method of pre-stack gathers[J]. China Petroleum and Chemical Standard and Quality, 2014(9): 63. [24] 骆璞, 王显, 姜传芳. AVO属性技术在含气砂岩储层预测中的应用[J]. 复杂油气藏, 2014, 7(4): 32–34, 56. LUO Pu, WANG Xian, JIANG Chuanfang. Application of AVO attribute technology in the prediction of gas-bearing sandstone[J]. Complex Hydrocarbon Reservoirs, 2014, 7(4): 32–34, 56. doi: 10.3969/j.issn.1674-4667.2014.04.008 [25] 陆基孟, 王永刚. 地震勘探原理[M]. 东营: 石油大学出版社, 2009. LU Jimeng, WANG Yonggang. Principle of seismic exploration[M]. Dongying: China University of Petroleum Press, 2009.