地学前缘 ›› 2020, Vol. 27 ›› Issue (4): 98-109.DOI: 10.13745/j.esf.sf.2020.4.26

• "第四届全国青年地质大会论文"专栏 • 上一篇    下一篇

薄互层干涉对叠前AVO属性的影响分析

陈珊1,2(), 陆蓉3, 刘力辉3, 徐兴友1,2, 刘卫彬1,2, 白静1,2   

  1. 1.中国地质调查局油气资源调查中心, 北京 100083
    2.中国地质调查局非常规油气工程技术中心, 北京 100083
    3.北京诺克斯达石油科技有限公司, 北京 100192
  • 收稿日期:2019-04-24 修回日期:2019-06-19 出版日期:2020-07-25 发布日期:2020-07-25
  • 作者简介:陈 珊(1983—),女,博士,工程师,主要从事地震资料解释、油气储层预测及页岩油资源调查工作。E-mail: chenshan_000@126.com
  • 基金资助:
    中国地质调查局项目“大兴安岭西缘中生界油气战略选区调查”(DD20160202);中国地质调查局项目“大兴安岭西缘中生界油气战略选区调查”(DD201901);“松辽盆地南部页岩油战略调查”(DD20190115)

Analysis of the influence of thin interbed interference on prestack AVO attributes

CHEN Shan1,2(), LU Rong3, LIU Lihui3, XU Xingyou1,2, LIU Weibin1,2, BAI Jing1,2   

  1. 1. Oil & Gas Survey, China Geological Survey, Beijing 100083, China
    2. Unconventional Oil and Gas Engineering Technology Center, China Geological Survey, Beijing 100083, China
    3. Beijing Rockstar Petroleum Technology Co. Ltd., Beijing 100192, China
  • Received:2019-04-24 Revised:2019-06-19 Online:2020-07-25 Published:2020-07-25

摘要:

常规AVO分析是以单一界面为前提,用来分析薄层的AVO响应特征存在误差。Brekhovski给出的层状传播矩阵方程考虑了层内波的反射和透射以及层厚等影响因素,更适合用于讨论薄互层的地震响应特征。对薄层进行Brekhovski正演,发现不同入射角下振幅与厚度关系不同,与叠后全叠加振幅相比,截距P属性和薄层厚度之间的线性关系更强,说明P属性比全叠加振幅更有利于薄层厚度预测。不同薄互层模型的Brekhovski正演结果表明:净厚度和泊松比是影响AVO曲线特征的两个主要因素,净厚度越小,泊松比对截距P和梯度G属性的影响越小;当泊松比一定时,净厚度和PG属性呈近似线性关系,P属性与净厚度关系更敏感,可用于薄互层净厚度预测。应用实例证明在薄互层区P属性用于砂地比预测效果比较好,叠后振幅和叠前反演的弹性阻抗预测的净砂岩厚度精度较差。

关键词: 薄互层, Brekhovski正演, AVO属性, 净厚度, 泊松比, 弹性阻抗

Abstract:

Conventional AVO analysis method based on single interface can result in errors in thin layer AVO response characteristics. The Brekhovski layered propagation matrix equation takes into account reflection and transmission of layer wave and thickness, therefore it is more suitable for discussing the seismic response characteristics of thin interbeds. We conducted Brekhovski forward modeling on thin layer and found different relationship between amplitude and thickness using different offsets. The results indicate that pitch attribute has stronger linear relationship with thickness comparing with post stack, full stack amplitude, and can be a good indicator for thin interbed thickness. In different thin interbed model tests by Brekhovski forward modeling, net thickness and Poisson's ratio are two main factors affecting AVO curve characters. Poisson's ratio has less influence on pitch and gradient attributes for small net thickness. While Poisson's ratio is constant, net thickness shows near linear relationship with pitch and gradient attributes, with pitch attribute more sensitive to net thickness, which means pitch attribute could be used for net thickness prediction. Testing results demonstrated that in thin interbed area, pitch attribute is promising for sandstone percentage prediction, whereas accuracy of net thickness prediction by poststack amplitude or prestack elastic impedance inversion is poor.

Key words: thin interbed, Brekhovski forward modeling, AVO attribute, net thickness, Poisson's ratio, elastic impedance

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