李金磊^1,2,,
尹成¹,
刘晓晶²,
陈超²,
王明飞²
1. 西南石油大学地球科学与技术学院, 成都 610500
2. 中国石油化工股份有限公司勘探分公司, 成都 610041

基金项目: 国家科技重大专项（2017ZX05036005）和中国石化基础研究项目（P18074-1）联合资助


详细信息

作者简介: 李金磊, 男, 1982年生, 研究员, 博士研究生, 主要从事地震资料综合解释、油气勘探方面的研究工作.E-mail:lijl.ktnf@sinopec.com

中图分类号: P631

收稿日期:2018-09-25
修回日期:2018-12-19
上线日期:2019-05-05

Robust pre-stack density inversion method for shale reservoir

LI JinLei^1,2,,
YIN Cheng¹,
LIU XiaoJing²,
CHEN Chao²,
WANG MingFei²
1. School of Geoscience and Technology, Southwest Petroleum University, Chengdu 610500, China
2. SINOPEC Exploration Company, Chengdu 610041, China


MSC: P631

--> Received Date: 25 September 2018
Revised Date: 19 December 2018
Available Online: 05 May 2019


摘要
摘要:密度参数是页岩储层评价的重要敏感参数，但通常认为准确获得密度信息难度较大.本文探索提出了一种稳定的基于弹性阻抗的叠前密度反演方法，以提高优质页岩的识别精度.首先，基于不同的参数化弹性阻抗方程开展密度敏感性分析，优选了敏感性最高的Aki-Richards近似弹性阻抗方程作为反演方程.然后，在弹性阻抗方程线性化的基础上，假设反演方程系数矩阵的逆存在，将密度（取对数）表示为多个角度弹性阻抗（取对数）的加权和，通过井旁道弹性阻抗反演结果与测井数据的回归求取加权系数，避免了常规反演方法对大型系数矩阵的求逆计算，从而提高了密度反演的稳定性，同时由于利用测井资料作为匹配目标，密度反演的精度也得到了提高.模型试算和涪陵页岩气田的实际资料应用实践均表明了该方法能够有效地提高密度反演的精度与稳定性.
关键词: 叠前密度反演/
弹性阻抗/
涪陵页岩气田/
敏感性/
稳定性/
精度

Abstract:Density is an important sensitive parameter in shale reservoir evaluation, but it is generally considered difficult to determine it accurately. This study proposes a robust pre-stack density inversion method based on elastic impedance to improve the accuracy of high-quality shale identification. Firstly, the density sensitivity of different parameterized elastic impedance equations are analyzed using a shale model, and the Aki-Richards approximate elastic impedance equation with the highest density sensitivity is chosen as the inversion equation. Then, the elastic impedance equation is linearized, and density parameter (logarithm) is expressed as a weighted sum of multiple angular elastic impedances (logarithm) assuming the inverse of the coefficient matrix exists. The weight coefficients are obtained by the regression of the inverted elastic impedance at wells location and density log data, which avoids calculating the inverse of the large-scale coefficient matrix, hence the stability of the density inversion is improved. Meanwhile, density well log is utilized as the matching target, so the accuracy of density inversion is also enhanced. The model test and the application to the Fuling shale gas field show that the proposed method can effectively improve the accuracy and stability of density inversion.
Key words:Pre-stack density inversion/
Elastic impedance/
Fuling shale gas field/
Sensitivity/
Stability/
Accuracy



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