基于精确Zoeppritz方程的储层流体识别  

Reservoir fluid identification based on exact Zoeppritz equation

作　　者：丁富峰 吴少波 姚志纯 马玉龙 林鹏 汪泳吉 DING Fufeng;WU Shaobo;YAO Zhichun;MA Yulong;LIN Peng;WANG Yongji(School of Earth Sciences and Engineering of Xi’an Shiyou University,Xi’an,Shaanxi 710065,China;Exploration Division,PetroChina Changqing Oilfield Company,Xi’an,Shaanxi 710016,China;The Fourth Gas Production Plant,PetroChina Changqing Oilfield Company,Xi’an,Shaanxi 710016,China)

机构地区：[1]西安石油大学地球科学与工程学院,陕西西安710065 [2]中国石油长庆油田公司勘探事业部,陕西西安710016 [3]中国石油长庆油田公司第四采气厂,陕西西安710016

出　　处：《石油地球物理勘探》2024年第6期1353-1361,共9页Oil Geophysical Prospecting

基　　金：中石油集团重大科技专项“深地煤岩气成藏理论与效益开发技术研究”(2023ZZ18);中石油集团重大科技专项“致密砂岩气藏提高采收率关键技术研究”(2023ZZ25)联合资助。

摘　　要：流体识别对于储层的预测至关重要。在各向同性介质中,Russell流体因子的获取主要基于Zoeppritz方程近似公式的反演或者弹性参数间接计算,然而,基于近似公式的反演容易受到小入射角和低对比度等假设的干扰,影响反演精度。为此,提出了一种基于精确Zoeppritz方程的储层流体识别方法。首先,将精确Zoeppritz方程重新改写为包含Russell流体因子、泊松比和密度的形式;其次,在贝叶斯反演框架下构建了流体因子、泊松比和密度同时反演的目标函数;最后,通过迭代重加权最小二乘法(IRLS)对反演目标函数进行非线性求解。合成数据和实际工区数据测试结果均表明,所提方法能够有效识别流体。该方法可为储层流体预测、储层流体标定工作提供新的研究思路。Fluid identification is critical for reservoir prediction.However,in isotropic media,the Russell fluid factor is mainly obtained through the inversion of the approximate formula based on the Zoeppritz equation or the indirect calculation of elastic parameters.However,the inversion based on the approximate formula is prone to disturbance by assumptions such as a small angle of incidence and a low contrast,which affects the iversion accuracy.Therefore,this paper proposes the reservoir fluid identification method based on the exact Zoeppritz equation.Firstly,the exact Zoeppritz equation is rewritten to include the Russell fluid factor,Poisson’s ratio,and density.Then,the objective function for the simultaneous inversion of the fluid factor,Poisson’s ratio,and density is constructed under the Bayesian inversion framework.The iteratively reweighted least square(IRLS)method is used to solve the inversion objective function nonlinearly.The test results of synthetic data and actual work area data show that the proposed method can effectively identify fluids,which indicates that this method can provide new research ideas on reservoir fluid prediction and reservoir fluid calibration.

关 键 词：ZOEPPRITZ方程 流体因子 贝叶斯 叠前反演 

分 类 号：P631[天文地球—地质矿产勘探]