摘要
针对目前陆上勘探主要采集的纵波资料与日益增长的弹性多参数模型预测需求之间的矛盾,文中从经典弹性动力学中本构方程出发,通过将本构方程分解为胀缩与剪切张量,推导出弹性介质中的声—弹方程耦合模式波动方程。该方程可以完美匹配纵波资料,同时波形信息中同时存在纵、横波速度和密度响应,具备反演弹性多参数模型功能,基于此搭建了基于纵波资料弹性参数反射波旅行时反演理论框架。由于全波形反演的高度非线性,准确的初始速度建模尤为重要,文中引入反射波波形反演理论,通过沿波路径成像恢复背景模型中、低波数信息,提高成像准确度,同时避免周期性跳跃导致反演失败。为验证方法的适用性和有效性,通过均匀模型对比不同震源激发下的声-弹方程耦合模式波动方程与声波方程、弹性波方程波的传播特征,并给出辐射模式验证试验;然后利用Sigsbee 2A重采样模型验证了反演方法在背景速度模型恢复的有效性。
To solve the problem that the P⁃wave data collected from land explorationcannot meet the increasing demand for elastic multi⁃parameter model prediction,this paper proposes a new wave equation of the acoustic⁃elastic equation coupled mode in elastic media,which is derived by decomposing the constitutive equation in classical elastodynamics into dilatation and shear tensors.The equation can perfectly match P⁃wave data,and waveform information contains P⁃and S⁃wave velocity and density responses,which can be used to invert elas⁃tic multi⁃parameter models.Then,the paper establishes a theoretical framework for elastic reflection travel⁃time inversion based on P⁃wave data.Since full waveform inversion is a highly nonlinear method,accurate ini⁃tial velocity modeling is particularly important.Therefore,this paper introduces reflection waveform inversion to recover the middle⁃and low⁃wavenumber information in the background model by imaging along the wave path,which can improve imaging accuracy and avoid the inversion failure caused by periodic skipping.To verify the applicability and effectiveness of the proposed method,a homogeneous model is used to compare the wave propagation characteristics of the new equation,acoustic wave equations,and elastic wave equations un⁃der the excitation of different sources,and the verification test of radiation pattern is also carried out.Finally,the effectiveness of the inversion method in recovering the background velocity model is verified using a Sigsbee 2A resampling model.
作者
李青阳
李斐
曾亚丽
段沛然
任雄风
葛炳妤
LI Qingyang;LI Fei;Zeng Yali;DUAN Peiran;REN Xiongfeng;GE Bingyu(Research Institute of Exploration and Development,Changqing Oilfield Company,PetroChina,Xi’an,Shaanxi 710018,China;National Engineering Laboratory for Low Permeability Oil&Gas Field Exploration and Development,Xi’an Shaanxi 710018,China)
出处
《石油地球物理勘探》
北大核心
2025年第2期402-409,共8页
Oil Geophysical Prospecting
基金
中石油长庆分公司科技专项“鄂尔多斯盆地页岩油勘探开发理论与关键技术研究”(2021DJ1806)与“陆相页岩油地球物理建模关键技术研究”(2023ZZ15YJ02)联合资助
关键词
反射波旅行时反演
纵波资料
弹性参数
声-弹方程耦合模式
速度建模
reflection travel⁃time inversion
P⁃wave data
elastic parameters
acoustic⁃elastic equation coupled mode
velocity modeling
