The parameter reconstruction of strong-scattering media is a challenge for conventional full waveform inversion(FWI).Direct envelope inversion(DEI)is an effective method for large-scale and strongscattering structures...The parameter reconstruction of strong-scattering media is a challenge for conventional full waveform inversion(FWI).Direct envelope inversion(DEI)is an effective method for large-scale and strongscattering structures imaging without the need of low-frequency seismic data.However,the current DEI methods are all based on the acoustic approximation.Whereas,in real cases,seismic records are the combined effects of the subsurface multi-parameters.Therefore,the study of DEI in elastic media is necessary for the accurate inversion of strong-scattering structures,such as salt domes.In this paper,we propose an elastic direct envelope inversion(EDEI)method based on wave mode decomposition.We define the objective function of EDEI using multi-component seismic data and derive its gradient formulation.To reduce the coupling effects of multi-parameters,we introduce the wave mode decomposition method into the gradient calculation of EDEI.The update of Vp is primarily the contributions of decomposed P-waves.Two approaches on Vs gradient calculation are proposed,i.e.using the petrophysical relation and wave mode decomposition method.Finally,we test the proposed method on a layered salt model and the SEG/EAGE salt model.The results show that the proposed EDEI method can reconstruct reliable large-scale Vp and Vs models of strong-scattering salt structures.The successive elastic FWI can obtain high-precision inversion results of the strong-scattering salt model.The proposed method also has a good anti-noise performance in the moderate noise level.展开更多
There are abundant igneous gas reservoirs in the South China Sea with significant value of research,and lithology classification,mineral analysis and porosity inversion are important links in reservoir evaluation.Howe...There are abundant igneous gas reservoirs in the South China Sea with significant value of research,and lithology classification,mineral analysis and porosity inversion are important links in reservoir evaluation.However,affected by the diverse lithology,complicated mineral and widespread alteration,conventional logging lithology classification and mineral inversion become considerably difficult.At the same time,owing to the limitation of the wireline log response equation,the quantity and accuracy of minerals can hardly meet the exploration requirements of igneous formations.To overcome those issues,this study takes the South China Sea as an example,and combines multi-scale data such as micro rock slices,petrophysical experiments,wireline log and element cutting log to establish a set of joint inversion methods for minerals and porosity of altered igneous rocks.Specifically,we define the lithology and mineral characteristics through core slices and mineral data,and establish an igneous multi-mineral volumetric model.Then we determine element cutting log correction method based on core element data,and combine wireline log and corrected element cutting log to perform the lithology classification and joint inversion of minerals and porosity.However,it is always difficult to determine the elemental eigenvalues of different minerals in inversion.This paper uses multiple linear regression methods to solve this problem.Finally,an integrated inversion technique for altered igneous formations was developed.The results show that the corrected element cutting log are in good agreement with the core element data,and the mineral and porosity results obtained from the joint inversion based on the wireline log and corrected element cutting log are also in good agreement with the core data from X-ray diffraction.The results demonstrate that the inversion technique is applicable and this study provides a new direction for the mineral inversion research of altered igneous formations.展开更多
With the objective of establishing the necessary conditions for 3D seismic data from mountainous areas in western China, we compared the application results of wave impedance technology in the lithology and exploratio...With the objective of establishing the necessary conditions for 3D seismic data from mountainous areas in western China, we compared the application results of wave impedance technology in the lithology and exploration of coal fields. First, we introduce principles and features of three kinds of inversion methods. i.e., Model-Based Inversion, Constrained Sparse Spike Inversion (CSSI) and Geology-Seismic Feature Inversion. Secondly, these inversion methods are contrasted in their application to 3D seismic data from some coalfields in western China. The main information provided by the research includes: improving the vertical resolution of coal deposit strata, inferring lateral variation of the lithology and predicting coal seams and their roof lithology. Finally, the comparison between the three methods shows that the model-based inversion has the higher resolution, while CSSI inversion has better waveform continuity. The geology-seismic feature inversion requires information from a large number of wells and many types of logging curves of good quality. All three methods can meet the requirements of seismic exploration for lithological exploration in coal fields.展开更多
广义有效介质极化理论(Generalized Effective Medium Theory for Induced Polarization,GEMTIP)提供了岩石物理参数与复电阻率(Complex Resistivity,CR)的频散关系,据此可基于观测到的激发极化(Induced Polarization,IP)数据反演岩矿...广义有效介质极化理论(Generalized Effective Medium Theory for Induced Polarization,GEMTIP)提供了岩石物理参数与复电阻率(Complex Resistivity,CR)的频散关系,据此可基于观测到的激发极化(Induced Polarization,IP)数据反演岩矿石的激电参数。然而,传统的反演方法在非线性优化问题上存在局部最小值、计算量大和对初始模型依赖度高等问题,且含噪数据反演结果不稳定。此外,当前的激电参数反演研究主要集中在微观岩石孔隙表征和电化学机制领域,基于宏观地球物理观测数据直接进行反演和解释的相关研究不足。为此,提出了一种基于U-Net深度学习网络的方法,利用该方法可基于GEMTIP三维地电模型的地面IP差分数据直接提取激电参数。该方法将多个频率下的差分观测磁场振幅和相位作为网络输入,将异常区域的零频电阻率、体积分数、充电率、时间常数及弛豫常数作为输出标签。通过合成GEMTIP三维地电模型的可控源电磁样本数据训练深度神经网络,得到能够准确预测地下异常区域激电参数分布的网络模型。对包含GEMTIP激电参数的综合模型测试了该网络模型,并将测试结果与传统的正则化共轭梯度(Regularized Conjugate Gradients,RCG)反演结果进行比较,表明U-Net网络反演在耗时、求解精度和抗噪声能力方面均更具优势,能够从地面观测到的IP数据中直接、准确地预测GEMTIP激电参数。最后,利用深度学习方法对亚利桑那州南部North Sliver Bell地区的辉铜矿实际勘测数据进行训练,成功预测了该地区地下辉铜矿富集层分布,并与传统反演方法获得的地质解释成果进行对比,进一步证明了本文方法在实际应用中的可靠性和有效性。该方法可用于矿物组成和储层孔隙空间分布的预测,有望在宏观地球物理反演解释中得到广泛应用。展开更多
基金financial support jointly provided by the National Key R&D Program of China under contract number 2019YFC0605503Cthe Major Projects during the 14th Five-year Plan period under contract number 2021QNLM020001+2 种基金the National Outstanding Youth Science Foundation under contract number 41922028the Funds for Creative Research Groups of China under contract number 41821002the Major Projects of CNPC under contract number ZD2019-183-003。
文摘The parameter reconstruction of strong-scattering media is a challenge for conventional full waveform inversion(FWI).Direct envelope inversion(DEI)is an effective method for large-scale and strongscattering structures imaging without the need of low-frequency seismic data.However,the current DEI methods are all based on the acoustic approximation.Whereas,in real cases,seismic records are the combined effects of the subsurface multi-parameters.Therefore,the study of DEI in elastic media is necessary for the accurate inversion of strong-scattering structures,such as salt domes.In this paper,we propose an elastic direct envelope inversion(EDEI)method based on wave mode decomposition.We define the objective function of EDEI using multi-component seismic data and derive its gradient formulation.To reduce the coupling effects of multi-parameters,we introduce the wave mode decomposition method into the gradient calculation of EDEI.The update of Vp is primarily the contributions of decomposed P-waves.Two approaches on Vs gradient calculation are proposed,i.e.using the petrophysical relation and wave mode decomposition method.Finally,we test the proposed method on a layered salt model and the SEG/EAGE salt model.The results show that the proposed EDEI method can reconstruct reliable large-scale Vp and Vs models of strong-scattering salt structures.The successive elastic FWI can obtain high-precision inversion results of the strong-scattering salt model.The proposed method also has a good anti-noise performance in the moderate noise level.
基金The project was supported by the National Natural Science Foundation of China(Grant No.42204122).
文摘There are abundant igneous gas reservoirs in the South China Sea with significant value of research,and lithology classification,mineral analysis and porosity inversion are important links in reservoir evaluation.However,affected by the diverse lithology,complicated mineral and widespread alteration,conventional logging lithology classification and mineral inversion become considerably difficult.At the same time,owing to the limitation of the wireline log response equation,the quantity and accuracy of minerals can hardly meet the exploration requirements of igneous formations.To overcome those issues,this study takes the South China Sea as an example,and combines multi-scale data such as micro rock slices,petrophysical experiments,wireline log and element cutting log to establish a set of joint inversion methods for minerals and porosity of altered igneous rocks.Specifically,we define the lithology and mineral characteristics through core slices and mineral data,and establish an igneous multi-mineral volumetric model.Then we determine element cutting log correction method based on core element data,and combine wireline log and corrected element cutting log to perform the lithology classification and joint inversion of minerals and porosity.However,it is always difficult to determine the elemental eigenvalues of different minerals in inversion.This paper uses multiple linear regression methods to solve this problem.Finally,an integrated inversion technique for altered igneous formations was developed.The results show that the corrected element cutting log are in good agreement with the core element data,and the mineral and porosity results obtained from the joint inversion based on the wireline log and corrected element cutting log are also in good agreement with the core data from X-ray diffraction.The results demonstrate that the inversion technique is applicable and this study provides a new direction for the mineral inversion research of altered igneous formations.
基金part of an ongoing project of the National Important Industry Technological Development Project (High Precision 3D Seismic Technology of Coal Resources of Western China)the financial support from the National Basic Research Program of China (No.2009CB 219603)the National Key Scientific and Technological Project of China (No.2008ZX05035-005-003HZ)
文摘With the objective of establishing the necessary conditions for 3D seismic data from mountainous areas in western China, we compared the application results of wave impedance technology in the lithology and exploration of coal fields. First, we introduce principles and features of three kinds of inversion methods. i.e., Model-Based Inversion, Constrained Sparse Spike Inversion (CSSI) and Geology-Seismic Feature Inversion. Secondly, these inversion methods are contrasted in their application to 3D seismic data from some coalfields in western China. The main information provided by the research includes: improving the vertical resolution of coal deposit strata, inferring lateral variation of the lithology and predicting coal seams and their roof lithology. Finally, the comparison between the three methods shows that the model-based inversion has the higher resolution, while CSSI inversion has better waveform continuity. The geology-seismic feature inversion requires information from a large number of wells and many types of logging curves of good quality. All three methods can meet the requirements of seismic exploration for lithological exploration in coal fields.
文摘广义有效介质极化理论(Generalized Effective Medium Theory for Induced Polarization,GEMTIP)提供了岩石物理参数与复电阻率(Complex Resistivity,CR)的频散关系,据此可基于观测到的激发极化(Induced Polarization,IP)数据反演岩矿石的激电参数。然而,传统的反演方法在非线性优化问题上存在局部最小值、计算量大和对初始模型依赖度高等问题,且含噪数据反演结果不稳定。此外,当前的激电参数反演研究主要集中在微观岩石孔隙表征和电化学机制领域,基于宏观地球物理观测数据直接进行反演和解释的相关研究不足。为此,提出了一种基于U-Net深度学习网络的方法,利用该方法可基于GEMTIP三维地电模型的地面IP差分数据直接提取激电参数。该方法将多个频率下的差分观测磁场振幅和相位作为网络输入,将异常区域的零频电阻率、体积分数、充电率、时间常数及弛豫常数作为输出标签。通过合成GEMTIP三维地电模型的可控源电磁样本数据训练深度神经网络,得到能够准确预测地下异常区域激电参数分布的网络模型。对包含GEMTIP激电参数的综合模型测试了该网络模型,并将测试结果与传统的正则化共轭梯度(Regularized Conjugate Gradients,RCG)反演结果进行比较,表明U-Net网络反演在耗时、求解精度和抗噪声能力方面均更具优势,能够从地面观测到的IP数据中直接、准确地预测GEMTIP激电参数。最后,利用深度学习方法对亚利桑那州南部North Sliver Bell地区的辉铜矿实际勘测数据进行训练,成功预测了该地区地下辉铜矿富集层分布,并与传统反演方法获得的地质解释成果进行对比,进一步证明了本文方法在实际应用中的可靠性和有效性。该方法可用于矿物组成和储层孔隙空间分布的预测,有望在宏观地球物理反演解释中得到广泛应用。
