Seismic velocity is important to migration of seismic data, interpretation of lithology and lithofacies as well as prediction of reservoir. The information of shear wave velocity is required to reduce the uncertainty ...Seismic velocity is important to migration of seismic data, interpretation of lithology and lithofacies as well as prediction of reservoir. The information of shear wave velocity is required to reduce the uncertainty for discriminating lithology, identifying fluid type in porous material and calculating gas saturation in reservoir prediction. Based on Zoeppritz equations, a numeral and scanning method was proposed in this paper. Shear wave velocity can be calculated with prestack converted wave data. The effects were demonstrated by inversion of theoretical and real seismic data.展开更多
Accurately estimated interval attenuation(1/Q)values have several applications,such as in quantitative interpretation and seismic resolution enhancement.Although Q values can be estimated by measuring the spectral rat...Accurately estimated interval attenuation(1/Q)values have several applications,such as in quantitative interpretation and seismic resolution enhancement.Although Q values can be estimated by measuring the spectral ratio between seismic reflections from a target and a reference reflector,the results are influenced by factors such as overburden inhomogeneities.Here,we quantitatively analyze the overburden influence on interval Q estimations using the spectral ratio method,time-space domain prestack Q inversion(PSQI),andτ-p domain PSQI.We compare these three methods using a synthetic dataset and a field dataset acquired onshore the Arabian Peninsula.Synthetic seismic gathers are generated from a three-layer model with a low-Q inclusion in the first layer to mimic overburden inhomogeneity.The fi eld data are preconditioned image gathers from a producing oil fi eld.The synthetic data test shows that the small low-Q body produces a considerable error in estimated Q values.The smallest error(i.e.,13.3%)is in theτ-p domain PSQI result.Theoretically,τ-p domain PSQI could obtain more accurate Q values when there are overburden infl uences because of the simultaneous inversion scheme and the application in theτ-p domain.The fi eld data application also illustrates that theτ-p domain PSQI produces reasonable interval Q values.Our measured Q values are also comparable with the Q values estimated from hydrocarbon saturated carbonate reservoirs.展开更多
Seismic Rock physics plays a bridge role between the rock moduli and physical properties of the hydrocarbon reservoirs.Prestack seismic inversion is an important method for the quantitative characterization of elastic...Seismic Rock physics plays a bridge role between the rock moduli and physical properties of the hydrocarbon reservoirs.Prestack seismic inversion is an important method for the quantitative characterization of elasticity,physical properties,lithology and fluid properties of subsurface reservoirs.In this paper,a high order approximation of rock physics model for clastic rocks is established and one seismic AVO reflection equation characterized by the high order approximation(Jacobian and Hessian matrix)of rock moduli is derived.Besides,the contribution of porosity,shale content and fluid saturation to AVO reflectivity is analyzed.The feasibility of the proposed AVO equation is discussed in the direct estimation of rock physical properties.On the basis of this,one probabilistic AVO inversion based on differential evolution-Markov chain Monte Carlo stochastic model is proposed on the premise that the model parameters obey Gaussian mixture probability prior model.The stochastic model has both the global optimization characteristics of the differential evolution algorithm and the uncertainty analysis ability of Markov chain Monte Carlo model.Through the cross parallel of multiple Markov chains,multiple stochastic solutions of the model parameters can be obtained simultaneously,and the posterior probability density distribution of the model parameters can be simulated effectively.The posterior mean is treated as the optimal solution of the model to be inverted.Besides,the variance and confidence interval are utilized to evaluate the uncertainties of the estimated results,so as to realize the simultaneous estimation of reservoir elasticity,physical properties,discrete lithofacies and dry rock skeleton.The validity of the proposed approach is verified by theoretical tests and one real application case in eastern China.展开更多
基金National 973 Key Basic Research Development Program (2005CB422104)SINOPEC's Scientific and Techno-logical Development Program(P05063)
文摘Seismic velocity is important to migration of seismic data, interpretation of lithology and lithofacies as well as prediction of reservoir. The information of shear wave velocity is required to reduce the uncertainty for discriminating lithology, identifying fluid type in porous material and calculating gas saturation in reservoir prediction. Based on Zoeppritz equations, a numeral and scanning method was proposed in this paper. Shear wave velocity can be calculated with prestack converted wave data. The effects were demonstrated by inversion of theoretical and real seismic data.
基金This work was carried out as part of a Ph.D.research at the University of Houston.We thank Saudi Aramco for funding the research and providing the seismic data.We thank Dr.Carl Reine from Sound QI for providing the PSQI code.The Center of Wave Phenomenon(CWP)Seismic Unix programs TRIMODEL and TRISEIS were used to generate the synthetic seismic data.We thank Dr.Hao Hu for his comments and the anonymous reviewers for their reviews and suggestions.
文摘Accurately estimated interval attenuation(1/Q)values have several applications,such as in quantitative interpretation and seismic resolution enhancement.Although Q values can be estimated by measuring the spectral ratio between seismic reflections from a target and a reference reflector,the results are influenced by factors such as overburden inhomogeneities.Here,we quantitatively analyze the overburden influence on interval Q estimations using the spectral ratio method,time-space domain prestack Q inversion(PSQI),andτ-p domain PSQI.We compare these three methods using a synthetic dataset and a field dataset acquired onshore the Arabian Peninsula.Synthetic seismic gathers are generated from a three-layer model with a low-Q inclusion in the first layer to mimic overburden inhomogeneity.The fi eld data are preconditioned image gathers from a producing oil fi eld.The synthetic data test shows that the small low-Q body produces a considerable error in estimated Q values.The smallest error(i.e.,13.3%)is in theτ-p domain PSQI result.Theoretically,τ-p domain PSQI could obtain more accurate Q values when there are overburden infl uences because of the simultaneous inversion scheme and the application in theτ-p domain.The fi eld data application also illustrates that theτ-p domain PSQI produces reasonable interval Q values.Our measured Q values are also comparable with the Q values estimated from hydrocarbon saturated carbonate reservoirs.
基金supported by the National Grand Project for Science and Technology(Grant Nos.2016ZX05024-004,2017ZX05009-001,2017ZX05036-005)the Science Foundation from SINOPEC Key Laboratory of Geophysics(Grant No.WTYJY-WX2019-0104)。
文摘Seismic Rock physics plays a bridge role between the rock moduli and physical properties of the hydrocarbon reservoirs.Prestack seismic inversion is an important method for the quantitative characterization of elasticity,physical properties,lithology and fluid properties of subsurface reservoirs.In this paper,a high order approximation of rock physics model for clastic rocks is established and one seismic AVO reflection equation characterized by the high order approximation(Jacobian and Hessian matrix)of rock moduli is derived.Besides,the contribution of porosity,shale content and fluid saturation to AVO reflectivity is analyzed.The feasibility of the proposed AVO equation is discussed in the direct estimation of rock physical properties.On the basis of this,one probabilistic AVO inversion based on differential evolution-Markov chain Monte Carlo stochastic model is proposed on the premise that the model parameters obey Gaussian mixture probability prior model.The stochastic model has both the global optimization characteristics of the differential evolution algorithm and the uncertainty analysis ability of Markov chain Monte Carlo model.Through the cross parallel of multiple Markov chains,multiple stochastic solutions of the model parameters can be obtained simultaneously,and the posterior probability density distribution of the model parameters can be simulated effectively.The posterior mean is treated as the optimal solution of the model to be inverted.Besides,the variance and confidence interval are utilized to evaluate the uncertainties of the estimated results,so as to realize the simultaneous estimation of reservoir elasticity,physical properties,discrete lithofacies and dry rock skeleton.The validity of the proposed approach is verified by theoretical tests and one real application case in eastern China.