Elastic Impedance Equation based on the Incident-angle Approximation and Inversion

2012 ◽  
Author(s):  
C. Li ◽  
X. Y. Yin ◽  
G. Z. Zhang
Keyword(s):  
Incident Angle ◽  
Elastic Impedance ◽  
And Inversion

Elastic impedance parameterization and inversion with Young’s modulus and Poisson’s ratio

Geophysics ◽  
2013 ◽  
Vol 78 (6) ◽  
pp. N35-N42 ◽  
Author(s):  
Zhaoyun Zong ◽  
Xingyao Yin ◽  
Guochen Wu
Keyword(s):  
Parameter Estimation ◽  
Young’S Modulus ◽  
Seismic Data ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Incident Angle ◽  
P Wave ◽  
Poisson's Ratio ◽  
Data Set ◽  
Elastic Impedance

Young’s modulus and Poisson’s ratio are related to quantitative reservoir properties such as porosity, rock strength, mineral and total organic carbon content, and they can be used to infer preferential drilling locations or sweet spots. Conventionally, they are computed and estimated with a rock physics law in terms of P-wave, S-wave impedances/velocities, and density which may be directly inverted with prestack seismic data. However, the density term imbedded in Young’s modulus is difficult to estimate because it is less sensitive to seismic-amplitude variations, and the indirect way can create more uncertainty for the estimation of Young’s modulus and Poisson’s ratio. This study combines the elastic impedance equation in terms of Young’s modulus and Poisson’s ratio and elastic impedance variation with incident angle inversion to produce a stable and direct way to estimate the Young’s modulus and Poisson’s ratio, with no need for density information from prestack seismic data. We initially derive a novel elastic impedance equation in terms of Young’s modulus and Poisson’s ratio. And then, to enhance the estimation stability, we develop the elastic impedance varying with incident angle inversion with damping singular value decomposition (EVA-DSVD) method to estimate the Young’s modulus and Poisson’s ratio. This method is implemented in a two-step inversion: Elastic impedance inversion and parameter estimation. The introduction of a model constraint and DSVD algorithm in parameter estimation renders the EVA-DSVD inversion more stable. Tests on synthetic data show that the Young’s modulus and Poisson’s ratio are still estimated reasonable with moderate noise. A test on a real data set shows that the estimated results are in good agreement with the results of well interpretation.

Prediction of deep-buried gas carbonate reservoir by combining prestack seismic-driven elastic properties with rock physics in Sichuan Basin, southwestern China

2014 ◽  
Vol 2 (4) ◽  
pp. T193-T204
Author(s):  
Jiqiang Ma ◽  
Jianhua Geng ◽  
Tonglou Guo
Keyword(s):  
Elastic Properties ◽  
Seismic Data ◽  
Sichuan Basin ◽  
Incident Angle ◽  
Rock Physics ◽  
Carbonate Reservoir ◽  
Southwestern China ◽  
Marine Carbonate ◽  
The Sichuan Basin ◽  
Elastic Impedance

The prediction of seismic reservoirs in marine carbonate areas in the Sichuan Basin, southwestern China, is very challenging because the target zone is deeply buried (more than 6 km), with multiphase tectonic movements, complex diagenesis, and low porosity, and the incident angle of the seismic data is finite. We developed reliable hydrocarbon indicators of a marine carbonate deposit based on prestack elastic impedance (EI) and well observations. Although the hydrocarbon indicators can be calculated from elastic parameters, the inversion for EI-driven elastic attributes is usually unstable. To constrain the inversion process, we discovered a new strategy to recover the elastic properties from EIs within a Bayesian framework (called Bayesian elastic parameter inversion from elastic impedance). We applied the strategy to a carbonate reef identified at the center of a study line based on the geologic context and the seismic reflection patterns. We then used rock-physics analyses to classify the lithologies and the reservoir at a well location. Rock-physics modeling quantified the hydrocarbon sensitivity of the elastic attributes. Fluid substitution was used to investigate the effects of pore fluids on the elastic properties. A comparison of two synthetic amplitude-versus-angle responses (for gas and brine saturation) with real seismic data showed that the reservoir was gas charged. Using well-based crossplot analyses, reliable direct hydrocarbon indicators can be constructed for a deeply buried gas reservoir and were effective for interpretation in an area of marine carbonates in the Sichuan Basin.

Fluid elastic impedance inversion based on the incident-angle approximation

2014 ◽  
Author(s):  
Chao Li* ◽  
Xingyao Yin ◽  
Guangzhi Zhang ◽  
Qian Liu
Keyword(s):  
Incident Angle ◽  
Impedance Inversion ◽  
Elastic Impedance

Eigenvalues and eigenvectors of linearized elastic inversion

Geophysics ◽  
1993 ◽  
Vol 58 (5) ◽  
pp. 670-679 ◽  
Author(s):  
Andrea de Nicolao ◽  
Giuseppe Drufuca ◽  
Fabio Rocca
Keyword(s):  
Incident Angle ◽  
Estimation Procedure ◽  
Eigenvalues And Eigenvectors ◽  
Uniform Background ◽  
Linearized Model ◽  
Value Decomposition ◽  
Elastic Inversion ◽  
And Inversion ◽  
General Estimation

Small contrasts in the parameters allow the linearization of elastic modeling and inversion. Although this assumption simplifies parameter estimation, it also impoverishes information: a linearized model, besides being an approximation, requires shrinking the data space to precritical angles. This work investigates the two basic questions regarding the type of information that can be retrieved and how to retrieve it. The method is the singular value decomposition of the transfer function between data and parameters. This tool allows a simple interpretation of the information contained in reflections, and it outlines a general estimation procedure. A medium characterized by a uniform background is considered; reflections are linearized according to the Born approximation. P-P reflections are analyzed. The simplicity of the model allows a theoretical study of the effects of velocity errors in the overburden. The analysis is performed for two different sets of elastic parameters. In both cases the conclusion is that only the estimate of one parameter can be accurate while the quality of the estimate of a second parameter critically depends upon the velocity uncertainty and the maximum incident angle; estimation of a third parameter is very difficult.

The Fine Structure of the Sheath of Volvox Carteri f. Weismannia

1977 ◽  
Vol 35 ◽  
pp. 346-347
Author(s):  
Regina Birchem
Keyword(s):  
Developmental Stages ◽  
Ruthenium Red ◽  
Sulfated Polysaccharides ◽  
Volvox Carteri ◽  
High Voltage Electron Microscopy ◽  
Ultrastructural Studies ◽  
Voltage Electron ◽  
Sheath Formation ◽  
And Inversion ◽  
Sheath Material

Spheroids of the green colonial alga Volvox consist of biflagellate Chlamydomonad-like cells embedded in a transparent sheath. The sheath, important as a substance through which metabolic materials, light, and the sexual inducer must pass to and from the cells, has been shown to have an ordered structure (1,2). It is composed of both protein and carbohydrate (3); studies of V. rousseletii indicate an outside layer of sulfated polysaccharides (4).Ultrastructural studies of the sheath material in developmental stages of V. carteri f. weismannia were undertaken employing variations in the standard fixation procedure, ruthenium red, diaminobenzidine, and high voltage electron microscopy. Sheath formation begins after the completion of cell division and inversion of the daughter spheroids. Golgi, rough ER, and plasma membrane are actively involved in phases of sheath synthesis (Fig. 1). Six layers of ultrastructurally differentiated sheath material have been identified.

Exsolution and inversion in pigeonite from the Whin Sill, Northern England

1978 ◽  
Vol 36 (1) ◽  
pp. 474-475
Author(s):  
P.P.K. Smith
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Homogeneous Nucleation ◽  
Silicate Mineral ◽  
Antiphase Boundaries ◽  
Two Phase ◽  
Primitive Form ◽  
The Core ◽  
Nucleation Mechanisms ◽  
And Inversion

Grains of pigeonite, a calcium-poor silicate mineral of the pyroxene group, from the Whin Sill dolerite have been ion-thinned and examined by TEM. The pigeonite is strongly zoned chemically from the composition Wo8En64FS28 in the core to Wo13En34FS53 at the rim. Two phase transformations have occurred during the cooling of this pigeonite:- exsolution of augite, a more calcic pyroxene, and inversion of the pigeonite from the high- temperature C face-centred form to the low-temperature primitive form, with the formation of antiphase boundaries (APB's). Different sequences of these exsolution and inversion reactions, together with different nucleation mechanisms of the augite, have created three distinct microstructures depending on the position in the grain.In the core of the grains small platelets of augite about 0.02μm thick have farmed parallel to the (001) plane (Fig. 1). These are thought to have exsolved by homogeneous nucleation. Subsequently the inversion of the pigeonite has led to the creation of APB's.

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