Enter the velocity information for angle calculation.Ībove are the A/B/C Attributes (intercept, gradient and curvature). Choose A/B/C (ThreeTerm Aki-Richards) for the Type of Analysis. In the Filter box at the top left hand corner, type the keyword Attribute. To start the Attribute Volume calculation: 1. This will be enough of an angle range where the A/B/C type of analysis can be used. In this example, there is about 45 degrees at the zone of interest.
The Color Data plot will appear showing the calculated angles. Choose either a Velocity table, a Single log or a SEG-Y volume.įor this example, 1. You need to provide the velocity information in order to calculate the maximum angle of the data. Under the Color Data Volume, select Incident Angle. To check the range of incident angles present in the data, click the or click the right mouse button. If you post the angle range, you can to determine whether to use the 2-term or the 3-term Aki-Richards equation. Load and display the gathers in the window. Workflow for Generating AVO Attributes in HRS9 This calculation is usually done with the more accurate Fatti equation. This attribute works well for Class 2 and 3 AVO responses (Ross, 2002).ĭerived Attributes Scaled S-wave Reflectivity : aA-bB The AVO difference (A-B) shows an increase in Shear Impedance at the top of the reservoir, which can be indicative of hydrocarbons. This attribute works well for a class 3 AVO response.ĭerived Attributes Scaled Poisson’s Ratio Change : aA+bB The AVO sum (A+B) shows a negative response at the top of the reservoir (a decrease in σ) and a positive response at the base (an increase in σ) indicating hydrocarbon-charged sands. The AVO product shows a positive response at the top and base of the clastic reservoir, which can indicate the presence of hydrocarbons. We normally display the AVO attribute volume in color. Based on the observation that a low impedance gas sand encased in shale will have larger negative A and B values than the associated non-pay reflectors (Castagna et al., 1998), A*B will have a positive, classical bright spots response at both top and base. Forming the product of A and B, we get:. This attribute works very well if you have a Class 3 anomaly (nomenclature of Rutherford and Williams 1989). We discuss the Fluid Factor attribute volume in the Fluid Factor Calculation knowledgebase document. AVO attributes extracted from well logs can be different from seismicallyextracted attributes because of the offset-dependent tuning and NMO stretch, selected angle range and the approximations in the equations.ĭerived Attributes The most popular AVO attributes are: (1) (2) (3) (4)ĪVO Product : A*B Scaled Poisson’s Ratio Change : aA+bB Scaled S-wave Reflectivity : aA-bB Fluid Factor. 
4.Ī/B (Two Term Aki-Richards) A/B/C (Three Term Aki-Richards) Rp/Rs (Two Term Fatti) Rp/Rs/Rd (Three Term Fatti)
#Hampson russell software software
3ĪVO Attribute Hampson-Russell Software has four types of analysis for AVO attributes. We will refer to this as the ABC equation. They separated the equation into three reflection terms, each weaker than the previous term: (1983) algebraically reformulated the Aki-Richards equation. Wiggins’ Form of the Aki-Richards Equation Wiggins et al.
The following slides will discuss AVO attribute theories and the workflow that the HRS-9 version of Hampson-Russell software uses. All of the seismic volumes in Hampson-Russell are, by default, saved under seismic.dir in the project directory. The AVO Attribute volumes are stored as SEG-Y files. AVO attributes are valuable when used in conjunction with other geophysical and geological inputs for reservoir modeling and characterization. 
The goal is to identify hydrocarbon anomalies in the reservoir.AVO attribute volumes allow you to measure a subset of the velocity-corrected gather to determine the zero-offset (intercept) and gradient components of the amplitude at a given time sample.AVO Attribute Volume Hampson-Russell’s Software HRS9 Houston, Texas 2011
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