Aug 30, 2017 the biotgassmann fluid substitution analysis at reservoir n01 reveals typical class iii amplitude variation with angle ava responses for lowimpedance hydrocarbon sands. Customisation to meet proprietary algorithms available. Reservoir characterization using fluid substitution and. Performing wellseismic tie, seismic inversion, biot gassmann fluid substitution, evaluating gas, oil, brine properties by using batzlewang calculator, avo modeling of fluid saturation changes. Then the swave velocity can be estimated using castagna and krief empirical relation before return it to the real condition using gassmann fluid substitution. Biotgassmann fluid substitution gassmann, 1951 and seismic amplitudevariationwithoffset avo mod eling was applied to the gasbearing sandstone reservoir encased by shale at well a to investigate the changes in the seismic signature with changing of reservoir pore fluid. The work of brown and korringa provides an explicit form for an anisotropic fluid substitution. Software presentation functionalities beicipfranlab. Poststack and prestack seismic inversion have been done over the area, utilizing the seismic data set along with the well log data to better understand the lithology and fluid distribution in the channel. The results are used to tie wells to seismic and hopefully gain an understanding of what properties of the formation are responsible for the observed seismic traces. This revision has been reported previously brown and korringa, 1975 in a limited context nonuniform mineralogy.
The biotgassmann fluid substitution model describing the seismic velocity. Gassmanns equation for fluid substitution petrowiki. Fluid substitution for thinly interbedded sandshale sequences using the mesh method. The lithology and fluid prediction maps extracted from vsand and.
The combined formulation is the biotgassmann theory2. Without leaving the petrel platform, petrel quantitative interpretation provides seamless seismic data conditioning, rock physics, fluid substitution, avoava analysis, and pre and poststack deterministic and stochastic inversion to. After presenting the field test site and the results of the seismic monitoring obtained during a drainfilling cycle of a basin, we show how we establish a 1d stratified viscoelastic model by combining active seismic measurements and biotgassmann fluid substitution poroelastic modelling. It is clear that the type of substitution event watergas, oilwater, oilgas and the mean value of porosity impact considerably the variance of v p2. This does not take into account diagenetic processes, such as cementation or dissolution, that vary with changing geochemical conditions in the pores. The combined formulation is the biotgassmann theory 2. Biotgassmanns equation for fluid substitution and equations described by batzlewang for fluid properties calculation are implemented as default petroelastic model algorithm. Biotgassmann fluid substitution signal simulation generation of a complete set of wavelets from analytic or userdefined characteristics.
Analysis of ballistic waves in seismic noise monitoring of. We designed the program as a seamless addon to the avo program. A gassmannconsistent rock physics template cseg recorder. Oct 22, 2016 biot gassmann fluid substitution gassmann, 1951 and seismic amplitudevariationwithoffset avo mod eling was applied to the gasbearing sandstone reservoir encased by shale at well a to investigate the changes in the seismic signature with changing of reservoir pore fluid at subsurface conditions. Gassmanns equation is one of the theories in fluid. Avo fluid inversion afi avo fluid inversion afi estimates uncertainty in fluid predictions from avo. Next, we will use biot gassmann substitution to create the equivalent wet model for the sand shown in figure 8, and again perform inversion.
Gassmanns fluid substitution formerly known as gassmanns equation is a lightweight software application whose purpose is to help you calculate and generate graphs with seismic velocity changes. Layerdependent biotgassmann analysis shows significant sensitivity of the pwave velocity and density to fluid substitution, indicating that presence of light saturating fluids clearly affects the elastic response of sands. Such study included crossplot analysis, biot gassmann fluid substitution, ava reflectivity modeling, and numerical simulation of synthetic gathers. This model assumes that the shear modulus is independent of the nature of the saturating fluid, as long as this latter. A tutorial on gassmanns fluid substitutions, by pierreolivier lys gassmanns equations are widely used in the industry to address the fluid substitution. The objective of this gassmann fluid substitution is to model the seismic properties seismic velocities. Petrel quantitative interpretation is a product development collaboration between schlumberger and ikon science. Consistent experimental investigation of the applicability of. Gassmanns equations provide a simple model to estimate fluid. Modelling the seismic responses of amangihydrocarbon field. The use of fluid substitution modeling for correction of mud. Apr 02, 2018 gassmann s fluid substitution formerly known as gassmann s equation is a lightweight software application whose purpose is to help you calculate and generate graphs with seismic velocity changes. In this study, we have analyzed the complexity of pore structure and its interaction with pore fluid.
The saturation of free gas in the pore space can be calculated by fluid substitution in the biotgassmann model gassmann, 1951. When performing fluid substitution on log data gassmanns 1951 model is the general tool of choice. The gassmann equation has been used for the calculation of the effects of fluid. Simulation of wave propagation in boreholes and radial profiling of formation elastic parameters. Improving the reliability of synthetic swave extraction using biotgassman fluid substitution, author. The avo effect represents a potentially powerful tool to discriminate between brine and hydrocarbon saturated reservoirs. Fluid substitution is an important part of seismic attribute work, because it provides the interpreter with a tool for modeling and quantifying the various fluid. Dry rock model prediction to be used in biotgassmann. Converting saturation data to seismic velocity biot gassmann biot gassman theory 8,9 is one of the approaches suggested to model fluid substitution. Software presentation easytracetm is an advanced 1d well data analysis.
Poststack and prestack seismic inversion have been done over the area, utilizing the seismic data set along with the well log data to better understand the lithology and fluid. Velocities and bulk densities resulting from the fluid substitution procedure depend on the initial estimate of elastic dryrock properties. Biotgassmanns equation for fluid substitution and equations described by batzlewang for fluid properties calculation are implemented as default petroelastic model algorithm supported seismic attributes are. The biotgassmann fluid substitution analysis at reservoir n01 reveals typical class iii amplitude variation with angle ava responses for lowimpedance hydrocarbon sands.
Gassmann fluid substitution is an essential tool of an amplitude analysis workbench. The result holds for both clean and shaly sandstones see fig. Sensitivity analysis of gassmanns fluid substitution. Fluid substitution and gassmann equation fluid substitution modeling is an important tool in reservoir characterization. Such study included crossplot analysis, biotgassmann fluid substitution, ava reflectivity modeling, and numerical simulation of synthetic gathers. You then use these maps to make a quantitative analysis of the probability of exploration success. Gassmanns fluid substitution crack and serial keys. Biotgassmann formulation for fluid substitution murphy, 1984 to estimate free gas saturations below the bottomsimulating reflector bsr. Whilst the equations and software implementations are straightforward, there are potential pitfalls. In seismic applications, it is normally assumed that gassmanns equation works best for seismic data at frequencies less than 100 hz mavko et al. This method relates the bulk modulus of a saturated rock k sat k d, pore fluid bulk modulus k fl and matrix bulk modulus k g by 10. Distinguishing gas bearing sandstone reservoirs within. Pdf application of biot gassman substitution method in.
An integrated analysis of petrophysics, crossplots and gassmann fluid substitution for characterization of fimkassar area, pakistan. Distinguishing gas bearing sandstone reservoirs within mixed. Integrated interpretation with gassmann fluid substitution. Accordingly, ava deterministic and stochastic inversions, which combine the advantages of. Fluid database with batzlewang estimation and reuss formula for mixture hashinshtrickman bound for petroelastic parameters s velocity estimation by greenbergcastagna method biotgassmann fluid substitution signal simulation generation of a complete set of wavelets from analytic or userdefined characteristics. Velocities and bulk densities resulting from the fluid substitution procedure depend on. Afi uses biotgassmann fluid substitution, monte carlo simulation and bayesian estimation to build fluid probability maps. Lithology and fluid prediction from simultaneous seismic. After empirically generating shear wave data from the available logs and verifying same by fluid substitution using the biotgassmann method, crossplots of elastic rock properties. Estimation of dryrock elastic moduli based on the simulation.
The fluid substitution method is the most commonly used technique using the. Fluid and lithology discrimination using rock physics. Gassmanns fluid substitution formerly known as gassmanns equation is a lightweight software application whose purpose is to help you calculate and. Reservoir characterization using fluid substitution and inversion. For all the sites, we generate a composite of the different logs associated with the sonic data and the presence of gas hydrate, including the. In the present study, an integrated approach of seismic, petrophysics, and gassmann fluid substitution has been. Are you interested in increasing the accuracy of your seismic. Improving the reliability of synthetic swave extraction using. Dry rock model prediction to be used in biotgassmanndomenico equations for computing acoustic properties of a carbonate rock. Gassmann fluid substitution requires that the porosity remain constant. The fluid substitution method is the most commonly used technique using the application of gassmanns equation. The optimum field development of area under exploration for hydrocarbons requires an integrated analysis of seismic and well log data. Regarding fluid substitution, biot gassmann model is the most popular model.
Despite the popularity of gassmanns equations and their incorporation within most software packages for. With water saturation, pwave velocity increases slightly, whereas swave velocity decreases slightly. Simulation of wave propagation in boreholes and radial. Pdf gassmanns fluid substitution and shear modulus variability. Gassmanns equation and fluidsaturation effects on seismic velocities. The basic use of the biotgassmann eq uations i s to. Several authors have noted the need for quality control qc of gassmann input parameters. Biotgassmann fluid substitution from 100% sw to deep sw this entire process was implemented as a workflow in petrosolutions software. Gassmann fluid substitution for seismic properties computation martemyevgassmann.
Equation 7 is one of the standard forms of the gassmann equation mavko et al. Biotgassman fluid substitution sudarmaji1, sismanto2, waluyo3and bambang soedijono4 1phd student of department of physics, gadjah mada university. The gassmann equation, first described by fritz gassmann, is used in geophysics and its relations are receiving more attention as seismic data are increasingly used for reservoir monitoring. T1 porosity concepts in gassmann fluid substitution. Figure 8a shows the well log curves for the wet sand on the left, with the smooth initial guess curves superimposed in red. Petrel quantitative interpretation schlumberger software. Biot gassmanns fluid substitution modeling and castagna equation were used to estimate shear wave velocity in the absence of acquired shear wave log. In this model, the expression for the bulk modulus, from which equation 8 is derived, is, with 10a. Practical gassmann fluid substitution in sandshale sequences. If the output from this process will be integrated with seismic data, the obtained elastic parameters must also be corrected for dispersion effects. The assumption being that, all other things being equal, different saturating fluids should not affect the porosity. Introduction well log data are commonly used to create synthetic seismograms that are then compared to real seismic data. A better option, yet more computationally intense, would be to use biot s frequencydependent equation to calculate the fluid substitution effects. The original and corrected vp, vs and density curves are shown in figure 2.
Effective porosity for gassmann fluid substitution fuyong yan, dehua han and qiuliang yao, rock physics lab, university of houston. The gassmann equation is the most common way of performing a fluid substitution model from one known parameter. Simulation of co2 injection into a baltic sea saline aquifer. I want to discuss how the work of biot and gassmann has shaped both hampsonrussells software and my own scientific development over the last 27 years. Synthetic seismograms were made from the original and. Afi avo fluid inversion estimates the uncertainty in the fluid predictions from avo. Jun 09, 2015 seismic data interpretation 127 vp vs. The purpose of this tutorial is to guide the reader through practical gassmann fluid substitution, and. The hydrodynamic characterization of the epikarst, the shallow part of the unsaturated zone in karstic systems, has always been challenging for geophysical methods. Fluid substitution is a process which provides a tool for fluid identification and quantification in a reservoir during the development phase. Sep 27, 2010 afi avo fluid inversion estimates the uncertainty in the fluid predictions from avo.
Sw 100% input logs output logs 1 fluid substitution the basic use of the biotgassmann equations is to substitute or replace the fluids in a set of target layers with another set of fluids. Lines abstract this paper draws together basic rock physics, avo, and seismic amplitude inversion to discuss how fluid discrimination. Avo fluid inversion afi avo fluid inversion afi estimates the uncertainty in the fluid predictions from avo. These maps help in quantitative analysis of the probability of exploration success. I will start with a discussion of gassmanns work, and how it. In our recent webinar learn how to increase the accuracy of your seismic interpretation we focused on how our logm advanced synthetics software, which is the industry leader for seismic synthetic generation, can help you increase the accuracy of your seismic interpretation. N2 in this study, porosity concepts in gassmanns fluid substitution model are examined and their implications for quantitative 4d seismic studies are discussed. In this case, fluid substitution equations were used to predict and to evaluate co2 injection in a specific area having well log information such as density and sonic. The fact that the gassmann equation falls out so naturally from a derivation of the dry and saturated pore space stiffnesses suggests that these physical quantities are fundamental to the way in which porosity. Generation of a complete set of wavelets from analytic or userdefined characteristics. The combined formulation is the biot gassmann theory2. In the present scheme of fluid substitution, v p1, v s1 and k gr contribute the most to the variance of v p2, in decreasing order of importance.
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