Determination of physical properties of carbonate rocks from P-wave velocity

2008 ◽  
Vol 67 (2) ◽  
pp. 277-281 ◽  
Author(s):  
Sair Kahraman ◽  
Tekin Yeken
Keyword(s):  
Physical Properties ◽  
Wave Velocity ◽  
Carbonate Rocks ◽  
P Wave ◽  
P Wave Velocity

scholarly journals Determination of vp/vs on Bali Province: Case of Bali Earthquake March 22, 2017

2018 ◽  
Vol 19 (2) ◽  
pp. 73
Author(s):  
Febi Niswatul Auliyah ◽  
Komang Ngurah Suarbawa ◽  
Indira Indira
Keyword(s):  
Case Studies ◽  
Wave Velocity ◽  
P Wave ◽  
S Wave ◽  
Diagram Method ◽  
P Wave Velocity ◽  
Before And After ◽  
Earthquake Data

P-wave velocity and S-wave velocity have been investigated in the Bali Province by using earthquake case studies on March 22, 2017. The study was focused on finding out whether there were anomalies in the values of vp/vs before and after the earthquake. Earthquake data was obtained from the Meteorology, Climatology and Geophysics Agency (BMKG) Region III Denpasar, which consisted of the main earthquake on March 22, 2017 and earthquake data in August 2016 to May 2017. Data was processed using the wadati diagram method, obtained that the vp/vs on SRBI, IGBI, DNP and RTBI stations are shifted from 1.5062 to 1.8261. Before the earthquake occurred the anomaly of the value of vp/vs was found on the four stations, at the SRBI station at 10.35%, at the IGBI station at 16.16%, at DNP station at 12.27% and at RTBI station at 4.62%.

scholarly journals Semiglobal viscoacoustic full-waveform inversion

Geophysics ◽  
2019 ◽  
Vol 84 (2) ◽  
pp. R271-R293 ◽  
Author(s):  
Nuno V. da Silva ◽  
Gang Yao ◽  
Michael Warner
Keyword(s):  
Physical Properties ◽  
Wave Velocity ◽  
Seismic Data ◽  
Waveform Inversion ◽  
P Wave ◽  
Full Waveform Inversion ◽  
Data Set ◽  
Intrinsic Attenuation ◽  
Full Waveform ◽  
P Wave Velocity

Full-waveform inversion deals with estimating physical properties of the earth’s subsurface by matching simulated to recorded seismic data. Intrinsic attenuation in the medium leads to the dispersion of propagating waves and the absorption of energy — media with this type of rheology are not perfectly elastic. Accounting for that effect is necessary to simulate wave propagation in realistic geologic media, leading to the need to estimate intrinsic attenuation from the seismic data. That increases the complexity of the constitutive laws leading to additional issues related to the ill-posed nature of the inverse problem. In particular, the joint estimation of several physical properties increases the null space of the parameter space, leading to a larger domain of ambiguity and increasing the number of different models that can equally well explain the data. We have evaluated a method for the joint inversion of velocity and intrinsic attenuation using semiglobal inversion; this combines quantum particle-swarm optimization for the estimation of the intrinsic attenuation with nested gradient-descent iterations for the estimation of the P-wave velocity. This approach takes advantage of the fact that some physical properties, and in particular the intrinsic attenuation, can be represented using a reduced basis, substantially decreasing the dimension of the search space. We determine the feasibility of the method and its robustness to ambiguity with 2D synthetic examples. The 3D inversion of a field data set for a geologic medium with transversely isotropic anisotropy in velocity indicates the feasibility of the method for inverting large-scale real seismic data and improving the data fitting. The principal benefits of the semiglobal multiparameter inversion are the recovery of the intrinsic attenuation from the data and the recovery of the true undispersed infinite-frequency P-wave velocity, while mitigating ambiguity between the estimated parameters.

scholarly journals Optimization of Rock Physics Models by Combining the Differential Effective Medium (DEM) and Adaptive Batzle-Wang Methods in “R” Field, East Java

2019 ◽  
Vol 17 (2) ◽  
Author(s):  
M. Wahdanadi Haidar ◽  
Reza Wardhana ◽  
M. Iskan ◽  
M. Syamsu Rosid
Keyword(s):  
Elastic Modulus ◽  
Wave Velocity ◽  
Carbonate Rocks ◽  
Effective Medium ◽  
Carbonate Reservoir ◽  
P Wave ◽  
S Wave ◽  
P Wave Velocity ◽  
Reservoir Conditions ◽  
Pore Types

The pore systems in carbonate reservoirs are more complex than the pore systems in clastic rocks. There are three types of pores in carbonate rocks: interparticle pores, stiff pores and cracks. The complexity of the pore types can lead to changes in the P-wave velocity by up to 40%, and carbonate reservoir characterization becomes difficult when the S-wave velocity is estimated using the dominant interparticle pore type only. In addition, the geometry of the pores affects the permeability of the reservoir. Therefore, when modelling the elastic modulus of the rock it is important to take into account the complexity of the pore types in carbonate rocks. The Differential Effective Medium (DEM) is a method for modelling the elastic modulus of the rock that takes into account the heterogeneity in the types of pores in carbonate rocks by adding pore-type inclusions little by little into the host material until the required proportion of the material is reached. In addition, the model is optimized by calculating the bulk modulus of the fluid filler porous rock under reservoir conditions using the Adaptive Batzle-Wang method. Once a fluid model has been constructed under reservoir conditions, the model is entered as input for the P-wave velocity model, which is then used to estimate the velocity of the S-wave and the proportion of primary and secondary pore types in the rock. Changes in the characteristics of the P-wave which are sensitive to the presence of fluid lead to improvements in the accuracy of the P-wave model, so the estimated S-wave velocity and the calculated ratio of primary and secondary pores in the reservoir are more reliable.

scholarly journals Correlation of P-wave velocity with mechanical and physical properties of limestone with statistical analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hasan Arman
Keyword(s):  
Physical Properties ◽  
Wave Velocity ◽  
Point Load ◽  
P Wave ◽  
Unit Weight ◽  
Empirical Equations ◽  
Thin Sections ◽  
X Ray ◽  
P Wave Velocity ◽  
Mechanical And Physical Properties

AbstractThis study aims to investigate the correlation between the P-wave velocity (Vp) and the mechanical and the physical properties of the limestone; Vp tests were conducted on over 320 limestone samples. Moreover, the effects of the mineralogical, textural, and chemical composition of limestone were also studied through thin sections, scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray fluorescence (XRF). The relationships between the Vp and the uniaxial compressive strength (UCS), point load index (PLI(Is(50)), 2nd cycle of slake durability index (Id2), natural unit weight (γn), specific gravity (Gs(c)), water absorption by weight (WA), and porosity (n) were estimated using representative empirical equations. The empirical equations were validated by Student’s t test that has indicated the existence of strong relationships between the mechanical and physical properties of the intact limestone with Vp; the calculated t-values were higher than the t-critical value. Furthermore, the results of previously available studies were compared with the results of this study in terms of the generated equations for Vp values and the slope of a 1:1 line, which was used to appraise the predicted and measured values. This study demonstrates that the UCS, PLI(Is(50)), Id2, γn, Gs(c), WA, and n values of an intact limestone can be predicted by using Vp, which is fast, easy, economical and nondestructive test.

Determining P- and S-wave velocities and Q-values from single ultrasound transmission measurements performed on cylindrical rock samples: it’s possible, when…

2020 ◽  
Author(s):  
Marc S. Boxberg ◽  
Mandy Duda ◽  
Katrin Löer ◽  
Wolfgang Friederich ◽  
Jörg Renner
Keyword(s):  
Wave Velocity ◽  
P Wave ◽  
S Wave ◽  
Standard Material ◽  
Rock Samples ◽  
Intrinsic Attenuation ◽  
Finite Element Software ◽  
Wave Velocities ◽  
P Wave Velocity

<p>Determining elastic wave velocities and intrinsic attenuation of cylindrical rock samples by transmission of ultrasound signals appears to be a simple experimental task, which is performed routinely in a range of geoscientific and engineering applications requiring characterization of rocks in field and laboratory. P- and S-wave velocities are generally determined from first arrivals of signals excited by specifically designed transducers. A couple of methods exist for determining the intrinsic attenuation, most of them relying either on a comparison between the sample under investigation and a standard material or on investigating the same material for various geometries.</p><p>Of the three properties of interest, P-wave velocity is certainly the least challenging one to determine, but dispersion phenomena lead to complications with the consistent identification of frequency-dependent first breaks. The determination of S-wave velocities is even more hampered by converted waves interfering with the S-wave arrival. Attenuation estimates are generally subject to higher uncertainties than velocity measurements due to the high sensitivity of amplitudes to experimental procedures. The achievable accuracy of determining S-wave velocity and intrinsic attenuation using standard procedures thus appears to be limited.</p><p>We pursue the determination of velocity and attenuation of rock samples based on full waveform modeling and inversion. Assuming the rock sample to be homogeneous - an assumption also underlying standard analyses - we quantify P-wave velocity, S-wave velocity and intrinsic P- and S-wave attenuation from matching a single ultrasound trace with a synthetic one numerically modelled using the spectral finite-element software packages SPECFEM2D and SPECFEM3D. We find that enough information on both velocities is contained in the recognizable reflected and converted phases even when nominal P-wave sensors are used. Attenuation characteristics are also inherently contained in the relative amplitudes of these phases due to their different travel paths. We present recommendations for and results from laboratory measurements on cylindrical samples of aluminum and rocks with different geometries that we also compare with various standard analysis methods. The effort put into processing for our approach is particularly justified when accurate values and/or small variations, for example in response to changing P-T-conditions, are of interest or when the amount of sample material is limited.</p>

Determination of P-wave Velocity of Carbonate Building Stones During Freeze–Thaw Cycles

2020 ◽  
Vol 38 (6) ◽  
pp. 5999-6009
Author(s):  
Vahid Amirkiyaei ◽  
Ebrahim Ghasemi ◽  
Lohrasb Faramarzi
Keyword(s):  
Wave Velocity ◽  
P Wave ◽  
Building Stones ◽  
Freeze Thaw ◽  
P Wave Velocity

scholarly journals Combined controls of sedimentology and diagenesis on seismic properties in lacustrine and palustrine carbonates (Upper Miocene, Samos Island, Greece)

2019 ◽  
Vol 219 (2) ◽  
pp. 1300-1315 ◽  
Author(s):  
C Bailly ◽  
M Adelinet ◽  
Y Hamon ◽  
J Fortin
Keyword(s):  
Physical Properties ◽  
Wave Velocity ◽  
Mineralogical Composition ◽  
Sedimentary Facies ◽  
P Wave ◽  
Seismic Properties ◽  
Diagenetic Processes ◽  
P Wave Velocity ◽  
Seismic Reflectors

SUMMARY For the subsurface characterization of carbonates, linking physical properties (e.g. porosity and seismic reflectors) with their geological significance (e.g. sedimentary facies and diagenesis) is of primary importance. To address this issue, we study the lacustrine and palustrine carbonates on Samos Island through a geological and geophysical characterization of a sedimentary succession. The microstructures of the samples are described, and the samples’ physical properties are measured (porosity, P-wave velocity and density). The results show that the identification of only the primary (i.e. sedimentary) microstructure is not sufficient for explaining the huge variations in porosity and P-wave velocity. Hence, we highlight two early diagenetic processes that strongly impact the microstructures and control the physical properties: (i) neomorphism occludes porosity and increases the P-wave velocity of mud- and grain-supported microstructures, which implies a mineralogical stabilization of the grains; (ii) conversely, the dissolution process creates porosity and decreases the P-wave velocity of grain-supported microstructures if the mineralogical composition of the grains is not previously stabilized. These two diagenetic processes thus depend on the primary microstructures and mineralogy of the sediments. This work aims to explain the variations in porosity and P-wave velocity for each defined primary microstructure. A 1-D seismogram is then built to highlight seismic reflectors with a metre-scale resolution. These reflectors are associated with several geological contrasts. Hard kicks (positive amplitude reflectors) match well with exposure surfaces related to palaeosols. They correspond to contrasts between non-modified primary microstructures and highly neomorphosed microstructures. Conversely, soft kicks (negative amplitude reflectors) are linked with diagenetic contrasts (e.g. neomorphosed microstructures versus non-modified primary microstructures) and sedimentary contrasts that can be overprinted by diagenesis (e.g. neomorphosed mud-supported microstructures versus dissolved grain-supported microstructures). This study highlights that high-resolution seismic reflectors of lacustrine and palustrine carbonates are strongly related to the spatial contrasts of primary microstructures overprinted by early diagenesis.

Pore-pressure prediction in carbonate rock using wavelet transformation

Geophysics ◽  
2014 ◽  
Vol 79 (4) ◽  
pp. D243-D252 ◽  
Author(s):  
Fu Yu ◽  
Yan Jin ◽  
Kang Ping Chen ◽  
Mian Chen
Keyword(s):  
Pore Pressure ◽  
Wave Velocity ◽  
Carbonate Rocks ◽  
Wavelet Transformation ◽  
Pressure Change ◽  
P Wave ◽  
Small Scale ◽  
Prediction Methods ◽  
P Wave Velocity ◽  
Pore Pressure Prediction

Accurate prediction of pore pressure can assist engineers to better work out and optimize an oilfield development plan. Because the P-wave velocity only experiences small-scale fluctuations for pore-pressure change in carbonate rocks, existing well-known pore-pressure prediction methods are incapable of predicting pore pressure in carbonate rocks with field-required accuracy. We evaluated a new method based on the P-wave velocity decomposition and wavelet transformation to predict pore pressure in carbonate rocks. The P-wave velocity was decomposed into contributions from the pore fluid and the rock framework using Biot’s theory. The effect of lithology, pore structure, porosity, and pore pressure on P-wave velocity was studied by theoretical analysis and experiments. Rapid triaxial rock-system tests were carried out to measure the P- and S-wave velocities when pore pressure, pore structure, and porosity were changed, and X-ray diffraction tests were used to measure mineral components. The small-scale fluctuations of the P-wave velocity can be extracted and amplified using wavelet transformation. We found that the small-scale fluctuations of the P-wave velocity were caused by pore-pressure change in carbonate rocks and the large-scale fluctuations of the P-wave velocity depended on the rock framework. Overpressure formation can be identified by the high-frequency detail of wavelet transformation of P-wave velocity. A pore-pressure prediction model relating the contribution from the pore fluid to the P-wave velocity was developed. This model is an improvement over existing pore-pressure prediction methods that mainly rely on empirical relations between the P-wave velocity and the pore pressure. This new method was successfully applied to carbonate rocks in Tazhong Block, Tarim oilfield, demonstrating the feasibility of the proposed pore-pressure prediction method.

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