Abstract We developed a system to explore the effects of pressure and fluid viscosity on dispersion attenuation fully saturated tight sandstones, especially at seismic frequencies. Calibration new revealed that can operate reliably frequencies [2–200, 10 6 ] Hz. Tight sandstone with “crack–pore” microstructure was tested under nitrogen gas (dry), brine, glycerin saturation. A frequency‐dependent effect not found for dry case. However, apparent undrained/unrelaxed transition clearly observed...

We built a broad-frequency-band measurement system for rock elastic parameters based on the stress-strain method following Batzle et al., Geophysics 71, N1–N9 (2006). The gives strain amplitude anomalies at some frequencies. These put limitations range of frequency and jeopardize credibility results over broad band. To overcome these limitations, we investigated cause anomalous strains by numerical model simulations with finite element experimental apparatus. Through systematic analysis...

Foams stabilized by surfactants are widely applied in many industrial practices; thus, the investigation of properties these foams is significance. The aim this study to examine influence gas flow rate and surfactant concentration on sodium dodecyl benzene sulfonate (SDBS). Experiments were conducted using a commercially available instrument, FoamScan, with which foamability, foam stability, bubble size, liquid content determined. results showed that as an increase at same foaming time...

SUMMARY In fully fluid-saturated rocks, two common phenomena are documented both experimentally and theoretically for frequency-dependent elastic moduli attenuation, that is, the drained/undrained transition relaxed/unrelaxed transition. When investigating these transitions with forced oscillation method in laboratory, it is crucial to consider boundary differences between laboratory underground. A 1-D poroelastic numerical model was previously established describe their effects; however,...

SUMMARY We conducted stress–strain oscillation experiments on dry and partially oil-saturated Fontainebleau sandstone samples over the 1–2000 Hz band at different confining pressures to investigate wave-induced fluid flow (WIFF) mesoscopic microscopic scales their interaction. Three tested rock have similar porosity between 6 7 per cent were saturated degrees with oils. The measurement results exhibit a single or two attenuation peaks that are affected by saturation degree, oil viscosity...

SUMMARY Elastic moduli and velocities of tight sandstones are strongly influenced by rock-frame heterogeneity, pore microstructure fluid in addition to pressure probing-wave frequency. The effects frequency on the elastic different from those conventional with high porosity permeability due complexity microstructure. To investigate these effects, we measured two sandstone samples for their dry saturation conditions using ultrasonic transmission technique low-frequency stress–strain method....

SUMMARY Understanding the effects of pressure and rock microstructure on seismic elastic properties fully saturated rocks is considerable importance in a range geophysical applications, especially at frequency range. A recently proposed theoretical model squirt attenuation dispersion can be used to interpret stress dependence basis triple porosity structure. The poroelastic requires knowledge variety pore parameters, particular, compliant pores with discrete distribution aspect ratio. We...

Using the stress–strain oscillation method, we conducted experiments on a sandstone over frequency range of 1–100 Hz at differential pressure 5 MPa to investigate effects oil saturation and oil/water substitution modulus dispersion attenuation. We first saturated with low viscosity (2#) different degrees, then replaced 2# more viscous (68#) finally injected distilled water in oil-saturated sample. Young's modulus, Poisson's ratio extensional attenuation were measured during these processes....

SUMMARY The squirt flow model, proposed by Mavko & Jizba, has been widely used in explaining the frequency-related modulus and velocity dispersion between ultrasonic seismic measurements. In this saturated bulk at high frequency is obtained taking so-called unrelaxed frame into Biot's or Gassmann's formula. When using formula, mineral taken as matrix modulus. However, soft pores (cracks) rocks have a weakening effect on calculated with higher than real values. To overcome shortcoming we...

The squirt flow model developed by Mavko and Jizba has been widely applied to quantify elastic moduli/velocities of fluid-saturated rocks at ultrasonic frequencies the related modulus/velocity dispersion between seismic frequencies. In model, high-frequency saturated bulk modulus is obtained taking unrelaxed frame as drained/dry one input Biot’s or Gassmann’s formula. However, when using formula, “new” rock matrix contains mineral soft pores, which heterogeneous microscopic scale thus breaks...

The similarities and differences in inherent mechanism characteristic frequency between the one-dimensional (1D) poroelastic model layered White were investigated. This investigation was conducted under assumption that rock homogenous isotropic at mesoscopic scale. For mechanism, both models resulted from quasi-static flow a slow P-wave diffusion mode, them originated saturated fluids boundary conditions. On other hand, for frequencies of models, 1D first modified because elastic constant...

It is important to know the seismic wave dispersion and attenuation in porous rocks for understanding variations elastic properties of reservoirs. The multi-frequency band parameters measurement system (MFBMS) has been developed estimate Young's modulus Poisson's ratio rock samples at frequency range ultrasonic frequency. Measurements dry partially water saturated tight sandstone were performed by MFBMS four different effective pressures. remain almost unchanged from low high frequencies...

We investigated the frequency dependence of Poisson’s ratio <math xmlns="http://www.w3.org/1998/Math/MathML" id="M1"> <mi>ν</mi> </math> in partially/fully fluid-saturated rocks. Based on one dominant fluid flow mechanism at each condition, we theoretically summarized that (1) when a rock is partially saturated or transits from drained state to undrained full saturation, id="M2"> increases monotonously with frequency, and associated attenuation id="M3"> <mfenced open="(" close=")"> <mrow>...

SUMMARY Squirt flow is an essential cause of wave dispersion and attenuation in saturated rocks. The squirt model, proposed by Gurevich et al., has been widely applied to explain the associated for rocks at sonic seismic frequency bands. In this bulk modulus obtained taking partially relaxed frame as dry into Gassmann's formula with mineral matrix modulus. However, because weakening effect soft pores on rock modulus, model cannot accurately predict when soft-pore fraction (the ratio porosity...

Summary The Ordovician carbonates of the Yingshan formation in Tarim Basin present a complicated pore structure due to diagenetic and secondary structures. Seismic elastic properties (e.g., velocity) depends on porosity as well structure. We estimated average specific surface, pore-throat radius, roundness, aspect ratio carbonate rocks from Tazhong area. Measuring results show that high P-wave velocity samples have small large ratio. Diversity dense result fluid-related variability. For or...

Abstract The seismic attributes of water‐rich sandstone contain much information about the rock's physical properties and wave parameters. They are commonly used to predict (e.g. porosity). However, affected by porosity, water saturation thickness. To eliminate influence thickness on porosity prediction improve accuracy prediction, authors propose a Lambert W – R transform method isolate contribution from attributes. First, rock model is calculate equivalent elastic parameters sandstones...

Summary A multi-frequency band elastic parameters measurement system was used to measure the dispersive nature of waves in a tight sandstone under nitrogen gas and glycerin saturation. The measurements were performed at effective pressure Peff = [2–35] MPa temperature 23°C, 40°C 60 °C. For saturated (dry) rock, velocities remained almost unchanged from low seismic high ultrasonic frequencies each pressure. But saturation, exhibited obvious velocity variations frequency region, which largely...

Summary Combining both geological and petrophysical properties, a reliable rock typing scheme can be achieved. Two steps are included in typing. Step 1: rocks classified into lithofacies based on core observations thin sections; 2: further subdivided types according to properties such as MICP K-Phi relationships. By correlating electrofacies (clusters of log data), we group the target formation 15 types. Then it is possible predict distributions laterally vertically using wireline logs. To...

Reflection coefficient is a significant parameter in seismic exploration and closely related to velocity contrast between different layers. In this paper, the reflection dispersion at interface of cap reservoir (saturated with fluid) studied. The ultrasonic pulse method used measure waveform tight sandstone (acting as layer). Besides, we also recorded waveforms an extra conventional (to simulate reservoir) placed under saturated fluids (gas, water oil #2/oil #68). With reflections top bottom...

Summary In our experiments, we investigated the effect of brine on characteristic frequency and attenuation peaks for a reservoir sandstone. We observed two-attenuation which may be caused by combination two different fluid flow mechanisms. Two poroelatic models squirt mechanisms are used to investigate cause dispersion. Based these observations analysis, attribute modulus drained/undrained regime relaxed/unrelaxed regime.

SUMMARY Squirt flow plays an essential role in elastic modulus dispersion and attenuation for fluid-saturated cracked porous rocks. The Mavko–Jizba model relevant modified models can describe the squirt well based on related moduli, such as dry/drained bulk modulus. However, when these moduli are challenging to attain, it is impossible squirt-flow-related attenuations with models. On other hand, effective medium theory (EMT) estimate but cannot predict undrained/relaxed partially relaxed...