Pore Space Of Rocks Research Articles

3D modeling of abnormal pore pressure in shallow offshore Niger delta: An application of seismic inversion

Pore pressure is the pressure associated with fluids in the pore spaces of sedimentary rocks. This pressure varies from hydrostatic to severe overpressure. It is classified as abnormal pressure when it deviates from hydrostatic pressure. Incorrect prediction or the absence of pore pressure evaluation can lead to severe damage of the drilling platform, loss of personnel, waste of resources and environmental pollution. This study was carried out in an offshore field in Niger Delta with an objective of predicting the abnormal pressure regime from the seismic volume using seismic inversion technique. First, we employed the Eaton’s and Bower’s model of predicting pore pressure from Well log. The predicted pore pressure from the well was used to calibrate the P-impedance that was used in the inversion process. A pressure-based model for the seismic inversion process was developed. This was constrained by the relationship between the P-impedance and pore pressure in the study area. The predicted pore pressure from the Well logs aligned with the measured pore pressure in the formation. At about 3600 m to end of the Well, depicts a pressure regime that is a deviation from the hydrostatic pressure trend. The abnormal pressure regime is marked by the region where a change is observed in the normal compaction trend line. The cross plot of acoustic impedance against pore pressure reveals a linear relationship; with a direct relationship indicating a normal pressure interval and the indirect relationship at the abnormal pressure regime. The inverted 3D pressure result from the seismic volume validates the normal compaction trend line and also the pressure values estimated from the Well logs. The abnormal pressure regime in the study area is predicted to be found towards the end of Agbada Formation and through the Akata Formation due to the un-compacted shales.

An innovative image-based workflow for quantitative pore structure characterization in reservoir rocks

Pore connectivity is a key parameter to affect reservoir quality (e.g. permeability). Routinely, this parameter is assessed with special core analysis (i.e. mercury injection capillary pressure analysis). In this paper, an innovative image-based pore structure workflow is proposed to quantitatively delineate the connectivity of pore space of reservoir rocks by using widely available thin section images. By borrowing the concept of mercury injection capillary pressure (MICP), this workflow is able to generate pseudo MICP curves that can be used to quantitatively characterize pore throat/body size distribution and pore connectivity of pore networks. This workflow consists of four steps: (1) HSV threshold-based pore identification; (2) K-D tree structure-based pore segmentation; (3) enhanced watershed-driven pore throat detection, and (4) pore throat distribution generation derived with a media-axis-maximal-circle algorithm. The pseudo MICP curves generated by the workflow can be used to quantitatively assess the variations in pore size, pore throat size, pore geometrical complexity as well as the density of pores of reservoir rocks. Two connectivity indices derived from pseudo MICP curves are introduced to evaluate the connectivity of pore network of reservoir rocks. This workflow provides an innovative and efficient tool for geologists and reservoir engineers to perform quantitative reservoir rock quality evaluation by utilizing widely-available thin section images.

Direct fluid flow simulation at pore scale with regularized hydrodynamic equations

Laboratory analysis of rock samples (core material) is one of the main tools used in an analysis of oil and gas field development and methods to enhance oil recovery. A number of drawbacks are intrinsic to the laboratory techniques, among which we note the practical impossibility of carrying out parametric studies on one sample, the impossibility (and / or high cost) of taking into account reservoir conditions, and the impossibility of analyzing non-cemented rocks (sludge). With the development of computational capabilities and computed tomography methods, the “digital rock physics” technology, which consists in direct simulation of physical processes in a rock sample with resolved pore space geometry, is gaining popularity today. This technology complements the traditional laboratory studies and compensates for a number of their shortcomings. The presented work is devoted to the direct simulation of fluid flow within the scope of the digital rock physics. For simulation regularized (according to quasi-hydrodynamic technique) hydrodynamic equations are used. Both single-phase single-component flows and two-phase two-component flows, taking into account interfacial tension, are discussed. The results of simulations of fluid flows both in model domains and in domains corresponding to the pore space of real rocks are presented.

Pore-scale imaging of asphaltene-induced pore clogging in carbonate rocks

We propose an experimental methodology to visualize asphaltene precipitation in the pore space of rocks and assess the reduction in permeability. We perform core flooding experiments integrated with X-ray microtomography (micro-CT). The simultaneous injection of pure heptane and crude oil containing asphaltene induces the precipitation of asphaltene in the pore space. The degree of precipitation is controlled by the measurement of differential pressure across the sample. After precipitation, doped heptane is injected to replace the fluid to enhance the contrast between precipitated asphaltene and doped heptane. The micro-CT images are segmented into three phases: void, precipitated asphaltene, and rock. In the experiment, we observed that the precipitated asphaltene which occupied 39.1% of the pore volume caused a 29-fold reduction in permeability. Furthermore, we analyze the spatial distribution of precipitated asphaltene which showed that the asphaltene tended to clog the larger pores. We also computed the flow field numerically on the images and obtained good agreement between simulated and measured permeability. The distribution of local velocity showed that after precipitation the flow was confined to narrow channels in the pore space. This method can be applied to any type of porous system with precipitation.

Geometrical and Topological Analysis of Pore Space in Sandstones Based on X-ray Computed Tomography

The pore geometry and topology properties of pore space in rocks are significant for a better understanding of the complex hydrologic and elastic properties. However, geometry and topology information about the sandstone pore structures is not fully available. In this study, we obtained the topological and geometrical pore parameters from a representative elementary volume (REV) for fluid flow in sandstone samples. For comparison, eight types of sandstones with various porosities were studied based on the X-ray micro-computed tomography technique. In this study, the REV size was selected based on the parameters from the respective pore network models (PNM), not just the porosity. Our analysis indicates that despite different porosity, all the sandstone samples have highly triangular-shaped pores and a high degree of pore structural isotropy. The high porosity group sandstones exhibit wider ranges of pore sizes than the low porosity group sandstones. Compared to the high porosity group sandstones, the low porosity group sandstones samples showing a higher global aspect ratio, indicating some pores exist in the form of bottlenecks. The pore topological properties of different sandstones show a high dependence of the porosity. The high porosity group sandstones obtain large coordination numbers, large connectivity densities and low tortuosities. The results from this study will help better understand the complex pore structure and the fluid flow in sandstone.

Gas and Dolomite Outbursts in Ore Mines—Analysis of the Phenomenon and the Energy Balance

In this paper, we present the problem of gas and dolomite outbursts in copper mines. The energy balance of the phenomenon is analyzed. An examination of the porosity of the dolomites is performed; in addition, the content and pressure of the gas accumulated in the pore structure of the rock are determined. The gas energy accumulated in the pore space of rocks is determined depending on the transformation occurring during gas decompression. The work needed to crush the rock for the grain distribution characteristic of post-outburst masses is examined. The gas energy needed to transport rocks is analyzed. The purpose of the research is to determine the limit values of parameters describing the gas and rock system for which there is a risk of dolomite and rock explosions. For the characteristic porosity of dolomites of −5%, gas and rock outbursts at 5 MPa pressure in isothermal transformation can be expected, and if the transformation is closer to adiabatic transformation, outbursts can be expected at 10 MPa pressure.

A Semianalytical Poroelastic Solution To Evaluate the Stability of a Borehole Drilled Through a Porous Medium Saturated with Two Immiscible Fluids

Summary Conventional drilling design assumes that the porous rock is fully saturated with a single fluid and therefore tends to inaccurately predict the mud weight needed for borehole stability because the pore space of the porous rock may actually have two or more fluids. This paper provides a new semianalytical poroelastic solution for the case of an inclined borehole subjected to nonhydrostatic stresses in a porous medium saturated with two immiscible fluids: water and gas. The new solution is obtained under plane-strain condition. The wellbore loading is decomposed into axisymmetric and deviatoric cases. The time-dependent field variables are obtained by performing the inversion of the Laplace transforms. On the basis of the expansion of the Laplace-transform solution, we derive the unsaturated poroelastic asymptotic solutions for early times and for a small radial distance from an inclined wellbore. Sensitivity analyses are performed on different ratios of bulk modulus of two fluid phases to pore pressures of the unsaturated case. In addition, the comparative analyses of pore-pressure differences are made between the unsaturated and saturated cases. The impact of the unsaturated poroelastic effect on pore pressure, stresses, and borehole stability is investigated. Our results show that the excess pore pressure caused by the poroelastic effect is generally higher for the saturated case (water) than the unsaturated case because of the large difference between the compressibility of fluid phases (water and gas). The time dependency of the poroelastic effect causes the safe-mud-pressure window of both the unsaturated and saturated cases to narrow and approach the long-time poroelastic one with increasing time. The safe-mud-pressure window narrows with increasing initial gas saturation. Contrary to the unsaturated case, the saturated case that assumes the formation to be saturated by one fluid (e.g., water) tends to optimistically predict a wider safe-mud-pressure window required for borehole stability. This new semianalytical poroelastic solution enables the drilling engineer to more accurately estimate the time-dependent stresses and the pore pressure around a borehole, thus allowing a mud weight design that will ensure borehole stability.

Mineral-hosted biofilm communities in the continental deep subsurface, Deep Mine Microbial Observatory, SD, USA.

Deep subsurface biofilms are estimated to host the majority of prokaryotic life on Earth, yet fundamental aspects of their ecology remain unknown. An inherent difficulty in studying subsurface biofilms is that of sample acquisition. While samples from marine and terrestrial deep subsurface fluids have revealed abundant and diverse microbial life, limited work has described the corresponding biofilms on rock fracture and pore space surfaces. The recently established Deep Mine Microbial Observatory (DeMMO) is a long-term monitoring network at which we can explore the ecological role of biofilms in fluid-filled fractures to depths of 1.5km. We carried out in situ cultivation experiments with single minerals representative of DeMMO host rock to explore the ecological drivers of biodiversity and biomass in biofilm communities in the continental subsurface. Coupling cell densities to thermodynamic models of putative metabolic reactions with minerals suggests a metabolic relationship between biofilms and the minerals they colonize. Our findings indicate that minerals can significantly enhance biofilm cell densities and promote selective colonization by taxa putatively capable of extracellular electron transfer. In turn, minerals can drive significant differences in biodiversity between fluid and biofilm communities. Given our findings at DeMMO, we suggest that host rock mineralogy is an important ecological driver in deep continental biospheres.

Resolution effect on image-based conventional and tight sandstone pore space reconstructions: Origins and strategies

A suitable choice of spatial resolution is essential to the three-dimensional (3D) image-based reconstruction of rock pore space: a too low spatial resolution may result in the omission of sub-resolution porosity while too high spatial resolution may lead to a field of view smaller than the representative volume. In this work, the 3D pore spaces of conventional and tight sandstone specimens are reconstructed by X-ray computed tomography with spatial resolutions of 2 μm, 5 μm, 10 μm, and 20 μm and equal image voxel quantities (600 × 600 × 600) to study the influence of spatial resolution on the reconstruction quality. Petrophysical properties such as porosities, permeabilities and pore-throat structure parameters are calculated from the 3D images and measured by helium porosity, Klinkenberg-corrected permeability and mercury intrusion capillary pressure porosimetry for comparison. High-resolution images are sampled from different positions in the specimens to evaluate the core-scale heterogeneities. Rock textures and pore-throat structures of the specimens are analyzed through casting thin sections and MICP to find out the origin of the resolution effect. The results show that 3D images with any single spatial resolution have limited detectivities to recover the full pore and throat distribution of sandstone specimens, which is the root cause of the resolution effect. The contributions of different pore genetic types with various pore sizes to petrophysical properties vary with simulation targets and methods. For conventional sandstone specimens with only one dominate pore genetic type, the appropriate spatial resolution can be chosen by calibrating the simulated petrophysical properties to actual measurements. For tight sandstone specimens with several pore genetic types, the contents and contributions to the petrophysical properties should be investigated before pore space reconstructions.

Electron-Microscopy Studies of the Pore Space in Oil and Gas Carbonate Reservoir Rocks

The procedure of identifying the microstructural types of pore space in carbonate rocks by the example of the Dimitrovskoe oil and gas condensate field is described. The microstructural features are studied with the use of an NVision 40 scanning electron microscope (Carl Zeiss) that allows us to examine the surface of fractures in the samples and polished sections prepared from the drilled rock core. As a result of the studies, rocks with different types of pore space are identified.

Changes in Water Quality in the Bureiskoe Reservoir Caused by a Large Landslide

The study considers the factors that had an effect on water quality in the Bureiskoe Reservoir (Far East) after a large landslide event in December 2018 (with a volume of 24.5 million m3) followed by blasting operations with the use of trinitrotoluene and hexogen. Changes in water quality were assessed with the use of methods of microbiological indication, gas chromatography and spectrophotometry. Water was examined upstream and downstream of the landslide body, in shore flooding ice and aqueous extracts of charred wood and rocks. Bioindication showed that the blasting operations contribute much to changes in water quality. The results of experimental studies of the toxicity of an aqueous extract from charred wood are given. The extracts were found to contain acetone, benzol, methanol, toluene, and o-xylene. Microbial complexes of water and shore aufeises were used for comparative analyses. The study showed that the inflow of organic substances of natural origin from the pore space of rocks had a considerable effect on water quality in the Bureiskoe Reservoir, which was aggravated by the products of trinitrotoluene and hexogen detonation after blasting operations.

Reevaluation of Perchlorate in Gale Crater Rocks Suggests Geologically Recent Perchlorate Addition

AbstractPerchlorate (ClO4−) was discovered in Martian soil by the Phoenix lander, with important implications for potential Martian biology, photochemistry, aqueous chemistry, and the chlorine cycle on Mars. Perchlorate was subsequently reported in both loose sediment and bedrock samples analyzed by the Sample Analysis at Mars instrument onboard the Curiosity rover in Gale crater based on a release of O2 at 200–500°C. However, the continually wet paleoenvironment recorded by the sedimentary rocks in Gale crater was not conducive to the deposition of highly soluble salts. Furthermore, the preservation of ancient perchlorate to the modern day is unexpected due to its low thermodynamic stability and radiolytic decomposition associated with its long exposure to radioactivity and cosmic radiation. We therefore investigate alternative sources of O2 in Sample Analysis at Mars analyses including superoxides, sulfates, nitrate, and nanophase iron and manganese oxides. Geochemical evidence and oxygen release patterns observed by Curiosity are inconsistent with each of these alternatives. We conclude that perchlorate is indeed the most likely source of the detected O2 release at 200–500°C, but contend that it is unlikely to be ancient. Rather than being associated with the lacustrine or early diagenetic environment, the most likely origin of perchlorate in the bedrock is late stage addition by downward percolation of water through rock pore space during transient wetting events in the Amazonian. The conclusion that the observed perchlorate in Gale crater is most likely Amazonian suggests the presence of recent liquid water at the modern surface.

Impact of mineralogy and wettability on pore-scale displacement of NAPLs in heterogeneous porous media

Subsurface formations often contain multiple minerals with different wettability characteristics upon contact with nonaqueous-phase liquids (NAPLs). Constitutive relationships between microstructure heterogeneity and NAPL fate and transport in these formations are difficult to predict. Several studies have used pore-scale network models with faithful representations of rock pore space topology to predict macroscopic descriptors of two-phase flow, however wettability is usually considered as a spatially random variable. This study attempts to overcome this limitation by considering more realistic representations of rock mineralogy and wettability in these models. This is especially important for heterogeneous rocks where properties vary at the pore-scale. The work was carried out in two phases. First, pore-fluid occupancy maps during waterflooding were obtained by X-ray microtomography to elucidate the impact of pore wall mineralogy and wettability on water preferential flow paths and NAPL trapping within a heterogeneous aquifer sandstone (Arkose). Then, microtomography images of the rock were used to generate a hybrid pore network model (PNM) that incorporated both pore space topology and pore wall mineralogy. In-situ contact angles (CA) measured on the surface of different minerals were assigned to the network on a pore-by-pore basis to describe the exact wettability distribution of the rock (Pore-by-pore model). The equivalent network was used as input in a quasi-static flow model to simulate waterflooding, and the predictions of residual NAPL saturation and relative permeabilities were compared against their experimental counterparts. To examine the sensitivity of the model to the underlying fluid-solid interactions, we also used traditional methods of wettability characterization in the input data and assigned them randomly to the PNM. Wettability in this case was assessed from macroscale CA distribution of oil droplets on the surface of unpolished Arkose substrates released by spontaneous imbibition of water (Arkose model) and from pendant drop measurements on polished quartz (Quartz model). Our results revealed that the Pore-by-pore model predicted waterflooding with the highest accuracy among all three cases. The Arkose model slightly overestimated NAPL removal whereas the Quartz model failed to predict the experiments. More in-depth analysis of the Pore-by-pore and Arkose models showed that macroscopic transport quantities are less dependent to microstructure heterogeneity if minerals are distributed uniformly across the rock. The predictions herein indicate the importance of incorporating mineralogy and wettability maps to improve the prediction capabilities of PNMs especially in systems with high mineral heterogeneity, where minerals are nonuniformly distributed, or selective fluid-mineral interactions are targeted.

Calculation and experimental method for determining the filtration parameters of the mixture “oil — aqueous solution of surfactants”

The article describes a physical and mathematical cluster precise model and a method for calculating the flow of a two-phase mixture “oil — aqueous solution of surface-active substances” in the pore space of rocks. This method allows us to predict the effect of the type of aqueous solution of surface-active substances and the temperature of the solution on the type of relative permeabilities (RPP). The results of an experimental study of stationary two-phase fluid filtration in a reservoir model through a composite column of core samples are presented. A method is given for determining the relative permeability functions using additional reagents based on the obtained generalized experimental data and calculating pressure losses due to friction, local resistances, and interfacial interaction during the flow of oil-water mixture in the pore channels. Formulas are proposed for calculating losses from interphase interaction taking into account the influence of the type of surfactant and formation temperature. The dependences of the relative amplitude of pressure loss on interfacial interaction and the position of the maximum loss of the bell-shaped curve on the type of surfactant, formation temperature and adhesion work are obtained, which allow approximating the magnitude of pressure loss on interfacial interactions taking into account surfactants and temperature. The effect of temperature on the type of relative permeabilities is shown. It was established that the use of the studied aqueous surfactant solutions instead of water for oil displacement leads to a decrease in the residual oil saturation in the core due to a decrease in interfacial tension at the oil-water interface, which as a result leads to an increase in oil recovery.

Microbial Life in Impact Craters.

Asteroid and comet impacts are known to have caused profound disruption to multicellular life, yet their influence on habitats for microorganisms, which comprise the majority of Earth's biomass, is less well understood. Of particular interest are geological changes in the target lithology at and near the point of impact that can persist for billions of years. Deep subsurface and surface-dwelling microorganisms are shown to gain advantages from impact-induced fracturing of rocks. Deleterious changes are associated with impact-induced closure of pore spaces in rocks. Superimposed on these long-term geological changes are post-impact alterations such as changes in the hydrological system in and around a crater. The close coupling between geological changes and the conditions for microorganisms yields a synthesis of the fields of microbiology and impact cratering. We use these data to discuss how craters can be used in the search for life beyond Earth.

ОПЫТ ПРИМЕНЕНИЯ ДИАГРАММЫ Д. У. ХАУСКНЕХТА ДЛЯ ОЦЕНКИ ВЛИЯНИЯ УПЛОТНЕНИЯ И ЦЕМЕНТАЦИИ НА ПОРИСТОСТЬ НИЖНЕ-СРЕДНЕЮРСКИХ ПЕСЧАНИКОВ НЮРОЛЬСКОЙ ВПАДИНЫ И КОЛТОГОРСКО-УРЕНГОЙСКОГО МЕГАПРОГИБА

Using D. U. Hausknecht diagram, the degree of impact of authigenic cementation, pressure solution and mechanical consolidation on the reduction of porosity and intergranular volume of the Lower - Middle Jurassic sandstones in the territory of the Tomsk region was determined. Sandstones of the Nadoyakha (Lower Toarcian – Lower Aalenian, bed Yu15), Vymskoye (Lower Bajocian, beds Yu11–Yu14), Leontievskiy (Lower-Upper Bajocian, beds Yu8–Yu10) and Malyshevka (Upper Bajocian – Bathonian, beds Yu3–Yu6) were analyzed horizons penetrated by a number of wells in western regions of the Nyurolka depression and the southern part of the Koltogor-Urengoy megatrough in the depth interval 2702–3326 m. It was found that the reduction in the intergranular volume of studied rocks is associated not only with their genesis, material composition, and structural and textural features, but also with the amount, type and composition of cement. It was revealed that the main factor influencing the reduction of the primary volume of the pore space of terrigenous rocks to a depth of ~ 2900–3000 m is the authigenic cementation, and below 3000 m the leading role is played by mechanical consolidation and dissolution of detrital grains under pressure. For Late Toarсian-Aalenian sandstones in the studied areas, the contribution of the factor of mechanical consolidation and pressure solution on the reduction of the primary intergranular volume was 38–53%, and for sandstones of the Bajocian – 20–30%. For the latter, the share of authigenic cementation was 24–56%. The work also considers circumstances that limit this method and possibilities of its application for other types of rocks.

Understanding the Cation-Dependent Surfactant Adsorption on Clay Minerals in Oil Recovery

Surfactants have the ability to mobilize residual oil trapped in pore spaces of matrix rocks by lowering the oil–water interfacial tension, resulting in a higher oil recovery. However, the loss of ...

An uncertainty approach to estimate recoverable reserves from the Bakken petroleum system in the North Dakota part of the Williston Basin

Instead of using discrete values for properties that influence the volumetric calculation for recoverable reserves from the Middle Bakken, Pronghorn, and Three Forks reservoir rocks in the Williston Basin in North Dakota, an uncertainty-based assessment method was used. Various estimates have been published in the past that attempt to quantify recoverable reserves from the Bakken petroleum system. The Bakken–Three Forks trend is regarded as an unconventional tight oil play typical of a continuous-type basin-centered accumulation. However, production data reveal that areas are unequal and that certain regions stand out as sweet spots whereas others exhibit fairly high water cuts. This paper is based on 28 well models, which have been porosity-calibrated and adjusted for the prevalent thermal regime. The area of interest was delineated by geological parameters such as shale maturity and reservoir rock presence as well as existing production data. The purpose of this study is to use an uncertainty assessment method based on hundreds of basin model simulations that sample ranges of probable input parameters to quantify the recoverable reserves from the Bakken petroleum system in North Dakota. The results are displayed in reverse cumulative probability plots, tornado sensitivity charts, as well as in maps of the 10% chance, 50% chance (P50), 90% chance values. This means that there is an X% chance of success or an X probablity of realizing a certain amount of hydrocarbon. The P50 results of the uncertainty assessment indicate that approximately 4 billion bbl of oil and 3.6 tcf (102 billion m3) of gas are recoverable from the Middle Bakken, Pronghorn, and Three Forks reservoir rocks in North Dakota. The Bakken–Three Forks trend appears to be an overcharged petroleum system, where the available pore space in reservoir rocks is the limiting factor for each accumulation.

Analysis of Variance of Porosity and Heterogeneity of Permeability at the Pore Scale

We present a new statistical variance approach for characterizing heterogeneities related to pore spaces in reservoir rocks. Laboratory-based computer microtomography data for reservoir sandstone samples were acquired and processed using advanced image segmentation techniques. The samples were processed using a method based on the digital rock physics concept using the high-performance Navier–Stokes flow solver in the GeoDict commercial software package. The digitized structures were subjected to computational fluid dynamic simulations. The effects of structural matrix modifications caused by the precipitation of minerals on the porosity–permeability relationship and the characterization of the representative elementary volume were assessed. The variances of the digital flow fields were compared at the pore scale (6 µm). The algorithm for analysing variance was benchmarked using a synthetic dataset that provided artificial repetitive structural patterns at both low and high resolutions. This gave an estimate of the sensitivity of the proposed algorithm to minor inhomogeneities. Representative elementary volume variance analysis was performed by comparing the correlation coefficients for various pore–grain composition patterns with the variances of simulated mean flow velocities. Probability density functions indicate that the flow velocities and pore space geometries differed greatly for different samples. The normalized probability density functions of the mean flows shifted to higher velocities as the resolution decreased. We found that a representative elementary volume analysis was more reliably achieved by analysing the mean flow velocity variance than by analysing the pore microstructure alone.

Modeling Attenuation of Diffusive-Viscous Wave Using Reflectivity Method

Seismic waves in earth materials are subject to attenuation and dispersion in a broad range of frequencies. The commonly accepted mechanism of intrinsic attenuation and dispersion is the presence of fluids in the pore space of rocks. The diffusive-viscous model was proposed to explain low-frequency seismic anomalies related to hydrocarbon reservoirs. But, the model is only a description of compressional wave. In this work, we firstly discuss the extended elastic diffusive-viscous model. Then, we extend reflectivity method to the diffusive-viscous medium. Finally, we present two numerical models to simulate the attenuation of diffusive-viscous wave in horizontal and dip multi-layered media compared with the results of viscoelastic wave. The modeling results show that the diffusive-viscous wave has strong amplitude attenuation and phase shift when it propagates across absorptive layers.