Carbonate rocks commonly contain a variety of pore types that can vary in size over several orders magnitude. Traditional pore-type classifications describe these structures but are inadequate for correlations to the rock's physical properties. We introduce digital image analysis (DIA) method produces quantitative pore-space parameters, which be linked properties carbonates, particular sonic velocity and permeability. The DIA derived from thin sections, capture two-dimensional (DomSize),...

Noninvasive 3D ground-penetrating radar (GPR) imaging with submeter resolution in all directions delineates the internal architecture and processes of shallow subsurface. Full-resolution requires unaliased recording reflections diffractions coupled migration processing. The GPR practitioner can easily determine necessary acquisition trace spacing on a frequency-wavenumber (f-k) plot representative 2D test profile. Quarter-wavelength spatial sampling is minimum requirement for full-resolution...

The elastic moduli of a rock are affected by three main factors: pore fluid, framework, and space. In carbonate rocks, the latter two factors function depositional environment diagenetic history. Cementation, recrystallization, dissolution processes can change mineralogy texture original framework thereby alter grain-to-grain contacts and/or occlude Dissolution enlarge interparticle space or dissolve grains entirely, increasing porosity. These alterations associated changes in frame...

The electrical resistivity log has proven to be a powerful tool for lithology discrimination, correlation, porosity evaluation, hydrocarbon indication, and calculation of water saturation. Carbonate rocks develop variety pore types that can span several orders magnitude in size complexity. A link between the carbonate structure been inferred, although no detailed understanding this relationship exists. Seventy-one plugs from outcrops boreholes carbonates five different areas ages were...

In laboratory experiments we measured the saturation effects on acoustic properties in carbonates and results question some theoretical assumptions. particular, these under dry wet conditions show that shear moduli do not remain constant during saturation. This change modulus puts Gassmann's assumption of a into also explains why velocities predicted with Gassmann equation can be lower or higher than velocities.

To assess saturation effects on acoustic properties in carbonates, we measure ultrasonic velocity 38 limestone samples whose porosity ranges from 5% to 30% under dry and water-saturated conditions. Complete of the pore space with water causes an increase decrease compressional- shear-wave as well significant changes shear moduli. Compressional velocities most are up [Formula: see text] higher than samples. Some show no change, a few even velocity. Shear-wave generally decreases, but nine...

Electrical and fluid flow properties of porous media are directly related to the morphology pores connectivity pore network. Both closely linked amount type intrinsic microporosity in carbonate rocks, which is not resolved by conventional techniques. Broad-ion-beam (BIB) milling produces high-quality true-two-dimensional cross sections for scanning electron microscopy (SEM) enables accurate quantification first time. The combination BIB-SEM mosaics with optical micrographs yields a...

Elastic shear moduli from ultrasonic measurements of carbonate rocks show an increase or decrease when saturated the dry state with brine. The induced changes on have been attributed to several rock-fluid interaction effects, including viscous coupling, reduction in free surface energy, and dispersion caused by local flow a subsequent effect acoustic velocities. As many studies recognized that velocity is dependent pore structure, relationship between structure observed must, certain extent,...

Research Article| November 01, 2004 Three-dimensional ground-penetrating radar imaging of sedimentary structures, fractures, and archaeological features at submeter resolution Mark Grasmueck; Grasmueck 1RSMAS Marine Geology Geophysics, University Miami, 4600 Rickenbacker Causeway, Florida 33149, USA Search for other works by this author on: GSW Google Scholar Ralf Weger; Weger Heinrich Horstmeyer 2Swiss Federal Institute Technology, ETH-Hönggerberg, CH-8093 Zürich, Switzerland Author Article...

We present a method for predicting permeability from sonic and density data. The removes the porosity effect on ratio [Formula: see text] of dry rock, it addresses specific surface as an indirect measure permeability. look at ultrasonic data, porosity, 114 carbonate core plugs. In doing so, we establish empirical relationship between solid phase (as calculated by Kozeny’s equation) (linearly transformed to remove effect). One must view derived using equation effective because only holds...

Active oolitic sandbars like those in the Bahamas (Figure 1) exhibit complex internal architecture with a multitude of stacked sedimentary structures. Ooids are round, carbonate-coated grains that form tropical climates. The anatomy carbonate is often too to be captured one- and two-dimensional data. Outcrops, cores, 2D geophysical profiles provide limited vertical view geologic record. Depositional processes confined momentary subhorizontal boundary surface between sediment water or air....

The relationship between P-wave velocity and porosity in carbonate rocks shows a high degree of variability due to the complexity pore structure. This introduces uncertainties seismic inversion, amplitude variation with offset analysis, estimation, pore-pressure prediction based on data. Elastic wave propagation porous media is numerically modeled scale investigate effects structure velocities rocks. We built 2D models using information similarity principle. Then, we simulated normal...

The term “beef” describes bedding-parallel calcite veins found commonly in the organic-rich matrix of unconventional resource plays. Although some authors have interpreted beef to be an early diagenetic feature, these are attributed precipitation at high temperatures and localized overpressure during hydrocarbon generation. temperature which formed is thus crucial ascertain process genesis. We use novel methodology clumped isotope analysis constrain both forms isotopic composition fluids...

Variations in the carbon isotopic composition of carbonate and organic (δ13Ccarb δ13Corg) are generally used to record perturbations global cycle, which turn closely linked changes climate. However, because climate gradients on Earth, assignment “global” signal ancient records is not straightforward. Here, we report δ13C values material Upper Jurassic Lower Cretaceous sedimentary Vaca Muerta Formation, situated Neuquén Basin, Argentina, show similar patterns those observed several northern...

Carbonate reservoir rocks of different pore structure have quite distinct and detectable 4D seismic signatures. Using three defined types (PST), these signatures are correlated with the permeability patterns carbonate rocks. In both high‐permeability PST3 intermediate‐permeability PST2 regions, gas injection is preferred than water for effective monitoring. low‐permeability PST1 region where lies most bypassed oil, options result in similar signal magnitude. Fluid saturation changes under...

The differential effective medium theory is used to model the velocity of carbonates with two predefined end‐member pore types and under dry water saturated conditions. dual porosity DEM takes into account input parameters derived from digital image analysis thin sections. In particular respective amount microporosity macroporosity aspect ratio macropores are incorporated. A conceptual 0.1 for micropores a measured 0.5 as (DEM) model. predicts that compliant have strong influence on sonic...

Velocity — porosity transforms and permeability are frequently used for upscaling of rock properties from core log scale to reservoir scale. Carbonate rocks often show a large scatter in the relationship between permeability. Hence further analyses required order better predict permeability, which would result more accurate modeling, reserve predictions. Incorporating image analysis enables us reduce uncertainties present velocity scatter. Obtaining microporosity by subtracting macroporosity...

Abstract Early marine cementation is a fundamental process for many characteristics of carbonates, like the stabilisation steep slopes. The genesis early cements often attributed to physicochemical processes but there evidence microbial mediation. To elucidate role microbes and associated organic material, in vitro experiments were undertaken presence absence indigenous microbiota ooids from Schooner Cays, Bahamas compared with native grapestones Joulter Bahamas. Microscopic examinations by...

The stable carbon isotopic compositions of carbonate sediments (δ13Ccarb) have been widely used to reconstruct the global cycle and as a stratigraphic correlation tool. This work investigates δ13Ccarb record marine organic-rich, mixed siliciclastic‐carbonate mudstones accumulated from Tithonian (late Jurassic) early Valanginian (early Cretaceous) in retro-arc basin connected Proto-Pacific Ocean (Neuquén Basin, Argentina). high-resolution values these strata outcrops at various locations...

The presence of round pores generally causes a positive deviation from Wyllie's equation (Anselmetti and Eberli 1993, 1999; Saleh Castagna 2004). However, carbonates contain large number different pore types that are not related roundness alone. Three quantitative shape parameters derived digital image analysis introduced to capture the complicated structure with goal enhance porosity prediction velocity. first parameter describes was by Anslemetti et al. (1998) called γ. second...

Abstract The modern history of North Atlantic sea surface temperature shows variability coinciding with changes in air and rainfall over the Northern Hemisphere. There is a debate about this and, particular, whether it internal to ocean‐atmosphere system or forced by external factors (natural anthropogenic). Here we present record, obtained using Sr/Ca ratio measured skeleton sclerosponge, that agreement instrumental record past 150 years as well multidecadal last 600 years. Comparison...