Effective Porosity Ratio Research Articles

Petrophysical properties of the reservoir unit (1C) for Upper Shale Member from Zubair formation in Luhais field

The research dealt with the reservoir division for Upper Shale Member from Zubair formation in Luhais field, Where it was divided into six units of reservoir and non-reservoir, including the main reservoir unit 1C, which is the subject of research in this study, and studied in terms of thickness and lithology. The reservoir unit 1C was associated with environmental sediment, which was the environment of the tidal channels, explaining the sedimentation mechanism that helped to form the oil traps and improve the petrophysical characteristics. The log interpretation was used to determine and calculate the petrophysical characteristics of reservoir unit 1C. The total and effective porosity ratio was calculated with the highest and lowest value, and its porosity was represented by a three-dimensional model representing its distribution in the field, In addition, permeability was calculated through the relationship between porosity and permeability from the pulp where the permeability equation was extracted from the best straight line values containing an unknown value, By compensating for the porosity value of the logs, the permeability could be calculated for the depths of wells that do not contain a core. The permeability of unit 1C is represented by three-dimensional models that are distributed across the field. The oil and water determinations of unit 1C were studied and their existence periods were determined for all wells of the field. The work of three-dimensional models and longitudinal and transverse sections represented the distribution of oil and water polysaccharides in unit 1C. The level of contact of oil - water was determined at a depth of 2753 meters.

Material Design and Performance Analysis of Porous Cement Stabilized Macadam

In order to use cement stabilized macadam in sponge road engineering, porous cement stabilized macadam was designed based on Bailey method and Taibal method, and theoretical porosity was taken as design index. Effective porosity, permeability coefficient, unconfined compressive strength, splitting strength and COD removal ability were analyzed by experiment. The results show that, effective porosity is proportional to theoretical porosity, ratio of effective porosity is lower while theoretical porosity is smaller. Unconfined compressive strength(UCS) and splitting strength are decreasing with theoretical porosity increasing, and downtrend is more significant while theoretical porosity is less than 20%. The removal ability of COD is enhancing with porosity increasing. So, if strength, water permeable ability, water storage ability, COD removal ability are taken into consideration, 20% is optimum porosity for porous cement stabilized macadam.

Vortex shedding control on a bare cylinder using hexagonal perforated outer cylinder

The aim of the study is to observe the effect of outer hexagonal perforated cylinder surrounding an inner cylinder on vortex structure behind bluff body. Vortex shedding characteristics from bluff body are experimentally studied by particle image velocimetry (PIV) in deep water. The inner cylinder had seven different diameters (Di), varied from 30 to 90 mm with an increment of 10 mm and the hexagonally perforated outer cylinder placed outside of the inner cylinder was used as a control element. Experiments were carried out with six perforated cylinders with a diameters of 100 mm (Do) and six porosities, β, with hole diameter 10 mm. The porosity, β, and diameter ratio, Di/Do, had substantial effect on the flow characteristics behind the cylinder. For the range of diameter ratios of 0.3 ≤ Di/Do≤ 0.5 the optimum porosity that controls the flow structure is found to be β = 0.6. For 0.6 ≤ Di/Do≤ 0.7 it is β = 0.5 and β = 0.4 for 0.8 ≤ Di/Do≤ 0.9. With increasing diameter ratio, Di/Do, peak magnitude locations of Reynolds shear stress, [Formula: see text], and turbulence kinetic energy approach the inner outer cylinder system slightly. For all diameter ratios, β = 0.6 is the most effective porosity ratio.

Fluid substitution for thinly interbedded sand-shale sequences using the mesh method

Gassmann’s fluid substitution model is intended for a monomineralic, homogeneous porous rock, in which pore pressures induced by applied loads can equilibrate throughout the pore space. These assumptions are violated when Gassmann’s equations are applied to measurements that represent effective medium averages over subresolution layers of alternating sand and shale. The conventional procedure for treating this problem has been to first downscale; i.e., estimate the properties of the fine-scale sand and shale endmembers from the coarse-scale measurements, apply Gassmann’s fluid substitution to the sand only, and then Backus average back to the original scale. This procedure, however, is very sensitive to errors in estimated sand fraction and shale properties and becomes particularly unstable at small sand fractions. A new method for fluid substitution combines rock-physics models for dispersed and interbedded sand-shale systems, which are often approximated with Reuss or lower Hashin-Shtrikman interpolations between endmembers quartz mineral, clean sand, and shale. When expressed as P-wave compliance versus porosity, these trends become approximately linear. The Backus average of the normal incidence P-wave compliance of thinly layered mixtures of various sand-shale facies is also a linear trend with porosity. As a result, the upscaled fluid substitution change of compliance of any point within the dispersed or layered sand-shale system is approximately proportional to the fluid-substituted change of compliance of the clean sand endmember, scaled by the ratio of effective porosity to clean sand porosity. The result is a fluid substitution procedure that operates directly at the measurement scale, without the need to downscale the measurements, while still changing fluid in the sand layers only.

Experimental Study of Static Disintegration on Unsaturated Soil

In order to explore the disintegration characteristics of compacted loess, through the unsaturated soil disintegration instrument by independently developed,conduct the soaking disintegration experimental study on remolded soil unsaturated samples,obtained a series of experimental results:①The curves can be divided into the slow disintegration, rapid disintegration and stabilization of disintegration in three stages，the degree of compaction and water rate impact on rapidly disintegrating stage;②When the degree of compaction is certain,the disintegration rate decreased with the water contented increasing,the decreased amplitude is increasing with the moisture content increased to18%,the disintegration characteristics disappeared with the moisture content increased to 22%;③When the initial moisture content is certain, the disintegration rate decreased with the degree of compaction increasing, The time significantly prolonged when the disintegration completed. the decreased amplitude is increasing with the degree of compaction increased to 95%,the disintegration characteristics basically disappeared. Based on the relationship of degree of compaction and the moisture content to void ratio, the thesis establishes the model between the disintegration rate and the effective porosity ratio,the formula can be used to calculate the disintegration rate of compacted loess.The specific conclusions are:①When the critical moisture content increased to 22%,the disintegration characteristics disappeared;②When the critical degree of compaction increased to95%，the disintegration characteristics also disappeared.

Evaluation of Anomalous Solute Transport in a Large Heterogeneous Soil Column with Mobile-Immobile Model

This study uses the mobile-immobile model (MIM) and the traditional convection-dispersion equation (CDE) to analyze the observed breakthrough curves (BTCs) at different distances in a 1,250-cm-long saturated and highly heterogeneous soil column. It provides a simple method to determine the mobile water fraction independently as the ratio of effective porosity over total porosity of the packed soil materials. The effective porosity is calculated a priori as the ratio of measured flow rate and estimated pore-water velocity. It is found that there is a significant amount of immobile water in the soil column, resulting in the anomalous early breakthrough and tailing behaviors of the measured BTCs. Comparing to the CDE, the measured asymmetric BTCs at various scales can be better described by the MIM, especially their early arrival and long tailing parts. The degree of anomalous transport behavior in this large heterogeneous soil column is reduced with transport scale due to the increased mobile water fraction...

Experimental assessment of the infiltration properties of a coarse soil medium in a dielectric infiltration test

An accurate determination of the hydrological characteristics of porous media, such as the values of the porosity and effective porosity, are essential. This is important to understand the transport processes of infiltration and the movement of water and contaminants in the porous media. In this study, a laboratory soil column experiment to estimate the porosity and effective porosity of Toyoura standard sand samples, using a dielectric method termed the frequency domain reflectometry with vector network analyzer (FDR-V), was performed. The FDR-V device uses high-frequency microwaves, ranging from 0.1 to 3 GHz, to measure the complex dielectric constants of the sample. From the measured complex dielectric constant, the two parameters of the soil samples then were derived, using a proposed dielectric mixture model and tracer concentration model. The effective porosity of the soil sample is measured at 0.311 with the FDR-V dielectric method and 0.345 by the soil tracer column test. Comparing this with the calculated porosities of the soil sample, the ratio of effective porosity is approximately 78% for the dielectric method, and approximately 86% for the tracer concentration method. These different values can be explained to be within the measurement range with regard to the measurement volume for the soil column. These results indicate that measurement by the dielectric method using an FDR-V device is an efficient and useful tool for estimating the hydrological parameters of porous media because of the dielectric response of earth materials.

Statistical Hydraulic Conductivity Models and Scaling of Capillary Phenomena in Porous Media

The 1956 Miller and Miller scaling theory predicts that the capillary pressure h(θ) and conductivity K(θ) at liquid content θ in a given member of a family of similar media are related to the corresponding functions h o (θ) and k o (θ) in a reference member by h(θ) = (1/α)h o (θ) and K(θ) = α 2 K o (θ), where α is a scale factor related to pore size. However, in field soils, hydraulic properties are better characterized by the set of scaling relations h(S) = (1/α h ) h o (S) and K(S) = (α K ) 2 k o (S), where S is the liquid-filled fraction of the effective porosity, and α h and α K are scale factors that are generally different from each other. Both results are shown to be theoretically possible through dimensional inspection of statistical hydraulic conductivity models. The models predict the scale factor relation α K = (α h )(α p ) n , where α p is the effective porosity ratio P/P o and n is a model-dependent constant. According to this result, α h = α K if α p = 1 as in Miller and Miller theory, but α h ¬= α K whenever α p ¬= 1.