Porosity and Permeability in Reservoirs Research Papers (original) (raw)

2025, Hydraulic Conductivity

2025, Geophysical Journal International

recently presented new experimental data regarding the dependence of the streaming potential coupling coefficient with the saturation of the water phase. Such experiments are important to model the self-potential response associated with the flow of water in the vadose zone and the electroseismic/seismoelectric conversions in unsaturated porous media. However, the approach used to interpret the data is questionable and the conclusions reached by Allègre et al. likely incorrect

2025, International Journal of Geoinformatics and Geological Science – IJGGS by Seventh Sense Research Group (SSRG)

A previous study from the "NEMA" field by Adizua and Uzu (2024) evaluated petrophysical properties such as porosity, permeability, net to gross (NTG), and water and hydrocarbon saturation from five wells in the field. In this complementary study, we seek to establish the degree of correlations between permeability-porosity derived from both log and core results in Well 09, where both data are available. The study aims to establish that if a high correlation exists between log and core-derived porosities and permeabilities, we can validate log-derived petrophysical parameters in other well locations (Wells 01, 04, 07 and 12) where core data are unavailable. Petrel routines were used to generate the cross plots. The results showed a correlation coefficient (R) of 0.732845 for the core permeability versus core porosity cross plot. A correlation coefficient (R) of 0.79945 for core porosity versus log porosity cross plot and a correlation coefficient (R) of 0.833588 for core permeability versus log permeability cross plot. The plots revealed that core-derived permeabilities correlated very well with log-derived permeability for NEMA 09. Therefore, we can conclude from our findings that in wells where core data were not available, log-derived permeabilities and porosities were true approximations of the actual subsurface petrophysical parameters in those wells. This would ultimately guide in field development planning and exploitation objectives in the field.

2025, Ciencia

Este trabajo se fundamenta en la construcción de un modelo de velocidades intervalicas basado en el cálculo de registros pseudosónicos considerando el factor de anisotropía delta para un medio anisotrópico. Estos son obtenidos a partir de las velocidades de superficie corregidas por el factor delta, y las velocidades en pozos. A partir de estos registros se construyeron dos secciones de velocidades intervalicas en profundidad controladas por pozos con registros sónicos conocidos en cada extremo. Estas secciones fueron usadas como base de comparación entre las secciones de velocidades interválicas corregidas por el factor delta y aquellas donde dicho factor no había sido aplicado con el fin de analizar el impacto generado por la aplicación de esta corrección en el modelo de velocidades sísmicas. En la sección AB se observaron anomalías de velocidad, las cuales son asociadas a variaciones estratigráficas propias de un ambiente depositacional de tipo fluvial. La sección BC muestra anomalías mucho más pronunciadas, en las cuales pudieran estar infiriendo la presencia de fluidos además de cambios estratigráficos. Esta metodología permitió identificar en forma certera las zonas con mayores variaciones laterales de velocidad, las cuales pueden ser usadas para orientar la adquisición de futuros registros sónicos en dicha área.

2025, Geophysical Journal International

Measuring and modelling the permeability of tight rocks remains a challenging task. In addition to the traditional sources of errors that affect more permeable formations (e.g. sample selection, non-representative specimens, disturbance introduced during sample acquisition and preparation), tight rocks can be particularly prone to solid-fluid interactions and thus more sensitive to the methods, procedures and techniques used to measure permeability. To address this problem, it is desirable to collect, for a single material, measurements obtained by different methods and pore fluids. For that purpose, a benchmarking exercise involving 24 laboratories was organized for measuring and modelling the permeability of a single low-permeability material, the Grimsel granodiorite. The objectives of the benchmark were: (i) to compare the results for a given method, (ii) to compare the results between different methods, (iii) to analyse the accuracy of each method, (iv) to study the influence of experimental conditions (especially Downloaded from .

2025, Journal of Physics - Conference Series by IoP Publishing Ltd

Nata de soya is a fermentation product derived from tofu and tempeh waste, known for its strong and stable cellulose structure. This study focuses on characterizing the porosity and permeability of nata de soya porous membranes modified with various raw material compositions. Porosity and permeability were characterized using Scanning Electron Microscopy (SEM) and fluid flow measurements. The results indicate that the composition of tofu and tempeh waste mixture (Composition A) produced membranes with the highest porosity (51%) and permeability (1.70191 x 10-9 m²). Membranes from tofu waste (Composition B) exhibited 47% porosity and permeability of 1.59554 x 10-9 m², while membranes from tempeh waste (Composition C) showed 43% porosity and permeability of 1.27643 x 10-9 m². This research demonstrates that variations in raw material composition and modification processes influence membranes' porosity and permeability characteristics, contributing significantly to the development of biomass-based materials for filtration applications and supporting efforts toward more sustainable management of organic waste.

2025

Resumen. El presente trabajo trata acerca de la valoracion de la eficiencia de un inhibidor de escala de base poliacrilato y de la tecnica de analisis, previo uso de Tubo de Dialisis y Titulaciones para identificacion de las concentraciones del quimico inhibidor en los fluidos de retorno de un pozo del Campo Sacha para el control de incrustaciones calcareas en dos zonas objetivo, las Arenas U y T sobre tres diferentes intervalos. Para el efecto se comprueba la tendencia incrustante de las aguas asociadas a la produccion de petroleo, historiales de los reacondicionamientos y completaciones dispuestos en el pozo durante su vida productiva, geologia y caracteristicas petrofisicas de las formaciones, todo esto con la descripcion de las dosis de quimicos aplicadas, con posterior monitoreo de los residuales del inhibidor en muestras tomadas directas del pozo posterior al tratamiento, separando los fluidos mediante centrifugacion y calentamiento para luego filtrarla con el tubo o membrana ...

2025, Minería y Geología

La discordancia angular del Eoceno, que pone en contacto las arenas B de la formación Misoa con la formación La Rosa, afecta, estructura arriba, el espesor del miembro B6, truncándolo hasta erosionarlo en dirección noroeste, con presencia de cambios de facies y fallas locales. Con el objetivo de contribuir a recuperar las reservas de gas se inició una revisión geológica para ubicar puntos de drenaje. La presente investigación tiene el propósito de identificar el marco estratigráfico y estructural favorable para situar, en la parte alta de la estructura, pozos monobore para drenar las reservas remanentes de gas del yacimiento B6 LL 370, del campo Tía Juana Lago. Se pudo establecer que la parcela A-226 es la de mayor prospectividad para el establecimiento de puntos de drenaje para la perforación de pozos monobore por presentar las mejores condiciones geológicas y de yacimiento. Se proponen dos localizaciones (LL-Z-AB-AC-306-A4 y LL-AC-6-C5A1) para completar monobore con tubería de 5-1/2" para un potencial de producción de 2,8 MMPCND.

2025, UDO

El análisis exhaustivo del nivel de producción del yacimiento RG-107, ubicado en la arena MO-I del Campo Santa Rosa, permitirá optimizar el desempeño de los pozos asociados. Para ello, se implementarán recomendaciones estratégicas enfocadas en mejorar la productividad de aquellos pozos con menor rendimiento. Este proceso incluirá la evaluación detallada de la capacidad de aporte del yacimiento, identificando el tipo de daño y su origen. Con base en la integración de datos clave, como parámetros petrofísicos, diseño de completación y comportamiento de producción, se desarrolló un procedimiento óptimo que incorpora el uso de productos químicos específicos, destinados a incrementar la eficiencia de los pozos actualmente en operación.

2025, ICTEA: International Conference on Thermal Engineering

Fulfilling worldwide energy demand in the 21st century is the most challenging problem. New kinds of energy sources along with the new technological breakthroughs to maintain enough oil and gas supply are needed to meet the tremendous rise in world's energy demand. Recent dramatic fall in oil prices has accentuated the problem. Now, the challenge is to fill out the increasing gap between energy demand and supply with more cost effective techniques. Recently, Abu Dhabi University has filed a patent application ( US -Patent Application No 15/342,664 ) reporting the invention of Dr. Omar Chaalal that fulfills practically all criteria discussed above. In this paper, a 'green' alternative to chemical flooding is proposed. The new technology proposed uses two types of plant extracts that increases the total oil recovery to 96% of initial oil in place (IOIP) during the tertiary recovery mode. While water flood recovered around 50% of the IOIP, 0.5% wt of the natural plant extract recovered 77% in the secondary recovery mode. The additives were extracted from two plants available in the United Arab Emirates (Product A and Product B). These natural extracts proved to be very effective in formations containing water with a salinity range of 70,000 to 180,000 ppm with temperature going up to 100° C.

2025, Developments in Sedimentology

2025, Geophysical Journal International

Induced polarization (more precisely the magnitude and phase of impedance of the subsurface) is measured using a network of electrodes located at the ground surface or in boreholes. This method yields important information related to the distribution of permeability and contaminants in the shallow subsurface. We propose a new time-lapse 3-D modelling and inversion algorithm to image the evolution of complex conductivity over time. We discretize the subsurface using hexahedron cells. Each cell is assigned a complex resistivity or conductivity value. Using the finite-element approach, we model the in-phase and out-of-phase (quadrature) electrical potentials on the 3-D grid, which are then transformed into apparent complex resistivity. Inhomogeneous Dirichlet boundary conditions are used at the boundary of the domain. The calculation of the Jacobian matrix is based on the principles of reciprocity. The goal of time-lapse inversion is to determine the change in the complex resistivity of each cell of the spatial grid as a function of time. Each model along the time axis is called a 'reference space model'. This approach can be simplified into an inverse problem looking for the optimum of several reference space models using the approximation that the material properties vary linearly in time between two subsequent reference models. Regularizations in both space domain and time domain reduce inversion artefacts and improve the stability of the inversion problem. In addition, the use of the time-lapse equations allows the simultaneous inversion of data obtained at different times in just one inversion step (4-D inversion). The advantages of this new inversion algorithm are demonstrated on synthetic time-lapse data resulting from the simulation of a salt tracer test in a heterogeneous random material described by an anisotropic semi-variogram.

2024, Journal of Zhejiang University

This study explores the use of rice husk ash (RHA) and manufactured sand (M-sand) as replacements for cement and fine aggregate, respectively, in lightweight oil palm shell concrete (OPSC). In the first stage of this study, the effect of various cement replacement levels, with RHA (5%, 10%, 15%, and 20%) and 100% sand replacement with M-sand and quarry dust (QD), on the compressive strength of OPSC was investigated. The results showed that the highest compressive strength of OPSC of about 51.49 MPa was achieved with the use of 15% RHA and M-sand. In the second stage of the work, the variables of RHA (0 and 15%) and M-sand (0, 50%, and 100%) were used to investigate their combined effects on the mechanical properties of OPSC. It was found that the combination of 15% RHA and 100% M-sand gave the best performance of OPSC in terms of mechanical properties, such as compressive, splitting tensile, flexural strength, and Young's modulus.

2024

La Saqta es un recurso natural oriundo de la sierra peruana, que cuenta con propiedades de detergencia que podría ser utilizado en los productos de limpieza como el shampoo. Siendo así, el objetivo de la presente investigación fue obtener un shampoo de Saqta como alternativa de disminución de los surfactantes químicos en aguas grises. El uso del shampoo de Saqta reduce los surfactantes químicos en aguas grises puesto que es un producto elaborado con componentes naturales como; goma xantana, esencia de romero, aceite esencial de almendras, conservante natural Procide CG Ecocert, aceite de ricino y Saqta como surfactante natural. La investigación fue de tipo aplicada y diseño experimental, su población fue las aguas grises de los centros de estética del Sector 3 Grupo 7 de Villa el Salvador y su muestra fue un compósito de 24 L. Los instrumentos empleados para la recolección de los datos fueron: Ficha de caracterización de la Saqta, ficha de caracterización de aguas residuales, etique...

2024

Estos agradecimientos van a todos esos seres que han sido un ejemplo, una guía, un apoyo y un empujón para llegar hasta este momento y que tal ves no están mencionadas en esta hoja pero que siempre están en mis oraciones, enfocándome al proyecto, el primero y más importante, DIOS que sin su ayuda nada es posible. A mis padres, Noemí Quinteros y Jorge Aguirre por ser un ejemplo de vida y por estar cuando más he necesitado y a mi hermano Darwin por ocupar el lugar de mi padre desde el momento que Dios lo llamó.

2024

Hydrocarbon production is a function of various elements such as reservoir quality, petrophysical properties, geophysical properties and also volume. Lateral extent of reservoir body is important information for estimation of hydrocarbon initially in place and the recoverable quantity. A method of integrated lateral prediction towards understanding reservoir geometry and rock properties towards enhanced hydrocarbon production is explored with dataset from Bohai bay, Northern China. The methods of conventional well log analysis, seismic interpretation and geostatistical modeling has been employed for this study. Computation of useful logs like Volume of shale, porosity, permeability, Acoustic impedance and Elastic impedance was primarily done on well logs followed by the identification of potential reservoir formation. Lateral extent of reservoir horizons was traced on seismic reflection data with precision through continuity and dominance. Seismic attributes were also computed to as...

2024, Revista Tecnica De La Facultad De Ingenieria Universidad Del Zulia

The aim of this study was to modify a synthetic clay with MgO and a non-ionic surfactant (Igepal CA-720), impregnated with Cu or Fe to evaluate the H2S removal. The Cu and Fe content was: 1.0; 8.0 and 15wt.%, bimetallic Cu-Fe solids were also prepared. The obtained materials were characterized by N2 adsorption, X-ray diffraction (XRD), X-ray fluorescence (XRF), temperature programmed reduction (TPR) and thermogravimetic analysis (TGA). An increase of surface area, pore volume and mesoporosity was observed after clay modification with surfactant and MgO. The modified clay impregnated with Cu showed, by XRD, CuO phases which were confirmed by TPR profiles. The highest H2S removal was obtained for clay sample containing 15% of Cu. It was established that the surface reaction occurred over metallic sites while the porous structure of the material was kept intact after reaction.

2024

Se construye un modelo de dano de formacion por procesos de particula, denominado ADAFOR, en el cual se ensambla la tecnica de Marquardt Levenberg, utilizada para resolver un modelo estadistico de regresion no lineal, con el modelo fenomenologico de Civan para simular dano de formacion en pruebas de desplazamiento en el laboratorio. La solucion del modelo estadistico permite obtener los mejores estimativos para las constantes fenomenologicas del modelo de Civan y permite aplicar ADAFOR para caracterizar los fenomenos de dano que prevalecen en una prueba de desplazamiento realizadas en muestras de roca de yacimiento y empaques de arena artificiales construidos en el laboratorio de yacimientos y fluidos de perforacion de la Universidad Nacional de Colombia. La validacion del modelo muestra que ADAFOR no solo reproduce con precision los resultados de las pruebas experimentales si no que ademas se constituye en una herramienta de analisis para caracterizar los fenomenos de dano de forma...

2024

2024, A Novel Analytical Technique for Evaluating Fractured and Non-Fractured Reservoirs

https://www.cambridgescholars.com/product/978-1-0364-0999-9
In the complex field of carbonate reservoir evaluation, the intricate structural features present significant obstacles. This study tackles the essential task of structural delineation, with a particular focus on fractured reservoirs, and highlights the crucial influence of permeability on the performance of wells and reservoirs. The Oil Based Mud Micro-Imager - resistivity of invading zone (OBMI-Rxo) offers a high-resolution curve that is sensitive to fluid mobility near the borehole wall, although it is often underexploited by oil companies. Maintaining borehole stability after drilling is critical for ensuring the longevity of wells. This research introduces a holistic workflow that combines borehole imagery, petrophysical logs, the Modular Formation Dynamics Tester (MDT), Xpress Pressure Tool (XPT), and core samples for sophisticated formation evaluation in both carbonate fractured and clastic reservoirs. The study reveals new insights into reservoir structure, fracture detection, visualization of rock texture, and permeability distribution, thereby improving our understanding of well conditions in these challenging geological environments.

2024, BOLETÍN DE …

En el área se definieron 5 transectas con 37 pozos en total. Realizando correlaciones estratigráficas aplicando estratigrafía de secuencias, se identificaron 7 ciclos estratigráficos, limitando zonas de mayor y menor relación A/S. Además... more

2024, 55th U.S. Rock Mechanics/Geomechanics Symposium

2024

Simple correlations have been developed for evaluating the primary recovery factor for thin oil rims with large gas caps prior to detailed reservoir simulation. The correlations are based on oil recovery factor estimates obtained from three dimensional, three-phase black oil reservoir simulation models for saturated reservoirs with overlying gas caps at their initial state, which capture spatial effects and the dynamics of oil rim and gas cap production. Dominant factors (oil rim thickness, horizontal permeability, gas cap size, oil viscosity, gas cap offtake, aquifer strength and reservoir dip) that affect oil rim and gas cap production were obtained using foldover Plackett-Burman screening designs. Response Surface Models (correlations) were then developed using BoxBehnken experimental design to obtain oil recovery estimates under conventional development and concurrent development at gas cap production up to 15% of the free gas initially in Place per annum. The oil recovery facto...

2024

The Upper Miocene lacustrine sandstones of the North Croatian Basin, located in the southwestern Pannonian Basin System, represent significant reservoirs for hydrocarbon exploration, yet their diagenetic evolution remains poorly understood. This study offers a comprehensive investigation into the diagenesis of these sandstones, analyzing samples from 14 exploration wells in the Sava and Drava depressions. Using petrographic analyses, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction (XRD), and petrophysical measurements, we aimed to explain the diagenetic processes affecting reservoir quality and hydrocarbon productivity. Our results reveal a consistent grain size distribution, modal composition, and diagenetic alterations across both depressions. Compaction, evidenced by evolving grain contacts and pressure dissolution, leads to a depth-dependent reduction in porosity. Carbonate cements, notably calcite and Fe-dolomite/ankerite, are primary contributors to reduction of primary intergranular porosity, alongside clay minerals, quartz, feldspar, etc. Secondary porosity resulting from dissolution and redistribution processes also significantly influences overall porosity evolution. Clay minerals, detrital and authigenic, exhibit a complex interplay with other diagenetic processes, further reducing porosity and permeability. Authigenic clay minerals, including illite, chlorite, and kaolinite, act as pore-filling cement or coatings, hindering fluid flow. Paragenetic processes delineate the intricate relationship between mineralogical transformations and petrophysical properties, defining reservoir quality. Understanding diagenetic dynamics is essential for predicting reservoir quality, fluid migration pathways, and hydrocarbon productivity. This study fills a crucial knowledge gap regarding the diagenesis of the Upper Miocene lacustrine sandstones in the southwestern part of the Pannonian Basin System, providing insights vital for the energy sector and supporting sustainable resource development in the region.

2024, Journal of the Geological Society of India

Bioturbation is a typically small scale yet potentially significant geological process altering rock properties by reworking. For many years, bioturbation studies found application in exploration geology to estimate paleobathymetry, interpreting depositional environment and identifying key stratigraphic surfaces. These act as vital inputs to the geological models, for determination of source rock potential, reservoir quality and modeling of petroleum systems. Recently geologists extended the application of bioturbation studies to address production related challenges. Recognizing the bioturbation effects and incorporating them in reservoir simulation models can improve production predictions and enhanced oil recovery operations. This paper discusses bioturbation and its effects on reservoir quality, its performance and production.

2024

The anthropogenic emissions of CO 2 have been amounted in 2004 to 26 billion tons, according to the actual scenario, the emissions of CO 2 will be doubled in the horizon of 2050 to reach more than 50 milliards tones of CO2 per year, and we will get 1000 ppm (part per million) as concentration of CO 2 in the upper atmosphere in the end of 21st century, which is completely unacceptable concentration in terms of impact on the climate and socioeconomic, In fact, according to climatologists, in order to keep the warming climate below 02°C we MUST keep the CO 2 concentration at 450 ppm, which should limit the consequences on ecosystems and the life of the society, Beyond of this level, climate models indicate a high changes will take place with an effect negative on the climate system what can lead to disaster scenarios in the coming decades and centuries. The target of 450 ppm obliges the humanity to reduce its emissions of CO 2 by the half in the horizon of 2050 compared to the current ...

2024, Geoenergy Science and Engineering

The three-dimensional porosity simulation plays a pivotal role in the exploration and prospecting of oil fields. In this study, we introduce a hybrid methodology for subsismic resolution porosity estimation, combining algorithms based on fuzzy logic and geostatistics. We demonstrate how it is possible to use simulated facies association surfaces and structural surfaces as input parameters for the fuzzy logic algorithm to derive porosity trends, subsequently refined using simple kriging with magnetic resonance log obtained from wells. The selected simulation area is the Sapinhoá field, located in the Santos Basin, Brazil, covering the age interval from 123 Ma to 113 Ma. To statistically validate the results, we employed the Pearson correlation coefficient, along with graphs comparing the measured and simulated porosity in the wells. The obtained results showed satisfactory levels of accuracy in the evaluated wells. Moreover, in areas lacking well data, the simulated porosity volumes aligned with the trends modeled using fuzzy logic.

2024, Fuentes El Reventon Energetico

2024

Reservoir characterization plays a critical role in appraising the economic success of reservoir management and development methods. This study identifies the different rock types that comprise reservoirs, marginal reservoirs and non-reservoirs. Porosity and permeability are the key parameters for identifying the rock types and reservoir characterization. The qualification of these parameters is usually measured directly from cores using conventional core analysis methods, and indirectly using geophysical well logs, well tests, and artificial neural network methods. However, for determination of rock types and reservoir evaluation, in addition to quantity of porosity and permeability we need to determine pore geometry and pore aperture size which are related to grain size, sorting and packing as well as to factors such as the mineralogy and diagenetic history of the reservoir. This paper presents the results of a combination of conventional core analysis, capillary pressure curve characteristics, compressional net stress analysis, thin sections and SEM petrographical investigations integrated with geophysical well logs. A total of 4 different rock types were identified within the reservoir interval, in addition to two types of pore throat, one with a larger flow capacity than the other. The low permeability in non-reservoir rock types is probably related to higher amounts of clay minerals that affect pore throat connectivity and fining the pore throats between the microcrystalline calcites in the reservoir.

2024, Journal of Applied Sciences 23(1):34-46

Characterizing fracture properties in naturally fractured reservoirs poses a significant challenge. While well-testing remains valuable, it often fails to provide precise descriptions of these properties. Bridging this gap requires the integration of geological expertise to enhance fracture assessment. This study addresses the limitations of well-test analysis and explores the application of Conventional Image Logs in structural, fracture, and geomechanical analysis. However, effectively combining these applications with well-test analysis on a field scale reveals a substantial knowledge gap. A critical challenge in this context is the absence of a defined procedure for calculating the variable "σ," a crucial parameter for simulating fractured carbonate reservoirs using image log fracture density. Integrating geological knowledge is essential to reduce uncertainties associated with well-test analysis and provide more accurate characterizations of fracture properties. Image log data processing emerges as a valuable avenue for gaining insights into the static attributes of naturally fractured reservoirs. This study focuses on Characterizing fractures using data from ten image logs and Developing a more accurate simulation model through the interpretation of images, with a particular emphasis on OBM imaging. The main goals of this fracture study revolve around establishing correlations between fracture densities well by well within the simulation and enhancing the accuracy of the simulation model by incorporating fracture data from image logs. Borehole imaging tools such as FMI/FMS and OBMI-UBI play a pivotal role in identifying significant structural features, including faults, fractures, and bedding. Fine-tuning fracture parameters during the history matching process, while potentially time-consuming, significantly impacts other historical match parameters. Consequently, the reliability of reservoir simulation results, predictions, and recovery enhancement strategies hinges on the precision of fracture properties and their distribution within the model. Recent advances in interpretation techniques have expanded the horizons of image interpretation, enabling the creation of more accurate simulation models for fractured reservoirs using fracture data obtained from image logs. The overarching goal of this project is to comprehensively evaluate a fractured reservoir field by integrating data from ten individual wells. Keywords: Well-testing, fracture evaluation, Image log data, fracture density, simulation sensitivity analysis.

2024, Russian Journal of Earth Sciences

Core description, well logs data, petrographic analysis and scanning electron microscope technique were conducted to unravel factors controlling the preservation of high porosity up to 25% in deeply-buried sandstones > 4 km of the Lower Cretaceous Nahr Umr reservoir, southern Iraq. The Nahr Umr Formation composed of sandstone interbedded with shale, minor siltstones and streaks of limestone. The sandstones are arenites and range from fine to coarse, and poor to moderate sorted. Parallel lamination, planer cross-bedded and lenticular bedding are common sedimentary structures found in the formation, suggesting that the Nahr Umr deposited in fluvial-deltaic to the shallow-marine environment. Cementation by syntaxial quartz overgrowth was retarded by the presence of illite coats, which was formed by the illitization of the infiltrated smectite that formed during the deposition around the quartz grains. Microquartz coats in the form of quartz crystals probably further prevented the quartz overgrowths. Thus, the porosity of Nahr Umr preserved by the illite coats and microquartz crystals, whereas, the process of K-feldspar dissolution has created secondary porosity. The stylolite formation and the quartz-calcite replacement are the main sources of silica for the precipitation of quartz overgrowth.

2024

With the aid of linear filter theory we analyze 13,824 permeability measurements to empirically address the question, What does an instrument measure? By measure we mean the sample support or sample volume associated with an instrument, as well as how the instrument spatially weights the heterogeneities comprising that sample support. Although the theoretical aspects of linear filter analysis are well documented, physical data for testing the filtering behavior of an instrument, particularly in the context of porous media flow, are rare to nonexistent. Our exploration makes use of permeability data measured with a minipermeameter on a block of Berea sandstone. Data were collected according to a uniform grid that was resampled with tip seals of increasing size (i.e., increasing sample support). Spatial weighting (filter) functions characterizing the minipermeameter measurements were then calculated directly from the permeability data sets. In this paper we limit our presentation to one of the six rock faces, consisting of 2304 measurements, as the general results for each rock face are similar. We found that the empirical weighting functions are consistent with the basic physics of the minipermeameter measurement. They decay as a nonlinear function of radial distance from the center of the tip seal, consistent with the divergent flow geometry imposed by the minipermeameter. The magnitude of the weighting function decreases while its breadth increases with increasing tip seal size, reflecting the increasing sample support. We further demonstrate, both empirically and theoretically, that nonadditive properties like permeability are amenable to linear filter analysis under certain limiting conditions (i.e., small variances). Specifically, the weighting function is independent of the power average employed in its calculation (e.g., arithmetic versus harmonic average). Finally, we examine the implications of these results for other instruments commonly employed in hydraulic testing (e.g., slug and pump tests).

2024, SPE Reservoir Evaluation & Engineering

Summary Over 75,000 permeability measurements were collected from a meter-scale block of Massillon sandstone, characterized by conspicuous crossbedding that forms two distinct nested scales of heterogeneity. With the aid of a gas minipermeameter, spatially exhaustive fields of permeability data were acquired at each of five different sample supports (i.e., sample volumes) from each block face. These data provide a unique opportunity to physically investigate the relationship between the multiscale cross-stratified attributes of the sandstone and the corresponding statistical characteristics of the permeability. These data also provide quantitative physical information concerning the permeability upscaling of a complex heterogeneous medium. Here, a portion of the data taken from a single block face cut normal to stratification is analyzed. The results indicate a strong relationship between the calculated summary statistics and the cross-stratified structural features visibly evident ...

2024, Geosciences

The petroleum industry has always been pursuing highly exploitable gas fields, which are often hosted in carbonate rocks. However, carbonates are highly heterogeneous and show different fabrics and structures as the result of sedimentation in various environments, and subsequent diagenesis and deformation. In this study, a multi-scale and multidisciplinary approach has been performed on classical reservoir rocks from the subsurface of the Hyblean Plateau (Sicily, Italy). We aim at unravelling the important and debated role of tectonic and diagenetic structures (mainly fractures as well as stylolites) in enhancing or reducing the porosity. Black shales, limestones, and laminites of intertidal environment represent the main lithologies. Structure cross-cutting relationships record different stages of the basin geological history, which are related to the tectonic evolution of the area. Our results show that porosity is uncommonly lightly affected by fractures and faults, because of th...

2024, Journal of Natural Gas Science and Engineering

Creating a mechanical earth model (MEM) during planning the well and real-time revision has proven to be extremely valuable to reach the total depth of well safely with least instability problems. One of the major components of MEM is determining horizontal stresses with reasonable accuracy. Leak-off and minifrac tests are commonly used for calibrating horizontal stresses. However, these tests are not performed in many oil and gas wellbores since the execution of such tests is expensive, time-consuming and may adversely impact the integrity of the wellbore. In this study, we presented a methodology to accurately estimate the magnitudes and directions of horizontal stresses without using any leak-off test data. In this methodology, full waveform acoustic data is acquired after drilling and utilized in order to calibrate maximum horizontal stress. The presented methodology was applied to develop an MEM in a wellbore with no leakoff test data. Processing of full waveform acoustic data resulted in three far-field shear moduli. Then based on the acoustoelastic effect maximum horizontal stress was calibrated. Moreover, maximum horizontal stress direction was detected using this methodology through the whole wellbore path. The application of this methodology resulted in constraining the MEM and increasing the accuracy of the calculated horizontal stresses, accordingly a more reliable safe mud weight window was predicted. This demonstrates that the presented methodology is a reliable approach to analyze wellbore stability in the absence of leak-off test.

2024, Journal of Natural Gas Science and Engineering

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2024, Marine and Petroleum Geology

A paucity of well data in frontier basins presents serious challenges for reservoir characterisation studies around the world. In this paper, we provide the first regional study addressing reservoir distribution, composition and quality in the frontier Canterbury Basin (CB) and Great South Basin (GSB) of New Zealand, and show how the results can be used to help reduce uncertainties associated with reservoir presence and effectiveness. Cretaceous strata in Canterbury and Great South basins represent two stages of basin history. The oldest Cenomanian-Coniacian (mid-Cretaceous) strata are syn-rift deposits that developed in response to the breakup of the eastern margin of Gondwana, while overlying Santonian-Maastrichtian (late Cretaceous) strata are postrift deposits that signify the start of rift-drift transgression. These Cretaceous deposits are characterised by a change in facies from predominantly alluvial-fluvial to marginal-shallow marine that is recognisable in outcrop and wells, and from seismic response. Based on our petrographic examination of 99 Cretaceous samples from well and outcrop locations, we conclude that there are significant differences in sandstone texture and mineralogy that are related to differences in depositional facies, basin stratigraphy, geographic location, and degree of diagenetic alteration. Sandstones from the earliest part of the syn-rift succession largely reflect the composition of the underlying basement geology; typically granitoid or quartzose Western Province rocks in GSB, and lithic-rich Eastern Province metasedimentary rocks in CB. Younger strata, representing part of the post-rift succession, are generally better sorted, with detrital compositions reflecting sediment mixing of several basement source areas. Based on available data, reservoir quality is directly related to sandstone texture and detrital composition (factors of provenance and facies), compaction (a factor of burial depth/temperature), and degree or type of diagenetic alteration. Best quality sandstones are predicted to occur in the late Cretaceous post-rift succession of GSB and locally in CB, either where sediment is derived from local granitoids, or where high-energy depositional processes have resulted in quartz-enriched compositions.

2024

Aims Porosity-permeability relationships in complex carbonates are poorly understood. The contribution of micro-, mesoand macropores to the connectivity needs to be unravelled. The aim of the study is to develop a multidisciplinary approach that leads to a better assessment of poro-perm relations. The focus lies on the integrated use of petrophysical analysis, CT, NMR and the necessity of the integration of these techniques for understanding the poroperm relationships. The samples used for this study are travertines from the Denizli Basin (Ballık area, Turkey) and are selected from four facies: i.e. pool, reed and cascade and waterfall facies (Guo & Riding, 1998).

2024, Petroleum Science and Technology

First and foremost thanks are due to Allah who gave me strength, patience and ability to accomplish the present work. Acknowledgment is due to the King Fahd University of Petroleum & Minerals for supporting this research. I wish to express my appreciation to Dr. Gharib M. Hamada, who served as my major advisor, for his guidance and patience through the thesis. His continuous support and encouragement can never be forgotten. I would like also to thank my thesis committee members Dr. Abdulaziz A. Al-Majed and Dr. Taha M. Okasha for their suggestions and valuable comments. Thanks are also due to the Chairman of the Petroleum Department Dr. Sidqi A. Abu-Khamsin for providing all the available facilities. I am also grateful to all faculty members for their encouragement and their direct or indirect help. Many thanks are also due to all the laboratory staff members in the Petroleum Section of the Research Institute for their cooperation and help during the experimental work. My special thanks are addressed to my family for their encouragement throughout my academic career. Also, I thank my friends in and out of campus. v

2024, Geophysical Journal International

SUMMARYOur limited knowledge of the relationship between changes in the state of an aquifer or reservoir and the corresponding changes in the elastic moduli, that is the rock physics model, hampers the effective use of time-lapse seismic observations for estimating flow properties within the Earth. A central problem is the complicated dependence of the magnitude of time-lapse changes on the saturation, pressure, and temperature changes within an aquifer or reservoir. We describe an inversion methodology for reservoir characterization that uses onset times, the calendar time of the change in seismic attributes, rather than the magnitude of the changes. We find that onset times are much less sensitive than magnitudes to the rock physics model used to relate time-lapse observations to changes in saturation, temperature and fluid pressure. We apply the inversion scheme to observations from daily monitoring of enhanced oil recovery at the Peace River field in Canada. An array of 1492 bur...

2024, Journal of Petroleum Science and Engineering

2024, Marine and Petroleum Geology

The Oolithe Blanche Formation was studied in three quarries, located at the south-eastern edge of the Paris Basin (France). Heterogeneities in reservoir properties were assessed through a sedimentological, diagenetic and petrophysical study. The relationships between depositional settings, diagenesis and petrophysical properties were analysed using detailed petrographic studies, image analysis, Nano CTscans and petrophysical measurements. The carbonate reservoir pore network is mainly controlled by intraparticle microporosity which ensures the connectivity with interparticle meso-and macroporosity. Early cementation vs. early compaction processes (mainly grain interpenetration) may have considerable influence on fluid-flow properties and parameters such as permeability, acoustic velocities and tortuosity. Better reservoir properties are found when compaction processes begin before cementation. From statistical analyses, e.g. Principal Component Analysis and Linear Discriminant Analysis, a sedimentological/diagenetic and petrophysical model is proposed that is in a good agreement with the geological model developed from field work.

2024, Journal of Applied Mathematics

In this study, new master theorems and general formulas of integrals are presented and implemented to solve some complicated applications in different fields of science. The proposed theorems are considered to be generators of new problems, including difficult integrals with their exact solutions. The results of these problems can be obtained directly without the need for difficult calculations. New criteria for treating improper integrals are presented and illustrated in four interesting examples and some tables to simplify the procedure of using the proposed theorems. The outcomes of this study are compared with those presented by Gradshteyn and Ryzhik in the classical table of integrations. The results in this study are simple and applicable in solving integrals, and some of the well-known theorems in calculating improper integrals are considered simple cases of our research.

2024, Arabian journal for science and engineering

The Kozeny-Carman and Timur-type equations 1 connecting porosity and permeability contain rock-textural 2 constants such as tortuosity and specific surface area. Some-3 times these are combined in single factors as Kozeny constant 4 or flow zone index. The partial differential equations of flow 5 in triple-porosity rocks contain transfer factors, interporos-6 ity flow shape factors between different kinds of pores, as 7 well as their individual storativities. Without knowing these 8 constants, no meaningful permeability prediction or flow 9 simulation is possible. The paper reviews the main ideas of 10 how to find such rock-textural properties directly from the 11 microscopic image.

2024, University of Tehran

Two surface sections of the Sarvak Formation in the Lurestan zone (Zagros Fold-Thrust Belt) were examined to inspect the naturally occurring fractures. The inspected sections are located in the Surgah anticline and the Kuh-e-Charmi anticline; in the Ilam and the Kermanshah provinces respectively. The Sarvak Formation was carefully examined to record the fracture types, their spatial distribution, spacing and cross-cutting relationships. Detailed examinations were undertaken on 420 fractures, 40 core plugs porosity and P-wave velocity and 205 thin sections. Three genetic types of fractures including tectonic, pressure-solution and dissolution related fractures were identified. The tectonic related fractures include two main sets (namely, with NW-SE and NE-SW trends). In addition, two types of stylolites including the bed-perpendicular and the tectonic stylolites (bed-parallel); were distinguished that postdate the fractures (veins). The Sarvak Formation underwent various diagenetic processes in couple with fracturing. The pore types include microporosity, intergranular porosity, moldic porosity and fracturestylolite. Petrophysical measurements (performed on some core plugs prepared from surface block samples), show that the carbonates of the Sarvak Formation have low porosity (more than 74% of the samples have less than 3%) and thereby high compressional wave velocity (Vp), (more than 96% of the samples have 6000 m/s), Therefore, it could be concluded that the Sarvak Formation is a tight interval in a reservoir aspect.

2024, Society of Economic Geologists and Mineral Technologists (SEGMITE)

The present research is focused on the diagenetic studies and reservoir characterization of the Cretaceous Kawagarh Formation exposed in the Gandab Village, Kala-Chitta Range, NorthWestern Himalayan Fold-and-Thrust Belt, Pakistan. The Formation is composed of argillaceous limestone and dark grey marls. A total of thirty three representative carbonate rock samples were collected at equal intervals of three meters. Various diagenetic features including cementation, micritization, pyrite precipitation, neomorphism, fracturing, sparitization and stylolitization were observed in the studied rocks which occur in the marine, meteoric and deep burial diagenetic environments respectively. Such diagenetic features control the reservoir quality of the rock unit. Porosity types include mostly vuggy and fracture while minor stylolitic porosity were noted with quantity ranging from 2.66% to 3.88%. The carbonates of Kawagarh Formation are highly fractured but filling of these fractures due to the precipitation of calcite or micritic mud has greatly reduced its reservoir potential while some unfilled fractures, stylolites and vuggs are the dominant factors that enhance the reservoir potentiality of the Kawagarh Formation. However, the porosity values still not marks the level of reservoir rock. These diagenetic studies revealed very less chances for hydrocarbon accumulation as no significant porosity values have been observed and overall reservoir potential is characterized as poor.

2024, Geophysical Journal International

2024, Middle East Journal of Applied Science & Technology (MEJAST)

Petrophysical evaluation of selected wells in FUBA field reservoir in Niger Delta, Nigeria are here presented. A suite of well logs comprising gamma ray, deep resistivity, density, sonic and neutron were used in the analysis. Petrophysical properties evaluated are; thickness, porosity, permeability, water saturation and hydrocarbon saturation. Two distinct horizons were mapped. The lithostratigraphy correlation section revealed that each of the sand units spread over the field differ in thickness with some units occurring at greater depth than their adjacent unit, that is possibly an evidence of faulting. From the result of Petrophysical evaluation, on average, net thickness, effective porosity, permeability, water saturation, hydrocarbon saturation and shale volume values are 13.50 ft, 23.50%, 463.70 mD, 30.50%, 69.50% and 12.50% for reservoir sand Q and 45.00 ft, 22.20%, 495.24 mD, 32% and 68% and 16.50% for reservoir sand R. The porosity and permeability values have been classed as good to excellent for reservoir sand Q and R respectively. The hydrocarbon saturation and water saturation values are good for reservoir development for production. The results of the sand-shale lithology calculated indicate the following (i) the fraction of shale in the reservoirs is quite low; (ii) sandstone volume decreased with increasing depth while shale volume increased with depth; (iii) an inverse relationship between permeability and shale volume and a direct relationship between permeability and the volume of sand in the reservoirs. This is typical of clastic reservoir systems in the Niger Delta. An analysis of the petrophysical attributes maps indicates how the petrophysical qualities vary across the reservoirs. The results for this work revealed the presence of hydrocarbon in both reservoirs across the wells in the study area.

2024, Arabian Journal of Geosciences

A significant percentage of the world's hydrocarbon reserves are found in shallow marine sandstone rocks. Understanding reservoir connectivity and quality of shallowmarine sandstones from outcrop analysis and facies characteristics is a challenging task. Here, we analyze well-exposed outcrops of the Miri Formation, Sarawak Basin, Borneo, to characterize reservoir properties (grain-size, petrography, pore-perm, and static connectivity) of different sandstone facies and to construct a 2D intermediate-scale model of sandstone distribution and connectivity. The outcrops, with lateral extent of ∼200-500 m, consist of mostly sandstone with mudrich deposits including some isolated sand bodies. Field description in terms of facies distribution and dimensions of sand bodies and rock sampling for grain-size (Folk and Ward methods), petrographic (point count method for porosity, sorting, grain-size, and sand-mud %), and poro-perm (for porosity and permeability) analyses were performed to quantify and examine seven different types of sandstones facies, i.e., (i) hummocky cross-stratified sandstones (HCSS, ∼0.5-4 m thick), (ii) herringbone cross-bedded (HBCBS, ∼0.5-3 m thick), (iii) trough cross-bedded sandstones (TCBS, ∼0.5-2 m thick), (iv) wavy-to flaser-bedded (W-FBS, ∼1-3 m thick), (v) cross-bedded sandstone (CS), ∼0.5-3 m thick), (vi) bioturbated sandstone (BS, ∼1-5 m thick), and (vii) massive sandstone (MS, ∼0.5-2 m thick). Our results show that compared to other sandstone facies, sandstones of HCSS and HBCBS are better sorted, have minimal mud content, and display increasing vertical and lateral connectivity due to depositional patterns even in bioturbated rich sand. Sandstones of BS and CB are of poor quality in terms of grain sorting and poro-perm, while TCB and MS sandstone facies are of less lateral and vertical extent. On the basis of these results, a 2-D outcrop-based model is constructed that provide additional insights into the significance of small-scale heterogeneity and static connectivity of shallow marine sandstone deposits which can be an analogue for subsurface reservoir quality analysis.

2024

Tras 60 años de inyección continua, el proceso de recuperación secundaria implementado en el Complejo Poza Rica se acerca a su fase terminal. Más del 29% del aceite in situ ha sido recuperado: 20.6% en la etapa primaria, 9.1% en la... more