Effective porosity

About: Effective porosity is a research topic. Over the lifetime, 1199 publications have been published within this topic receiving 26511 citations.

Application of well log analysis to estimate the petrophysical parameters and evaluate the reservoir quality of the Lower Goru Formation, Lower Indus Basin, Pakistan

Abstract: The present study deals with the petrophysical evaluation using well log data of Lower Goru Formation from five selected wells namely Nara-1, Kadanwari-3, Kadanwari-4, Gajwaro-1 and Mehrab-1 in the Lower Indus Basin. Various cross plots indicate that the formation of interest is mainly composed of sandstone, shale and carbonates. In addition, clay content is also analysed using potassium versus thorium and PEF versus Th/K ratio plots. Interactive Petrophysics (IP-2013) software is used to assess the petrophysical parameters. The volume of shale has been estimated between 6.1% and 14.07% from the studied wells. Similarly, the total porosity is observed between 14.6% and 18.02% while the effective porosity ranges 12.5–16.5%. The water saturation is quite low and exhibits between 14.05% and 31.58%. Moreover, the hydrocarbon saturation ranges 68.42–85.95% in the studied wells. 23 pay zones of variable thickness and significant hydrocarbons presence have been identified within the studied wells, thus proving the Lower Goru Formation as a promising reservoir. The study also indicates Nara-1 Well as the most prolific in terms of high hydrocarbon saturation and low water saturation. The study method can be used within the vicinity of Lower Indus Basin and similar basin elsewhere in the globe to quantify petrophysical properties of oil and gas wells and comprehend the reservoir potential.

Elongation of textile pelvic floor implants under load is related to complete loss of effective porosity, thereby favoring incorporation in scar plates.

Abstract: Use of textile structures for reinforcement of pelvic floor structures has to consider mechanical forces to the implant, which are quite different to the tension free conditions of the abdominal wall. Thus, biomechanical analysis of textile devices has to include the impact of strain on stretchability and effective porosity. Prolift(®) and Prolift + M(®), developed for tension free conditions, were tested by measuring stretchability and effective porosity applying mechanical strain. For comparison, we used Dynamesh-PR4(®), which was designed for pelvic floor repair to withstand mechanical strain. Prolift(®) at rest showed moderate porosity with little stretchability but complete loss of effective porosity at strain of 4.9 N/cm. Prolift + M(®) revealed an increased porosity at rest, but at strain showed high stretchability, with subsequent loss of effective porosity at strain of 2.5 N/cm. Dynamesh PR4(®) preserved its high porosity even under strain, but as consequence of limited stretchability. Though in tension free conditions Prolift(®) and Prolift + M(®) can be considered as large pore class I meshes, application of mechanical strain rapidly lead to collapse of pores. The loss of porosity at mechanical stress can be prevented by constructions with high structural stability. Assessment of porosity under strain was found helpful to define requirements for pelvic floor devices. Clinical studies have to prove whether devices with high porosity as well as high structural stability can improve the patients' outcome.

Simultaneous measurement of rock permeability and effective porosity using laser-polarized noble gas NMR.

Abstract: We report simultaneous measurements of the permeability and effective porosity of oil-reservoir rock cores using one-dimensional NMR imaging of the penetrating flow of laser-polarized xenon gas. The permeability result agrees well with industry standard techniques, whereas effective porosity is not easily determined by other methods. This NMR technique may have applications to the characterization of fluid flow in a wide variety of porous and granular media.

Scale dependence of intragranular porosity, tortuosity, and diffusivity

Abstract: [1] Diffusive exchange of solutes between intragranular pores and flowing water is a recognized but poorly understood contributor to dispersion. Intragranular porosity may also contribute to the “slow sorption” phenomenon. Intragranular pores may be sparsely interconnected, raising the possibility that accessible porosity and diffusive exchange are limited by pore connectivity. We used a pore-scale network model to examine pore connectivity effects on accessible porosity, tortuosity, and diffusivity in spherical particles. The diffusive process simulated was release of a nonsorbing solute initially at equilibrium with the surrounding solution. High-connectivity results were essentially identical to Crank's analytical solution. Low-connectivity results were consistent with observations reported in the literature, with solute released at early times more quickly than indicated by the analytical solution, and more slowly at late times. Values of accessible porosity, tortuosity, and diffusivity scaled with connection probability, distance to the sphere's exterior, and/or the sphere's radius, as predicted by percolation theory. When integrated into a conventional finite difference model, the scaling relationships provide a consistent and physically sound way to incorporate such nonuniformities into models of intragranular diffusion.