Experimental study of the relationship between porosity and surface area of carbonate reservoir rocks

Abstract

Over the time by increasing global demand for source of energy and decreasing hydrocarbon production from reservoirs, recovery methods have become important. The surface area and porosity are central physical characteristics that highly affect the estimation of original oil and gas in place and understanding the mechanisms incorporating in production. The surface area is the internal surface area per unit of pore volume and determines the amount of space in rocks exposed to injectant during injection operation. The occurrence of fractures system in carbonated reservoirs increases the complexity and decreases the homogeneity; hence, it is difficult to determine the correct surface area of reservoir. Therefore, the existence of a local correlation which relates effective porosity to specific surface area is needed and it can help to estimate effective surface area exposed to chemicals during Enhanced Oil Recovery (EOR) process. In this study, the specific surface area in carbonate reservoir rocks was measured by gas adsorption (nitrogen) method and petro-graphical image analysis. In addition, the effective porosity was determined by a gas porosimeter, followed by plotting specific surface area measured by the Brunauer, Emmett and Teller (BET) method versus specific surface area determined from core scan and calibration curve. According to this calibration curve, a new relationship was developed (with R 2 = 0.92) that could give BET data for a known data of core scan. The relationship between porosity and specific surface area was analyzed statistically and a relationship with accuracy of R 2 = 0.89 was proposed. This relationship was compared with other models such as Pirson and Kotyakhov. Results show that the latter one is more accurate than other models and is more compatible with experimental data (with R 2 = 0.84). The results obtained from the experiment indicate that the specific surface area shows an initial decrease upon increasing of porosity up to 0.2. After this decrease, the curve indicates an increasing trend. Moreover, a novel relationship was developed depending on the specific surface area, porosity and permeability and some constant parameters for carbonate rocks (with R 2 = 0.95).

Research Advances, Maturation, and Challenges of Hydrate-Based CO2 Sequestration in Porous Media

“…Porous media properties are mostly interdependent and could vary greatly for different particle sizes. For example, the surface area is a function of particle size and porosity . The range of grain size used for studying hydrate formation in porous media is 0.0007–1000 μm.…”

“…These contrasting findings arise from the knowledge that the trend of hydrate formation depends on the particle size distribution properties such as specific surface area and pore network structure but not necessarily on the porosity. The surface area is the internal surface area per unit of pore volume representing the amount of space or sites in the sediments that can enhance hydrate formation during the injection of CO 2 . The model of Palodkar et al proved the role of porous media’s effective surface area on CO 2 hydrate growth.…”

“…For example, the surface area is a function of particle size and porosity. 46 The range of grain size used for studying hydrate formation in porous media is 0.0007−1000 μm. At the same time, porosity ranges from 0.24 to 0.559 are studied at different water saturation.…”

Eudragit-Coated Sporopollenin Exine Microcapsules (SEMC) of Phoenix dactylifera L. of 5-Fluorouracil for Colon-Specific Drug Delivery

“…Here, we exposed the porous and solid SEMC to N 2 at liquid nitrogen conditions (i.e., 77 K) as probe molecule at different conditions and evaluated the weight uptake/the volume of N 2 adsorbed by macroporous SEMC, 5-FU-loaded SEMC (F2) and the ERS-coated SEMC (F2-ERS). Here, the software of the instrument (TriStar-3000) employed the BET technique/equation to the portion of the isotherm to examine the surface area of the porous SEMC [53]. The pore size distribution of the macroporous SEMC, 5-FU-loaded SEMC (F2), and the ERS-coated (F2-ERS) was examined using Langmuir N 2 adsorptiondesorption isotherms, as illustrated in Figure 3.…”

Modelling the effect of grain anisotropy on inter-granular porosity

“…A threshold value is assigned in such a way that each pixel in the image is classified as object or background. The threshold value defines the cut-off greyscale values that differentiate grains and pores and aids in measuring grains or features in an image (Mohammadi et al 2020). The FESEM images acquired are 2D raster images of the sample surface.…”