Effective porosity

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

Evaluation of the damages of permeability and effective porosity of tectonically deformed coals

Abstract: A high rank coal was tested in terms of loading and unloading to characterize changes in the permeability and effective porosity of tectonically deformed coals. The coal sample, an anthracite, is subdivided into four types according to its structure, namely, the primary structure coal, cataclastic coal (the weakest deformation coal), granulated coal (the moderate deformation coal), and mylonitic coal (the intensest deformation coal); the latter three types are considered to be tectonic deformation coals. Permeability of tectonically deformed coals shows a negative exponential relation to stress. The intenser the structural deformation in coal is, the lower the permeability. Two evaluation parameters, namely, loss rate m (0.8318–0.9476) and damage rate n (0.447–0.6556), which are related to changes in permeability, increase with increasing structural deformation in coal. The cleat compressibility factor declines with increasing difference in effective stress and increases with increasing structural deformation in coal. This study proposes a calculation method for evaluating the porosity damage. Similar to the loss ratio and damage rate, this parameter (η) increases with increasing structural deformation in coal and reveals the relationship between the porosity damage and the structural deformation in coal.

Petrophysical Evaluation of the Tensleep Sandstone Formation Using Well Logs and Limited Core Data at Teapot Dome, Powder River Basin, Wyoming, USA

Abstract: This study presents a petrophysical analysis carried out to evaluate the rock properties of the Tensleep Sandstone Formation (TSF) at Teapot Dome, Powder River Basin, Wyoming. The TSF is dominated by porous and permeable eolian cross-bedded sandstones of dune and interdune origin, but also contains marine carbonate/dolomite beds. A-sandstone, B-dolomite, and B-sandstone units of TSF were identified by the stratigraphic well log correlations and further evaluated for hydrocarbon potentiality. Shale volume, lithofacies, porosity, and fluid saturation were identified from the well logs. Permeability was empirically driven from available core data from one well. The computed effective porosity range in TSF subunits is 4–8, 5–14, and 5–20% for A-sandstone, B-dolomite, and B-sandstone, respectively. Permeability was deduced to be 0.001–3.9, 0.01–14, and 0.1–234 mD, respectively. B-sandstone was identified as the most hydrocarbon-bearing potential zone in the TSF with its hydrocarbon saturation ranging up to 72%.

Characterisation of potato crisp effective porosity using micro-CT

Abstract: Background The effective porosity is an important quantitative parameter for food products that has a significant effect on taste and quality. It is challenging to quantify the apparent porosity of fried potato crisps as they have a thin irregularly shaped cross section containing oil and water. This study uses a novel micro-CT technique to determine the solid volume fraction and hence the effective porosity of three types of potato crisps: standard continuously fried crisps, microwaved crisps, and continuously fried ‘kettle’ crisps. Results It was found that continuously fried kettle crisps had the lowest effective porosity at 0.54, providing the desired crunchy taste and lower oil contents. Crisps produced using a microwave process designed to mimic the dehydration process of standard continuous fried crisps had an effective porosity of 0.65, which was very similar to the effective porosity of 0.63 for standard continuously fried crisps. The results were supported by the findings of a forced preference consumer test. Conclusion The effective porosity affects the product taste and is therefore a critical parameter. This study shows that micro-CT analysis can be used to characterise the change in effective porosity of a thin irregularly shaped food product, caused by a change of cooking procedure.

Decomposing J-function to Account for the Pore Structure Effect in Tight Gas Sandstones

Abstract: The J-function predicts the capillary pressure of a formation by accounting for its transport properties such as permeability and porosity. The dependency of this dimensionless function on the pore structure is usually neglected because it is difficult to implement such dependency, and also because most clastic formations contain mainly one type of pore structure. In this paper, we decompose the J-function to account for the presence of two pore structures in tight gas sandstones that are interpreted from capillary pressure measurements. We determine the effective porosity, permeability, and wetting phase saturation of each pore structure for this purpose. The throats, and not the pores, are the most important parameter for this determination. We have tested our approach for three tight gas sandstones formations. Our study reveals that decomposing the J-function allows us to capture drainage data more accurately, so that there is a minimum scatter in the scaled results, unlike the traditional approach. This study can have major implications for understanding the transport properties of a formation in which different pore structures are interconnected.

Reservoir units of Mishrif Formation in Majnoon Oil field, Southern Iraq

Abstract: The reservoir units of Mishrif Formation in Majnoon oil field were studied by using available wireline logs (gamma ray, porosity and resistivity) and facies that derived from core and cutting samples for three wells including Mj-1, Mj-15, and Mj-20. The reservoir properties were determined and interpreted by using IP software. The results showed that unit D have the best reservoir properties due to high effective porosity, low water saturation and very low volume of shale. Furthermore, a large part of this unit was deposited in shoal environment. The other reservoir units are then graded in reservoir properties including units B, A, F & E respectively, except unit C, which is considered as a cap unit, because it consists of restricted marine facies so that; it has high volume of shale and water saturation and very low effective porosity.