Effective porosity

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

Water Saturation and Porosity Prediction Using Back-propagation Artificial Neural Network (BPANN) from Well Log Data

Abstract: Porosity and water saturation are two fundamental parameters in reservoir characterization. In this study, for predicting both mentioned parameters artificial neural network was used as intelligent technique. Five variables include neutron log, effective porosity, caliper log, bulk density, and sonic log were used from 3 wells from one of the Iranian oil fields. After normalizing data Seventy percent of data were used as training dataset and remainder for testing the network. Several feed –forward neural networks were operated to obtain best performance of different algorithms to train the network. Levenberge-Marquardt back-propagation algorithm was chosen as the training algorithm which had the best performance and was faster than other algorithms. Optimum neurons in the hidden layer for porosity and water saturation were obtained respectively. Results shown that Backpropagation artificial neural network (BPANN) has a high ability to predict porosity and water saturation which correlation between real output and predicted output using BPANN were 0.82 and 0.93 respectively.

Hydrogeological testing to characterize a fractured granite

Abstract: A comprehensive program of in situ testing has been carried out in an iron ore mine in Stripa, Sweden, to investigate the problems of obtaining a hydrogeological characterization of a fractured granite rock mass. The field investigations consisted of: (1) the collection of fracture geometry and borehole injection test data to determine directional permeabilities, (2) a macropermeability experiment to determine the bulk rock mass permeability, (3) groundwater sampling for investigations of geochemistry and isotope hydrology, (4) pump testing of surface wells, and (5) tracer tests to determine effective porosity. This report summarizes results from all but the last item, the tracer work, which had not been carried out when the field work ended in 1981.

Determination of effective porosity of soil materials

Abstract: Hazardous waste disposal landfills require liners constructed of compacted soil material to help prevent the migration of hazardous wastes. The performance of a compacted soil liner is partly a function of the porosity. Porosity is important because the transport of materials through the liner will occur via the pore space. The main purpose of this project is to study the pore spaces of compacted soil materials and to estimate the effective porosity, which is the portion of the pore space where the most rapid transport of leachate occurs. The pore space of three soil materials, till, loess, and paleosol, is studied by using mercury intrusion porosimetry, water desorption, and image analysis. These analyses provide cumulative porosity curves from which the pore size distribution of a soil sample may be estimated. Theory is developed to estimate the effective porosity of a compacted soil material based upon a model of its pore size distribution and pore continuity. The effective porosities of the compacted till, loess, and paleosol materials are estimated to be 0.04, 0.08, and 0.09, respectively. These values are 10 to 20% of the total porosities. Comparisons between measured and predicted Cl travel times through compacted soil samples are made in order to verify the estimated effective porosities. The estimated effective porosities are reasonable because predicted Clfirst breakthrough times are similar to the measured first breakthrough times in compacted till, loess, and paleosol materials. For the three soil materials used in this study., predicted first breakthrough times are 5 to 10 times earlier when effective porosity is used in the Darcy-equation-based calculations as compared to Darcy-equation-based calculations that u~ilize total porosity. This report was submitted in fulfillment of cooperative agreement CR-811093-01-0 by Iowa State University under the sponsorship of the U.S. Environmental Protection Agency. This report covers a period from 10/1/83 to 4/30/86, and work was completed as of 12/31/85.

Diagenetic analysis of the Early Eocene Margala Hill limestone, Pakistan: A synthesis for thin section porosity

Abstract: The diagenetic fabric and its implications for the thin section porosity in carbonate facies of the Margala Hill Limestone in the Haripur area of North Pakistan is documented here. The facies analysis suggests deposition of the unit in a carbonate shelf platform setting having characteristic sediments of the inner shelf lagoon to middle shelf subtidal environments. The diagenetic overprinting of these facies includes micritization, neomorphism (microspar, aragonite calcite transformation, dolomitization) and compaction (disorientation of biocalst, pressure dissolution fabric). The inner shelf facies have an enhanced porosity due to transformation of calcite to dolomite and micritization of skeletal fragments. The occlusion of the effective porosity in the middle shelf and sub-tidal distal shelf facies is related to the stylonodular, stylobrecciated fabric and calcite filled veins. The overall assessment of the unit suggests that the middle part of rock intervals have fair porosity (8-13%), in contrast to the lower and upper part which has negligible porosity (0-5%).