Showing papers on "Effective porosity published in 2001"

Estimating Saturated Hydraulic Conductivity from Soil Porosity

Abstract: Measuring the tempospatial variability of saturated hydraulic conductivity (Ks ) is time consuming, expensive, and encounters many uncertainties. This work aimed to develop a new model (REPM, Relative Effective Porosity Model) that estimates Ks from relative effective porosity (er ) and then compare it with a model (EPM, Effective Porosity Model) that estimates it from effective porosity (e ). The effective porosity (e ) is defined as the total porosity minus field capacity (FC), and the relative effective porosity (er ) is defined as effective porosity (e ) divided by FC. Both er and e can be estimated from FC and bulk density (Bd ). Data from 11 homogeneous textural–class mean soils and several international and American soils were used to evaluate REPM and EPM. For the 11 textural–class mean soils, log (Ks ) was highly correlated to log (er ) as well as to log (e ). For the international soils, log (Ks ) was highly correlated to log (er ) (r 2 = 0.77), but the correlation was less pronounced between log (Ks ) and log ( e ) (r 2 = 0.58). The saturated hydraulic conductivity of soils from an international database was more accurately predicted by REPM (RMSE of 539 cm d –1 ) than by EPM (RMSE of 733 cmd –1 ), while both of them performed as well for American soils. The slope and the intercept of REPM and the slope of EPM were independent of soil. These results suggest that our new model gives reasonable estimates of Ks for different soils.

Challenges of Porosity Based Pore Pressure Prediction

Abstract: O-25 CHALLENGES OF POROSITY BASED PORE PRESSURE PREDICTION DR R E SWARBRICK 1 GeoPOP University of Durham Department of Geological Sciences South Road Durham DH1 3LE UK Abstract Porosity is used as a rock property implicitly reflecting the degree of compaction of sediment The porosity values may be derived from wireline response or a porosity attribute may be used directly for example velocity data derived from seismic Where undercompaction occurs due to fluid retention and overpressure porosity is retained above the level referred to as “normal compaction” Hence a methodology has been developed which can work well in low temperature

Results of Detailed Hydrologic Characterization Tests - Fiscal Year 1999

Abstract: This report provides the results of detailed hydrologic characterization tests conducted within newly constructed Hanford Site wells during FY 1999. Detailed characterization tests performed during FY 1999 included: groundwater flow characterization, barometric response evaluation, slug tests, single-well tracer tests, constant-rate pumping tests, and in-well vertical flow tests. Hydraulic property estimates obtained from the detailed hydrologic tests include: transmissivity, hydraulic conductivity, specific yield, effective porosity, in-well lateral flow velocity, aquifer flow velocity, vertical distribution of hydraulic conductivity (within the well-screen section) and in-well vertical flow velocity. In addition, local groundwater flow characteristics (i.e., hydraulic gradient and flow direction) were determined for four sites where detailed well testing was performed.

Influences of asphaltene precipitation on capillary pressure and pore size distribution of carbonate reservoirs

Abstract: Asphaltene depositio n has profound effects on oil flow through porous medium. The investigation of the influences of asphaltene precipitation on carbonate reservoir rocks has minor interests in comparison to studies investigated sandstones ones. Therefore, this study is undertaken to provide accurate insights, especially for carbonate reservoirs of low permeability. In this study, two groups of experiments are undertaken. The first experimental group investigates effects of asphaltene precipitation on (a) petrophysical properties of carbonate rocks, including absolute permeability, effective porosity, and hydraulic radius, and (b) on oil-water relative permeability and water flooding performance. The second group searches for the effects of asphaltene precipitation on capillary pressure and pore size distribution of low permeability carbonate reservoirs. Conducted experiments are achieved using actual reservoir liquids of crude oil and brine, flowing through actual carbonate cores under similar reservoir...

Effect of fluid-rock interaction on porosity of reservoir rocks in tertiary system,dongying sag

Abstract: The effect of fluid rock interaction on porosity of reservoir rocks in Tertiary System of Dongying Sag has been analyzed in the paperThe results indicate:(1)organic inorganic interaction and the amount of organic acid and CO 2 produced in the action in source rock pore fluid system are the key factor of the formation of porosity in sandstone; (2)the dissolution of carbonate and aluminosilicate are the important fluid rock interactions to control porosity in sandstone; (3)the amount of carbonate in mudrock has an important influence on the scale of the formation of porosity in sandstone; (4)the abilities of inflow and outflow of fluid during fluid rock interaction determines the development of porosity in sandstoneDue to the influences of the geological and geochemical factors and fluid rock interaction,the three regional porous zones and three regional cemented zones are formed in the profile in Dongying Sag