A numerical approach is used to estimate effective permeability in sand‐shale formations under steady state uniform flow conditions. Permeability modeled as a binary, second‐order stationary random function taking on two possible values K ss and sh sandstone shale, respectively. This model realistic since experience with reservoirs has shown that randomly dispersed low‐permeability shales are the single dominant heterogeneity affecting behavior. The cases of both spatially correlated...

ABSTRACT A binary type permeability distribution with spatial autocorrelation is introduced to model the transition between shales and sand in a reservoir. The contrast two modal values can be made realistically high, ranges large anisotropic. steady state, single phase flow simulation run over network whose block grids are informed from previous distribution. resulting effective permeabilities plotted vs. shale proportion show that power averaging process would yield good estimate much more...

Macrodispersion in sand‐shale sequences is investigated by a series of numerical tracer tests. Hydraulic conductivity modeled as binary, spatially correlated random function. Realizations the field are simulated on nodal grid discretizing heterogeneous formation. Corresponding realizations velocity obtained solving equation for saturated steady state flow. Particle tracking, with flux‐weighted injection and detection, used to generate experimental residence time distributions (RTDs). Moments...

An anistropy of magnetic susceptibility (AMS) study the relatively fresh Mealy diabase dyke swarm indicates a correlation between AMS and deformational effects in rocks. Several components were revealed during experimental work on 211 samples that had been heated to 640°C paleomagnetic 22 progressively treated alternating fields. Seventeen sites with slight or no deformation have fabric composed two major components. The stable component, attributed primary shape anisotropy, has minimum...

Abstract Numerical groundwater flow modeling, reverse particle tracking, and environmental tracers are used to locate the source of geogenic As affecting an aquifer in West Bengal. The is hosted by point‐bar sands deposited a meandering fluvial environment. Wells tapping exhibit concentrations up 531 μg/L. High‐As groundwaters recharged ponds marking abandoned river channel. traced underlying fine‐grained channel‐fill sediments. Arsenic release within these sediments accompanied concomitant...

Anyone who has examined core or petrophysical logs from well bores wondered at the rhythmic successions of sedimentary fades and puzzled their sudden disruption reappearance. Such wonderment is no doubt shared by those have stood a quarry face gazing up intricate hierarchy depositional patterns varied textures sediments. A fortunate few even slogged along mine drift observed close hand perplexing relationship between geological fabric rock mass occurrences groundwater inflow. Happily,...

Steady state nonuniform flow in a heterogeneous medium is investigated using combined numerical‐empirical approach. The objective of the study to determine effective transmissivity square field with constant‐head external boundary and constant‐rate well at its center. Transmissivity point scale modeled as an isotropic multivariate lognormal spatial random function. Block transmissivities are defined empirical scaling up support values within field. process weighted geometric averaging where...

This study examines the spatial variability of conductivity within sandstone Wabiskaw member Lower Cretaceous, Middle Mannville in Alberta Basin. The is an important regional hydrostratigraphic unit. Vertical aquifer characterized by downhole variograms log from core measurements. They are found to exhibit pseudoperiodic structures due alternating sand and shale layers. Horizontal using transmissivity indicator data. These show a steady increase over length scales ranging 400 m 100 km,...

An analog method is used to simulate a discrete transmissivity field free of the artifacts inherent in conventional multivariate Gaussian statistical generation methods. The simulated provides realistic model formation exhibiting spatial continuity extreme transmissivities which gives rise barriers and preferential channels for flow. heterogeneous corresponding steady‐state head discharge fields are characterized geostatistical framework observed statistics compared with theoretical results...

Abstract The source of geogenic arsenic (As) contaminating a shallow aquifer in West Bengal was traced to fine‐grained sediments deposited an abandoned river channel. Along with As‐bearing phases, these contain 0.46% codeposited organic carbon. release As and the geochemistry groundwater within channel‐fill deposits is investigated using detailed mass balance model supported by aqueous, solid‐phase, mineralogical data. describes evolution chemistry along flow path extending from its recharge...

Numerical models of flow in the vadose zone require capillary pressure‐saturation relationships for grid blocks discretizing medium. However, scale these is generally much larger than sample at which are measured. This study investigates upscaling curves under static conditions capillary‐gravity equilibrium. The averaging regions horizontal layers, parallel to phreatic surface, as one‐dimensional infiltration. At point or it assumed that all can be normalized using Leverett (1941∥ approach a...

Numerical models of groundwater flow in the unsaturated zone require relative conductivity and moisture retention curves at a discretization scale much larger than that which these constitutive relationships are measured. This study seeks to identify simple scaling laws linking parameters block‐scale with their measurement‐scale counterparts represented here using Gardner‐Russo models. The two models, saturated pore‐size distribution parameter, viewed as cross‐correlated regionalized...

Summary A geostatistical method is presented to determine the absolute horizontal and vertical effective permeabilities at reservoir block scale from core support-scale values required for 3D flow simulations. The key element of model definition as spatial power average core-support over volume a gridblock. Block are then found be function permeability variogram, averaging volume, power-averaging constant, which derived separately with numerical approach. application proposed requires that...