Nitrogen turnover in the soil-crop system; comparison of fourteen simulation models

1991 ◽  
pp. 141-149 ◽  
Author(s):  
P. de Willigen
Keyword(s):  
Simulation Models ◽  
Nitrogen Turnover ◽  
Crop System

Nitrogen turnover in the soil-crop system; comparison of fourteen simulation models

1991 ◽  
Vol 27 (2-3) ◽  
pp. 141-149 ◽  
Author(s):  
P. Willigen
Keyword(s):  
Simulation Models ◽  
Nitrogen Turnover ◽  
Crop System

Correlation of Pore Structure and Permeability by SEM-Image Analysis

1990 ◽  
Vol 48 (1) ◽  
pp. 428-429
Author(s):  
C. A. Callender ◽  
Wm. C. Dawson ◽  
J. J. Funk
Keyword(s):  
Image Analysis ◽  
Pore Structure ◽  
Imaging System ◽  
Pore Space ◽  
Simulation Models ◽  
Image Analyzer ◽  
Imaging Data ◽  
Sem Images ◽  
Thin Sections ◽  
Rock Types

The geometric structure of pore space in some carbonate rocks can be correlated with petrophysical measurements by quantitatively analyzing binaries generated from SEM images. Reservoirs with similar porosities can have markedly different permeabilities. Image analysis identifies which characteristics of a rock are responsible for the permeability differences. Imaging data can explain unusual fluid flow patterns which, in turn, can improve production simulation models.Analytical SchemeOur sample suite consists of 30 Middle East carbonates having porosities ranging from 21 to 28% and permeabilities from 92 to 2153 md. Engineering tests reveal the lack of a consistent (predictable) relationship between porosity and permeability (Fig. 1). Finely polished thin sections were studied petrographically to determine rock texture. The studied thin sections represent four petrographically distinct carbonate rock types ranging from compacted, poorly-sorted, dolomitized, intraclastic grainstones to well-sorted, foraminiferal,ooid, peloidal grainstones. The samples were analyzed for pore structure by a Tracor Northern 5500 IPP 5B/80 image analyzer and a 80386 microprocessor-based imaging system. Between 30 and 50 SEM-generated backscattered electron images (frames) were collected per thin section. Binaries were created from the gray level that represents the pore space. Calculated values were averaged and the data analyzed to determine which geological pore structure characteristics actually affect permeability.

Evaluation of five simulation models for predicting aldcarb and bromide behavior under field conditions

1990 ◽  
Vol 26 (11) ◽  
pp. 2679-2693 ◽  
Author(s):  
K. D. Pennell
Keyword(s):  
Simulation Models ◽  
Field Conditions
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