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Title: HYBRID MESOSCALE MODELING OF DYNAMIC GRAIN FRAGMENTATION

Fines created by grain fragmentation from shaped-charge, jet perforation treatment often plug-up pores in the vicinity of the perforation tunnel. We analyze and model grain damage on samples recovered from impact tests of dry and water saturated sandstone at stress levels and duration similar to that of perforation loading. Analyses of Scanning Electron Microscope (SEM) images and laser particle size measurements on portions of the recovered samples characterize grain damage and changes in grain size distribution. Hybrid modeling that combines the Discrete Element Method (DEM) with Smooth Particle Hydrodynamics (SPH), and includes mesoscale representation of grain/pore structure, shows how grain damage evolves for dry and wet conditions. Modeling defines behavior in accord with recovered sample analyses as follows: (1) Increase in grain damage is obtained with an increase in stress level and pulse duration. (2) The grains in dry samples are extremely and irregularly fragmented with extensive reduced porosity. (3) Less grain damage and higher porosity is obtained in saturated samples. The influence of pore fluid mitigates the interaction between grains, thus reducing fragmentation damage. (4) Computed particle size distributions are similar in character to measurements.
Authors:
; ;
Publication Date:
OSTI Identifier:
777449
Report Number(s):
LA-UR-01-1943
TRN: AH200124%%138
DOE Contract Number:
W-7405-ENG-36
Resource Type:
Conference
Resource Relation:
Conference: Conference title not supplied, Conference location not supplied, Conference dates not supplied; Other Information: PBD: 1 Apr 2001
Research Org:
Los Alamos National Lab., NM (US)
Sponsoring Org:
US Department of Energy (US)
Country of Publication:
United States
Language:
English
Subject:
02 PETROLEUM; DISTRIBUTION; ELECTRON MICROSCOPES; FRAGMENTATION; GRAIN SIZE; HYDRODYNAMICS; IMPACT TESTS; LASERS; PARTICLE SIZE; POROSITY; SANDSTONES; WATER