Hybrid mesoscale modeling of dynamic grain fragmentation.

Swift, R. ; Hagelberg, C. ; Hiltl, M.

Technical Information Center Oak Ridge Tennessee

关键词: Grain fragmentation;    Distribution;    Electron microscopes;    Fragmentation;    Grain size;   

RP-ID  :  DE2001777449

学科分类：工程和技术（综合）

美国|英语

来源: National Technical Reports Library

【 摘 要 】

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.