Reconstruction of Sedimentary Rock Based on MechanicalProperties

Jin, Guodong ; Patzek, Tad W. ; Silin, Dmitry B.

Lawrence Berkeley National Laboratory

关键词: Sedimentary Rocks;    Mechanical Properties;    Cements;    Dimensions;    58;   

DOI  :  10.2172/929000
RP-ID  :  LBNL--55038
RP-ID  :  DE-AC02-05CH11231
RP-ID  :  929000

美国|英语

来源: UNT Digital Library

【 摘 要 】

We describe a general, physics-based approach to numericalreconstruction of the geometrical structure and mechanical properties ofnatural sedimentary rock in 3D. Our procedure consists of three mainsteps: sedimentation, compaction, and diagenesis, followed by theverification of rock mechanical properties. The dynamic geologicprocesses of grain sedimentation and compaction are simulated by solvinga dimensionless form of Newton's equations of motion for an ensemble ofgrains. The diagenetic rock transformation is modeled using a cementationalgorithm, which accounts for the effect of rock grain size on therelative rate of cement overgrowth. Our emphasis is on unconsolidatedsand and sandstone. The main input parameters are the grain sizedistribution, the final rock porosity, the type and amount of cement andclay minerals, and grain mechanical properties: the inter-grain frictioncoefficient, the cement strength, and the grain stiffness moduli. We usea simulated 2D Fontainebleau sandstone to obtain the grain mechanicalproperties. This Fontainebleau sandstone is also used to study theinitiation, growth, and coalescence of micro-cracks under increasingvertical stress. The box fractal dimension of the micro-crackdistribution, and its variation with the applied stress areestimated.