Iranian Journal of Mechanical Engineering Transactions of the ISME

Iranian Journal of Mechanical Engineering Transactions of the ISME

The Effect of Repeated Impact Loading on Reservoir Rock Properties

Document Type : Research Paper

Authors
Marzieh Naderan Tahan
Khosro Naderan Tahan
Seyed Saied Bahrainian
Mechanical Engineering Department, Shahid Chamran University of Ahvaz, Iran
10.30506/jmee.2020.115766.1204
Abstract
The objective of this paper is to present the results of a research program launched to investigate the mechanism and amount of changes of reservoir rock properties due to pulse stress waves. These waves are induced in cylindrical samples by applying repeated impact loading along the sample axes in a falling weight testing apparatus. The samples are dry and free from any fluid and no confining pressure. After each step of loading, permeability, effective porosity, wave velocities are measured by standard methods and CT images are prepared. Results show that if the amplitude of dynamic stress exceeds the dynamic fracture strength and spall strength of the samples, micro fracture will emerge and permeability will increase significantly while the effective porosity decreases at first steps of loading but, recovers during the subsequent steps. Emerging and growth of new fractures are visible in CT images, too. Initial structure of samples, total energy consumption prior to complete breakage, and the strain rate of incident wave, affect the results.
Keywords
dynamic fracture strength
effective porosity
permeability
spallation
Subjects