Effect of Test Mode on Stress Sensitivity Evaluation of Full-Diameter Volcanic Rock

Abstract:

some reservoir property change which occurs during reservoir development has been studied, however, the study about the effect of test mode on stress sensitivity evaluation of full-diameter volcanic rock is few since the volcanic gas reservoir in Da-qing is buried deeply and the properties and flow mechanics are extremely complex. Therefore, there are two different test modes for stress sensitivity to study the effect of test mode on stress sensitivity evaluation. One of the test modes is to keep the internal pressure constant and change the confining pressure and the other is to change the internal pressure and keep the confining pressure constant. The study results are as follows: (a) the permeabilitys variation law at different test mode is similar when the net stress varies. There are two type, one is sensitive with high permeability since for well development of micro-fracture and pore connectivity, the other is not sensitive with high permeability since for the weak pore connectivity and micro-fracture; (b) the permeability could decrease with times of pressure cycling , so, the times of flow/shut in operation should be decreased as few as possible; (c) the relative variation of permeability in the mode of changing confining pressure is smaller than it in changing internal pressure, which means the stress sensitivity of changing confining pressure is weaker; (d) the results of changing internal pressure should be used since the test mode is more similar with the actual operation. The results are significant for gas-water RPs accurate determination and efficient development of volcanic reservoirs.

• Periodical: Advanced Materials Research (Volumes 718-720)
• Pages: 525-531
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.718-720.525
• Online since: July 2013
• Authors: Juan Wang, Ping Guo, Cai Zhen Peng, Fang Wang
• Keywords: Keeping Confining Pressure Constant, Keeping Internal Pressure Constant, Stress Sensitivity Evaluation, Two Pressure Cycling, Varying Confining Pressure, Varying Internal Pressure, Volcanic Rock with Full-Diameter

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