OF EARTH SCIENCES. Geomechanics, rock destruction
Hou Bing, Li Dandan, Chen Mian, Liang Chuan, Jin Yan
HOU BING, PhD, Associate professor, State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing), Beijing 102249, China, e-mail: houbing9802@163.com
LI DANDAN, Master Candidate, State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing), Beijing 102249, China, e-mail: wilber-will@163.com
CHEN MIAN, Professor, Dean, State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing), Beijing 102249, China. Key Laboratory of Reservoir Stimulation, CNPC, Langfang, China, e-mail: chenmian@vip.sina.com
LIANG CHUAN, PhD Candidate, State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing), Beijing 102249, China, e-mail: liangchuan@gmail.com
JIN YAN, Professor, State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing), Beijing 102249, China, e-mail: 13701222683@vip.163.com
The sensibility of mechanical behavior to loading rate for shale gas reservoir with different weak planes
Triaxial compression tests are performed on shale samples from Longmaxi reservoir formation with GCTS RTR1500 mechanical testing system. The failure modes and mechanical parameter sensitivity characteristics of shale under different loading rates are investigated. Longmaxi shale gas reservoir is well-developed laminations, featured by matrix and fractures, which has been called “dual pore structure”, and is dramatically sensitive to loading rates. The relationship between compressive strength and loading rate is generally linear under different conditions of weak plane angles (β), yet in the meanwhile, elastic modulus manifests obviously nonlinear. When the loading rate is increased from 0.05 mm/min to 0.2 mm/min, specimens with the angle βof 30° has the largest growth amplitude , reaching to 17.16%, while the β =70° group has the largest amplification in elastic modulus. Moreover, elastic modulus is most sensitive to the loading rate at 0.12 mm/min. Since then, this trend is beginning to stabilize. Specially, shear failure is in charge under the rate of 12 mm/min, while tensing cracks begin to increase as loading rates going up.
Key words: shale, weak plane, triaxial test, loading rate, dual pore structure.
REFERENCES
1. Chen M., Zhang Y., Jin Y., et al. Experimental study of influence of loading rate on Kaiser effect of different lithological rocks. Chinese Journal of Rock Mechanics and Engineering. 2009;(1)28.
2. Xu J.Y., Liu S. Effect of impact velocity on dynamic mechanical behaviors of marble after high temperatures. Chinese Journal of Geotechnical Engineering, 2013;35(005): 879-883.
3. Wang H.L., Fan P.X. Influence of strain rate on progressive failure process and characteristic stresses of red sandstone [J]. Rock and Soil Mechanics. 2011;32(5):1340-1346.
4. Paterson M.S.,Wong T.F. Experimental rock deformation-the brittle field [M]. 2nd ed. New York, Springer-Verlag, 2005, р. 155-158.
5. Huang D., Huang R.Q., Zhang Y.X. Experimental investigations on static loading rate effects on mechanical properties and energy mechanism of coarse crystal grain marble under uniaxial compression. Chinese Journal of Rock Mechanics and Engineering. 2012;31(2):245-255.
6. Jin X.T., Ge R.X., Li C.G. et al. Influences of loading rates on mechanical behaviors of rock materials. Chinese Journal of Rock Mechanics and Engineering. 2010;29.
7. Zhang G.Q., Jin Y., Chen M. Measurement of in-situ stress by Kaiser effect under confining pressures. Chinese Journal of Rock Mechanics and Engineering. 2002;21(3):360-363.
8. Stavrogin A.N., Tarasov B.G. Experimental physics and rock mechanics：results of laboratory study [M]. Tokyo, A.A. Balkema, 2001, р. 204-220.
9. Liu S.J.,Wu L.X. et al. Remote sensing rock mechanics (VI)-features of rock fraction-sliding and analysis on its influence factors. Chinese Journal of Rock Mechanics and Engineering. 2004;23(8):1247-1251.
10. Mahmutoğlu L. The effects of strain rate and saturation on a micro-cracked marble. Engineering Geology. 2006; 82(3):137-144.
11. Zhou X.P., Yang H.Q., Zhang Y.X. Rate dependent critical strain energy density factor of Huanglong limestone [J]. Theoretical and Applied Fracture Mechanics. 2009;51(1):57-61.
