Науковий вісник НГУ

Rock Mechanical Properties and Borehole Stability of Gas Shale

• 
• 

User Rating:  / 1

PoorBest 

Details

Category: Mining

Last Updated on 16 July 2014

Published on 21 March 2014

Hits: 4102

Authors:

Chuanliang Yan, Jingen Deng, Baohua Yu, Wenliang Li, Lianbo Hu

State Key Laboratory of Petroleum Resource and Prospecting, China University of Petroleum, Beijing, China

Abstract:

Serious borehole instability occurs frequently during drilling in shale gas reservoirs. Shale gas reservoirs are featured by tight matrix, well-developed micro-fissures and laminations, and their peculiar mechanical properties are different from those of ordinary tight sandstones or carbonates. Thus, implementing correlative studies is of great significance to drilling and subsequent reservoir stimulation. Rock mechanical tests are performed to gas shale from south of China by the MTS-816 Rock Test System. The variation of rock mechanical properties with the angle between axial stress and the bedding plane normal (coring angle) is analyzed by the laboratory tests and a failure criterion is verified and applied to determine the strength of gas shale. The shale strength decreases first and then increases with the increasing of coring angle. It gets the maximum value with the coring angle of 0° and gets the minimum value with the coring angle of about 60°. The Young’s modulus and Poisson’s ratio increase with the increase of coring angle. Besides, the borehole stability model of shale gas well is established by combining transverse isotropic constitutive model and the continuously variable cohesion strength criterion. The collapse pressure is lowest when drilling to the maximum horizontal stress direction and reaches its maximum when drilling to the minimum horizontal stress direction.

References:

1. Zou, C., Dong, D., Wang, S., Li, J., Li, X., Wang, Y. and Cheng, K. (2010), “Geological characteristics and resource potential of shale gas in China”, Petroleum exploration and development, vol. 37, no.6, pp. 641–653.

2. Narayanasamy, R., Barr, D. and Milne, A. (2010), “Wellbore Instability Predictions within the Cretaceous Mudstones, Clair Field, West of Shetlands”, SPE Drilling & Completion, vol. 25, no.4, pp. 518–529.

3. Suarez-Rivera, R., Green, S., Handwerger, D., Martin, W. and Kieschnick, J. (2005), “Accounting for Heterogeneity Provides a New Perspective for Completions in Tight Gas Shales”, In Alaska Rocks 2005, The 40th US Symposium on Rock Mechanics (USRMS).

4. Mao, H.J. and Yang, C.H. (2005), “Study on effects of discontinuities on mechanical characters of slate”, Chinese Journal of Rock Mechanics and Engineering, vol. 24, no. 20, pp. 3651–3656.

5. McLamore, R. and Gray, K.E. (1967), “The mechanical behavior of anisotropic sedimentary rocks”, Journal of Engineering for Industry, Translation of the A.S.M.E., vol. 89, pp. 62–73.

6. Yuan, J.L., Deng, J.G., Tan, Q., Yu, B.H. and Jin, X.C. (2012), “Borehole Stability Analysis of Horizontal Drilling in Shale Gas Reservoirs”, Rock Mechanics and Rock Engineering, in press.

7. Xu, Z.L. (1998), [Elastic Mechanics], Beijing, Higher Education Press.

8. Deng, J.G. (1997), “Calculation method of mud density to control borehole closure rate”, Chinese Journal of Rock Mechanics and Engineering, vol. 16, no. 6, pp. 522–528.

9. Khan, S., Williams, R., Ansari, S. and Khosravi, N. (2012), “Impact of Mechanical Anisotropy on Design of Hydraulic Fracturing in Shale”, In Abu Dhabi International Petroleum Conference and Exhibition, Abu Dhabi, UAE.

Hornby, B.E. (1998), “Experimental laboratory determination of the dynamic elastic properties of wet, drained shale”, Journal of Geophysical Research, vol. 103, no. B12, pp. 29945–29964.

2014_1_baohua
2014-07-16  202.81 KB  1120

• < Prev
• Next >