Archives
 
Year 2023
 
Vol 64, Issue 2, [04 - 2023]

Analysis of the stress state around wellbores in saturated porothermoelastic rock

DOI:10.46326/JMES.2023.64(2).10

  • Affiliations:

    1 Le Quy Don Technical University, Hanoi, Vietnam
    2 Hanoi University of Mining and Geology, Hanoi, Vietnam

  • *Corresponding:
    This email address is being protected from spambots. You need JavaScript enabled to view it.
  • Received: 26th-Dec-2022
  • Revised: 2nd-Mar-2023
  • Accepted: 17th-Mar-2023
  • Online: 30th-Apr-2023
Pages: 101 - 114
Views: 1522
View onlineView online
Downloads: 14
Downdload PDF
★★★★★Rating: 1.0, Total rating: 1
  • ★
  • ★
  • ★
  • ★
  • ★
Yours rating

Abstract:

In the oil and gas exploitation or geo-thermal energy exploitation industries, wellbores can be drilled at great depths where the formation would be hot and saturated. In such case, a large temperature difference between the rock mass and drilling fluid can occur and cannot be ignored. During drilling the wellbores, thermic, hydraulic and mechanical phenomena appear simultaneously and interact with each other within the rock. This study presents the analysis of stress state around the wellbore located in saturated hot rock based on the fully thermo-hydro-mechanical behavior model of the rock mass by the finite element method. Two scenarios involving thermal conditions at the well wall are taken into account, i.e. the drilling fluid temperature is lower or higher than the formation temperature so-called the cases of “cooling” and “heating”, respectively. In this study, the influence of some thermic, hydraulic and initial stress field parameters of the rock mass on the stress state around the wellbore was also clarified. The obtained results showed that, in the cooling case, the well wall may be destabilized by fracture failure while in the heating case this would be collapse failure. The maximum points of tangential and axial stresses appear at the same locations for the two scenarios. In addition, the thermal expansion coefficient, the initial shear stress in the rock mass greatly affect the stress state around the wellbore whilst the permeability of the formation does not influence on the stresses on the well wall but only on the stresses inside the surrounding formation.

How to Cite
Tran, H.Nam, Trieu, T.Hung and Nguyen, N.Thu Thi 2023. Analysis of the stress state around wellbores in saturated porothermoelastic rock (in Vietnamese). Journal of Mining and Earth Sciences. 64, 2 (Apr, 2023), 101-114. DOI:https://doi.org/10.46326/JMES.2023.64(2).10.
References

Aadnoy, B. S., and Looyeh, R., (2019). Petroleum rock mechanics: drilling operations and well design. Gulf professional publishing.

Aadnoy, B. S., and Ong, S., (2003). Introduction to special issue on borehole stability. Journal of Petroleum Science and Engineering, 3(38), 79-82.

Abousleiman Y., Ekbote S., (2005). Solutions for the inclined borehole in a porothermoelastic transversely isotropic medium. Jour. Appl. Mech., 72, 102-114.

Booker, J. R., and Savvidou, C., (1985). Consolidation around a point heat source. International Journal for Numerical and Analytical Methods in Geomechanics, 9(2), 173-184.

Bradley, W.B., (1979). Failure of inclined boreholes. J. Energy Resour. Technol., Trans. AIME, 102, 232-239.

Do D. P., Tran N.H., Hoxha D., Dang H. L., (2017). Assessment of the influence of hydraulic and mechanical anisotropy on the fracture initiation pressure in permeable rocks using a complex potential approach. Int. Jour. Rock Mech. and Min. Scien. 100, 108-123.

Ghassemi, A., Diek, A., (2002). Porothermoelasticity for swelling shales. J. Pet. Sci.Eng., 34, 123-135.

Granet S., (2014). Modelings THHM. General information and algorithms: https://code-aster.org/V2/doc/default/en/man_r/r7/r7.01.10.pdf .

Kanfar M. F., Chen Z., Rahman S. S., (2015). Effect of material anisotropy on time-dependent wellbore stability. Int. Jour. Rock Mech. and Min. Scien. 78, 36-45.

Kanfar M.F., Chen Z., Rhaman S.S., (2016). Fully coupled 3D anisotropic conductive-convective porothermoelasticity modeling for inclined boreholes. Geothermics, 61, 135-148.

Jaeger, J. C., Cook, N. G. W., and Zimmerman, R. W., (2007). Fundamentals of rock mechanics, 4th edn Blackwell. Maiden, MA.

Roland W. L., Perumal N., Seetharamu K. N., (2004). Fundamentals of the Finite Element Method for Heat and Fluid Flow. John Wiley and Sons, 3.

Sayers, C., and Dewhurst, D., (2008). Introduction to this special section—Shale geophysics. The Leading Edge, 27(6), 736-737.

Tran N.H., Do D. P., Vu M. N., Nguyen T. T. N., Pham D. T., Trieu H. T., (2022). Com-bined effect of anisotropy and uncertainty on the safe mud pressure window of hori-zontal wellbore drilled in anisotropic saturated rock. Int. Jour. Rock Mech. and Min. Scien. 152, 105061, 1-20.

Zhu, Z., Wang, C., Guan, Z., and Lei, W., (2021). Thermal Characteristics of Borehole Stability Drilling in Hot Dry Rock. ACS omega, 6(29), 19026-19037.

Other articles