Dear sir,I have a question about whether the deep underground mudstone contains water. This problem involves the weakening of the drilling fluid (due to water absorption) and the establishment of the elastic constitutive equation of the hole (usually considered saturated brine). Can you explain the contradiction? Do you think there's water in the pores?
@@dnicolasespinoza5258 Thank you very much. I understand through your explanation. There is another question: is the surrounding rock under triaxial compression at any time? It has been reported that the tangential stress of borehole wall is tensile stress due to low temperature drilling fluid, resulting in contraction joints. So I think there are certain in-situ stresses and drilling fluid density, temperature, salt concentration, and the rock is not always triaxial compression at any given point. If that is true, then the M-C strength criterion may not apply. Do you think I have a point there？
@@rlouis1866 Thanks for the comment, the calculation of stresses on the wellbore wall due to far-field stresses, mud pressure and temperature are covered in chapter 6. Wellbore Stability dnicolasespinoza.github.io
Dear sir,I have a question about whether the deep underground mudstone contains water. This problem involves the weakening of the drilling fluid (due to water absorption) and the establishment of the elastic constitutive equation of the hole (usually considered saturated brine). Can you explain the contradiction? Do you think there's water in the pores?
The weakening of mudrocks due to "freshening" of brine within pores is discussed here: th-cam.com/video/-fMyO53M51c/w-d-xo.html
@@dnicolasespinoza5258 Thank you very much. I understand through your explanation. There is another question: is the surrounding rock under triaxial compression at any time? It has been reported that the tangential stress of borehole wall is tensile stress due to low temperature drilling fluid, resulting in contraction joints. So I think there are certain in-situ stresses and drilling fluid density, temperature, salt concentration, and the rock is not always triaxial compression at any given point. If that is true, then the M-C strength criterion may not apply. Do you think I have a point there？
@@rlouis1866 Thanks for the comment, the calculation of stresses on the wellbore wall due to far-field stresses, mud pressure and temperature are covered in chapter 6. Wellbore Stability dnicolasespinoza.github.io