Method for the estimation of rock mechanical properties using downhole measurements of borehole ovality

A system for determining rock mechanical properties of a subterranean formation, comprising:

• a computer processor;
• and
• memory storing instructions, when executed by the computer processor, comprising functionality for:
• obtaining, at a selected depth location of a borehole penetrating the subterranean formation, initial radial geometry measurements of the borehole and initial borehole fluid pressure measurements of a borehole fluid;
• perturbing a pressure of the borehole fluid;
• obtaining, in response to perturbing the pressure of the borehole fluid and at the selected depth location of the borehole, dynamic radial geometry measurements of the borehole and dynamic borehole fluid pressure measurements of the borehole fluid;
• analyzing a difference of the initial radial geometry measurements and the dynamic radial geometry measurements to determine differences in radial and axial components of strain tensor at a surface of the borehole at the selected depth location;
• determining the rock mechanical properties at the selected depth location by analyzing the differences in the radial and axial components of the strain tensor;
• and
• facilitating, based at least on the determined rock mechanical properties, a drilling operation of the subterranean formation.

A well system for performing a drilling operation of a subterranean formation, comprising:

• a bottom hole assembly (BHA) coupled to a drill string that is suspended in a borehole penetrating the subterranean formation;
• and
• a rock property analysis system coupled to the BHA and comprising functionality for:
• obtaining, at a selected depth location of the borehole, initial radial geometry measurements of the borehole and initial borehole fluid pressure measurements of a borehole fluid;
• perturbing a pressure of the borehole fluid;
• obtaining, in response to perturbing the pressure of the borehole fluid and at the selected depth location of the borehole, dynamic radial geometry measurements of the borehole and dynamic borehole fluid pressure measurements of the borehole fluid;
• analyzing a difference of the initial radial geometry measurements and the dynamic radial geometry measurements to determine differences in radial and axial components of strain tensor at a surface of the borehole at the selected depth location;
• determining rock mechanical properties at the selected depth location by analyzing the differences in the radial and axial components of the strain tensor;
• and
• performing, using the BHA and based at least on the determined rock mechanical properties, a drilling operation of the subterranean formation.