The Well Integrity Screening Tool is based on an analytical model describing the thermo-poro-elastic behaviour of wells in the so-called drained conditions and plane-strain conditions. The analytical model takes into account the pore pressure, uniform temperatures changes across the well and the cement’s initial state of stress. The tool estimates the potential for debonding, tensile and shear fracturing of the rock and the cement sheath using computed stress profiles and the Mohr-Coulomb failure criterion. The tool is suited to study vertical well sections consisting of a single casing and cement sheath inside a porous or non-porous rock formation.

Net-Zero Geosystems is currently developing a new version of the WIST. This will include transient poro-elasticity, anisotropic stress conditions and experiment-backed models for the initial state of stress in the cement sheath, stay tuned. For inquiries or assistance with the tool please email clement.joulin@netzerogeosystems.com

For details on the equations and the solution procedure, please refer to the publication:

Joulin C., Lagarde F., Le Goff T.-H.  An Open-Access Well Integrity Tool to Study Legacy Wells Re-Purposed for CO2 Injection. 56th US Rock Mechanics Symposium, ARMA 2022