Course content

Reservoir geomechanics: Introduction to poroelasticity theory. Reservoir compaction, linear elastic model and inelastic effects. Surface subsidence. Stress evolution during production. Compaction as a drive mechanism. Stress effects on porosity and permeability. Coupled geomechanic reservoir simulation. Link to 4D-seismics. Borehole stability: Diagnostics. Critical mud weight limits to prevent hole collapse and mud losses. Effects of temperature and mud composition on borehole stability. Stability of deviated and horizontal holes. Effects of plasticity. Modelling of borehole stability. Formation of shale barriers around cased boreholes. Sand and particle production: Basic mechanisms. Sand control. Sand prediction. Volumetric sand production. Hydraulic fracturing: Initiation and growth of hydraulic fractures. Thermal fracturing during water injection. Use of fracturing during simulation, for stress determination, and for waste storage.

Learning outcome

Knowledge: The students shall understand how stresses change as a result of fluid withdrawal from or injection into the subsurface, and how such changes influence subsurface storage of CO2 and other waste materials, recovery of petroleum or water (e.g. geothermal energy) from subsurface reservoirs, borehole stability during drilling and production.

Skills: The students shall be able to perform calculations of induced stresses within and outside subsurface reservoirs, including compaction / extension and surface subsidence / uplift and estimates of cap rock integrity, mud weight window for stable drilling, critical drawdown and estimated produced mass of solids (e.g. sand, chalk) during fluid production, plus well pressure for initiation of hydraulic fracturing and simple estimates of fracture propagation.

General competence: The students shall develop their ability to work in teams solving multidisciplinary tasks, and obtain experience in presentation of their own work.

Digital component: Through their group exercise the students will learn how to use and build simple models with a Finite Element Modelling software.

Learning methods and activities

Lectures, compulsory exercises and semester project. There are compulsory exercises through the semester. Students will participate in seminars linking field practice to the theoretical part of the course, and accomplish a semester project (in groups or individually) and present the results oral and in writing. This work is compulsory. The lectures are held in English if international master's students attend. Evaluation of the course is done by a reference group consisting of students in collaboration with the responsible professor.

Compulsory assignments

• Exercises

Recommended previous knowledge

Basis in mechanics.

Course materials

Recommended textbook: Fjær, E., Holt, R.M., Horsrud, P., Raaen, A.M., Risnes, R.: "Petroleum Related Rock Mechanics", Elsevier 2021. Curriculum will be given at semester start. Presentations from lectures are provided.

Credit reductions