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 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.
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 reservoir recovery, underground storage, and hole stability during drilling and production.

Skills:
The students shall be able to perform calculations of reservoir compaction and surface subsidence, mud weight window for stable drilling, critical drawdown for initiation of sand production and estimated produced sand mass, plus well pressure for initiation of hydraulic fracturing.

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

Learning methods and activities

Lectures and exercises. PBL. Students will accomplish a semester project and present the results oral and in writing. This work counts for 25% of the final grade. The lectures are held in English if international masterstudents attend. Retake exams may be oral.

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 2008. Curriculum will be given at semester start. Presentations from lectures are posted on it's learning.

Credit reductions