Masterprosjekt vår 2019 ved GEO - David Peacock

Project description

Joints are important conduits for fluid in rock, so understanding their distribution is important to the geology of fractured reservoirs, with application to petroleum, geothermal energy, hydrogeology, and CO 2 sequestration. Reservoir models commonly use discrete
fracture network (DFN) models (e.g. Lei, Q., Latham, J.P., Tsang, C.F., 2017. The use of discrete fracture networks for modelling coupled geomechanical and hydrological behaviour of fractured rocks. Computers and Geotechnics 85, 151-176). Such models are, however, based on limited data (e.g. core or borehole images) and make simple assumptions (e.g. that joint spacing is proportional to bed thickness). Joint patterns are commonly significantly different in nearby beds of the same lithology and thickness, suggesting there are other factors controlling fracturing.

Methodologies are becoming available to characterise fracture networks in terms of their geometries, topologies, age relationships, kinematics and mechanics (Peacock, D.C.P., Sanderson, D.J., 2018. Structural analyses and characterising fracture networks: seven
pillars of wisdom. Earth-Science Reviews 184, 13-28). In particular, a new philosophy has been developed in which fracture networks are described in such terms as to allow reproducibility, i.e. the description can be used by another researcher to generate a reasonable facsimile of the network. This gives us scope to rigorously compare different fracture networks, to answer the question “what is the difference between this network and that network?”

This project aims to gain a better understanding of joint patterns and the controls on these patterns.

Hypothesis

That joint networks can:
(1) be characterised in terms of their geometries, topologies and age relationships such that descriptions can be used to reproduce reasonable facsimiles of the networks,
(2) that these descriptions can form the basis of rigorous comparisons between different networks, and
(3) that the results will help understand the difference between joint networks in different beds.

Descriptions will be made of joint patterns (including their geometries and topologies), and results for different beds will be compared.

Field work

The project requires one week of fieldwork on the Devon and Cornwall coast, UK, between Hartland Point and Crackington. This will involve photographing joints on bedding planes and measuring bed thicknesses. The photographs will be used to characterise joint patterns, and data will be analysed using Excel spreadsheets.

Proposed course plan during the master degree

GEOV221 Karstgeologi og karsthydrologi (10)
GEOV251 Videregående strukturgeologi (10)
GEOV260 Petroleumsgeologi (10)
GEOV272 (10 stp) – Seismisk tolking
GEOV352 Petroleumsgeologisk feltkurs (5)
GEOV362 Pyrenneene feltkurs i sedimentologi og tektonikk (5)
Enten: AG-322 (UNIS) Fold and Thrust Belts and Foreland Basin Systems (10)
Eller: AG-336 Rift Basin Reservoirs: From Outcrop to Model (10 ECTS)