Faults in Coal

Lead Research Organisation: University of Strathclyde
Department Name: Civil and Environmental Engineering

Abstract

The project will look to address the clear gap in understanding of the mechanical and hydrological properties of faults cutting coal-bearing sediments, with the aim of informing predications of their properties at depth. Uncertainty in the mechanical and fluid flow properties of faults cutting coal presents a major risk for unconventional oil and gas, mine safety (water inrush accidents and gas blowouts), mine waste water drainage and fault reactivation. Improving the understanding of the mechanical and hydrological properties of faults cutting coal will aid prediction, prevention and management of the above problems. This is of upmost importance in deep underground mine safety where faults remain the single greatest risk leading to subsurface fatal accidents.

The major questions that will look to be addressed, and that will enable prediction of faults cutting coal include:
- What are the main processes governing fault development in these rock types?
- What processes act to enhance or reduce fault zone permeability and/or strength?
- Which aspects of the resulting fault rocks can be quantified from site-scale data and which can only be characterised in a statistical, risk-based way?
- What data could be collected to quantify risk of the hazards associated with faults cutting coal and how can this data be used to reduce the risk of the hazard?

The use of field mapping, analysis of microstructure, analysis of core and the investigation of mine records (e.g. mine maps) will be used to improve models of sub-surface fluid flow applicable to a number of industry applications (e.g. Mine safety, fault reactivation related subsidence, coal bed methane, carbon capture and storage).

A number of key sites will be used to gain an understanding of faults cutting coal bearing sediments including the well exposed fault traces at Spireslack surface coal mine, other UK outcrops and outcrops in Utah. Field studies will be used to constrain the key parameters that control the fault architecture (e.g. thickness and mechanical properties of host rock layering). Lab based analysis of samples collected from the field will constrain mechanical and permeability properties along with characteristic microstructures to enable permeability modelling. The temporal element of fault evolution will also be investigated through field and microscopic analysis of coal bearing faults.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N509760/1 01/10/2016 30/09/2021
1857013 Studentship EP/N509760/1 01/10/2016 31/03/2020 Billy Andrews
 
Description 1. Existing small-scale sedimentary layering/features greatly effects the development of faults in coal measures.
2. The collection of fracture data is effected by subjective bias such that people see or interpret fracture networks very differently
3. Organics (e.g. Coal) disproportionally effect how faults and fractures develop in coal measures.
4. The effect of mechanical layering displays scale independent behaviour across several scales of observation.
Exploitation Route While there has been many advances associated with this project, the analysis of how microstructures evolve as faults in coal grow remains uninvestigated. There is clear scope for further study here through the use of either samples collected during this study or through additional sampling of fault rocks. This could be furthered through the use of mechanical or fluid flow modelling of coal bearing sequences. How the findings stemming from this research relate to both sites outside those which were studied is another direction this research could take.
Sectors Energy,Environment,Other

 
Description Geological Society Research Grant
Amount £876 (GBP)
Organisation Geological Society of London 
Sector Learned Society
Country Unknown
Start 04/2018 
End 04/2018
 
Description Sapienza Università di Roma 
Organisation Sapienza University of Rome
Country Italy 
Sector Academic/University 
PI Contribution A day long workshop (June 23rd) was held at the University of Strathclyde where collaborators from Sapienza Università di Roma and members of the Faults and Fluid Flow (University of Strathclyde) gave a combination of talks and demonstrations. This was followed by B. Andrews leading a four-day fieldtrip (24th to 27th July 2018) to my primary field area in Whitley Bay where discussions on the field area and the collection of field data was undertaken. Field data collected during this trip, along with additional field data collected my B. Andrews, is being used for the preparation of a manuscript which covers looks at the effect of sampling strategy on the generation of Discrete Fracture Network models. B. Andrews and members of the project will assist in the preparation of this manuscript, however, collaborators from Sapienza Università di Roma will lead the process. During the final day of the trip (27th July) data was collected and field discussions undertaken which, along with follow up workshops (held both at the University of Strathclyde and Sapienza Università di Roma), underpinned a manuscript which has been submitted to Solid Earth titled 'How do we see fractures? Quantifying subjective bias in fracture data collection' which is currently in review for Solid Earth.
Collaborator Contribution Collaborators contributed by hosting B. Andrews for a research visit to the Sapienza Università di Roma including leading field trips to the Central Apennines, Latera Caldera and Sardinia to observe faults and fractures at a variety of geological locations. These discussions included the discussions of observations and field techniques used by the collaborators research group, which is directly applicable to this project. Provided discussions, edits and feedback during the preparations and submission of the manuscript submitted to Solid Earth and have been leading the preparation of a manuscript which investigates the effect of sampling strategy on the generation of Discrete Fracture Network models.
Impact Preparation and submission of Andrews, B.J., Roberts, J.R., Shipton, Z.K., Bigi, S., Tartarello, M.C., Johnson, G.O. in review. How do we see fractures? Quantifying subjective bias in fracture data collection. Solid Earth.
Start Year 2018