Alexander Thomas Hughes-Wharton

Produce several 1-D burial models across the extent of the Cheshire Basin.

Model a series of alternate scenarios for the burial history of the Northern Cheshire Basin.

Develop the models utilising Novva software.

Sedimentary fill is of Permian-Jurassic age

Vast erosion leads to removal of younger sediments

Thicknesses are variable within the basin

Source

Units

Blacon East – Input Stratigraphy

Mikkelsen and Floodpage 1997

Modified from Plant et al. 1999

IGas 2014

Basin models generated using Novva software

Data used in the modelling process was taken from publicly available sources

Kerogen kinetics information was available for all source units

Mikkelsen and

Floodpage 1997

Reduced Original Increased

Variscan Inversion 150m 300m 600m

Cimmerian Inversion 125m 250m 500m

Tertiary Inversion 400m 800m 1600m

Cimmerian Inversion controls final maturity

Re-generation is unlikely in the Tertiary

Difference of 15% in the transformation ratios of the Bowland-Hodder Shales

Increased

Reduced

Adsorption increases with:

Increasing pressure due to: -burial-generation pressure-ice shield development

Decreasing temperature due to:-uplift / erosion-decreasing heat flow or thermal gradient-glaciations

Increasing TOC due to:-higher original organic matter content

Adsoprtion Potential

vs Temperature & Pressure

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Adsorption Potential

vs TOC & Pressure

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0.5 (%)

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Increasing TOC

Declining Temperature

Maximum generation in the Cretaceous

Partial desorption possible during the Tertiary igneous event

Overall there is good evidence for adsorption through time

More aesthetic outputs

More accurate heat-flow reconstruction

User-defined kerogen input

Accessibility

Requires addition of more features

Most prominent area for exploration is on the northern basin slope, at a depth of around:1500-2000m.

Peak maturity is achieved around 180Ma (Cimmerian inversion).

Understanding the maximum burial and amount of erosion during this event is paramount to identifying the most prospective areas for shale-gas exploration.

Re-triggering of generation in the Tertiary was unlikely with the Carboniferous source rocks partially matured.

Future exploration work should be targeted on the basin slope – at depths of around 1750m to top Permo-Trias.

A technical evaluation of the source units; to determine the effectiveness of artificial fracturing. -No public domain data -Common analogues are not applicable (Waters et al.2009).

Novva software needs to continue being developed, improving reliability and adding functionality.

Supervisors – James Armstrong and Kevin Taylor

Software – Sirius Exploration Geochemistry

Kerogen Kinetics data – Petroleum Systems ltd.

Andrews, I. J. 2013. The Carboniferous Bowland Shale gas study: geology and resource estimation. British Geological Survey for Department of Energy and Climate Change, London.

Armstrong, J. P., Smith, J., D’Elia, V. A. A., & Trueblood, S.P. 1997. The occurrence and correlation of oils and Namurian source rocks in the Liverpool Bay-North Wales area. In: Meadows, N. S., Trueblood, S.P., Hardman, M. & Cowan, G. (eds.) Petroleum Geology of the Irish Sea and Adjacent Areas. Geological Society, London, Special Publications, 124, 195-211.

Igas Energy (Ltd.) 2012. Results Presentation & Shale Update. June 2012. Energy Institute, London.

Mikkelsen, P. W. & Floodpage, J. B. 1997. The hydrocarbon potential of the Cheshire Basin. In: Meadows, N. S., Trueblood, S. P., Hardman, M. & Cowan, G. (eds.) Petroleum Geology of the Irish Sea and Adjacent Areas. Geological Society, London, Special Publications, 124, 161-183.

Plant, J. A., Jones, D. G. & Haslam, H. W. (eds.) 1999. The Cheshire Basin: Basin evolution, fluid movement and mineral resources in a Permo-Triassic rift setting. British Geological Survey for Department of Energy and Climate Change, London.

Waters, C. N., Waters, R. A., Barclay, W. J. & Davies, J. R. 2009. A lithostratigraphical framework for the Carboniferous successions of southern Great Britain (Onshore). British Geological Survey Report, Nottingham.

Thank you for

your attentionQuestions?

Figure - Early Carboniferous basins and platforms of northern England. (Modified from Andrews 2013) *CLH = Central Lancashire High; HH = Holme High

Input Reason

TOC Evaluate present and assess original organic

richness

Depths/thicknesses of stratigraphic units Assess present day overburden

Eroded thicknesses Restore previously removed overburden

Lithology Aid in assessment of thermal conductivity,

enabling estimation of heat-flow through

history

Vitrinite Reflectance Calibrate the models heat-flow history

Geothermal Gradient Calibrate the post-depositional thermal

regime

As well as the key data, additional information was also gathered in order to produce more precise models:

Present day surface temperature

Palaeo-surface temperature

Well location

Well datum

Downhole temperature

Sea level fluctuations through time (Palaeoelevation/palaeobathymetry)

Tectonic history

Kerogen information

Event/Unit Start age (Ma) Reference

Glacial 1 Aitkenhead et al. 2002

Tertiary unconformity 54 Kirby et al. 2000

Mesozoic deposition 176 Kirby et al. 2000

Mercia Mudstone Group 235 Aitkenhead et al. 2002

Sherwood Sandstone Group 245 Aitkenhead et al. 2002

Manchester Marl 251 Aitkenhead et al. 2002

Collyhurst Sandstone 260 Pearson and Russell2000

Variscan unconformity 277 Kirby et al. 2000

Westphalian deposition 312.5 Aitkenhead et al. 2002

Upper Namurian Limestone 316 Aitkenhead et al. 2002

Holywell Shales (Upper and Lower) 320 Fraser and Gawthorpe 1990

Lower Namurian Limestone 324 Pearson and Russell 2000

Upper Bowland Shale 328 Fraser and Gawthorpe 1990

Upper Dinantian Limestone Group 330 Fraser and Gawthorpe 1990

Lower Bowland Shale 334 Fraser and Gawthorpe 1990

Lower Dinantian Limestone Group 335 Fraser and Gawthorpe 1990

Hodder Shale 339 Fraser and Gawthorpe 1990

Reduced Original Increased

Variscan Inversion 150m 300m 600m

Cimmerian Inversion 125m 250m 500m

Tertiary Inversion 400m 800m 1600m

Original Inverted Average

Cimmerian Inversion 250m 800m 525m

Tertiary Inversion 800m 250m 525m