Kevin J Keogh1, Wayne Bailey2, John H Rippon3, David Hodgetts1, Tom Manzocchi2, Steve S Flint1, John Walsh2, Phillip Nell4, John Howell1
(1) University of Liverpool, Liverpool, United Kingdom
(2) University College Dublin, Dublin 4, Ireland
(3) International Mining Consultants, Sutton-in_Ashfield, United Kingdom
(4) Badley Technology Ltd, Spilsby, United Kingdom
ABSTRACT: A Deterministic Sequence Stratigraphic and Structural Reservoir Model for a Coal-Bearing Delta Top Analogue: East Pennine Coalfield, UK
Challenges in 3D reservoir modelling include conditioning of models by 'soft knowledge' of stratigraphic architecture, sediment body geometries and fault populations, densities and locations. One solution is to build a "close to deterministic" control model from datasets of sufficient coverage to allow exact solutions to these stratigraphic and structural uncertainties. Such a model can be used to test the closeness of fit of stochastic modelling software in terms of net:gross and connectivity in pre- and post-faulted models.
The East Pennine Coalfield includes deep and opencast mines, outcrops and thousands of cored boreholes. A 20 x 20 km x 500 m thick, deterministic, object-based, 3-D model of this faulted, coal-bearing, delta top reservoir analogue has been built from 1100 boreholes, 400 mine plans and outcrop data. The accommodation context of channel and sheet sandbodies has been honored with respect to sequence boundaries and flooding surfaces. The model has been faulted using deterministic maps of all faults with maximum displacements from 140m down to 1 m (equivalent to seismically imaged and sub-seismic faults in reservoirs).
Model analyses include sensitivity of net:gross to well distribution and body geometry/orientation and connected volume per systems tract on the unfaulted model. Analyses of faulted models, using 20 m, 10 m and 1 m maximum displacement cut-offs, quantified the effects of faulting at different scales on connected and drainable volumes for different systems tracts. The results are non-linear and reflect the combined properties of dimensionality and connectivity of sedimentary bodies and size scaling and connectivity of faults.
AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado