PROJECT DETAILS ONLY - NO DATA. The aim of the proposed project is to study evolution in the spatial characteristic of coupled flow and porosity development in heterogeneous porous media. We will develop a modelling engine and methodologies to generate porosity templates for use in flow and transport models of fractured aquifers. Although the primary motivation for this study is to enhance our ability to predict flow and contaminant transport in vulnerable fractured aquifers, such as the chalk, the approach is generic and we foresee a wide range of scenarios where the model may be applied. The work has three specific objectives: 1) to produce a generic model of porosity development, 2) to investigate percolation, scaling and self-organisation phenomena in porosity development due to flow, and 3) to model pore structure and flow histories for a range of natural and anthropogenic problems.

PROJECT DETAILS ONLY - NO DATA. This project will use the techniques of stereolithography and PIV directly to measure the fluid velocity field in complex, 2D, geologically realistic media with multi-scaled heterogeneities. The resulting velocity fields will be published widely and will provide an invaluable resource for the validation of models of fluid flow in complex geometries for which validation ID presently impossible. Three specific studies will also be undertaken; a) a detailed investigation of the non-linear interaction between matrix and fracture flow, b) a study of the scaling laws in the region of the percolation threshold in the presence of fractal fracture populations and significant matrix permeability and c) an examination of the scaling of the velocity flow field and how this reflects material scaling with a view to identifying potential rules for upscaling of fluid simulations.

PROJECT DETAILS ONLY - NO DATA. The project will develop and explore the application of scaling methods to strongly heterogeneous flow fields; investigate the loss and retention of information by scaling over large space and long time scale ranges; and, define the dependence between large space/long time scale migration behaviour and the underlying geological model. High resolution, highly accurate flow and transport simulation data sets for a large number of realisations possessing the high variance and strong textures observed in actual geological systems using alternative geological simulators will be used to test upscaling approaches reported in the physical sciences literature and to identify improving upscaling laws where the existing laws are inadequate.

PROJECT DETAILS ONLY - NO DATA. This project is designed to integrate geological structural characterisation of fault zones with numerical modelling of flow behaviour at different scales. We will develop a 3D flow simulator which can model the impact of geological heterogeneities (clustered fault / fracture arrays) under different stress conditions on fluid flow. The project is collaboration between a structural geology research group (the rock deformation research group), an applied mathematics group (the centre for computational fluid dynamics) and a series of industrial partners (Arco, BP, Shell and Midland Valley).

PROJECT DETAILS ONLY - NO DATA. This project will integrate micro- and meso-scale structural and geochemical data from the Irish midlands in order to understand the fluid flow and fluid mixing responsible for the development of world-class Zn-Pb orebodies. These data will be used to characterise "building blocks" of differing scales which will constrain numerical modelling of flow associated with individual faults as well as the regional system. We have assembled a multi-disciplinary, international team from Leeds, Imperial College, SURRC, Edinburgh, CSIRO (Australia) and Colorado together with assistance from Tara mines in Ireland to tackle this project.

PROJECT DETAILS ONLY - NO DATA. The influence of biofilm growth on the hydraulic properties of sediments and rocks will be investigated experimentally over scales from microscopic (10-10m) to macroscopic (102m). In addition, the effects of biofilms on the formation of fine oxide precipitates (FeO, OH, MnO.OH. etc.) and on the sorption behaviour of fluid transported trace impurities (U, Tc, Sr) will also be studied over these scales. These fundamental data will be obtained using a unique combination of experimental methods which will allow the results to be scaled up to field dimensions of distance and time, such that the results may be used by our industrial partners as input to field scale models of the migration of fluids and contaminants.

PROJECT DETAILS ONLY - NO DATA. This proposal is to test the hypothesis that secondary (crack) porosity can be treated as a scaling problem in both fracture and fluid percolation theory. This will be achieved by measurements of elastic, transport and mechanical properties on rock samples with known and controlled crack densities (crack porosities) that span the percolation threshold under a wide range of stress conditions. The measured data will be used to calibrate and validate generic models for fluid and fracture percolation that can then be upscaled to predict permeability at the reservoir scale from wireline logs.

PROJECT DETAILS ONLY - NO DATA. Predicting oil production from chalk reservoirs relies on quantifying contributions from fracture and matrix porosity, which change during compaction. Cl isotopes in water characterise fluid transport processes. Chalk matrix microporosity and fractures will give different values. We will combine two novel methods, trace water extraction from dry oil and Cl isotopes to characterise porosity from produced fluid. High pressure lab. experiments carrying fracture/matrix porosity in cores will give characteristic brine geochemistry related to poroperm to calibrate field values. We will compare fluid derived porosity regime with values measures on field core. Porosity changes from geochemistry will be compared with compaction in the field.

PROJECT DETAILS ONLY - NO DATA. Coupled (mechanical-hydraulic) numerical models based on the distinct element method will be used to investigate the behaviour of fluid flow in fractured rock-masses under stress. Flow localization is predicted at some critical stress; parameters affecting this localization will be investigated. Flow in the vicinity of boreholes and by grain infiltration will be simulated. The models will be tested against field observations and hydraulic tests in boreholes.

PROJECT DETAILS ONLY - NO DATA. Stability of a reactive front in a heterogeneous porous medium characterised by a statistical description of a permeability and/or reactivity will be studied. Stochastic partial differential equations will be formulated. The feasibility of solving these stochastic differential equations will be evaluated in this proof of concept proposal, and the expected values and variances for the growth rate and wavelength of the disturbances determined as a function of input parameters. The results will have significant impact on areas such as reactive diagenesis in oil reservoirs and acid treatments of well bores. The investigators will interact with Mobil Tec Co., who are partially matching the proof of concept grant.