Equivalent volume modelling of dual porosity dual permeability hydrocarbon reservoirs.

Duration - 01/01/96 - 31/12/98

Funding - Funded by the European Union Fourth Framework Hydrocarbon Reservoir Programme.

Co-ordinator - GEUS (Geological Survey of Denmark & Greenland).

Industrial Partners

Enterprise Oil (GB)
Norsk Hydro (Norway)

Other research partners

BRGM (Bureau de Recherches Geologiques et Minieres) (France)
Nansen Environmental & Remote Sensing Centre (Norway)
Chalmers University of Technology (Sweden)

Summary - This project is directed towards the development of techniques for optimising production from fractured dual porosity, dual permeability hydrocarbon reservoirs (hereafter dual poroperm). In a dual poroperm reservoir, fluids exist in two interconnected systems: the porous rock (called the matrix) and the highly permeable fractures in the rock. The bulk of the oil in such fields is held in the rock matrix which is of relatively low permeability compared to the fracture network. Successful production from dual poroperm reservoirs depends on the accurate siting of wells and careful control of production rates.

The project aims to translate geological models, describing fracture and matrix, into reservoir engineering flow models. However, even if a geologist could describe all of the fractures in a reservoir, the fractures could not all be directly incorporated into a multiphase flow model. Therefore it is necessary to upscale and average specific features of smaller fracturemodels.

The project involves the following activities:

Geological fracture characterisation
Use of streaming potential to measure fluid flow in rocks
3-D discrete fracture modelling
2-D two phase discrete fracture flow modelling
3-D single phase discrete fracture flow modelling
Two phase physical and numerical modelling of a dual poroperm system
Use of data from a producing field
Application of modelling to a producing field

Example of output from the discrete fracture flow model, showing the variation in flow rates across a region of fractured porous rock. Flow is from right to left across the model. The orange and red colours show that the fractures provide pathways of high fluid flow rates through the region. Shadow areas of low flow rates(blue) exist between the fractures.

Courtesy of Noelle Odling, Nansen Research center

This project is a development from an earlier project, Fluid Flowin Dual Permeability Hydrocarbon Reservoirs, involving the same partners,with the exception of Chalmers University. A report resulting from thefirst Dual Permeability project is currently in press, the Interim Guideto Fracture Interpretation & Flow Modelling in Fractured Reservoirs, which is a European Commission Publication.

$Aerial photograph of fractured limestone$ Detail from aerial photograph from the Burren, Co. Clare, Ireland, showing part of a fractured Carboniferous limestone pavement. The visual signature of the fractures has been naturally enhanced by karst processes. The longitundinal fractures are veins, while the transverse fractures are later-formed joints.

Contact John Walsh
Tel: +353 1 716 2606
Email: fault@fag.ucd.ie