A Geologic Strain and Reservoir Attribute-Based Discrete Fracture Network (DFN) Model of the Humma Field, Partitioned Neutral Zone

Sherilyn Williams-Stroud¹, Stewart Griest², and Scott Meddaugh^2
1 Midland Valley Exploration Ltd, Glasgow, United Kingdom
² Chevron International Exploration and Production Company, Houston, TX

Sparse well data were used to validate a fracture property model generated from a DFN (Discrete Fracture Network) model in the Humma Field, PNZ. The development of the Humma structure 4-way closure was modelled with two scenarios: detachment buckle fold and transpressional accommodation structure. Restoration of the structure followed by forward modelling was done to generate a strain-populated volume to use to determine the fracture density. Fracture attributes for the two models were based on the strain orientations and proposed stress regime responsible for each model. Fracture orientations throughout the volume were constrained by the appropriate eigenvalues of the strain tensor calculated from the kinematic forward model. The fracture intensities were further constrained by the use of the reservoir property model. The matrix properties, matrix permeability, and seismic attributes also were used to constrain the fracture density for the relevant fracture sets. The output fracture density and orientations were analyzed and validated against the measured well data, and where needed, the fracture set parameters were adjusted to account for fracture permeability response from the in-situ stress field. A fracture model was developed that honors well data and provides a method for predicting fracture character and flow properties away from the well bore. The properties are output directly into the reservoir property model as a property associated with the DFN to create a fracture permeability property model ready for input to a flow simulator.