Development of a Fractured Reservoir Model for the Mesaverde Formation to Support Hydrofracturing Design, Natural Buttes Area, Uinta Basin, UT
Paul La Pointe and Hope Sisley
Golder Associates Inc.
The role of natural fractures in the stimulation and production of tight sand and shale reservoirs has been the subject of numerous investigations. Newly-developed geomechanical multiphase models provide a more comprehensive way to understand the interaction between the induced hydrofractures and the natural fracture system and optimize development. A conceptual model for the origin of the natural fracture system in the Mesaverde Formation of the Uinta Basin was developed to test this technology. This conceptual model was then implemented as a Discrete Fracture Network (DFN) model, and the DFN model was validated by comparing the model to subsurface fracture data, and the model's simulated microseismic response to measured microseismicity. Field studies of fracturing in the Mesaverde Formation and other formations within the Uinta Basin, supplemented by subsurface fracture image log data and core were used to develop a conceptual model for the origin and variability of natural fractures in the Uinta Basin. They indicated that there were two families of natural fractures, one related to structural folding, and a second related to in-situ hydrofracturing produced by excess fluid or gas pressures in the rock during hydrocarbon generation and burial. This model was then evaluated in the Natural Buttes area and predicted fracture geometry that matched image log data. A well-scale DFN model was created and used to simulate the growth and interaction of the hydraulic fracture with the natural fracture system. The microseismicity of the model compared well with the measured microseismicity of a nearby well, validating the conceptual model of fracturing and providing a new means to study the interaction between the natural fracture system and the hydrofracturing process.
AAPG Search and Discovery Article #90169©2013 AAPG Rocky Mountain Section 62nd Annual Meeting, Salt Lake City, Utah, September 22-24, 2013