Australian School of Petroleum

Permanent URI for this collection

https://hdl.handle.net/2440/84916
This collection contains Honours, Masters and Ph.D by coursework theses from University of Adelaide postgraduate students within the Australian School of Petroleum. The material has been approved as making a significant contribution to knowledge.

Browse

Browsing Australian School of Petroleum by Advisors "Abul Khair, Hani"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    ItemOpen Access
    The effect of stress regime, pre-existing natural fracture geometric and hydraulic parameters and stimulation design parameters on fracture stimulation and fluid flow dimensions in the Otway Basin
    (2014) Benson, Robert; Abul Khair, Hani; Australian School of Petroleum
    The development of unconventional oil and gas resources is becoming increasingly important as conventional reserves start to decline. In order to make the recovery of unconventional resources from low permeability reservoirs economically viable, the process of hydraulic fracturing is critical. At present, only engineering measures are implemented in the design phase to enhance the stimulation process as there is very little understanding of how the geometry and properties of pre-existing natural fractures influences hydraulic fracturing. This study analyses the effect of the in-situ stress regime and pre-existing natural fracture intensity, orientation, hydraulic parameters and stimulation treatment design parameters on fracture stimulation and fluid flow dimensions. Wellbore image logs from 6 wells in the Otway Basin were used for the analysis of fracture orientation, intensity and size distribution. This was used to generate a model of the natural fracture network for simulation and evaluation of pressure transient testing and fracture stimulation. Discrete fracture network modelling is an effective approach for evaluating hydraulic fracturing and fluid flow dimensions in naturally fractured reservoirs. It was found that hydraulic fractures do not necessarily propagate as a symmetrical bi-wing fracture exactly parallel to the direction of maximum principal stress. Propagation occurs in the direction of maximum principal stress, in a complex manner, involving initiation, connectivity and reactivation of the fractures. The microseismic-event density, percolation zone size and stimulated reservoir volume, as a result of fracture stimulation is directly correlated to pre-existing natural fracture intensity, fracture compressibility and stimulation pump rate, pump pressure and slurry density. Pressure derivatives show very different characteristics and therefore fluid flow dimensions with different fracture intensity and fracture orientation.
  • No Thumbnail Available
    ItemOpen Access
    The effect of the stress regime and pre-existing natural fracture densities, orientations and hydraulic parameters on fracturing stimulation and fluid flow dimension in the Cooper Basin
    (2014) Ibraheem, Kazeem A.; Abul Khair, Hani; Australian School of Petroleum
    Fracture stimulation has played a key role in making oil and gas unconventional resources economically viable and has contributed towards domestic energy production. This has (to some extent) been a very similar situation in the Moomba field of the Cooper Basin. In order to further increase the gas fluid flow for commercial production, it is important to understand the stress state and pre-existing natural fracture densities, orientations and hydraulic parameters which are the critical parameters influencing the shale gas production from unconventional reservoirs. Pressure transient tests analysis (to test the reservoir deliverability and stimulation treatment evaluation) conducted on discrete fracture networks (DFN) (generated from image log data) showed that change in diffusivity, storativity, mobility and transmissivity of the reservoir fluid due to the changes in the hydraulic parameters will determine the relative lag time of the fracture radial and linear flow regimes on the pressure derivative plot and the well test speed. This also affected the radius of investigation growth with respect to the fracture boundary. Fracture stimulation was conducted focusing on the effects of geomechanic properties (elastic modulus, fracture size, and shear stress) of unconventional reservoir rocks and controllable fracture stimulation operation parameters (flow rate, pump pressure, and slurry density) on stimulated reservoir volume (SRV) and total percolation area. High elastic modulus (HEM) rock property was found to be the critical parameter affecting this reservoir performance. Further fracture stimulation studies were conducted focusing on the relationship between the controllable fracture stimulation operation parameters and HEM rock property. High flow rate (HQ) or low pump pressure (LPP) was found to be the controllable parameter that would further enhance the gas production from an unconventional reservoir with HEM. This study, therefore, suggests that fracture densities and orientations (fracture distributions) played a major role in the enhancement of SRV and total percolation area. Fracture density improved the connectivity of the stimulated fractures (and hydraulic fractures) for fluid flow and hence the total percolation area. The scenarios that resulted in low SRV and total percolation area were predominantly caused by low fracture density and increased pump pressure and this situation caused a “tip screen-out” effects around the wellbore.