Abstract
This thesis concentrates on some of the aspects of a ‘Total Petroleum System’ including natural gas and oil stored in conventional and unconventional reservoirs.
The original contributions of this thesis include:
1) The use of electromagnetic mixing rules for construction of dual and triple porosity models with a view to quantifying matrix, fracture and non-effective porosity and the porosity exponent (m) of naturally fractured reservoirs.
2) The use of electromagnetic mixing rules for construction of dual and triple porosity models with a view to quantify the water saturation exponent (n) and to estimate the wettability of reservoir rocks in naturally fractured reservoirs.
3) Measurements of porosity and permeability in drill cuttings collected directly in a horizontal well. Although these measurements have been carried out previously in drill cuttings collected in vertical and deviated wells, this is the first time that they are performed in horizontal well drill cuttings.
The models developed in Items 1 and 2 are compared successfully against core laboratory data. Water and/or oil stored in each of the porous media considered in the models, affects rock wettability and consequently the values of n. Robustness of the models is important because, in practice, while logging a well in a naturally fractured reservoir, the tool will probably go through some intervals with only matrix porosity; some intervals with matrix porosity and fractures, some with matrix porosity and isolated porosity; and some intervals with matrix, fractures and non-connected porosities. As there are variations in the contribution of each porosity system with depth, there are also variations in m with depth that have to be taken into account.
The laboratory measurements of porosity and permeability from drill cuttings mentioned above in Item 3 were conducted at the University of Calgary. Based on a thorough review of literature this is the first time that this measurements are conducted in drill cuttings samples collected in horizontal wells.
Starting with only drill cuttings measurements of porosity and permeability, the methodology developed in this thesis allows for complete formation evaluation and geomechanical analysis through the use of a successive approach for determination of several parameters of interest including pore throat aperture radius (rp35), water saturation, porosity exponent (m), true formation resistivity, capillary pressure, Knudsen number, depth to the water contact (if present), construction of Pickett plots, Young’s Modulus, Poisson’s ratio and brittleness index throughout the horizontal length of the well, and for locating the best hydraulic fracture initiation points during multi-stage fracturing jobs.
It is concluded that the use of electromagnetic mixing rules and drill cuttings provide a valuable and practical addition for quantitative characterization of conventional and unconventional petroleum reservoirs.
