An integrated workflow for reservoir modeling and flow simulation of the Nikanassin tight gs reservoir in the western Canada sedimentary basin
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AbstractThis thesis presents an innovative workflow and learning curve for characterization and reservoir simulation of the tight gas Nikanassin Group in a study area, which centers primarily in Township 65 Range 09. The workflow and learning curve starts with LiDAR scanning of the Milk River Formation (porosities and permeabilities larger than 20% and 100 mD, respectively) in Writing on Stone Provincial Park (WOSPP), moves to rocks of the Doig Formation in British Columbia with poorer properties (about 6 to 9% porosity for clean sandstones and permeabilities of 0.7 to 34 mD) and closes the cycle evaluating rocks of the Nikanassin Group with even worse rock properties. The learning curve provides the necessary tools for studying the very complex, very heterogeneous Nikanassin Group characterized by porosities that are generally less than 5% and permeabilities that are typically a fraction of mD, i.e., properties much lower than the ones mentioned above for the Milk River and Doig formations. Previous petrographic studies of the Nikanassin Group show the presence of (1) intergranular, (2) microfracture + slot, and (3) isolated (non effective) porosities. These studies inspire the introduction of a mathematical triple porosity model for improved petrophysical analysis of the Nikanassin Group. Another novel approach developed in this thesis is the integration of lithofacies and pore throat apertures (rP35) that facilitate facies mapping for reservoir simulation purposes. Support to the reservoir simulation is given by geostatistical analysis and numerical well test evaluation. The result is a sound full field model that permits a reasonable match of production and pressure (limited amounts) histories, and forecasting of gas recovery under different well-spacing and depletion scenarios. As most Nikanassin tight gas wells are completed commingled, this research develops a procedure for production allocation of individual contributing formations. The study shows that there is a very large gas potential in the Nikanassin group, particularly in the Lower Monteith Formation that can be exploited by reducing significantly the well spacing. For example, detailed simulation indicates that doubling the number of Monteith wells in the study area will also double the cumulative gas production over a 10-year period. The finding is significant as the tight gas Nikanassin Group extends for more than 15,000 km² within Alberta and British Columbia. This suggests preliminary that there is potential for drilling thousands of Nikanassin well in these two provinces.
Bibliography: p. 301-310