Geothermal Reservoir Characterization And Power Production Estimates Of The South Swan Hills Reef Complex, Alberta
Wells in the South Swan Hills oil-pool penetrate into a Devonian reef build-up. The wells have historically played a role in extracting hydrocarbons, however, active wells in the field also produce over 200,000 m3 of hot (≥100° Celsius) water annually. The objective of this research is to understand the behavior of the hot water in the subsurface and quantify the power that can be generated through targeted extraction. To achieve this, a 3-D model of the reef is developed to highlight permeable zones conducive to significant water flow. Developing a three-dimensional geo-model is standard practice within the oil and gas industry, but geothermal applications have not been explored. The geo-model focuses on characterizing the three dimensional array of petrophysical properties, fluid types, temperatures and pressures that govern water flow through the Swan Hills Reef complex, using many of the same techniques used to characterize hydrocarbon resources. The workflow begins with lithological data from core. The lithological data, tied to well logs, are used to re-construct the paleo-environment and establish the lateral positions where porous lithofacies are deposited. Using a sequence stratigraphic framework, it is possible to map and predict how the paleo- environment shifted in response to sea level. Understanding these shifts allow for vertical variability to be mapped. The primary benefit in creating a detailed model is that it can be used to locate the vertical and horizontal geometry and continuity of reservoir units within the reef. Parameterizing large continuous reservoir units with porosity and permeability data allow for estimates of the electrical power generation of the reservoir. These estimates suggest that the reservoir can sustain 8.2-12.4 MW for a 50-year project lifetime. The model allows for flexibility when testing production and injection scenarios, which is necessary when considering costly variables such as production/injection well configuration.
AAPG Datapages/Search and Discovery Article #90346 ©2019 AAPG European Region, 3rd Hydrocarbon Geothermal Cross Over Technology Workshop, Geneva, Switzerland, April 9-10, 2019