Evaluating the Potential to Increase Oil Production from Legacy Fields in Montana

Abstract This research assesses the potential for Enhanced Oil Recovery (EOR) techniques to boost oil production in Montana. Eight major oil basins in Montana, comprising over 350 oil fields, were analyzed. Using a volumetric analytical method, the original oil in place (OOIP) was estimated for 42 fields where sufficient data were available for the calculation. By comparing the cumulative oil production with the OOIP, fields with significant remaining reserves were identified. Data for this project was obtained from the Montana Geological Society (MGS) and the Montana Board of Oil and Gas (MBOG), which provided comprehensive information on reservoir properties, fluid characteristics, and production histories. The analysis identified that approximately 3.51 billion stock tank barrels (STB) of oil remain within the 42 reservoirs suggesting considerable untapped potential. The study utilized a screening criterion based on reservoir rock properties and fluid characteristics to select appropriate EOR methods for the 42 fields. Carbon dioxide (CO2) injection, hydrocarbon injection and polymer flooding were identified as the most viable techniques. In general, fields at depths greater than 4,000 feet were recommended for CO2 injection, while fields at shallower depths were more suited to polymer flooding. The Breed Creek oil field was selected for detailed modeling and simulation due to its available reservoir data. Preliminary simulations indicated that CO2 injection could increase recovery by approximately 10%, potentially extracting an additional 880,000 STB of oil from this field. Applying the results from this field to other fields in Montana could result in hundreds of millions of additional barrels of oil production, unlocking significant potential across the region. This study validates that EOR techniques could significantly enhance oil production in Montana, and further simulations and economic analyses will guide the feasibility and implementation of these methods in the field. This research not only provides valuable insights for the revitalization of Montana’s oil industry but also offers a scalable pathway for improving oil recovery in other states facing similar challenges. The methodologies and EOR techniques explored in this study can be adapted to diverse geological settings across the U.S., offering a broader impact on oil production. By tailoring these approaches to the specific reservoir characteristics of various oil fields nationwide, states with declining oil output can benefit from increased hydrocarbon recovery, contributing to both regional and national energy sustainability.