Correlating Petrophysical Calculations from Density Logs to Production Trends in the Elm Coulee Field, Montana

摘要

This thesis investigates correlations between estimated upper Bakken total organic carbon (TOC) and production data in the Elm Coulee field, and tests two hypotheses for defining simulation model properties with the results. The purpose of this research is to investigate potential correlations between upper Bakken TOC and production and exploit any correlations to develop better methods for defining simulation model properties. This may reduce time necessary to history match production from an Elm Coulee model and help to explain the production variability. The study area is in Montana townships 24N-57E, 23N-57E, and 24N-55E. Public domain completion and production data for producing horizontal wells in this area were used.TOC for the upper Bakken was estimated using density logs from vertical wells. These values were upscaled and kriged to a reservoir grid and plotted against cumulative production data. After normalizing the data, some statistically significant correlations were discovered, most notably for TOC versus cumulative gas production and TOC versus cumulatively produced water-oil ratio.Simulation cases were developed to test two hypotheses for modeling properties using correlations between TOC and production data. The first hypothesis is that upper Bakken TOC can be used to define the intensity of secondary permeability generated from natural fracturing. The second hypothesis is that upper Bakken TOC can be used to define water saturation since the conversion of bitumen to expelled oil consumes water. Neither hypothesis substantially improved the history matching process. However, this research affirms the Elm Coulee Bakken is oil wet, and that simulation properties affected by wetting characteristics should reflect this. Correlations found between TOC and production data also merit further research using dual permeability modeling.