Statistical Analysis of Core and Wireline Log Data from the Northern Niagaran Pinnacle Reef Trend to Inform Static Earth Modeling for CO2 Storage Fields

Abstract

The Northern Niagaran Pinnacle Reef Trend (NPRT) is composed of over 800 identified reefs in the Michigan Basin. Well coverage and data availability vary greatly between fields and create a significant challenge in characterizing and modelling. Methodology was established to statistically analyze core and wireline log data to determine characteristic property distributions of porosity and permeability for specific formations and facies that can be applied in areas of scarce data. The analysis was conducted in three parts: 1) descriptive statistics of formations and facies were run using wireline logs and core data, 2) correlations were developed between wireline log and core data to build predictors, and 3) results were applied to static earth models with different data availability to demonstrate the influence on modelling. Core data was compiled for over 250 wells across the NPRT capturing a variety of reef types, including: dolomite, limestone, mixed carbonate, salt-plugged, vugular and fractured, oil producing, gas producing, and water filled. This included data for off-reef Niagaran rocks and overlying A-1 Carbonate. Associated wireline log data was digitized, key formation tops identified, and depth shifts between core and log data were corrected. A statistical analysis program, R, was used to establish distributions and apply machine learning techniques to develop predictors. Prediction models were validated by comparing predicted properties to actual measured properties. Static earth models were constructed for multiple reefs and results were applied to better populate properties within the reef structure. Additionally, results of models were compared between non-informed and informed property models. Results show property distributions were controlled by facies, lithology, and diagenesis. Unique distributions were established to represent specific reef facies and were successfully applied to static earth models. Where data was scarce, the statistical results provided a solution for property modelling which better matched geologic and reservoir interpretations. Results of this study can be applied across the NPRT to better predict reservoir properties and aid in future modelling efforts. The study is part of the Midwestern Regional Carbon Sequestration Partnership (MRCSP) Michigan Basin Large-Scale Injection Project under DOE/NETL Cooperative Agreement # DE- FC26-0NT42589 with co-funding by Core Energy, LLC, and several other partners. Data was provided by the Michigan Geologic Repository for Research and Education (MGRRE).

AAPG Datapages/Search and Discovery Article #90335 © 2018 AAPG 47th Annual AAPG-SPE Eastern Section Joint Meeting, Pittsburgh, Pennsylvania, October 7-11, 2018