2014 Rocky Mountain Section AAPG Annual Meeting

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A Comprehensive Deterministic Petrophysical Analysis Procedure, For Reservoir Characterization: Conventional and Unconventional ReservoirsCopyright 2014, held by the submitting authors. This paper was prepared for presentation at the AAPG RMS Annual Meeting in Denver, CO, July 20-22, 2014.


The past ten years, we have developed a number of petrophysical models for specific requirements: Rock Physics Modeling Create pseudo acoustic (both compressional and shear) curves, based on Gassmann and Krief geophysical models. The model allows for the estimate of acoustic data where no (or limited) acoustic data exists. From this modeling, mechanical properties can be made. Reference Holmes, SPWLA 2004, SEG 2005. Relative Permeability Modeling Profiles of irreducible water saturation, are compared with the actual water saturation. Reference Holmes AAPG 2009. Using the technique of Corey (1954) continuous profiles of relative and effective permabilities to both fluid phases can be created. Knowing viscosities of reservoir fluids water/hydrocarbon can be determined as continuous curves. Petrophysical Analysis of Unconventional Reservoirs Involves examination of the shale intervals independently of the clean formation. Additionally consideration of the total organic carbon (TOC) content of the reservoir is required. Quantitative calculations of free and adsorbed hydrocarbons need to be assessed for a complete analysis. Reference AAPG 2010, 2011, 2013. A Technique (unpublished) to Identify Fractures Developed to estimate the presence of fractures, both open and healed-from standard open hole logs. Anonymously rapid rates of change with depth are attributed to fractures. If the trend is to higher porosity, open fractures are suggested. SUMMARY This paper presents how these various models can be combined: -Porosity, fluid saturation, shale volume, permeability -In-place and recoverable hydrocarbons -Free hydrocarbons in the shale fraction -TOC and adsorbed hydrocarbons -Profiles of relative and effective permabilities to the fluid phases -Profile of water/hydrocarbon ratios -Brittle vs. ductile distinction Examples from unconventional oil and gas reservoirs of North America are presented and include Niobrara, Bakken (oil), Western Canada, Barnett and Utica (gas). ABOUT THE AUTHORS Michael Holmes has a Ph.D., University of London in geology and a MSc. From the Colorado School of Mines in Petroleum Engineering. His professional career has involved employment with British Petroleum, Shell Canada, Marathon Oil Company and H.K. van Poollen and Associates. For the past 20 years he has worked on petrophysical analyses for reservoirs worldwide under the auspices of Digital Formation, Inc. Antony M. Holmes has a BS in Computer Science, University of Colorado. He has been involved with the development of petrophysical software for 20 years with Digital Formation, Inc., particularly with regards to the implementation of petrophysical analyses. Dominic I. Holmes has a BS in Chemistry and a BS in Mathematics, Colorado School of Mines. He has been involved with the development of petrophysical software for 20 years with Digital Formation, Inc., particularly with regards to the presentation of petrophysical information in a graphical format.