Upper Devonian Study

Reservoir Characterization and Production Properties

Several members of our highly successful Marcellus Shale Project have encouraged Core Lab to initiate a similar project in the Upper Devonian black, organic-rich shales in the gas and liquids maturity windows of northwest Pennsylvania and possibly in New York. The sequence of Upper Devonian shales include in ascending stratigraphic order the Burket, Geneseo, Middlesex, Rhinestreet, and Huron.

Several companies are embarking on an evaluation of the Upper Devonian shales and have either drilled, or are planning to drill, pilot wells with the acquisition of cores. The Upper Devonian shales may have similar or very different reservoir properties than the Marcellus and should be challenging in terms of reservoir characterization, predicting producibility potential, estimating ultimate recovery, and optimizing fracture stimulation techniques.

Project Objectives

The primary objective of this project is to provide operators with measured geological, petrophysical, geomechanical, geochemical, and production properties of the Upper Devonian shales in order to improve their formation evaluation and to optimize stimulation and production. Our work suggests that understanding the similarities and differences in these shales on a regional basis is the key to successful exploration and exploitation. The resultant database will be an invaluable tool to operators in evaluating, comparing, and designing completion and stimulation methods for the Upper Devonian shales. Specifically, the project objectives are as follows:

  • Geologically characterize the cored shales in terms of depositional facies, environment of deposition, and rock types.
  • Characterize and classify the shales in terms of lithology, mineralogy, clay content, clay types, and pore structure including macro- and micro-fractures.
  • Measure the various petrophysical properties such as porosity, permeability, grain density, and saturations (i.e. water saturation, gas saturation, mobile oil saturation, gas-filled porosity and bound water).
  • Measure and characterize the organic content of the shales in terms of total organic content (TOC), Rock Eval pyrolysis, and maturity.
  • Measure the key geomechanical properties that are required for optimizing fracture designs and/or horizontal wells such as Young’s Modulus, Poisson’s Ratio, Bulk Modulus, fracture conductivity, horizontal stress, and proppant embedment.
  • Core-log calibration of open-hole logs for the development of petrophysical models to determine Upper Devonian shales properties.
  • Determine the rock-fluid compatibilities of various stimulation fluids with the prospective shales and evaluate the appropriate proppant and fluid carrier systems with fracture conductivity tests.
  • Integrate the core data with well logs, fracture stimulation techniques, and production test results to aid companies in their evaluation and exploitation of Utica reservoirs.
  • Provide a regional assessment of the Upper Devonian shales to aid in exploration and exploitation.
  • Develop relationships from the database to aid in evaluating and comparing the various shales properties.
  • Provide operators with a searchable database for Upper Devonian shales properties that can be used as analogs to aid in the appraisal and exploitation of “unknown or newly discovered” Upper Devonian shales reservoirs.