Abstract

The Montney Formation in Alberta and British Columbia presents many challenges for core analysis. Its high saline and sub-irreducible formation water, organic matter content and type, nanometer sized pores, and friability from laminations prevent core analysis from being dependable. Despite this, Routine Core Analysis (RCA) is still commonly performed without modifying the techniques to address these challenges.

Over the past five years, RCA has been conducted and examined by the author on over thirty Montney cores. Each step of RCA has been assessed to identify and quantify sources of error and uncertainty. The Montney Formation has been found to be very sensitive to errors that are associated with the limitations of RCA methods. Excluding standard errors, the combination of inappropriate analysis types, ineffective RCA processes, and RCA method limitations, can lead to additional absolute porosity errors that range from −0.8% to +0.6%. The presence of unobservable fractures has been found to incorrectly increase permeability up to three orders of magnitude. The low porosity and permeability of the Montney Formation magnify the relative errors which significantly affect the accuracy stated by American Petroleum Institute Recommended Practice 40 (API RP 40) (1998).

Modifications to the RCA process have been made to minimize errors and uncertainties. The techniques discussed were developed to improve accuracy on the Montney Formation, but most are applicable to any rock types that are suitable for RCA.