The Distribution of Sector-Scale Permeability From Production Data Within Naturally-Fractured Folds of the Canadian Foothills

Abstract

The advent of Unconventionals was the beginning of the demise of Foothills exploration in Western Canada. The increasing scarcity of new opportunities that relied primarily on structural closure meant that this well-established play could not compete with the vast regional extent that Unconventional resources promised. A consequence of the maturity of Foothills plays meant that there was a deep understanding of the controls upon production performance. However, the competitive landscape at that time also precluded industry-wide sharing of much learning. With Foothills development spanning over seventy years, Shell Canada's wealth of data, both dynamic (i.e. flow) and static (i.e. rock) is probably unparalleled. In particular, folds in the Livingstone formation are highly productive; including the Moose Mountain, Jumping Pound and Waterton fields. Because the depositional facies and gross thickness within the Livingstone is relatively uniform on the length-scale of a fold, lateral variability in matrix permeability is minimal. This formation therefore provides an ideal opportunity to evaluate changes in open natural fracture connectivity from production data. Analysis of data from core and image logs is useful in constraining the timing, intensity and morphology of discrete fractures. These data were used to guide drilling azimuth, but were typically poor at predicting long-term production performance of wells, with production commonly dominated by a few features. Dynamic data, such as pressure build-up tests and initial rates however, are more indicative of fracture connectivity, essential for longer-term flow behavior (i.e. EUR). Structural domains extracted using dip and curvature (at appropriate length-scales) from 3D seismic, proved to be sufficiently granular to correlate with permeability extracted from flow data, thereby delineating the most connected and most productive parts of these fields. The robustness of the seismic interpretation is increased by balanced cross-sections, utilizing traditional Foothills rules. This compilation of sector-scale permeability and corresponding flow domains from various fields is useful for global conventional exploration, providing ranges of flow metrics for wells in analogue fields. Furthermore, it may provide reference for future Canadian Foothills exploration in outstep areas; to be triggered when the current Unconventionals boom has run its course.

AAPG Datapages/Search and Discovery Article #90259 ©2016 AAPG Annual Convention and Exhibition, Calgary, Alberta, Canada, June 19-22, 2016