De-Risking the Duvernay

Abstract

The Duvernay Liquids Rich Shale is one of Canada's most promising emerging unconventional plays. The play broke in 2011 with horizontal discovery wells drilled by several companies. Shell recognized the potential of the play, quickly built a land position of ∼350,000 net acres in two separate sub-basins (Kaybob and Willesden Green), and in 2012 initiated an exploration and appraisal campaign. Shell has since become the industry leader in the play in terms of the cumulative number of wells drilled and cumulative oil and gas produced, and has taken the most promising play segment in the Kaybob sub-basin into commercial development within 3 years of the start of field operations. The Duvernay is a complex reservoir that requires deep technical understanding in order to convert promising geology into business success. It's variable thickness, hydrocarbon storage capacity, pore pressure, H2S content, stratigraphic architecture, and condensate and NGL yields create sharply defined geologic play segments. Overprinting these geologic play segments are rapidly evolving drilling and completion practices that have significant impact on economic viability. Shell's strategy for de-risking the Duvernay has been underpinned by several key premises: gaining early operational scale in order to test multiple geologic play segments to enable focused piloting and demonstrate cost learning curves; gathering adequate subsurface data to provide high confidence answers to key questions relating static rock and fluid properties to dynamic well performance; and conducting early dedicated pilots to optimize landing zone, completion intensity, lateral length, well spacing, and well azimuth, so that commercial development decisions are underpinned by ∼2 years of dynamic production data from representative development well designs. The Duvernay play occupies a prominent position in Shell's unconventional portfolio despite its relative immaturity. Fully integrated thinking has been essential to achieving this result.

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