Redevelopment of the Cardium Formation Using Fractured Horizontal Wells: Reservoir Engineering Perspectives and Early Case Histories

Abstract

AbstractAccording to the Alberta Energy Resources Conservation Board, the Cardium Formation holds about 25% of Alberta's total discovered conventional oil resource, amounting to over 10 billion barrels of oil-in-place. In spite of its enviable size, oil quality (36 to 40 degrees API) and significant dissolved gas content, the cumulative production from this clastic play, as of December 2009, was approximately 1.75 billion barrels (since the onset of oil production in 1957). This represents an achieved Recovery Factor of only 17%, from a combination of primary, secondary and tertiary recovery schemes with predominantly vertical drilling in various parts of the formation. Since late 2008, however, operators have shown that redeveloping the Cardium Formation with multi-stage hydraulically fractured horizontal wells has the potential to significantly increase production by increasing reservoir contact in the undeveloped and under-developed areas.This paper presents a brief review of the historical performance of vertical wells in the low reservoir quality areas of the Cardium and then describes the impact of placing multi-stage fractured horizontal producers in these areas. The paper deals with the redevelopment of the Cardium Formation from a primary recovery perspective only – with a focus on the fringe areas around the super-giant Pembina field as well as the development of the largely untapped resource in the "A" lobe of the Cardium in the Garrington/Caroline areas. The development of these portions of the Cardium constitutes an extension to previous estimates of Original Oil-In-Place and significant additional recovery potential. The performance of the over 120 multi-stage fractured horizontals that have been placed on production (as of June 2010) is discussed from geologic, reservoir engineering, development modeling and economic analyses perspectives. The authors include some proposals for "typical" Cardium horizontal well performance profiles for reserves assignment purposes and, in closing, they present some data-gathering and forward-modeling recommendations for Cardium operators/stake-holders that would enable them to maximize the near- and long-term values of their assets.