Evaluation of Reservoir Properties and Their Affects on Production in the Cardium Formation: A Light Tight-Oil Play in Garrington, Alberta, Canada

Abstract

The unconventional, light tight oil halo play in the Upper Raven River Member of the Cardium Formation in the Garrington Field spans roughly 330 square kilometers. The sandstone reservoir is an 8 to 10 m thick, offshore to lower shorface deposit that is highly heterogeneous due to extensive mud laminations, intense bioturbation, and diagenesis that create flow barriers. Core plugs and limited full diameter porosity and permeability values from the Upper Raven River Member reflects a mean porosity value of 9.05% with values ranging from 1% to 25.4%, and a mean permeability value of 21.47 mD with values ranging from 0.01mD to 696 mD. Although possessing good reservoir properties, production from vertical wells is uneconomical because hydrocarbons in the reservoir are mainly stored within isolated, porous sand filled burrows, sand lenses and within micro-porous, authigenic clay particles, resulting in highly tortuous flow paths. Since 2010, horizontal multi-stage fractured wells have unlocked this large resource play, but production rates and cumulative oil and gas production significantly changes laterally with varying pay thickness across the study area. The correlation between cumulative production and net pay is poor, and therefore production in areas with similar porosity and permeability are different. Production rates in the Raven River Member are not only influenced by facies distribution or diagenesis alone, but more so by a combination of sedimentology and pressure. There are similarities in the facies distribution in the study area, but production rates generally increase with increasing pressure, from east to west. After 12 months of production, horizontal wells in lower pressurized areas to the east have lower production rates ranging from 15 to 53 bopd of oil and 40 to 470 mcf/day of gas compared to higher pressurized areas to the west, where rates range from 20 to 80 bopd of oil and 40 to 260 mcf/day of gas.

AAPG Datapages/Search and Discovery Article #90216 ©2015 AAPG Annual Convention and Exhibition, Denver, CO., May 31 - June 3, 2015