Instow a Full Field,Multi-Patterned Alkaline-Surfactant-PolymerFlood-Analyses and Comparison of Phases 1 and 2

摘要

An Alkaline-Surfactant-Polymer(ASP)project in the Instow field,Upper Shaunavon formation inSaskatchewan Canada was planned in three phases.The first two multi-well pattern phases are nearingcompletion.Beginning in 2007,an ASP solution was injected into Phase 1.Phase 1 polymer drive injectionbegan in 2011 after injection of 35% pore volume(PV)ASP solution.Coincident with the polymer driveinjection into Phase 1,Phase 2 ASP solution injection began.Phase 2 polymer drive began in 2016 afterinjection of 47% PV ASP solution.Polymer drive continues in both phases with Phase 1 and Phase 2 injectedvolume being 55% PV and 35% PV,respectively.Phase 1 and Phase 2 oil cut response to ASP injectionshowed an increase of approximately four times from 3.5% to 12 to 16% and an increase in oil rate fromapproximately 3,200 m3/m(20,000 bbl/m)to 8,300 m3/m(52,000 bbl/m)in Phase 1 and from 2,200 m3/m(14,000 bbl/m)to 7,800 m3/m(49,000 bbl/m)in Phase 2.Phase 1 pattern analysis indicates the pore volumesof ASP solution injected varied from 13% to 54% PV of ASP with oil recovery percentage increasing withincreasing injected volume.Oil recoveries in the different patterns ranged from 3% OOIP up to 21% OOIPwith lower oil recoveries correlating with lower volume of ASP injected.The response from some of thepatterns correlates with coreflood results.Wells in common to the two phases show increase oil cut and oilrate responses to chemical injection from both Phases 1 and 2.Oil recovery as of August 2019 is 60% OOIPfor Phase 1 and 57% OOIP for Phase 2.Phase 1 economic analysis indicated chemical and operation costwould be approximately C$26/bbl resulting in the decision to move forward with Phase 2.