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Rejuvenation of a mature oil field: Underground Gas Storage and Enhanced Oil Recovery, Schönkirchen Tief Field, Austria IEA-EOR Conference 2009. Torsten Clemens, Joop de Kok, Yannick Yanze. Gas supply shortage in 2008. Outline. Reservoir overview
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Rejuvenation of a mature oil field: Underground Gas Storage and Enhanced Oil Recovery, Schönkirchen Tief Field, AustriaIEA-EOR Conference 2009 Torsten Clemens, Joop de Kok, Yannick Yanze
Outline • Reservoir overview • Concept Underground Gas Storage (UGS) + Enhanced Oil Recovery (EOR) • Simulation setup • Optimization of UGS • Dewatering • Cycling • EOR • Conclusions
Reservoir overview • Highly fractured dolomite • Water- to mixed wet • 19 mn Sm3 STOIIP • GOC at 2550 mss • OWC 2740 mss • Producing since 1962 • Current recovery factor 59 % • Water flooded
Historical production – current conditions Sorw = 25%
Underground Gas Storage & EOR - matrix Sorg = 15% Sorw = 25%
Simulation setup • Is it possible to build up the required volumes of gas? • How long does it take to build up the UGS? • Is dewatering required? • How much cushion gas is required to safely produce the gas volumes? • How many wells are necessary to inject and produce the required gas volumes? • Where to place the injection / production wells? • What are the risks and uncertainties? • Is there any EOR potential? • Is there an opportunity to accelerate current production?
Matrix grid Fracture grid km, fm kf, ff, σ input properties fracture-fracture exchanges matrix-fracture exchanges unknowns Pm, Sm Pf, Sf matrix-matrix exchanges Simulation setup Dual-permeability approach: two superimposed grids
History match • Multiple history matches • Multiple predictions
Optimization of UGS – phased approach 3 Phase 1 2 Total injected gas [billion m³] 1 0 0.5 2.5 5.5 Time in years
Optimization of UGS – phased approach 3 Phase 1 Monitoring phase 2 Total injected gas [billion m³] 1 0 0.5 2.5 5.5 Time in years
Optimization of UGS – phased approach Phase 2 3 Phase 1 Monitoring phase 2 Total injected gas [billion m³] 1 0 0.5 2.5 5.5 Time in years
Dewatering to increase gas volume 1.8 1.5 1.2 Without dewatering 0.9 Total injected gas [billion m³] 0.6 0.3 0 0 0.1 0.2 0.3 0.4 0.5 Time in years
Dewatering to increase gas volume 1.8 With dewatering 1.5 1.2 Without dewatering 0.9 Total injected gas [billion m³] 0.6 0.3 0 0 0.1 0.2 0.3 0.4 0.5 Time in years
Dewatering to increase gas volume Water injection into sandstone Horizontal gas injection wells Original oil/water contact Vertical dewatering wells
UGS & EOR - concept Crestal gas injection wells Oil rim Residual oil 15 % Residual oil 25 % Original oil/water contact Downdip production wells
Enhanced Oil Recovery (EOR) 2008 2030
Enhanced Oil Recovery (EOR) • Production of incremental oil after several cycles • Up to 5 % recovery of incremental oil in place
Gas/Oil Contact in Fractures and Matrix Gas Injection Gas Production Gas invasion in matrix Gas invasion in matrix Gas/Oil Gravity Drainage in Matrix Gas/Oil Gravity Drainage in Matrix Gas/Oil Contact in Fractures Well Well Water/Oil Contact in Fractures
Conclusions • Schönkirchen Tief is good candidate reservoir for high performance Underground Gas Storage • 1.5 bn m³ gas can be injected in phase one and 3 bn m³ gas in phase two (dewatering required)
Conclusions • Schönkirchen Tief is good candidate reservoir for high performance Underground Gas Storage • 1.5 bn m³ gas can be injected in phase one and 3 bn m³ gas in phase two (dewatering required) • De-watering can be optimised by drilling vertical wells deep below the original oil/water contact • Enhanced Oil Recovery can be achieved due to the difference in residual oil saturation towards water and gas • Up to 5 % incremental oil can be recovered
Acknowledgements Thanks to: • OMV E&P for the permission to publish this paper