International Joint Study on CO2-EOR

1. International Joint Study on CO2-EOR - Study on Applicability of CO2-EOR to Rang Dong Field, offshore Vietnam - IEA Collaborative Project on Enhanced Oil Recovery 30thAnnual Workshop and Symposium 21-23, September, 2009, Australia Sunao Takagi, Komei Okatsu

2. Objectives To study the CO2 EOR applicability to the offshore oil field in Vietnam through an international joint study between Japan and Vietnam International Joint Study Laboratory Study Slimtube Test Interfacial Tension Swelling Coreflood Simulation Study Geological Model Upscale History Match EOS Model Optimized CO2 EOR CO2 Source Study Site Survey Facility Modification Cost Estimation

3. Outline • Reservoir Description and Model • Laboratory Study • Compositional Model Study • CO2 Source Selection • Conclusions

4. Reservoir Description and Model Field Overview • Offshore Vietnam, Water Depth 50-60 meters • Production from 1998, Cumulative Production >150MMbbls • Reservoir : Fractured Basement and Lower Miocene Sand • Water Injection for both Reservoirs • Production Depletion Phase • Pressure Depletion • High GOR • High Water Cut

5. Reservoir Description and Model Reservoir Overview (Lower Miocene) • Depth / Thickness ： 2,100 m / 50 m • Thin Layered Sand • Porosity : 25% average • Permeability : md ~ 1,000 md • Heterogeneity • Light Oil, API 38 deg, Viscosity<1cp • Cumulative Production >70 MMbbls • Reservoir Pressure Depletion <Pb • Areal Difference • High P, High WC Area • Low P, High GOR Area • Wells : • 24 Production Wells (1km well spacing) • 2 Injection wells 12 km 7 km

6. Reservoir Description and Model Production History Water Drive Reservoir Pressure Depletion Maintained Pressure High Water Cut Depleted Pressure High GOR

7. Reservoir Description and Model Porosity - Permeability Geological Model

8. Reservoir Description and Model Simulation Model and History Match Old Model New Model History Matching New Model Old Model Simulation Model Grid X : Y : Z = 97 : 116 : 40

9. Laboratory Study Slimtube Test Injection Pore Volume: 1.2 PV Measurement point: 5 points Packing media: Glass beads Length: 12.192 m Internal Diameter 4.6 mm Porosity: 0.3748 Pore volume: 80.25 cc Permeability: 9 Darcy

10. Laboratory Study Interfacial Tension

11. Laboratory Study Coreflood Test

12. Compositional Model Study EOS Model PVT Matching Pseudoization Slimtube Matching

13. Compositional Model Study Simulation Results Peripheral > Dispersed WAG > Continuous

14. Compositional Model Study Simulation Results

15. CO2 Source Selection CO2 Sources Fertilizer Plant 0.4 Million Ton/Year 135 Km from Target Field 700 Million $(incl. Rang Dong Mod.) CO2 Rich Gas Field 1.0 Million Ton/Year 520 Km from Target Field 1.0 Billion $ (incl. Rang Dong Mod.)

16. Conclusions • Environmental friendly project (CCS oriented) • Suitable reservoir fluid for CO2-EOR • Preferable MMP (2,950 psi) • High microscopic sweep efficiency (about 90%) • Unlikely asphaltene damage around miscible pressure • Successful EOS model to match to the experimental data • Gross CO2 utilization factor : 5.5 MSCF/STB • Peripheral CO2 WAG injection selected • Costly Project (Distant CO2 source) • Further Study (1) Cost reduction / optimization study (2) Further laboratory and simulation studies on enriched hydrocarbon gas injection case (3) Pilot test design for both CO2 injection and hydrocarbon gas injection cases

17. Thank You!!Arigato!!Xin Cam On !!