RESERVOIR ENGINEERING

Overview of Reservoir Engineering Outcome: Data in put: PVT Scale Reservoir Simulation: Natural depletion Water Injection Reservoir Management:

Reservoir Fluid Studies There are several laboratory tests that being conducted to characterize the reservoir fluid. The test results are then being used as input for Petral software analysis: Compositional Analysis Constant composition expansion test Differential liberation test Separator test Swelling test for CO2 and N2

Compositional Analysis Samples of oil and gas are taken from test separator or from stock tank. The fluid then combined in laboratory on the basis of the produced GOR. The method is by flashing the sample from reservoir to atmospheric condition to obtain oil and gas at equilibrium condition

Result of Compositional Analysis Gas Chromatography Component Mole % Molecular Density@   Separator Oil Separator Gas Wellstream Weight 60°F CO2 0.08 1.49 0.91 N2 0.00 0.27 0.16 C1 1.91 60.66 36.47 C2 1.60 15.32 9.67 C3 2.40 10.14 6.95 i-C4 0.81 1.88 1.44 n-C4 2.66 4.82 3.93 i-C5 1.45 1.43 n-C5 1.57 1.30 1.41 C6 6.81 2.59 4.33 C7+ 80.71 0.09 33.29 218  0.8515  TOTAL 100.00 Wellstream composition calculated based on GOR of 130 scf/stb

Constant Composition Expansion Test (CCE) The objectives of the CCE test are: Determine the saturation pressure. Compressibility factor of gas phase. Total hydrocarbon volume as a function of pressure.

CCE Test Result Pressure (psig) Relative Volume 5000 0.9453 2516 1.0001 4500 0.9541 2401 1.0243 4000 0.9638 2253 1.0599 3500 0.9746 2090 1.1066 3000 0.9867 1897 1.175 2900 0.9893 1698 1.2655 2800 0.992 1477 1.4006 2700 0.9948 1292 1.5557 2620 0.997 1040 1.8696 2605 0.9974 830 2.2956 2591 0.9978 640 2.9457 472 3.9877

Reported Reservoir Conditions Constant Composition Expansion Reservoir Characterization & PVT information data Reported Reservoir Conditions Reservoir Pressure 2516 psia Reservoir Temperature 220 degF Constant Composition Expansion Bubble point Pressure 2516.7 psia

Differential Liberation Test (DL) Based on the DL test it is possible to determine amount of gas in solution, the shrinkage in the oil volume, density of the remaining oil as a function of pressure. Therefore, the gas compressibility factor and specific gravity can also be determined.

DE Test Result Pressure (psig) Vapor Z-Factor Liquid Density (lb/ft3) Gas-Oil Ratio (Mscf/stb) Oil Relative Volume (rb/stb) Gas Gravity Gas FVF (rb/Mscf) 2516.7 45.11 1.1342 1.7493 2350 0.8686 45.669 1.0526 1.7095 0.7553 1.2574 2100 0.8692 46.502 0.9378 1.6535 0.7547 1.407 1850 0.8719 47.331 0.8309 1.6013 0.7565 1.6006 1600 0.8767 48.16 0.7307 1.5523 0.7614 1.8586 1350 0.8836 48.992 0.6361 1.5057 0.7704 2.2164 1100 0.8926 49.835 0.546 1.4609 0.7859 2.7411 850 0.9036 50.699 0.4591 1.4171 0.8121 3.5773 600 0.9167 51.608 0.3732 1.3726 0.8597 5.105 350 0.9324 52.632 0.2824 1.3234 0.9618 8.7518 159 0.9481 53.673 0.196 1.272 1.1726 18.685 56.323 1.1228 1.8901

Differential Vaporization Test (at 2014 psig and 155 °F) Reservoir Characterization & PVT information data Differential Vaporization Test (at 2014 psig and 155 °F) Oil Formation Volume Factor 1.1 bbl/stb Solution Gas Oil Ratio 1.1342scf/stb Oil Density 45.11lb/ft3 Reservoir Fluid Viscosity (at 2014 psig and 155°F) Oil Viscosity 1.33 CP

Separator Testing Tested to determine the changes in volumetric behavior of reservoir fluid as fluid pass through separator then into stock tank.

Swelling Test Performed for very specific applications where if a reservoir is to be depleted under miscible gas injection or a gas cycling scheme Swelling Test of (CO2) Swelling Test of (N2) Mole Fraction Gas Added Saturation Pressure (psig) Swell Factor (Relative Volume) 2519 1 5 2607 1.024 10 2705 1.0504 20 2913 1.1136 30 3159 1.1949 40 3285 1.3031 Mole Fraction Gas Added Saturation Pressure (psig) Swell Factor (Relative Volume) 2521 1 5 3216.6 1.0117 10 4019 1.0242 20 5784 1.0528 30 8057 1.0879