Seismic Data Driven Reservoir Analysis FORT CHADBOURNE 3-D Coke and Runnels Counties, TX ODOM LIME AND GRAY SAND

Comments, Well Data 20 wells used for multi-mineral evaluation; 72 wells used for porosity estimation. For 3 wells with no sonic log, correlations were applied (FCOLU_A_106, FCOLU_17_11 and FCOLU_51_33). 4 Wells with shear velocity (FCOLU_08_30, FCOLU_51_32, FCOLU_A_107 and FCOLU_A_110). A shear velocity model was calibrated and applied to the other 16 wells. Main interval of interest: ODOM LIME; secondary intervals: GRAY SAND and CAMBRIAN SAND. Main clay types used for modeling: Illite and Chlorite. Sandstone, Limestone, Dolomite and Feldspar were used in also in the modeling. Fluids: water 108.000 ppm of salinity and OIL of 30 API. Fluid susbtitution made in well FCOLU_51_32.

Petrophysical analysis Observations & Conclusions Clay type analysis indicates presence of chlorite and illite. 6 main facies types determined. An extra facies was used to differentiate bad-hole sections. Odom lime thickness is fairly constant throughout the area, varying from 42 to 54 ft gross thickness. Two exceptions are, FCOLU_52_02 (86 ft thick) and FCOLU_51_32 (61 ft thickness). Gray sand thickness is highly variable, but usually ranging from no sand to ~40 ft thick. Exceptions though are FCOLU_17_11 (51 ft) and Sallie_Odom (61 ft). Multi-mineral analysis of the Odom lime indicates an average effective porosity between 8 and 10%, and water saturations from 25 to 75%. Gray sand effective porosities average 9%, while water saturations are normally very high, between 80 and 90%. Wells FCOLU_8_33, FCOLU_13_93, FCOLU_13_95, FCOLU_17_11 and Sallie_Odom have few feet with water saturations lower than 70%.

Observations & Conclusions Elastic Properties Observations & Conclusions Shear wave velocity estimation in all wells was based on a correlation made with the recorder shear data in 4 wells (FCOLU_08_30, FCOLU_51_32, FCOLU_A_107 and FCOLU_A_110). Acoustic impedance (AI) vs. Poisson’s ratio (POIS) cross plot shows a very good differentiation between facies. Facies with high AI (> 42.000 f/s.g/c3) and high POIS (>0.25) are the limestone facies. In this group the points with less AI correspond to the porous limestone's. AI < 42.000 f/s.g/c3 correspond to the clastic facies, POIS less than 0.25 correspond to the porous sands, and porosity increases when decreasing Poisson’s ratio. POIS greater than 0.25 correspond to very shaley sands and shales. Lambda Rho vs. Mu Rho cross plot can also be used to differentiate facies and porosity. Acoustic vs. Elastic impedance cross plot is ambiguous for facies discrimination

Observations & Conclusions Fluid Substitution Observations & Conclusions Fluid substitution for ODOM LIME in well FCOLU_51_32 shows only a very small change in elastic properties for 100% water saturated limestone versus 90% oil saturated. This effect is mainly due to the low porosities observed in ODOM, and the small density difference between Oil and Water. Fluid substitution in Gray sand also shows also very small difference between the oil and water saturated cases. However, increased oil saturation decreases AI and Poisson’s ratio.

Location Map and Selected Well Data Seismic Grid New well For inversion Update Wells added for structural control Wells with No DT Log Well with Shear Log 2 Miles N

Lithology Review – Clays type Z axis: well number Z axis: well number Chlorite trend Chlorite trend Ratio Neutron / Density porosity Illite trend Illite trend Difference Neutron – Density porosity (v/v) Odom lime Gray sand

Lithology Review – Matrix lithology Z axis: well number Z axis: well number Ratio Neutron / Density porosity Clean points between sandstone and limestone region, both lithologies can be expected Clean points in Limestone region, some sandstone and dolomite can be expected Difference Neutron – Density porosity (v/v) Odom lime Gray sand

Summary of Reservoir Properties (ODOM) WELL NAME Gross / Net (G/N) Thickness (ft) Effec. Porosity/ Total Porosity (%) Sw (%) Petrophysical Evaluation (see attachments) FCOLU_08_27 48 / 39 (0.81) 8.1-13.6 / 8.6-14.2 30-55 FCOLU_08_30 48 / 27 (0.56) 6-14 / 6.5-14 20-50 FCOLU_08_31 47 / 27 (0.57) 5.3-13 / 5.6-13 50 FCOLU_13_87 54 / 8 (0.15) 6.8-8.9 / 7-8.9 50-65

Summary of Reservoir Properties (ODOM) WELL NAME Gross / Net (G/N) Thickness (ft) Effec. Porosity/ Total Porosity (%) Sw (%) Petrophysical Evaluation (see attachments) FCOLU_13_93 45 / 24 (0.53) 6-7.6 / 6-7.8 20-30 FCOLU_13_95 44 / 4 (0.09) 6-10 / 6-10 35 FCOLU_17_11 42 / 2 (0.05) 6.4 / 6.5 38 FCOLU_26_18 43 / 21 (0.49) 7.4-11.8 / 7.4-11.8 10-40

Summary of Reservoir Properties (ODOM) WELL NAME Gross / Net (G/N) Thickness (ft) Effec. Porosity/ Total Porosity (%) Sw (%) Petrophysical Evaluation (see attachments) FCOLU_33_12 54 / 20 (0.37) 6.5-10 / 6.6-11 15-38 FCOLU_50_01 57 / 0 (0) - FCOLU_51_31 51 / 25 (0.49) 6.3-9.7 / 6.5-9.9 36-50 FCOLU_51_32 61 / 41 (0.67) 6-12.5 / 6.6-13 36-60

Summary of Reservoir Properties (ODOM) WELL NAME Gross / Net (G/N) Thickness (ft) Effec. Porosity/ Total Porosity (%) Sw (%) Petrophysical Evaluation (see attachments) FCOLU_51_33 50 / 12 (0.24) 6.2-7.8 / 6.6-7.8 55-70 FCOLU_52_02 86 / 38 (0.44) 6.1-12.5 / 6.6-12.7 70-100 FCOLU_8_33 52 / 17 (0.33) 6.2-10 / 7-11 23-32 FCOLU_A_106 47 / 12 (0.26) 6.1-9.1 / 6.1-9.1 45-85

Summary of Reservoir Properties (ODOM) WELL NAME Gross / Net (G/N) Thickness (ft) Effec. Porosity/ Total Porosity (%) Sw (%) Petrophysical Evaluation (see attachments) FCOLU_A_107 52 / 30 (0.58) 6-11.3 / 6.2-11.5 33-78 FCOLU_A_110 49 / 26 (0.53) 6.1-13 / 6.7-13.5 65-15 MCDONALD_1 50 / 15 (0.3) 6-10 / 6.3-12.1 40-100 SALLIE_ODOM_101 44 / 0 (0) -

Summary of Reservoir Properties (GRAY) WELL NAME Gross / Net (G/N) Thickness (ft) Effec. Porosity/ Total Porosity (%) Sw (%) Petrophysical Evaluation (see attachments) FCOLU_08_27 34 / 32 (0.94) 7-10 / 10-13 90 FCOLU_08_30 9 / 9 (1) 7-12.7 / 10-13.4 80 FCOLU_08_31 39 / 19 (0.49) 6.6-13 / 8-15 FCOLU_13_87 19 / 15 (0.79) 7-12.8 / 10-14.3 85 FCOLU_13_93 22 / 6 (0.27) 8-12 / 11-12 27 FCOLU_13_95 18 / 15 (0.83) 10-12.8 / 11-13.2 67-85

Summary of Reservoir Properties (GRAY) WELL NAME Gross / Net (G/N) Thickness (ft) Effec. Porosity/ Total Porosity (%) Sw (%) Petrophysical Evaluation (see attachments) FCOLU_17_11 51 / 19 (0.37) 7-10 / 10-13 54-100 FCOLU_26_18 13 / 5 (0.38) 8-13.4 / 11-14.9 95 FCOLU_33_12 41 / 10 (0.24) 6-9 / 9.9-12.1 80 FCOLU_50_01 15 / 0 (0) - FCOLU_51_31 9 / 6 (0.67) 8-10.7 / 12-13.9 85 FCOLU_51_32 26 / 10 (0.38) 7-11.4 / 8.7-11.4

Summary of Reservoir Properties (GRAY) WELL NAME Gross / Net (G/N) Thickness (ft) Effec. Porosity/ Total Porosity (%) Sw (%) Petrophysical Evaluation (see attachments) FCOLU_51_33 7 / 3 (0.43) 7 / 8.2 100 FCOLU_52_02 NO SAND - FCOLU_8_33 28 / 17 (0.61) 8-12.4 / 10-14.4 68 FCOLU_A_106 16 / 12 (0.75) 8-11.1 / 11-12.7 FCOLU_A_107 30 / 12 (0.4) 8.3-12.4 / 12.2-14.5 FCOLU_A_110 31 / 14 (0.45) 6-9.2 / 8.4-12.3

Summary of Reservoir Properties (GRAY) WELL NAME Gross / Net (G/N) Thickness (ft) Effec. Porosity/ Total Porosity (%) Sw (%) Petrophysical Evaluation (see attachments) MCDONALD_1 24 / 18 (0.75) 7-13 / 9-13 100 SALLIE_ODOM_101 61 / 59 (0.96) 11 / 12 30-100

Facies and Elastic Rock Property Analysis

Facies Analysis 6 facies were determined. Facies No 7 was included to differentiate bad-hole readings. The productive facies are No. 5 and 6. Elastic properties analysis was performed over Gray sand and Odom lime intervals, together with shales above and below. Elastic properties analysis was done in the 4 wells with Shear recorded data.

Shear Wave Estimation Shear wave estimation was based on a correlation established from 4 wells with recorded shear data: FCOLU_08_30, FCOLU_51_32, FCOLU_A_107 and FCOLU_A_110. Z-axis: facies Vels (ft/s) Correlation in Odom lime Correlation in Gray sand Velc (ft/s)

Shear Wave Estimation Vels (ft/s) 4 wells recorded shear Correlation in Odom lime Correlation in Gray sand Vels (ft/s) Z-axis: facies Z-axis: facies Z-axis: facies 4 wells recorded shear 4 wells estimated shear 13 wells estimated shear Velc (ft/s)

AI vs. POIS, Clastic Facies Porous sandstone (yellow) has the lowest Poisson’s ratio and the presence of shale in sands (green) increases the Poisson’s ratio, making them hard to differentiate from the background. Z-axis: facies 20000 - AI (ft/s.g/c3) - 60000 Background shale (purple) has very low acoustic impedance. 0 - POIS - 0.5

AI vs. POIS, Carbonate Facies No porosity limestone (dark blue) has the highest acoustic impedance; the acoustic impedance gets lower when porosity is present (orange). Z-axis: facies 20000 - AI (ft/s.g/c3) - 60000 When carbonate cement is present in sands (light blue), the Poisson’s ratio becomes higher as well as the acoustic impedance. Placing the points in an transition position between the carbonate and sandstone facies. 0 - POIS - 0.5

AI vs. POIS, Facies Analysis Acoustic impedance differentiates the carbonate from the shale facies. But there is overlap between porous limes and the sands. Z-axis: facies 20000 - AI (ft/s.g/c3) - 60000 While Poisson’s ratio differentiate the porous sands from the shales, cemented sandstones and carbonates 0 - POIS - 0.5

AI vs. POIS, Facies Analysis Z-axis: facies 20000 - AI (ft/s.g/c3) - 60000 Within the carbonates, the lower the acoustic impedance the higher the porosity. This can be seen in more detail in the next slide. 0 - POIS - 0.5

AI vs. POIS Cross-Plot Analysis Shale increase (more POIS and less AI) Z-axis: Calcite Z-axis: Quartz Z-axis: Clay 20000 - AI (ft/s.g/c3) - 60000 Porosity trend in carbonates (less AI) Porosity trend in sandstones (less POIS) Z-axis: PHIT Z-axis: PHIE 0 - POIS - 0.5

AI vs. POIS Analysis 20000 - AI (ft/s.g/c3) - 60000 Z-axis: Calcite Z-axis: Quartz Z-axis: Clay 20000 - AI (ft/s.g/c3) - 60000 Porosity trend in carbonates (less AI) Porosity trend in sandstones (less POIS) Z-axis: PHIT Z-axis: PHIE 0 - POIS - 0.5

LambdaRho vs. MuRho 0 - MuRho - 100 0 - LambdaRho - 250 LambdaRho vs. MuRho crossplot is also very useful to differentiate facies. Z-axis: facies LambdaRho can separate carbonates (dark blue and orange) from sandstones, while MuRho will help to differentiate sand (yellow) from shale (purple) and shaley sands (green). 0 - MuRho - 100 0 - LambdaRho - 250

LambdaRho vs. MuRho 0 - MuRho - 100 Shale trend in sandstones Z-axis: Calcite Z-axis: Quartz Z-axis: Clay 0 - MuRho - 100 LambdaRho it’s highly affected by porosity in sandstone, while in carbonates both LambdaRho and MuRho has an important effect. Porosity trend in carbonates Porosity trend in sandstones Z-axis: PHIT Z-axis: PHIE 0 - LambdaRho - 250

LambdaRho vs. MuRho 0 - MuRho - 100 LambdaRho it’s highly affected by porosity in sandstone, while in carbonates both LambdaRho and MuRho has an important effect. Z-axis: Calcite Z-axis: Quartz Z-axis: Clay 0 - MuRho - 100 Porosity trend in carbonates Porosity trend in sandstones Z-axis: PHIT Z-axis: PHIE 0 - LambdaRho - 250

AI vs. EI30 (30 degrees) Analysis Elastic impedance poorly differentiates facies and petrophysical properties. Z-axis: Calcite Z-axis: Quartz Z-axis: Clay 20000 - AI (ft/s.g/c3) - 60000 Z-axis: PHIT Z-axis: PHIE 20000 - EI30 (ft/s.g/c3) - 60000

Fluid Substitution

Odom lime – AI vs. Pois, FCOLU_51_32 100% WATER 75% WATER – 25% OIL 10% WATER – 90% OIL Increasing oil saturation, decreases AI and POIS. A greater effect is seen in AI. 20000 - AI (ft/s.g/c3) - 60000 Z-axis: PHIE Z-axis: PHIE Z-axis: PHIE Z-axis: PHIE 0 - POIS - 0.5

Odom lime – AI vs. Pois, FCOLU_51_32 100% water 60000 - AI (ft/s.g/c3) - 20000 Z-axis: PHIE 0 - POIS - 0.5

Odom lime – AI vs. Pois, FCOLU_51_32 75% water – 25% oil 60000 - AI (ft/s.g/c3) - 20000 Z-axis: PHIE 0 - POIS - 0.5

Odom lime – AI vs. Pois, FCOLU_51_32 10% water – 90% oil 60000 - AI (ft/s.g/c3) - 20000 Z-axis: PHIE 0 - POIS - 0.5

Gray Sand – AI vs. Pois – FCOLU_51_32 100% WATER 75% WATER – 25% OIL 10% WATER – 90% OIL Increasing oil saturation, decreases AI and POIS 20000 - AI (ft/s.g/c3) - 60000 Z-axis: PHIE Z-axis: PHIE Z-axis: PHIE 0 - POIS - 0.5

Gray sand - AI vs. Pois – FCOLU_51_32 100% water 60000 - AI (ft/s.g/c3) - 20000 Z-axis: PHIE 0 - POIS - 0.5

Gray sand - AI vs. Pois – FCOLU_51_32 75% water – 25% oil 60000 - AI (ft/s.g/c3) - 20000 Z-axis: PHIE 0 - POIS - 0.5

Gray sand - AI vs. Pois – FCOLU_51_32 10% water – 90% oil 60000 - AI (ft/s.g/c3) - 20000 Z-axis: PHIE 0 - POIS - 0.5

ATTACHMENTS Multi-min Analysis

Petrophysical Properties - Well FCOLU_08_27 Lithology Depth (ft) Porosity Sw

Petrophysical Properties - Well FCOLU_08_30 Lithology Depth (ft) Porosity Sw

Petrophysical Properties - Well FCOLU_08_31 Lithology Depth (ft) Porosity Sw

Petrophysical Properties - Well FCOLU_13_87 Lithology Depth (ft) Porosity Sw

Petrophysical Properties - Well FCOLU_13_93 Lithology Depth (ft) Porosity Sw

Petrophysical Properties - Well FCOLU_13_95 Lithology Depth (ft) Porosity Sw

Petrophysical Properties - Well FCOLU_17_11 Lithology Depth (ft) Porosity Sw

Petrophysical Properties - Well FCOLU_26_18 Lithology Depth (ft) Porosity Sw

Petrophysical Properties - Well FCOLU_33_12 Lithology Depth (ft) Porosity Sw

Petrophysical Properties - Well FCOLU_50_01 Lithology Depth (ft) Porosity Sw

Petrophysical Properties - Well FCOLU_51_31 Lithology Depth (ft) Porosity Sw

Petrophysical Properties - Well FCOLU_51_32 Lithology Depth (ft) Porosity Sw

Petrophysical Properties - Well FCOLU_51_33 Lithology Depth (ft) Porosity Sw

Petrophysical Properties - Well FCOLU_8_33 Lithology Depth (ft) Porosity Sw

Petrophysical Properties - Well FCOLU_A_106 Lithology Depth (ft) Porosity Sw

Petrophysical Properties - Well FCOLU_A_107 Lithology Depth (ft) Porosity Sw

Petrophysical Properties - Well FCOLU_A_110 Lithology Depth (ft) Porosity Sw

Petrophysical Properties - Well MCDONALD_1 Lithology Depth (ft) Porosity Sw

Petrophysical Properties - Well SALLIE_ODOM_101 Lithology Depth (ft) Porosity Sw