Integration of Geochemistry & Reservoir Fluid Properties

1. Integration of Geochemistry &Reservoir Fluid Properties PTTC Workshop June 25, 2003 Kevin Ferworn, John Zumberge, Stephen Brown GeoMark Research, Inc.

2. Introduction • GeoMark has undertaken a number of projects integrating geochemistry and reservoir fluid properties. • Presentation separated into two parts. • Part I. John Zumberge • Introduction to oil and gas geochemistry • Petroleum Systems studies • Part II. Kevin Ferworn • Results from interpretive studies (models, correlations and charts) used to predict Reservoir Fluid and Flow Assurance properties .

3. Oil Quality Controlled by 4 Elements • Source Rock Type • Marine Shales • Marine Carbonates • Lacustrine Shales • Thermal History of Source Rock • Depth of Burial • Timing of Generation • Post Generative Alteration • Biodegradation • Reservoir Mixing

4. % Sulfur 0 - 0.4 0.4 - 1 1 - 2 > 2

5. Geochemistry Fundamentals • Predict depositional environments, thermal maturity, and geological ages of petroleum source rocks from corresponding crude oils • Why use crude oils and not source rock extracts? • Oils are widely available, accessible, abundant, and carry the same kind of evolutionary & environmental information that is buried in source rocks • Molecular Fossils – a.k.a Biomarkers • Oils reflect the natural ‘average’ in source rock variation • The source rock type and age for many of the oils in GeoMark’s database are known based on extensive integration of geology and geochemistry

6. Geochemical Approach • Petroleum Systems Geochemistry – GOM Example • Crude Oil Geochemistry - Few Source Rocks Available in GOM • Unparalleled Oil Sample Collection • Comparison with Known Petroleum Systems Onshore • Homogeneous Data Set • Multivariate Statistics • Production Geochemistry • Detailed comparison of samples from multiple formations or wells to evaluate continuity • Often called “Fingerprinting”

7. Sterane & TerpaneBiomarkers time abundance Whole Crude Gas Chromatogram C7 C17 Pr C27

8. R GC/MS Mass Chromatograms C27 C29 C28 Sterane Biomarkers m/z = 218

9. GC/MS Mass Chromatograms C23 Tricyclic Terpane Biomarkers m/z = 191

10. Carbonate Source Rocks Shale Source Rocks Tricyclic Terpane Biomarker Ratios

11. Carbonate Source Rocks Shale Source Rocks Lacustrine Source Rocks Terpane Biomarker Ratios

12. OLEANANE GC/MS Mass Chromatograms Pentacyclic Terpane Biomarkers m/z = 191(a.k.a. Hopanes)

13. Oleanane vs Source Rock Age

14. 1.0 0.8 0.6 0.4 0.2 Cluster AnalysisDendrogram Family B-Tertiary Coaly-Resinous Family A - Tertiary Paralic Shales Cognac, Tahoe, Gemini Petronius, Pompano, Shasta, Popeye, Snapper Family C2 - Wilcox Distal Family C1 - L. Cretaceous Shales East Texas Field Austin Chalk Trend Family D - U. Cretaceous Shales Family SE1 ????????? Mahogany, Agate, Teak, Mars, Bullwinkle, Jolliet, Baldpate, Auger, Tick 0.63 Family SE2 - Tithonian Marls/ Carbonates Europa, Lobster, Fuji, Tampico, Salina, Campeche (Cantarell) Family F -Oxfordian Smackover Carbonates/ Marls La Luna/Napo - Cretaceous Marls/Carbonates

15. Principal Component Analysis Factor 2 Factor 1 Factor 3

16. Principal Component Analysis Factor 2 Factor 3 Factor 1

17. Principal Component Analysis Factor 2 Factor 3 Factor 1 Smackover

18. LK TERT MIX UJ Gulf of Mexico Oil Source Rock Families Family A: Tertiary Shales Family C1: LK ShalesFamily SE1: Mixed Family SE2: UJ Marls

19. Factors Affecting Oil Quality Oil Quality is affected by four elements. • Source Rock Depositional Environment and Age • Thermal Maturity • Biodegradation • In-situ Mixing

20. Non degraded Biodegradation and Mixing in Oils Heavy biodegradation ‘Polyhistory’ Oil

21. MC AT EB GB GC AC LD WR KC “Polyhistory” Oils

22. Gas Geochemistry • No biomarkers present in Gases, therefore different markers used for classification. • Composition & Stable Isotopes • C1 - C4 • 13C vs. 12C • 2H vs. 1H • Origin of Gas: Thermogenic vs. Biogenic • Gas samples used for geochemical analyses may come from flashed PVT lab samples or from Mud Gases (i.e., Isotubes) • Geochemical analyses also offer insight on quality of Deep Shelf gas

23. Location Map of Offshore Gas Samples

24. -70 -70 Biogenic -60 -60 Mixed   -50 -50 Oil Associated  13Cmethane -40 -40 / Condensate   Post Mature Dry Gas -30 -30 -20 -20 0 10 20 30 40 0 10 20 30 40 Gas Wetness (%C2+) Gas Wetness (%C2+) Genetic Classification of GOM Gases GeoMark Research, Inc. Houston, Texas (after Schoell, 1983)

25. 2.0 3.0 Ro 1.5 1.0 0.7 Ro Thermogenic Mixed Biogenic Isotopic Cross Plots for GOM Gases  13C Methane ‰ and  13C Propane‰ B A  13C Ethane ‰

26. Biogenic Methane Trends

27. Inorganic CO2 Organic CO2 Inorganic vs. Organic Origin of Carbon Dioxide  13C CO2 Normalized Percent CO2

28. % Carbon Dioxide vs. Reservoir Depth

29. Maturity Trends

30. gEngineering Studies • gPVT study completed in Gulf of Mexico in 2000. • 12 member companies contributed PVT reports and matching stock tank oil samples for full geochemical analyses and interpretation. • Traditional PVT correlations were tested against the data set and then improve by tuning against main Geochemical Parameters: • Source rock type / family • Thermal maturity • Level of biodegradation. • Importance of associated gas was discovered. In particular, the influence of Biogenic Methane.

31. LK TERT MIX UJ Gulf of Mexico Oil Source Rock Families Family A: Tertiary Shales Family C1: LK ShalesFamily SE1: Mixed Family SE2: UJ Marls

32. Level of Thermal Maturity M1 Low to Moderate M2 Moderate M3 Moderate to High Degree of Biodegradation B0 Nondegraded B1 Mild B2 Heavy B2* Polyhistory Oils Sulfur Oil Quality Matrix 0.3 1.6 1.0 2.3

33. Vasquez-Beggs Sat. Pressure Correlation Vasquez-Beggs: Psat = f(GOR, Gas Gravity, Oil Gravity, Temperature) Regression Oil Family Coefficient (R2) Entire Data Set 0.6032 (original constants) Entire Data Set 0.8429 (updated constants) C1 0.9097 SE1 0.9194 SE2 0.8779 C1-Biodegraded 0.9969 SE1-Biodegraded 0.9248 SE2-Biodegraded 0.9816

34. GOR / Res. Fluid MW Relationship

35. Biodegraded Samples Gas Wetness vs. Res. Fluid MW

36. Psat / Composition Relationship

37. Predicting PVT from FT Gradients • Pressure Gradients from Wireline Formation Test Tools (e.g. RCI, MDT, RDT) can be directly converted to Reservoir Fluid Densities: • i.e., Pressure Gradient P/z = rres . g • Pressure Gradient Densities are unaffected by Oil-Based Drilling Fluid. • Correlations have been developed to predict Downhole Petroleum Fluid PVT Properties from Reservoir Fluid Densities and Geochemical Parameters derived from GeoMark’s global database of oils and seeps. • Input requirements: • Pressure Gradient • Reservoir Pressure/Temperature • Three Geochemical Parameters: Source Rock, Maturity, Biodegradation • Mud Logging Dryness Factor: C1 / (C1 + C2 + C3) • Algorithms are used to predict PVT parameters real-time, prior to the availability of physical samples.

38. Input Parameters GOMExample Reservoir Fluid MW 102.9 103.7 Reservoir Fluid GOR 639 677 Saturation Pressure 3140 3387 Reservoir Fluid Viscosity .87 .81 Saturated FVF 1.310 1.314 Reservoir Fluid C1 47.10 45.06

39. Flow Assurance Studies • In 2001 a study was undertaken to compare stock tank oil geochemical analyses to wax and asphaltene stability measurements • Extended Compositions by HTGC • Cloud Points by CPM • Asphaltene stabilities by n-Heptane Titration • It was found that source rock type, thermal maturity and level of biodegradation each had an influence on solids stability. • “Live oil” flow assurance data is beginning to appear in the Reservoir Fluid Database. • Future work includes a new study to collect and interpret Live Oil flow assurance data with geochemical analyses.

40. FID response C40 Expanded Scale C50 UCM retention time (min) High Temperature GC Example

41. Example Cloud Point Trial (CPM) CPM Crystal Growth Plot CPM Micrograph

42. Cloud Point vs. nC30+

43. Distal Shale Sample Cloud Points Sample RU115 Sample LA952 Cloud Point = 49°F Cloud Point = 115°F

44. Cloud Point Histogram

45. Regional Cloud Point Maps Larger Symbols Indicate Higher Cloud Points Symbol Colors by Source Rock Oil Type Symbol Sizes by Paraffin Cloud Point Range Southeast Asia Middle East

46. Example Asphaltene STO Onset Test

47. Asphaltene Stability Histogram

48. Asphaltene Stability HistogramHigh Thermal Maturity Samples

49. Regional Asphaltene Stability Maps Larger Symbols Indicate More Unstable Asphaltenes Symbol Colors by Source Rock Oil Type Symbol Sizes by Asphaltene Onset Titration Ratio Middle East Southeast Asia

50. “de Boer” Asphaltene Stability Plot