Mike Solt, a WVU GEOL alumnus just sent a message, which might be of interest to those of you looking for an internship this summer:

Transcription

1 Mike Solt, a WVU GEOL alumnus just sent a message, which might be of interest to those of you looking for an internship this summer: My company, Langan Engineering, is offering a summer internship in Philadelphia. Please encourage any geology students interested in working in the environmental field to contact me. msolt@langan.com

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6 Tim Carr - West Virginia University

7 Elements Source Rock Migration Route Reservoir Rock Seal Rock Trap Processes Generation Migration Accumulation Preservation 7

8 South Anticlinal element of trap North Sealevel -10,000-20,000-30,000 Prudhoe Bay Oil Field (1968) - Largest field in North America - Over 8 Billion barrels recoverable Houston Geological Society 8

9 1. Define prospect elements 2. Estimating trap volume 3. HC Presence & Type 4. Assessment 5. Risk Modified from ExxonMobil 9

10 1. Define prospect elements 2. Estimating trap volume 3. HC Presence & Type 4. Assessment 5. Risk Plumbing To Connect the Container to the Kitchen Correctly Placed Wells A Container From Which Oil & Gas Can Be Produced Courtesy of ExxonMobil A Kitchen Where Organic Material Is Cooked 10

11 ... Characterizing the type, history and origin of petroleum Predict Oil Quality Gama DensityResistivity Determine Ageof Oils Heavy Oil Lite Oil Gas Generation Rate Coaly SourceModel Leakage 10my SourceRockPrediction 0my Seal Reservoir Petroleum Charge Acumulation Petroleum Migration Sequence Stratigraphy SourceRock MigrationPathways 11

12 Questions for Exploration Geologist Does the rock have sufficient organic matter? Is the organic matter capable of generating? Has this organic matter generated petroleum? Has the generated petroleum migrated out? Is the organic material oil-prone or gasprone? 12

13 Preservation of Organic Matter Demaison and Moore,

14 The Origin of Petroleum Organic-rich Source Rock Thermally Matured Organic Matter Oil 14

15 Source Material Non-Biogenic Origins Biogenic (Kerogen) Host rock (Shale and Coal) Kerogen Types Type I Algal (oil prone) sapropelic Type II Mixed Type III Woody (gas prone) humic 15

16 Types of Organic Material Oil and gas are formed by the thermal cracking of organic compounds buried in fine-grained rocks. Algae = Hydrogen rich = Oil-prone Wood = Hydrogen poor = Gas-prone 16

17 Kerogen Types Type 1 Type 2 Type 3 17

18 Kerogen Types From the Paleontological Research Institute < 18

19 Conversion of Kerogen Original Organic Matter Methane Kerogen Mature Kerogen Bitumen/ Crude Oil Condensate Graphite Modified from Barker, 1996 Methane Losing Hydrogen Gaining Hydrogen 19

20 Thermal Maturation History Diagenesis Less Hydrogen K More Hydrogen Kerogen Burial to Greater and Hotter Depths R o = 0.5% Catagenesis K 2 K 1 K Onset of Oil Generation Oil Oil Oil Gas Gas Gas K 3 Oil Phase-Out Cond Gas R o = 2.0% K 4 Metagenesis Gas Horsfield and Rullkotter,

21 Petroleum System Hydrocarbon Generation GEOGRAPHIC EXTENT OF PETROLEUM SYSTEM A Trap Present-Day Trap Trap A STRATIGRAPHIC EXTENT OF PETROLEUM SYSTEM Petroleum accumulation Top of oil window Bottom of oil window Overburden Seal Reservoir Source Underburden Magoon and Dow,

22 Elemental Data For Kerogen Peters,

23 Tissot & Welte,

24 Source Rock for Petroleum Organic-Rich Thin Laminae Total Organic Carbon Hydrogen Index Inch LOMPOC Quarry Sample Monterey Formation, CA 24

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26 Vitrinite Reflectance Profile, Elmsworth Field, Canada Maturity Welte et al.,

27 Vitrinite Reflectance Profile, Louisiana Gulf Coast Vitrinite: woody, Type III kerogen Maturity Barker,

28 Disturbing of Vitrinite Reflectance Barker,

29 Pyrolysis Analysis Increase of S1 with Depth S2 S1 Barker, 1996 Tmax 29

30 Pyrolysis Analysis Yield of Hydrocarbons with Increasing Temperature S2 S1 S1 S2 Barker, 1974 Tmax 30

31 Source rocks are black shale with high total organic content (TOC) Source rocks have very low permeability 1x10-9 to 1x10-7 Darcy 31

32 Shale Diameter, nm Porosity Bakken, ND Cherokee, OK Monterrey, CA Tertiary, Gulf Coast Molecule Water 0.3 Methane 0.5 N-alkanes 0.5 Complex rings 1-3 Diameter, nm Asphaltene

33 Oil Window Expulsion during compaction? (wrong timing) North Slope Wells Rowan et al. 2003) 33

34 Solubility in Water Proposed Expulsion Mechanisms Dissolution in water? (Insufficient) Oil Window Wood and Hewett,

35 Proposed Expulsion Mechanisms Natural Detergents (micelles)? (also insufficient) 35

36 Proposed Expulsion Mechanisms Dissolution in Gas Phase? (Works for light oil, but not for heavy oil) Hydrostatic Gradient Condensate-Gas Ratio (CGR) for oilsaturated gas. Spindletop crude and methane. England,

37 Proposed Expulsion Mechanisms Oil Phase Migration (this is the good one) Kerogen is 5-10% of source rocks and is loadbearing Maturation transforms kerogen to a hydrocarbon fluid. The fluid is also load-bearing, therefore overpressured Overpressure fractures the rock Hydrocarbons escape through microcracks Cracks close up until a new episode of generation takes place 37

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40 drillinginfo.com 40

41 Trap Must Be Available Before/During Migration Trap Processes: Generation Migration Accumulation and Preservation Elements: Source Rock Migration Avenue Reservoir and Seal 41

42 Lithology Depth (Km) Source Reservoir Seal Overburden Burial History Chart Paleozoic Mesozoic Cen. Rock Unit D M P P T R J K P N Generation Thick Fm 1 2 Placer Fm George Sh Top oil window Top gas window Boar Ss Deer Sh 3 Elk Fm Critical Moment Magoon and Dow, 1994 Time of Expulsion and Migration. (Trap must already exist) 42

43 The Petroleum Kitchen Temperature-Pressure-Time Geothermal Gradient: (thermogenic hydrocarbons) Range: <1 to 11 degrees F per 100 Typical Sedimentary Basins: degrees F per 100 Good average 1.2 Oil window of ~ F (50-150C), or about 5,000-20,000 In practice, oil below 15,000 rare Gas no practical limit to stable depth Cracking of oil to gas controlled by source kerogen and temperature Deep basins mostly gas Practical limits related to maturity of source not reservoir 43

44 Draupne Shale organic rich serves as a source rock Heather Shale Sognefjord Shale both organic poor Fault Leak Point Oil Spill Point Facies Change Brent Sandstone acts as a reservoir Courtesy of ExxonMobil HC Generation & Expulsion oil & gas from the Draupne, gas from coals in the Brent HC Migration into Brent carrier beds and up faults HC Fill & Spill late gas displaces early oil 44

45 Take Home Ideas Source Rock is Critical Type of Organic Material Woody or Algal Gas or Oil-Prone Stage of Maturation Time and Temperature Expulsion and Migration Hydrocarbon maturation creates overpressure and fracture porosity that allows they oil and gas to escape the impermeable source rock Economic Potential 45

46 Assignments Reading for this week Jacobson, Petroleum Source Rocks p Reading for next week England et al. Migration Source to Trap, p Read Today in Energy for Tuesday (2/17) at Be Prepared to Discuss in Class - Wednesday Discussion Leader Ryan McGonagle Quiz on Friday 2/20 Open at 1:00pm Closes on 2/23 at 11:00am Test on Friday 2/27 46