Vail et al., 1977b. AAPG 1977 reprinted with permission of the AAPG whose permission is required for further use.

Transcription

1 Well 5 Well 4 Well 3 Well 2 Well 1 Vail et al., 1977b AAPG 1977 reprinted with permission of the AAPG whose permission is required for further use.

2 Well 5 Well 4 Well 3 Well 2 Well 1 Vail et al., 1977b AAPG 1977 reprinted with permission of the AAPG whose permission is required for further use.

3 A B C D E F A B C D E F G A B C D E F G A B C D E F H Vail et al., 1977b AAPG 1977 reprinted with permission of the AAPG whose permission is required for further use. Well 5 Well 2 Well 3 Well 4 Well 1

4 Tim Carr - West Virginia University

5 Structural Stratigraphic Combination Other 5

6 Fault (impermeable) Hydrocarbon accumulation in the reservoir rock Top of maturity Oil/water contact (OWC) Migration route Seal Reservoir rock Source rock 6

7 7

8 8

9 Plate Boundaries Divergent Convergent Transform Structural Environments Extensional Compressional Strike-slip Passive (Salt) 9

10 EXTENSION COMPRESSION LATERAL UPLIFT, SUBSIDENCE BASEMENT INVOLVED extensional fault blocks contractional fault blocks strike-slip or wrench faulting basement warps BASEMENT DETACHED detached normal faulting fold-andthrust belts tear faults (detached) salt, shale diapirism 10

11 Shale Oil Trap Structural Hydrocarbon Traps Oil/Gas Contact Gas Closure Fracture Basement Oil/Water Contact Oil Fold Trap Salt Dome Salt Diapir Oil modified from Bjorlykke, 1989) 11

12 Structural Observations Structural Concepts 12

13 Structural Observations Fault segments on seismic lines Fault plane orientation Sense of motion Magnitude of offset Range of depths Relative timing when faults moved when structures grew Structural Concepts Tectonic Setting Divergent zones Convergent zones Strike-slip zones Mobile substrate How Structures Evolve Fault-bend folds Fault-propagation folds Salt movement etc. 13

14 Hydrocarbon Traps - Dome Gas Oil Sandstone Shale Four Dip Closure 14

15 Triassic Permian Carboniferous 3D Structural Closure, Cooper Basin (Australia) Cooper Basin Triassic Inerval Toolachee Fm Roseneath Shale Epsilon Fm Murteree Fm Patchawarra Tirrawarra Fm Merrimelia Fm Merrimelia Fm: - Starts the Cooper Basin - Waxing and waning of glacial sediments 15

16 Salt and shale layers can become mobile when subjected to differential loading Imaging beneath salt is very difficult, but the rewards can be great! Many oil and gas fields have been found associated with salt & shale diapirs 16

17 Targeting the structural high with faults creating a trap 8km 17

18 18

19 19

20 Fault Trap Oil / Gas 20

21 basement involved basement detached 1 mile Courtesy of ExxonMobil 21

22 22

23 23

24 Fossen,

25 25

26 26

27 27

28 Seismic section from the JDZ between Nigeria and Sao Tome/Principe. The blue lines indicate thrust faults. PGS 28

29 Positive Flower Structures 29

30 Gulf of Guinea, West Africa Intense tectonic activity occurring along a transform margin 30

31 Depositional Channels Bars Pinch outs Reefs Unconformity Traps Above Unconformity Onlap Valley Fill Channels Diagenetic Traps Permeability Barriers 31

32 Stratigraphic Observations Stratigraphic Concepts 32

33 Stratigraphic Observations Seismic Terminations Base of Sequence Top of Sequence Lateral Geometry Map View Channel Pinch Out Reef Relative timing Stratigraphic Concepts Environment of Deposition Fluvial Shallow Marine Deep Marine Carbonate or Terrigenous 33

34 Stratigraphic Hydrocarbon Traps Unconformity Pinch out Oil/Gas Uncomformity Oil/Gas Channel Pinch Out Oil/Gas (modified from Bjorlykke, 1989) 34

35 Biddle and Wielchowsky 35

36 Younger Beds Younger Beds Erosion A top-discordant relationship in which strata terminate along an unconformity surface due to post-depositional erosion Toplap A top-discordant relationship in which strata terminate against a surface mainly as a result of non-deposition (bypass) 36

37 Older Beds Older Beds Onlap A base-discordant relationship in which younger strata terminate progressively against a surface of greater inclination Downlap A base-discordant relationship in which younger inclined strata terminate progressively against a surface of lower inclination Courtesy of ExxonMobil 37

38 Onlaps 38

39 NW SE Tertiary Deep water slope Continued regional subsidence Interbedded shale and sandstone Submarine fan and turbidite deposits 39

40 Braided Stream Meandering Stream 40

41 Sandstone Mudstone 41

42 42

43 3D seismic slice- Fluvial meander at ~2.3 seconds in the West Natuna Basin, Indonesia. ConocoPhillips, Indonesia 43

44 44

45 45

46 46

47 Recoverable Reserves: Oil : 10 billion bbls Condensate : 1.3 billion bbls Reservoir: Turbidite sands in a major Eocene submarine canyon Reservoir Thickness 200 to 500 meters Discovered while drilling for deeper Cretaceous limestone. 10% recovery factor 47

48 Busch, ft sand max 48

49 Eocene Submarine Canyon System Busch,

50 50

51 51

52 52

53 53

54 Water Oil Structural Contours 4200 Gas 4100 Oil production: 600 mmbbls 54

55 There is angular discordance between reflections at the yellow line 55

56 Other Traps Asphalt Trap Water Partly Biodegraded Oil Meteoric Water Biodegraded Oil/Asphalt Hydrodynamic Trap Shale Hydrostatic Head Oil Water (modified from Bjorlykke, 1989) 56

57 Tozer et al

58 Tozer et al

59 Gas Oil 59

60 60

61 Traps Structural Stratigraphic Combination Other Unconformities are Important Traps Above Valley Fill or Onlap Traps Below - Truncation 61

62 Assignments Complete All Homework Discuss Current Energy Events Read Today in Energy for Thursday (4/2) at Be Prepared to Discuss in Class Monday (4/6) Discussion Leader Alexander Ekvall Test Wednesday April 8 Material Through Monday (4/6) will be on Test 62