1. Migration of Petroleum
University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
Migration of Petroleum

2. University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
VIII. Migration
Primary migration - passage of petroleum out of the source rock in which it was generated.
Problem/conundrum:
Petroleum (organic molecules generally larger than water molecules) must move through fine-grained sedimentary rock that has been compacted and made (more) impermeable to water.
Another way to look at this conundrum: shales are seemingly the most abundant seals of traps and thus epitomize impermeability to oil migration - but shales are the most common source rocks and thus necessarily must be rocks out of which primary migration takes place.

3. University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology

4. University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
VIII. Migration
Primary migration - passage of petroleum out of the source rock in which it was generated.
Problem/conundrum:
Petroleum (organic molecules generally larger than water molecules) must move through fine-grained sedimentary rock that has been compacted and made (more) impermeable to water.
Another way to look at this conundrum: shales are seemingly the most abundant seals of traps and thus epitomize impermeability to oil migration - but shales are the most common source rocks and thus necessarily must be rocks out of which primary migration takes place.

5. University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
Bjørlykke 2010

6. University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
VIII. Migration
Primary migration - passage of petroleum out of the source rock in which it was generated.
Problem/conundrum:
Petroleum (organic molecules generally larger than water molecules) must move through fine-grained sedimentary rock that has been compacted and made (more) impermeable to water.
Another way to look at this conundrum: shales are seemingly the most abundant seals of traps and thus epitomize impermeability to oil migration - but shales are the most common source rocks and thus necessarily must be rocks out of which primary migration takes place.

7. University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology

8. Old explanations largely assumed that petroleum was sufficient soluble
University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
VIII. Migration
Primary migration - passage of petroleum out of the source rock in which it was generated.
Old explanations largely assumed that petroleum was sufficient soluble
that it could be transported in water moving out of shales. This
seems to have been resort to an improbable explanation for lack
of any other.
Specific concepts:
Expulsion of “proto-petroleum” molecules (but this entity is unknown).
Transport of petroleum in aqueous solution (but hydrocarbons aren’t soluble).
Transport in solution of CO2 (but production of CO2 is not coincident with generation
of petroleum).
Transport by micelles (soap-like molecules with a hydrophyllic end (thus soluble in
water) and a hydrophobic end (to which organic molecules can bond)
(but micelles are uncommon).
Flushing of hydrocarbons with water generated by dehydration of smectite in its
conversion to illite (but this involves either solution of hydrocarbons or pushing large molecules through small pores).

9. Old explanations largely assumed that petroleum was sufficient soluble
University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
VIII. Migration
Primary migration - passage of petroleum out of the source rock in which it was generated.
Old explanations largely assumed that petroleum was sufficient soluble
that it could be transported in water moving out of shales. This
seems to have been resort to an improbable explanation for lack
of any other.
Specific concepts:
Expulsion of “proto-petroleum” molecules (but this entity is unknown).
Transport of petroleum in aqueous solution (but hydrocarbons aren’t soluble).
Transport in solution of CO2 (but production of CO2 is not coincident with generation
of petroleum).
Transport by micelles (soap-like molecules with a hydrophyllic end (thus soluble in
water) and a hydrophobic end (to which organic molecules can bond)
(but micelles are uncommon).
Flushing of hydrocarbons with water generated by dehydration of smectite in its
conversion to illite (but this involves either solution of hydrocarbons or pushing large molecules through small pores).

10. Old explanations largely assumed that petroleum was sufficient soluble
University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
VIII. Migration
Primary migration - passage of petroleum out of the source rock in which it was generated.
Old explanations largely assumed that petroleum was sufficient soluble
that it could be transported in water moving out of shales. This
seems to have been resort to an improbable explanation for lack
of any other.
Specific concepts:
Expulsion of “proto-petroleum” molecules (but this entity is unknown).
Transport of petroleum in aqueous solution (but hydrocarbons aren’t soluble).
Transport in solution of CO2 (but production of CO2 is not coincident with generation
of petroleum).
Transport by micelles (soap-like molecules with a hydrophyllic end (thus soluble in
water) and a hydrophobic end (to which organic molecules can bond)
(but micelles are uncommon).
Flushing of hydrocarbons with water generated by dehydration of smectite in its
conversion to illite (but this involves either solution of hydrocarbons or pushing large molecules through small pores).

11. Old explanations largely assumed that petroleum was sufficient soluble
University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
VIII. Migration
Primary migration - passage of petroleum out of the source rock in which it was generated.
Old explanations largely assumed that petroleum was sufficient soluble
that it could be transported in water moving out of shales. This
seems to have been resort to an improbable explanation for lack
of any other.
Specific concepts:
Expulsion of “proto-petroleum” molecules (but this entity is unknown).
Transport of petroleum in aqueous solution (but hydrocarbons aren’t soluble).
Transport in solution of CO2 (but production of CO2 is not coincident with generation
of petroleum).
Transport by micelles (soap-like molecules with a hydrophyllic end (thus soluble in
water) and a hydrophobic end (to which organic molecules can bond)
(but micelles are uncommon).
Flushing of hydrocarbons with water generated by dehydration of smectite in its
conversion to illite (but this involves either solution of hydrocarbons or pushing large molecules through small pores).

12. Old explanations largely assumed that petroleum was sufficient soluble
University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
VIII. Migration
Primary migration - passage of petroleum out of the source rock in which it was generated.
Old explanations largely assumed that petroleum was sufficient soluble
that it could be transported in water moving out of shales. This
seems to have been resort to an improbable explanation for lack
of any other.
Specific concepts:
Expulsion of “proto-petroleum” molecules (but this entity is unknown).
Transport of petroleum in aqueous solution (but hydrocarbons aren’t soluble).
Transport in solution of CO2 (but production of CO2 is not coincident with generation
of petroleum).
Transport by micelles (soap-like molecules with a hydrophyllic end (thus soluble in
water) and a hydrophobic end (to which organic molecules can bond)
(but micelles are uncommon).
Flushing of hydrocarbons with water generated by dehydration of smectite in its
conversion to illite (but this involves either solution of hydrocarbons or pushing large molecules through small pores).

13. Old explanations largely assumed that petroleum was sufficient soluble
University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
VIII. Migration
Primary migration - passage of petroleum out of the source rock in which it was generated.
Old explanations largely assumed that petroleum was sufficient soluble
that it could be transported in water moving out of shales. This
seems to have been resort to an improbable explanation for lack
of any other.
Specific concepts:
Expulsion of “proto-petroleum” molecules (but this entity is unknown).
Transport of petroleum in aqueous solution (but hydrocarbons aren’t soluble).
Transport in solution of CO2 (but production of CO2 is not coincident with generation
of petroleum).
Transport by micelles (soap-like molecules with a hydrophyllic end (thus soluble in
water) and a hydrophobic end (to which organic molecules can bond)
(but micelles are uncommon).
Flushing of hydrocarbons with water generated by dehydration of smectite in its
conversion to illite (but this involves either solution of hydrocarbons or pushing large molecules through small pores).

14. University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology

15. University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
Selley 1998

16. R.C. Selley (1998) Elements of Petroleum Geology (2nd edn)
University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
VIII. Migration
Primary migration - passage of petroleum out of the source rock in which it was generated.
Old explanations largely assumed that petroleum was sufficient soluble that it could be transported in water moving out of shales. This seems to have been resort to an improbable explanation for lack
of any other.
“Primary hydrocarbon generation is to many people the last great mystery of petroleum geology”
R.C. Selley (1998) Elements of Petroleum Geology (2nd edn)

17. University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
VIII. Migration
Primary migration - passage of petroleum out of the source rock in which it was generated.
Old explanations largely assumed that petroleum was sufficient soluble that it could be transported in water moving out of shales. This seems to have been resort to an improbable explanation for lack
of any other.
Newer (post 1990s) explanations assumed petroleum travels on its own (not in solution) and that pressure resulting from increased volume in maturation causes its expulsion directly, or causes fracturing that allows primary migration.
Mackenzie et al., 1987, The expulsion of petroleum from Kimmeridge Clay source rocks in the
area of the Brae Oilfield, U.K. continental shelf, in Brroks & Glennie, eds., Petroleum Geology
of North West Europe (London, Graham and Trotman), p (See G&S p. 141 ff.
England and Fleet, 1991, Petroleum Migration: Geological Society of London Special Publicaton 59.
Warning: Selley (1998) devoted lots of attention to solubility-based ideas; Assaad (2009) still said
petroleum is soluble, citing Levorsen (1954)!

18. University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
Bjørlykke 2010

19. University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
Bjørlykke 2010

20. University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology

21. University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology

22. B. Secondary migration - passage of petroleum through porous and
University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
VIII. Migration
A. Primary migration - passage of petroleum out of the source rock in which it was generated.
B. Secondary migration - passage of petroleum through porous and
permeable media, driven by buoyancy contrast between petroleum
and water that otherwise fills porosity.
Media:
Porous and permeable sands and sandstones.
Porous and permeable carbonate sediments and rocks.
Fractures and faults.
The first two, or all three, are potential reservoir rocks.
C. Tertiary migration

23. University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology

24. B. Secondary migration - passage of petroleum through porous and
University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
VIII. Migration
A. Primary migration - passage of petroleum out of the source rock in which it was generated.
B. Secondary migration - passage of petroleum through porous and
permeable media, driven by buoyancy contrast between petroleum
and water that otherwise fills porosity.
Media:
Porous and permeable sands and sandstones.
Porous and permeable carbonate sediments and rocks.
Fractures and faults.
The first two, or all three, are potential reservoir rocks.
C. Tertiary migration

25. B. Secondary migration - passage of petroleum through porous and
University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
VIII. Migration
A. Primary migration - passage of petroleum out of the source rock in which it was generated.
B. Secondary migration - passage of petroleum through porous and
permeable media, driven by buoyancy contrast between petroleum
and water that otherwise fills porosity.
Media:
Porous and permeable sands and sandstones.
Porous and permeable carbonate sediments and rocks.
Fractures and faults.
The first two, or all three, are potential reservoir rocks.
C. Tertiary migration

26. Petroleum System 1) Early Generation 2) Late Generation
University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
Petroleum System
1) Early Generation
Spill Point
Spill Point
Seal Rock
(Mudstone)
Reservoir Rock
(Sandstone)
Migration from
‘Kitchen’
Gas beginning to displace oil
2) Late Generation
Displaced oil accumulates
Gas displaces all oil
From a U of OK course ppt file

27. University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
An example from Pakistan, from a U of OK course ppt file

28. University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
Selley 1998

29. B. Secondary migration - passage of petroleum through porous and
University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
VIII. Migration
A. Primary migration - passage of petroleum out of the source rock in which it was generated.
B. Secondary migration - passage of petroleum through porous and
permeable media, driven by buoyancy contrast between petroleum
and water that otherwise fills porosity.
Media:
Porous and permeable sands and sandstones.
Porous and permeable carbonate sediments and rocks.
Fractures and faults.
The first two, or all three, are potential reservoir rocks.
(more to follow)

30. B. Secondary migration - passage of petroleum through porous and
University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
VIII. Migration
A. Primary migration - passage of petroleum out of the source rock in which it was generated.
B. Secondary migration - passage of petroleum through porous and
permeable media, driven by buoyancy contrast between petroleum
and water that otherwise fills porosity.
Media:
Porous and permeable sands and sandstones.
Porous and permeable carbonate sediments and rocks.
Fractures and faults.
The first two, or all three, are potential reservoir rocks.
C. Tertiary migration

31. University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
Gluyas &
Swarbrick
2004, in
a very
North-Sea
example

32. University of Georgia Department of Geology GEOL 4320 Petroleum Geology

33. University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology

34. Title White sans-serif Helvetica text Light gray Times New Roman text
University of Georgia Department of Geology GEOL 4320/6320 Petroleum Geology
Sources
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Asquith and Krygowski 2004
Light gray Times New Roman text
Assaad 2008
AAPG Basic Well Log Analysis course notes
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Baker-Hughes Atlas of Log Responses
Bjørlykke 2010
Conaway 1999
Crain’s Petrophysical Handbook
Title
Glover’s Petrophysique
Gluyas & Swarbrick 2004
North 1980
Jonathan B. Martin UF class notes
Rigzone
Schlumberger Log Interpretation P&I
Schlumberger Oilfielld Glossary
Selley 1998
Shell Petroleum Handbook (1983)
Notes
Shepherd 2009
Tissot & Welte (1984)
Wikipedia