aapg weimer_ex. 2_lecture slides new

•• Many frontier basins still exist globally with Many frontier basins still exist globally with few to no exploration wells, both onshore and few to no exploration wells, both onshore and offshore.offshore.

•• Some of the basins with high potential are Some of the basins with high potential are offshore in water depths > 200 m (called offshore in water depths > 200 m (called ““deepwaterdeepwater””). ).

•• Today, about 28 basins have discoveries or Today, about 28 basins have discoveries or produce from water depths greater than 200 m produce from water depths greater than 200 m of water. of water.

•• LetLet’’s look at several examples from one s look at several examples from one deepwater basin.deepwater basin.

•• You have been given 9 seismic profiles and You have been given 9 seismic profiles and wireline logs for 12 fields.wireline logs for 12 fields.

Theme 2: Frontier explorationTheme 2: Frontier exploration

•• Analyze the seismic profiles: where are the Analyze the seismic profiles: where are the fields? fields?

•• Analyze the logs: where are the reservoirs? Analyze the logs: where are the reservoirs? •• Where are the new plays in this deepwater Where are the new plays in this deepwater

basin?basin?•• The data are from one portion of the northern The data are from one portion of the northern

deep Gulf of Mexico.deep Gulf of Mexico.•• Reservoirs are primarily middle Miocene Reservoirs are primarily middle Miocene

through lower Pleistocene sandstones (15 to through lower Pleistocene sandstones (15 to 1.6 Ma) that were deposited in the continental 1.6 Ma) that were deposited in the continental slope or deep basinal settings. Three slope or deep basinal settings. Three discoveries have been made in Upper Jurassic discoveries have been made in Upper Jurassic eolian sandstones.eolian sandstones.


Theme 2: Frontier explorationTheme 2: Frontier exploration•• The area is characterized by extensive salt The area is characterized by extensive salt

features, both original salt (called features, both original salt (called autochthonous salt: Middle Jurassic).autochthonous salt: Middle Jurassic).

•• Extensive salt is present in the shallow Extensive salt is present in the shallow subsurface called allochthonous salt. This subsurface called allochthonous salt. This salt has been detached from the original salt has been detached from the original autochthonous salt.autochthonous salt.

•• There is complex relationship between the There is complex relationship between the sedimentation on the slope and the active sedimentation on the slope and the active deformation of the shallow salt. deformation of the shallow salt.

•• Several trapping styles are present in the area.Several trapping styles are present in the area.

THIN-BED LEVEES CHANNELS SHEETSHatchures illustratehypothetical hydrocarbondistribution

0.5 - 5 miles

~100

ft

1.5 miles

2 - 10 miles10

0s 100s

TaTbTaTa

Core Log Correlation

1

1-10

Ripl

TcdeRipl

Partial(upper)BoumaCyclesRippledSandLenses

Mod-Poor 50

-250

'


OftenStackedMassiveSandCycles

Poor

10-1

000'


StackedMassiveSandBeds

Full toBaseAbsentBoumaCycles

TaTbTa

Ta

Ta-e

Ta-e

AM

ALG

AMAT

ED

SH

EETS

LAYE

RE

DS

HEE

TS

1-5'

1-5'

External = Excellent

Internal = Poor

Moderate - Excellent

-Seismic Facies: "Gull-wing" to Subparallel, Poorto Fair Continuity-Log Profile: Subdued, Serrate (to Fining-up)-Log Correlatability: Moderate to Poor-Thinly Bedded/ Laminated Sands/Silts (<4" beds)-Insignificant Amalgamation

-Seismic Facies: Discontinuous, Subparallel-Log Profile: Variable (to Fining-up)-Log Correlatability: Poor-Thick- to Thin-Bedded Sands-Most Thick Sands (>5') Are Amalgamated

-Seismic Facies: Parallel (to Slightly Shingled),Laterally Continuous-Variable to Coarsening-Up Log Profile-Log Correlatability: Moderate - Excellent-Mostly Thick Sand Beds (>4"); Boumas-Most Thick Sands (>5') Are Amalgamated

Chapin et al., 1994

Major deepwater depositional elements


Map showing the global distribution of deepwater basins with Map showing the global distribution of deepwater basins with production or announced discoveries. Major prospective areas andproduction or announced discoveries. Major prospective areas and ultradeepwater basins are also shown. Yellow=deepwater (200ultradeepwater basins are also shown. Yellow=deepwater (200--2000 2000 m) . Orange areas= ultradeepwater (> 2000 m).m) . Orange areas= ultradeepwater (> 2000 m).

Paul Weimer, Renaud Bouroullec

Petroleum Geology of the Mississippi Canyon, Petroleum Geology of the Mississippi Canyon, Atwater Valley, Western Desoto Canyon, and Atwater Valley, Western Desoto Canyon, and Western Lloyd areas, Northern Deep Gulf of Western Lloyd areas, Northern Deep Gulf of Mexico: Traps, Reservoirs, and TectonoMexico: Traps, Reservoirs, and Tectono-- Stratigraphic Evolution Stratigraphic Evolution


•• IntroductionIntroduction•• Drilling recordsDrilling records•• Regional setting: structureRegional setting: structure

-- StratigraphyStratigraphy•• Study areaStudy area•• Regional setting: structureRegional setting: structure•• Salt systemsSalt systems•• Salt systemsSalt systems-- trap typestrap types•• Ages of reservoirs Ages of reservoirs •• Future playsFuture plays

OutlineOutline

Record water depths for drillingRecord water depths for drilling

Regional settingRegional setting

Regional tectonic setting: playsRegional tectonic setting: plays

•• Up to 50,000 feet (15 km) of Middle JurassicUp to 50,000 feet (15 km) of Middle Jurassic--Cenozoic Cenozoic strata strata

•• MultiMulti--level salt systems: autochthonous salt: Middle level salt systems: autochthonous salt: Middle Jurassic). Jurassic). allochthonousallochthonous salt: detached from the salt: detached from the original autochthonous salt.original autochthonous salt.

•• Multiple structural styles: faults, foldsMultiple structural styles: faults, folds•• Complex relationship between the sedimentation on the Complex relationship between the sedimentation on the

slope and the active deformation of the shallow salt. slope and the active deformation of the shallow salt. •• Several trapping styles are present.Several trapping styles are present.•• Source rocks: Upper Jurassic, Lower CretaceousSource rocks: Upper Jurassic, Lower Cretaceous•• Late generation and migration (last 5Late generation and migration (last 5--10 Ma): vertical10 Ma): vertical

Regional geologic settingRegional geologic setting

Regional Regional stratigraphicstratigraphic settingsetting

Regional settingRegional setting

Regional structural settingRegional structural setting

Shallow allochthonous salt bodies in continental slope

MS Fan Foldbelt

Regional structural settingRegional structural setting

Edges of shallow allochthonous salt bodies in continental slope

Regional structural setting: salt systemsRegional structural setting: salt systems

Regional structural setting: salt stylesRegional structural setting: salt styles


Base-of slope foldbelt, rests on Early Cretaceous allochthonous salt level

Regional geologic evolution: timingRegional geologic evolution: timing

Trap typesTrap types

Regional structural setting: trap typesRegional structural setting: trap types

StratigraphicStratigraphic setting: reservoir agessetting: reservoir ages

Regional geologic evolution: timingRegional geologic evolution: timing

Regional distribution of source rocksRegional distribution of source rocks

Figure 8 11--D generation model D generation model

Figure 13.

22--D generation model D generation model

22--D generation model D generation model

Summary diagramsSummary diagrams

OkayOkay……where do we drill next?where do we drill next?

Regional tectonic setting: playsRegional tectonic setting: plays


Mesozoic plays: Jurassic eolian,

Lower Cretaceous Tuscaloosa downdip deepwater

Shiloh Shiloh

Aconcagua


Mesozoic plays: Jurassic eolian, Lower Cretaceous Tuscaloosa downdip deepwaterSub-salt plays: Miocene, Eocene

PostPost--stack, timestack, time--migrated datamigrated data

PrePre--stack, depthstack, depth--migrated datamigrated data

Thunder Horse FieldThunder Horse Field


Mesozoic plays: Jurassic eolian, Lower Cretaceous Tuscaloosa downdip deepwaterSub-salt plays: Miocene, EoceneAbyssal plain: multiple playsSubsea tiebacks: 147 of 215 deepwater fields in Gulf of Mexico produce from subsea tiebacks. This technology opens up potential for developing smaller fields

Trap typesTrap types

aapg weimer_ex. 2_lecture slides new

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