U. S. DEPARTMENT OF THE INTERIOR
U.S. GEOLOGICAL SURVEY
APPENDIX A | ||||||||
Input for Monte Carlo simulations of the Agbada Reservoir Assessment Unit | ||||||||
Date:
28 May 1998
Assessment Geologist: Michele L. Tuttle, Michael Brownfield, Ronald Charpentier Region (name, no.): Sub-Saharan Africa/Antartica, Region 7 Province Name: Niger Delta Province Number: 7192 Priority or Boutique? Priority Total Petroleum System (name, no.): Cenozoic Niger Delta, 719201 Assessment Unit (name, no.): Agbada Deltaic Reservoirs, 71920101 * Notes from Assessor |
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CHARACTERISTICS OF ASSESSMENT UNIT | |||||||
Oil or Gas (<20,000 cfg/bbl oil overall): . | Oil | ||||||
What is the minimum field size? . | 1 mmboe grown (>1mmboe) | ||||||
(the smallest field that has potential to be added to reserves in the next 30 years) | |||||||
Number of discovered fields exceeding minimum size: ..... | .Oil: | 481 | Gas: | 93 | |||
Established (>13 fields) | X | Frontier (1-13 fields) | Hypothetical (no fields) | ||||
Median size (grown) of discovered oil fields (mmboe): | |||||||
1st 3rd | 60 |
2nd 3rd
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22 |
3rd 3rd
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23 | ||
Median size (grown) of discovered gas fields (bcfg): | |||||||
1st 3rd | 116 |
2nd 3rd
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58 |
3rd 3rd
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119 | ||
Assessment-Unit Probabilities: | |||||||
Attribute | Probability of occurrence (0-1.0) | ||||||
1. CHARGE: Adequate petroleum charge for an undiscovered field >minimum size | 1.0 | ||||||
2. ROCKS: Adequate reservoirs, traps, and seals for an undiscovered field > minimum size | 1.0 | ||||||
3. TIMING OF GEOLOGIC EVENTS: Favorable timing for an undiscovered field > minimum size | 1.0 | ||||||
Assessment-Unit GEOLOGIC Probability (Product of 1, 2, and 3): ... ..... . | 1.0 | ||||||
4. ACCESSIBILITY: Adequate location to allow exploration for an undiscovered field | |||||||
> minimum size .. .. .. | 1.0 | ||||||
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UNDISCOVERED FIELDS | |||||||
Number of Undiscovered Fields: How many undiscovered fields exist that are > minimum size?: | |||||||
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Oil fields: .. . ... | ..min. no. (>0) | 200 | median no. | 580 | max no. | 1000 | |
Gas fields: .. .. | ..min. no. (>0) | 100 | median no. | 250 | max no. | 400 | |
Size of Undiscovered Fields: What are the anticipated sizes (grown) of the above fields?: | |||||||
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Oil in oil fields (mmbo) .. | ...min. size | 1 | median size | 12 | max. size | 1500 | |
Gas in gas fields (bcfg): ... | ...min. size | 6 | median size | 60 | max. size | 7000 | |
AVERAGE RATIOS FOR UNDISCOVERED FIELDS, TO ASSESS COPRODUCTS | |||||||
(uncertainty of fixed but unknown values) | |||||||
Oil Fields: | minimum | mean | maximum | ||||
Gas/oil ratio (cfg/bbl oil) ... | 1000 | 1770 | 3000 | ||||
NGL/gas ratio (bbl ngl/mmcfg) .... . | 20 | 34 | 45 | ||||
Gas fields: | minimum | mean | maximum | ||||
Total liquids/gas ratio (bngl/mmcfg) .. | 50 | 61 | 70 | ||||
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SELECTED ANCILLARY DATA FOR UNDISCOVERED FIELDS | |||||||
(variations in the properties of undiscovered fields) | |||||||
Oil Fields: | minimum | median | maximum | ||||
API gravity (degrees) . . | 10 | 40 | 60 | ||||
Sulfur content of oil (%) ... .. | 0.07 | 0.15 | 0.60 | ||||
Drilling Depth (m) .. . | 350 | 2100 | 4500 | ||||
Depth (m) of water (if applicable) ... .. | 0 | 40 | 200 | ||||
Gas Fields: | minimum | median | maximum | ||||
Inert gas content (%) ..... | low | ||||||
CO2 content (%) ..... | low | ||||||
Hydrogen-sulfide content(%) ... | low-nil | ||||||
Drilling Depth (m) .. .. | 680 | 2200 | 4500 | ||||
Depth (m) of water (if applicable) ... | 0 | 40 | 200 | ||||
ALLOCATION OF UNDISCOVERED RESOURCES IN THE ASSESSMENT UNIT | |||||||
TO COUNTRIES OR OTHER LAND PARCELS | |||||||
(uncertainty of fixed but unknown values) | |||||||
1. Nigeria represents 90 areal % of the total assessment unit | |||||||
Oil in Oil Fields: | minimum | median | maximum | ||||
Richness factor (unitless multiplier): . .. .. | 1 | ||||||
Volume % in parcel (areal % x richness factor): . | 90 | ||||||
Portion of volume % that is offshore (0-100%) . | 40 | ||||||
Gas in Gas Fields: | minimum | median | maximum | ||||
Richness factor (unitless multiplier): .. .. | 1 | ||||||
Volume % in parcel (areal % x richness factor): . | 90 | ||||||
Portion of volume % that is offshore (0-100%) . | 40 | ||||||
2. Cameroon represents 5 areal % of the total assessment unit | |||||||
Oil in Oil Fields: | minimum | median | maximum | ||||
Richness factor (unitless multiplier): . .. .. | 1 | ||||||
Volume % in parcel (areal % x richness factor): . | 5 | ||||||
Portion of volume % that is offshore (0-100%) . | 70 | ||||||
Gas in Gas Fields: | minimum | median | maximum | ||||
Richness factor (unitless multiplier): .. .. | 1 | ||||||
Volume % in parcel (areal % x richness factor): . | 5 | ||||||
Portion of volume % that is offshore (0-100%) . | 70 | ||||||
*Uncertainty about this mean will be calculated using statistical methods | |||||||
3. Equitorial Guinea represents 5 areal % of the total assessment unit | |||||||
Oil in Oil Fields: | minimum | median | maximum | ||||
Richness factor (unitless multiplier): . .. .. | 1 | ||||||
Volume % in parcel (areal % x richness factor): . | 5 | ||||||
Portion of volume % that is offshore (0-100%) . | 100 | ||||||
Gas in Gas Fields: | minimum | median | maximum | ||||
Richness factor (unitless multiplier): .. .. | 1 | ||||||
Volume % in parcel (areal % x richness factor): . | 5 | ||||||
Portion of volume % that is offshore (0-100%) . | 100 |