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 | ||||||
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