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| |- | | |- |
| | Water | | | Water |
− | | * Quality of aquifer pore geometry comparable to reservoir pore geometry * Aquifer volume at least 10 times greater than reservoir volume * Flat to gradual production and pressure declines * Gradually to rapidly increasing water production late in life of reservoir * Early increasing water production from downdip wells * GOR (gas–oil ratio) relatively constant * High recovery factor (50% or more) | + | | |
− | | + | * Quality of aquifer pore geometry comparable to reservoir pore geometry |
| + | * Aquifer volume at least 10 times greater than reservoir volume |
| + | * Flat to gradual production and pressure declines |
| + | * Gradually to rapidly increasing water production late in life of reservoir |
| + | * Early increasing water production from downdip wells |
| + | * GOR (gas–oil ratio) relatively constant |
| + | * High recovery factor (50% or more) |
| |- | | |- |
| | Gas expansion | | | Gas expansion |
− | | * Moderate drop in reservoir pressure * Moderate production decline * Water-free production (or relatively minor) * GOR flat for first 50% of production, then increases * GOR increases rapidly in structurally high wells * Moderate recovery factor (typically 30%) | + | | |
− | | + | * Moderate drop in reservoir pressure |
| + | * Moderate production decline |
| + | * Water-free production (or relatively minor) |
| + | * GOR flat for first 50% of production, then increases |
| + | * GOR increases rapidly in structurally high wells |
| + | * Moderate recovery factor (typically 30%) |
| |- | | |- |
| | Solution gas | | | Solution gas |
− | | * Rapid drop in reservoir pressure early in production history * Exponential production decline * Water-free production (or relatively minor) * Increasing GOR early, decreasing later as gas is exhausted * Low recovery factor (20% or less) | + | | |
− | | + | * Rapid drop in reservoir pressure early in production history |
| + | * Exponential production decline |
| + | * Water-free production (or relatively minor) |
| + | * Increasing GOR early, decreasing later as gas is exhausted |
| + | * Low recovery factor (20% or less) |
| |- | | |- |
| | Rock drive | | | Rock drive |
− | | * Unconsolidated reservoir such as sandstone, chalk, or diatomite * Reservoir in overpressure section * No decline while reservoir compacts, then rapid production decline | + | | |
− | | + | * Unconsolidated reservoir such as sandstone, chalk, or diatomite |
| + | * Reservoir in overpressure section |
| + | * No decline while reservoir compacts, then rapid production decline |
| |- | | |- |
| | Gravity | | | Gravity |
− | | * Steeply dipping beds or vertical [[permeability]] greater than horizontal * Fractured reservoir * Low-viscosity oil (in general) * Rapid production decline * High recovery rate (75% or more), but often with low recovery volume | + | | |
− | | + | * Steeply dipping beds or vertical [[permeability]] greater than horizontal |
| + | * Fractured reservoir |
| + | * Low-viscosity oil (in general) |
| + | * Rapid production decline |
| + | * High recovery rate (75% or more), but often with low recovery volume |
| |} | | |} |
| | | |
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| {| class = "wikitable" | | {| class = "wikitable" |
| |- | | |- |
− | ! Reservoir drive mechanism | + | ! rowspan=2 | Reservoir drive mechanism |
− | ! Percent ultimate recovery | + | ! colspan=2 | Percent ultimate recovery |
| + | |- |
| ! Gas | | ! Gas |
| ! Oil | | ! Oil |
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| The American Petroleum Institute conducted a study to determine recovery amounts and efficiencies for water vs. solution gas drives for sandstone and carbonate reservoirs, summarized in the table below (Arps, 1967). Use the table to project recoveries for your prospects. | | The American Petroleum Institute conducted a study to determine recovery amounts and efficiencies for water vs. solution gas drives for sandstone and carbonate reservoirs, summarized in the table below (Arps, 1967). Use the table to project recoveries for your prospects. |
| | | |
− | {| class = "wikitable" | + | {| class = "wikitable sortable" |
| + | |- |
| + | ! rowspan=2 | Drive |
| + | ! rowspan=2 | Units |
| + | ! colspan=3 | Sandstone |
| + | ! colspan=3 | Carbonate |
| |- | | |- |
− | ! Drive
| |
− | ! Units
| |
− | ! Sandstone
| |
− | ! Carbonate
| |
| ! Min. | | ! Min. |
| ! Ave. | | ! Ave. |
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| ! Max. | | ! Max. |
| |- | | |- |
− | | Water | + | | rowspan=3 | Water |
| | bbl/acre-ft | | | bbl/acre-ft |
| | 155 | | | 155 |
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| | 1,422 | | | 1,422 |
| |- | | |- |
− | | m<sup>3</sup> /h-m | + | | m<sup>3</sup>/h-m |
| | 199 | | | 199 |
| | 735 | | | 735 |
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Line 141: |
| | 1,831 | | | 1,831 |
| |- | | |- |
− | | % <xref ref-type="table-fn" rid="ch09tblfn1"> * </xref> | + | | % STOOIP |
| | 28 | | | 28 |
| | 51 | | | 51 |
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| | 80 | | | 80 |
| |- | | |- |
− | | Solution gas | + | | rowspan=3 | Solution gas |
| | bbl/acre-ft | | | bbl/acre-ft |
| | 47 | | | 47 |
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Line 158: |
| | 187 | | | 187 |
| |- | | |- |
− | | m<sup>3</sup> /h-m | + | | m<sup>3</sup>/h-m |
| | 60 | | | 60 |
| | 198 | | | 198 |
Line 143: |
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| | 241 | | | 241 |
| |- | | |- |
− | | % <xref ref-type="table-fn" rid="ch09tblfn1"> * </xref> | + | | % STOOIP |
| | 9 | | | 9 |
| | 21 | | | 21 |