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| After lithofacies analysis, a careful petrophysical analysis of shows and production should be made and compared to lithofacies distribution. The table below suggests a procedure for petrophysical analysis. | | After lithofacies analysis, a careful petrophysical analysis of shows and production should be made and compared to lithofacies distribution. The table below suggests a procedure for petrophysical analysis. |
| | | |
− | {| class = "wikitable"
| + | # Gather all available fluid data regarding production, shows, and pressures from prospective intervals. |
− | |-
| + | # On structural [[cross section]]s, plot intervals that … |
− | ! Step
| + | #* Were perforated |
− | ! Action
| + | #* Had DSTs |
− | |-
| + | #* Had RSTs |
− | | 1
| + | #* Had mud log shows |
− | | Gather all available fluid data regarding production, shows, and pressures from prospective intervals.
| + | ## Annotate the intervals with the results. |
− | |-
| + | # Divide potential reservoir units on the cross sections into intervals of similar petrophysical character (flow units) using log data and, if available, porosity-[[permeability]] data. Categorize each flow unit by port type as mega-, macro-, meso-, or microporous. |
− | | 2
| + | # Calculate water saturation (S<sub>w</sub> ) of intervals that … |
− | | On structural [[cross section]]s, plot intervals that …
| + | #* Are productive |
− | * Were perforated | + | #* Had shows |
− | * Had DSTs | + | #* Are potential reservoirs |
− | * Had RSTs | + | ## Annotate the log intervals with S<sub>w</sub> values. |
− | * Had mud log shows | + | # Estimate the height above free water for zones that appear to have oil or gas. |
− | | + | # Analyze the fluid data in the context of the petrophysical data. |
− | Annotate the intervals with the results. | + | #* Do S<sub>w</sub> values, shows, and fluid pressures make sense in context with other geological data, including hydrocarbon column height? |
− | |-
| + | #* Do the shows or S<sub>w</sub> values indicate the presence of an updip or downdip trap? |
− | | 3
| + | # Determine whether a relationship exists between the development of reservoir-quality rocks, seal-quality rocks, and lithofacies that can be used to predict location and economic viability of prospective traps. |
− | | Divide potential reservoir units on the cross sections into intervals of similar petrophysical character (flow units) using log data and, if available, porosity-[[permeability]] data. Categorize each flow unit by port type as mega-, macro-, meso-, or microporous.
| |
− | |-
| |
− | | 4
| |
− | | Calculate water saturation (S<sub>w</sub> ) of intervals that …
| |
− | * Are productive | |
− | * Had shows | |
− | * Are potential reservoirs | |
− | | |
− | Annotate the log intervals with S<sub>w</sub> values. | |
− | |-
| |
− | | 5
| |
− | | Estimate the height above free water for zones that appear to have oil or gas.
| |
− | |-
| |
− | | 6
| |
− | | Analyze the fluid data in the context of the petrophysical data.
| |
− | * Do S<sub>w</sub> values, shows, and fluid pressures make sense in context with other geological data, including hydrocarbon column height? | |
− | * Do the shows or S<sub>w</sub> values indicate the presence of an updip or downdip trap? | |
− | |-
| |
− | | 7
| |
− | | Determine whether a relationship exists between the development of reservoir-quality rocks, seal-quality rocks, and lithofacies that can be used to predict location and economic viability of prospective traps.
| |
− | |}
| |
| | | |
| ==Example: calibrating logs to cores and shows== | | ==Example: calibrating logs to cores and shows== |