− | PI data are misleading if the S1 peak includes nonindigenous [[hydrocarbon]]s, such as drilling additives or [[Migration|migrated]] hydrocarbons. Expulsion characteristics of a [[source rock]] are not considered when looking at PI numbers. If the [[expulsion saturation threshold]] of the source rock is high, the PI data will be overestimated. If the expulsion saturation threshold is low, the data will be underestimated. | + | PI data are misleading if the S1 peak includes nonindigenous [[hydrocarbon]]s, such as [[drilling additive]]s or [[Migration|migrated]] hydrocarbons. Expulsion characteristics of a [[source rock]] are not considered when looking at PI numbers. If the [[expulsion saturation threshold]] of the source rock is high, the PI data will be overestimated. If the expulsion saturation threshold is low, the data will be underestimated. |
− | A trend is valid only if developed over a uniform source internal. If the [[depositional environment]] changes significantly, establish a different PI trend for each unique source rock type. | + | A trend is valid only if developed over a uniform source interval. If the [[depositional environment]] changes significantly, establish a different PI trend for each unique source rock type. |