[[:file:Mth16Ch7Figure7-1.jpg|Figure 1]] is a flowchart for one such scanning technique. Note that it has two paths, one for clastics and one for carbonates. In the clastic case, the resistivity log is the primary reconnaissance measurement because clastics tend to consist of reservoirs surrounded by shales of slowly varying resistivity. The changes in resistivity due to changes in fluid content of the reservoirs tend to stand out against this relatively constant background. On the carbonate path, on the other hand, formation resistivities tend to vary widely with changing rock types, and commonly there are few shales against which to measure changes. In this case, the porosity log is the primary reconnaissance measurement. By first finding the porous zones, those with the capacity to hold fluids (of any type) can be identified. | [[:file:Mth16Ch7Figure7-1.jpg|Figure 1]] is a flowchart for one such scanning technique. Note that it has two paths, one for clastics and one for carbonates. In the clastic case, the resistivity log is the primary reconnaissance measurement because clastics tend to consist of reservoirs surrounded by shales of slowly varying resistivity. The changes in resistivity due to changes in fluid content of the reservoirs tend to stand out against this relatively constant background. On the carbonate path, on the other hand, formation resistivities tend to vary widely with changing rock types, and commonly there are few shales against which to measure changes. In this case, the porosity log is the primary reconnaissance measurement. By first finding the porous zones, those with the capacity to hold fluids (of any type) can be identified. |