Changes

==Porosity-depth plots==

==Porosity-depth plots==

[[file:predicting-reservoir-system-quality-and-performance_fig9-54.png|300px|thumb|{{figure number|1}}Example of regression porosity–depth plots for different formations along the U.S. Gulf Coast. From Loucks et al., 1984; courtesy AAPG.]]

[[file:predicting-reservoir-system-quality-and-performance_fig9-54.png|300px|thumb|{{figure number|1}}Example of regression porosity–depth plots for different formations along the U.S. Gulf Coast. From Loucks et al.;<refname=Loucks>Loucks, R. G., M. M. Dodge, and W. E. Galloway, 1984, [http://archives.datapages.com/data/specpubs/sandsto2/data/a059/a059/0001/0000/0015.htm Regional controls on diagenesis and reservoir quality in Lower Tertiary sandstones along the Texas Gulf Coast], in D. A. McDonald and R. C. Surdam, eds., Clastic Diagenesis: AAPG Memoir 37, p. 15–45.</ref> courtesy AAPG.]]

A pitfall of using porosity–depth plots for porosity prediction is that regression relationship averages out anomalies and complicates predictions of unusually porous sandstones. Use porosity–depth plots for porosity prediction with caution. If enough porosity data are available to make a meaningful plot, keep the “data cloud” on the plot in order to view the ranges of porosity at different depths. In a frontier exploration setting, the usefulness of porosity–depth plots may be limited if global data sets must be used.

A pitfall of using porosity–depth plots for porosity prediction is that regression relationship averages out anomalies and complicates predictions of unusually porous sandstones. Use porosity–depth plots for porosity prediction with caution. If enough porosity data are available to make a meaningful plot, keep the “data cloud” on the plot in order to view the ranges of porosity at different depths. In a frontier exploration setting, the usefulness of porosity–depth plots may be limited if global data sets must be used.