| Since most fields have few cores available, wireline logs must be used to identify rock fabric elements. This requires the calibration of wireline log responses with core data. | | Since most fields have few cores available, wireline logs must be used to identify rock fabric elements. This requires the calibration of wireline log responses with core data. |
− | Particle [[Grain sizes|size]] can be determined from [[Basic open hole tools#Gamma ray|gamma ray]], [[Basic open hole tools#Porosity|porosity]], and [[Basic open hole tools#Resistivity|resistivity]] logs. [[Gran-supported carbonate|Grain-supported]] rocks commonly have lower gamma ray activity then do [[Mud-supported carbonate|mud-supported]] rocks. Other fine-grained rocks, such as shaley and [[organic-rich carbonates]], commonly have the highest gamma ray activity. However, the level of gamma ray activity in some carbonates ([[dolostones]] in particular) is not related to particle size because of the presence of anomalous concentrations of [[uranium]]. [[Calculating Sw from the Archie equation|Water saturation]] is a function of particle size and [[interparticle porosity]], and [[crossplots]] of [[porosity]], water saturation, and reservoir height can be used to determine particle size. | + | Particle [[Grain sizes|size]] can be determined from [[Basic open hole tools#Gamma ray|gamma ray]], [[Basic open hole tools#Porosity|porosity]], and [[Basic open hole tools#Resistivity|resistivity]] logs. [[Gran-supported carbonate|Grain-supported]] rocks commonly have lower gamma ray activity then do [[Mud-supported carbonate|mud-supported]] rocks. Other fine-grained rocks, such as shaley and [[organic-rich carbonate]]s, commonly have the highest gamma ray activity. However, the level of gamma ray activity in some carbonates ([[dolostones]] in particular) is not related to particle size because of the presence of anomalous concentrations of [[uranium]]. [[Calculating Sw from the Archie equation|Water saturation]] is a function of particle size and [[interparticle porosity]], and [[crossplot]]s of [[porosity]], water saturation, and reservoir height can be used to determine particle size. |
| Interparticle porosity can be determined by subtracting separate vug porosity from [[total porosity]]. Total porosity can be calculated from porosity logs, while separate vug porosity can be estimated from crossplots of [[Interval transit time|acoustic transit time]] versus crossplot porosity. Touching vug pore systems can be identified using borehole televiewer and resistivity scanner logs. (For more details, see [[Borehole imaging devices]].) | | Interparticle porosity can be determined by subtracting separate vug porosity from [[total porosity]]. Total porosity can be calculated from porosity logs, while separate vug porosity can be estimated from crossplots of [[Interval transit time|acoustic transit time]] versus crossplot porosity. Touching vug pore systems can be identified using borehole televiewer and resistivity scanner logs. (For more details, see [[Borehole imaging devices]].) |