Changes

  | part    = Predicting the occurrence of oil and gas traps

  | part    = Predicting the occurrence of oil and gas traps

  | chapter = Predicting reservoir system quality and performance

  | chapter = Predicting reservoir system quality and performance

  | frompg  = 9-1

  | frompg  = 9-49

  | topg    = 9-156

  | topg    = 9-53

  | author  = Dan J. Hartmann, Edward A. Beaumont

  | author  = Dan J. Hartmann, Edward A. Beaumont

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch09/ch09.htm

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch09/ch09.htm

==Density log==

==Density log==

The [[Basic open hole tools#Density|density log]] measures the electron density of a formation. The logging device is a contact tool that emits gamma rays from a source. Emitted gamma rays collide with formation electrons and scatter. A detector, located a fixed distance from the tool source, counts the number of returning gamma rays. The number of returning gamma rays is an indicator of formation bulk density. The litho-density tool (LDT) also provides a photoelectron (P_e) cross section curve, an independent indicator of lithology.

The [[Basic open hole tools#Density|density log]] measures the electron density of a formation. The logging device is a contact tool that emits gamma rays from a source. Emitted gamma rays collide with formation electrons and scatter. A detector, located a fixed distance from the tool source, counts the number of returning gamma rays. The number of returning gamma rays is an indicator of formation bulk density. The litho-density tool (LDT) also provides a photoelectron (P_e) [[cross section]] curve, an independent indicator of lithology.

==Obtaining porosities from a density log==

==Obtaining porosities from a density log==

| Sandstone || 2.65 || 1.8

| Sandstone || 2.65 || 1.8

|-

|-

| Limestone || 2.71 || 4.8

| [[Limestone]] || 2.71 || 4.8

|-

|-

| Dolomite || 2.876 || 3.0

| [[Dolomite]] || 2.876 || 3.0

|-

|-

| Anhydrite || 2.977 || 5.05

| [[Anhydrite]] || 2.977 || 5.05

|-

|-

| Salt || 2.032 || 4.6

| Salt || 2.032 || 4.6

==Obtaining porosities from a neutron log==

==Obtaining porosities from a neutron log==

Lithology, porosity, fluid type, and tool type affect neutron log response. When interpreting neutron logs, use the specific log for the specific tool, i.e., the charts in logging chart books that are specific to the sidewall neutron log (SNP) or the compensated neutron log (CNL).

Lithology, porosity, fluid type, and tool type affect neutron log response. When interpreting neutron logs, use the specific log for the specific tool, i.e., the charts in logging chart books that are specific to the sidewall neutron log (SNP) or the [[compensated neutron log]] (CNL).

To obtain porosity, read the value directly from the log. If the log is recorded in limestone units and the formation you wish to evaluate is sandstone or dolomite, then correct the log value by using the appropriate chart in a log interpretation chartbook.

To obtain porosity, read the value directly from the log. If the log is recorded in limestone units and the formation you wish to evaluate is sandstone or dolomite, then correct the log value by using the appropriate chart in a log interpretation chartbook.

[[Category:Predicting reservoir system quality and performance]]

[[Category:Predicting reservoir system quality and performance]]

[[Category:Pages with badly formatted tables]]

[[Category:Pages with badly formatted tables]]