Changes

==Gas extraction methods==

==Gas extraction methods==

Samples of gas must generally be extracted from the drilling mud by the gas trap. The gas trap is a metal box immersed in the shale shaker possum belly, preferably in a location of maximum mudflow rate (Figure 1). Ports in the lower part of the trap allow mud to enter and leave the trap. An agitator provides both pumping and degassing of mud passing through the trap. Gas evolved from the mud is mixed with ambient air in the upper part of the trap and is then drawn through a vacuum line to the logging unit for analysis (Figure 2).

[[file:mudlogging-gas-extraction-and-monitoring_fig1.png|left|thumb|{{figure number|1}}Mud system. (From <ref name=pt03r51>Whittaker, A., 1991, Mud logging handbook: Englewood Cliffs, NJ, Prentice-Hall.</ref>.)]]

[[file:mudlogging-gas-extraction-and-monitoring_fig1.png|thumb|{{figure number|1}}Mud system. (From <ref name=pt03r51>Whittaker, A., 1991, Mud logging handbook: Englewood Cliffs, NJ, Prentice-Hall.</ref>.)]]

Samples of gas must generally be extracted from the drilling mud by the gas trap. The gas trap is a metal box immersed in the shale shaker possum belly, preferably in a location of maximum mudflow rate ([[:file:mudlogging-gas-extraction-and-monitoring_fig1.png|Figure 1]]). Ports in the lower part of the trap allow mud to enter and leave the trap. An agitator provides both pumping and degassing of mud passing through the trap. Gas evolved from the mud is mixed with ambient air in the upper part of the trap and is then drawn through a vacuum line to the logging unit for analysis ([[:file:mudlogging-gas-extraction-and-monitoring_fig2.png|Figure 2]]).

[[file:mudlogging-gas-extraction-and-monitoring_fig2.png|thumb|{{figure number|2}}Location of gas trap in possum belly. (From <ref name=pt03r51 />.)]]

[[file:mudlogging-gas-extraction-and-monitoring_fig2.png|thumb|{{figure number|2}}Location of gas trap in possum belly. (From <ref name=pt03r51 />.)]]