Changes

==Data acquisition==

==Data acquisition==

Downhole MWD hardware consists of sensors built into a drill collar positioned near the bit (Figure 1). Electrical energy for the system is provided by a battery pack or generated by a small turbine.

[[file:measurement-while-drilling_fig1.png|left|thumb|{{figure number|1}}Location of MWD hardware (not drawn to scale). (From <ref name=pt03r5>Anadrill,, 1988, Measurement While Drilling-Formation Logging System service brochure, 2000(A-4/89).</ref>.)]]

[[file:measurement-while-drilling_fig1.png|thumb|{{figure number|1}}Location of MWD hardware (not drawn to scale). (From <ref name=pt03r5>Anadrill,, 1988, Measurement While Drilling-Formation Logging System service brochure, 2000(A-4/89).</ref>.)]]

Downhole MWD hardware consists of sensors built into a drill collar positioned near the bit ([[:file:measurement-while-drilling_fig1.png|Figure 1]]). Electrical energy for the system is provided by a battery pack or generated by a small turbine.

In a battery pack MWD system, information is recorded and stored downhole in the microprocessor. The data are retrieved when the MWD collar is brought to the surface and are transferred to the computer in the logging unit for additional processing.

In a battery pack MWD system, information is recorded and stored downhole in the microprocessor. The data are retrieved when the MWD collar is brought to the surface and are transferred to the computer in the logging unit for additional processing.