Table T4. Measurements made by logging-while-drilling and measurement-while-drilling tools.

Table T4. Measurements made by logging-while-drilling and measurement-while-drilling tools.


Tool	Measurement	Approximate vertical resolution (cm)
ADN	Bulk densityPorosity	15
	Bulk densityPorosity	30
RAB	Resistivity-at-the-bitGamma ray	5-8
	Resistivity-at-the-bitGamma ray	46
MWD	Drilling parameters-at-the-bit	NA

Notes: All tool names are trademarks of Schlumberger. See Table T6 for explanations of acronyms used to describe the tools. For additional information about tool physics and use consult ODP Logging Services at www.ldeo.columbia.edu/BRG/ODP. NA = not applicable.