IODP Proceedings    Volume contents     Search


Data report: Site C0011 LWD resistivity–derived porosity1

Joanne Tudge,2 Mike Lovell,3 and Sarah Davies3


During Integrated Ocean Drilling Program (IODP) Expedition 322 for the Nankai Trough Seismogenic Zone Experiment project, no logging-while-drilling (LWD)–based porosity measurements were acquired at Site C0011. Here we calculate porosity from both the ring and bit resistivity measurements. Core-derived thermal conductivity coefficients are used to estimate constant thermal gradients and variable thermal gradients for the different lithologies encountered. Temperature profiles are then generated based on the calculated thermal gradients to estimate water resistivity. Using the temperature-corrected water resistivity in Archie’s equation, porosity is calculated from the two LWD resistivity measurements. When compared to core-based porosity measurements, the ring resistivity–derived porosity, with a constant thermal gradient of 91.3°C/km, provides the more accurate estimate of porosity.

1 Tudge, J., Lovell, M., and Davies, S., 2013. Data report: Site C0011 LWD resistivity–derived porosity. In Saito, S., Underwood, M.B., Kubo, Y., and the Expedition 322 Scientists, Proc. IODP, 322: Tokyo (Integrated Ocean Drilling Program Management International, Inc.). doi:10.2204/iodp.proc.322.201.2013

2 Department of Geoscience, University of Wisconsin-Madison, 1215 West Dayton Street, Madison WI 53706, USA.

3 Department of Geology, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom.

Initial receipt: 1 November 2010
Acceptance: 21 March 2013
Publication: 22 May 2013
MS 322-201