Data report: Site C0011 LWD resistivity-derived porosity 1

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.