LWD paradise!April 28, 2012
Data from the record-breaking JFAST hole turned from a trickle into an avalanche last night. The logging while drilling (LWD) tool measures a variety of physical properties of the rock penetrated by the drill bit. During the drilling operation, measurements are sent back up the drill string to the ship via a pressure-pulse in the drilling mud. We were receiving these measurements throughout the drilling, watching the monitor for a new point every 2 minutes. The communication system transfers data at a much slower rate than data are collected, so the majority of the measurements is stored locally on memory inside the tool itself. After the decision was taken to stop penetrating further into the subsurface, the tool was withdrawn and arrived on deck yesterday.
The new data were immediately downloaded from the memory inside the tool and the logging staff scientists and contractors got to work processing to make them available to the science team. We now have huge print outs of the entire section penetrated by the LWD hole, as well as the digital versions of the data. It’s like a treasure trove of information suddenly arrived on deck! Everyone in the science team is fascinated to see what the results show: the resistivity measurements and images and the gamma ray measurements give information on the different rock types, various deformation features, and the stability of the hole itself. But the big question on everyone’s mind is ‘where is the earthquake fault?’ The logging while drilling scientists are in overdrive getting the data processed, and interpretations developed. Several scenarios are possible based on the LWD data so we might need the long-term observatory data and the core observations to confirm the location of the fault. The LWD tool has given us the first glimpse into the subsurface and the plate boundary interface.
The science team devours the 5m long print out showing the newly available LWD data.
WOWApril 5, 2012
Chikyu arrived on the JFAST drill site yesterday and was greeted by typhoon-strength (30m/s) winds whipping up the Pacific into a surging mass of 8-10m high waves. The same storm has shut down airports on the mainland and left many stranded. Tasks scheduled for the drilling preparations have been delayed because the ship is rolling around too much. Fortunately the cruise here from Shimizu went well and we arrived ahead of schedule so the storm has not set things back too badly so far.
This satellite image shows the extent of the storm we are currently experiencing
(Tuesday, April 3, 2012, Japan Meteorological Agency)
Even though Chikyu is huge, being on board in this weather feels like being in an airplane in severe turbulence. Except the storm has been raging for 24 hours! Walking in straight line is a distant memory and all of the outside deck areas are currently off limits thanks to the wind. The science party has had a tough introduction to the high seas, even the old hands are impressed at the longevity of this storm! Some people seem to have been completely unaffected, but there are definitely some green faces around, mine included.
The view from the porthole. 8 ? 10 m waves are crashing constantly against the side of the boat and the swell is causing the boat to roll and rock significantly. Hopefully it will blow over soon!
Despite the conditions, the science party continues to work hard to prepare for the drilling phase of the expedition. We are in an intense planning and training phase, working around the clock. As a group we are finalizing the design of the experiment here, deciding on the optimum layout for the drill holes. Every scientist will have a specific role once the operation is underway. Each person needs to become intimate with the tools they will be using, but it is fantastic how everyone is working together and sharing experience and ideas for improving on established methods, techniques and technologies. As a newcomer to the ocean drilling program, I feel lucky to be able to work and learn from the collection of world experts that make up the science team. The learning curve is steep but it the enthusiasm of the group is amazing, and the sense of working towards a common goal is inspiring.
Legendary scientist Casey Moore explains how faults are identified in drill holes from logging data.
The first stages of the drilling operation will be incredibly exciting: an underwater TV will be lowered 7km down to the sea floor to peer around and scope out the site. The engineers will try to find two sites to locate the drill head amongst the rocks. Will there be any friendly crabs to help out? Who knows, but one thing for sure is I can’t wait for the drilling to begin!
For now the plan is to Wait Out the Weather.