The JOIDES Resolution left Astoria, Oregon on June 27, 2004 (Figure 1) for a two-month drilling expedition on the east ridge of the Juan de Fuca Ridge. This expedition marks the beginning of the Integrated Ocean Drilling Program (IODP), an international drilling program that traces its origin back to the late 1960’s when it was named the Deep Sea Drilling Project (DSDP) and later becoming the Ocean Drilling Program (ODP).

IODP Expedition 301 is building on the results of ODP Leg 168 where 19 holes were drilled to study the hydrothermal fluid flow processes of a sedimented ridge flank environment. Expedition 301 is also the first of two proposed expeditions that will attempt to install borehole observatories for temperature, pressure, fluid chemistry and microbiology long term experiments as well as the first cross hole seismic and permeability experiments in the history of scientific ocean drilling. Dr. Gerardo J. Iturrino is sailing on IODP Expedition 301 as the Logging Staff Scientist in charge of wireline logging operations and serving as a mentor to the first IODP Teacher at Sea, Jonathan Rice, Ph.D., an 8th grade teacher from Green Mountain Union High School in Vermont.

During Expedition 301 two new holes will be drilled in the Second Ridge site (Figure 2) and long-term observatories will be installed. Each long term observatory, also known as Circulation Obviation Retrofit Kit or CORK (Figure 3) will be able to measure permeability, temperature and pressure conditions for up to five years and will sample formation fluids for geochemistry and microbiology studies. Expedition 301 will also replace two CORK installations that were deployed during ODP Leg 168 in Holes 1026B and 1027C. The new CORK instrumentation will allow for more diverse studies of hydrothermal environments and will be one of the primary objectives for subsequent cross-hole experiments.

Figure 1. JOIDES Resolution as it is departing Astoria Oregon for the initial IODP Expedition 301 to the eastern flank of the Juan de Fuca Ridge	Figure 2. Basement topography map showing the location of the Second Ridge (SR) sites where new holes will be drilled during IODP Expedition 301 and long term observatories will be installed.	Figure 3. Schematic diagram of one of the CORKs that will be installed in the Second Ridge site of the eastern Juan de Fuca Ridge and a picture of the four CORK installations that are scheduled for deployment during IODP Expedition 301.

We began drilling operations in Site 1301 (Second Ridge) with the intentions of drilling two holes and installing a CORK in each of the boreholes. The operational plans began with a jet-in test to determine the hardness of the sediment cover and the length of the 20" casing that would be attached to the re-entry cone (Figure 4). The installation of the reentry cone and 20" casing to ~39 mbsf went well and we quickly started assembling a 18.5" pilot bit and underreamer that was going to be used for opening the hole for the next casing string (Figure 5). We only drilled down with the underreamer and pilot bit until the sediments got too hard because this system is not designed for hard formations. At this point, we tripped the pipe to replace the underreamer with a bicenter bit (Figure 6) that was better suited for the task of drilling through hard formations. The entire opening of the hole (with both the underreamer and bicenter bit) took ~3 days.


The bicenter bit worked well, reaching the target depth of ~271 mbsf. After circulating a mud pill (~20 barrels of mud) to help clean cuttings out of the hole, a wiper trip was conducted (raising the bit up and down in the newly drilled portion of the hole to make sure the walls of the hole are stable). Then a 16" casing string was assembled and deployed followed by similar procedures to install 10-3/4" casing in a newly drilled 14-3/4" section of the hole. The 14-3/4” hole reached 107.1 m into basement or 369.5 mbsf however, a wiper trip before pulling out of the hole indicated the presence of an interval of rapid drilling penetration rate that would be the cause of some trouble ahead of us.


We reentered Hole 1301A with a 360.4 m-long string of 10-3/4 inch casing (~98.4 m into basement) until ~4 m above where the casing hanger would land in the reentry cone. After we halted circulating to install the cementing manifold before landing the casing, we could not lower the casing. We suspected that rocks falling out of the fast drilling interval were causing the problems and after several attempts to lower the casing, we decided to recover the casing string. An attempt to deploy a shorter casing string (273.3 m-long) was then successful and we therefore made Hole 1301A the shallow basement-monitoring hole.


We are currently drilling and casing Hole 1301B (47° 45.2276‘ N, 127° 45.8269' W; water depth: 2666.5 mbrf) with the intentions of making this location the deep basement monitoring hole. We have successfully deployed 20" and 16" casing strings to 268.5 mbsf (2 m into basement) and we will continue drilling until the 10-3/4" casing is in place. Coring and logging operations will then follow prior to the CORK installations in Holes 1301A and 1301B.

Figure 4. Deployment through the moonpool of the re-entry cone and 20" casing that was installed in Hole 1301A to an initial depth of ~39 mbsf.	Figure 5. Test of the under reamer that was placed behind the pilot bit for opening a 20" hole prior to the installation of the deeper casing strings in Hole 1301A. This system shoots water at elevated pressures to open the arms that are used for opening the hole.	Figure 6. Assembly of the bicenter bit on the rigfloor prior to deployment in Hole 1301A.

Gerardo Iturrino has been preparing for the potential wireline logging operations that are scheduled for the deep basement hole as well as advising Jonathan Rice (8th grade teacher sailing in Expedition 301) in the production of a daily journal (http://iodp.ldeo.columbia.edu/EDU/TAS/) about his experiences at sea and laboratory briefs that will be used as educational materials for students and other teachers.

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