The Latest Technology of"CHIKYU", Deep Sea Drill Ship
TAKASHI OHMURA* 1

EIICHI HIGASHI* 1

TAKAYUKI YAMAGAMI* 1

KAZUYASU WADA* 2

TOMOYA INOUE* 2

Compensator (CMC), Riser Handling Equipment, WireRope, etc.) of this ship was designed to be 1 250 tons, theworld's largest, in contrast to that of most other similar
oil drill ships, which is approximately 907 tons. Accordingly, the derrick and hoisting equipment of this ship were
specially developed as up-rated versions, the strength ofwhich has been confirmed. Good operability and safetyfeatures have also been achieved taking into considerationequipment-to-equipment interface, equipment layout,equipment automation and so forth.

1. Introduction"CHIKYU", a deep sea drill ship, was delivered to theJapan Agency for Marine-Earth Science and Technology(JAMSTEC) in July 2005. Construction of "CHIKYU",
featuring the latest technology in this field, opens up anew era of deep sea drilling, with a scientific drill ship
adopting the riser drilling method for the very first timein the world. This scientific drill ship was built for thepurposes of clarifying long-time environmental changes
in the earth, exploring life in the earth's crust, studying
the mechanism of earthquakes and so forth, through investigation deep into the earth's core. This paper
introduces the Hoisting Equipment, Dual Elevator System, Core Sampling System and Waste Mud Treatment
System that form a part of the new technologies developed and adopted in the building of "CHIKYU".

3. Automation of the Dual Elevator SystemDuring drilling operation, if the pipe is suspended on
the drill floor using a wedge known as 'slips', high stressis generated which makes the deep drilling impossible.
For this reason, existing scientific drill ships adopt themethod of suspending the pipe by using two elevators
alternately. However, all work (including attaching anddetaching) is performed manually using two elevators.
In the case of "CHIKYU", however, a true dual elevatorsystem for the integrated control and operation of thetwo elevators has been developed and adopted. This system automatically detects the work being done by thetwo elevators and also their operating condition and withthe provision of various interlocks on all equipment, including peripheral equipment, this enables drilling work
to be performed safely and efficiently.

2. Hoisting Equipment
The hoisting equipment for lifting and lowering thedrill pipe, the riser pipe and the Blow-out Preventer (BOP)
is installed in the derrick. The ship has been engineered
to operate in severe environmental conditions, anywherein the world. It is also intended to be capable of riser drilling in deeper water and of achieving a drilling depth,
deeper than ever before. Through analysis of the balance
between the hull motion and the weight/vertical vibration/strength of the suspended sub-sea equipment underthese conditions, the rated load of the derrick and hoisting equipment (Traveling Block, Crown Mounted Heave
Table 1 Hoisting equipment rated load
Hoisting Equipment

Rated Load (t)Remarks

Travelling Block

1 250 tWorld's largest

1 250 MT Link

1 250 tWorld's largest

Riser Handling Elevator

1 250 tWorld's largest

Riser Running Tool

1 250 tWorld's largest

Crown Block (CMC)

1 250 tWorld's largest

Power Swivel (main load path)907.2 tPresently in serviceSystem Link

907.2 tPresently in service

Dual Elevator

680.4 tWorld's first
integrated control

Hydraulic Elevator

453.6 tPresently in service

Fig. 1 Dual elevator

Mitsubishi Heavy Industries, Ltd.
Technical Review Vol. 43 No. 1 (Jan. 2006)*1 Nagasaki Shipyard & Machinery Works*2 Japan Agency for Marine-Earth Science and Technology

1Drill Drain
Tank

Drill drain
Shale shaker

Drill Drain
Thickening System

Waste Mud
Tank

Drill Water
Tank

Waste
mud

Filteredwater

Cuttings

Cuttings Transfer
System

Evaporated
water

Cohesion/
Dehydration SystemSludge

Stabilizedsludge

CuttingschuteSqueezed liquidBig bag
Stabilizing
Mixer

Stabilizing
Tank Unit

Evaporated Water
Filtration SystemBig bag fillingsystemBags to bebrought outby crane.

Onboard Drill Waste Treatment SystemFig. 3 Waste Mud Treatment System flow

5. Drill Waste Treatment System
Hydropiston Corer

To accord with its status as a "Scientific Drill Ship","CHIKYU" adopts the concept of zero waste discharge toenable worldwide drilling operation. Discharge water containing mud is distilled and filtered for re-use as drill water.
Deteriorated mud is cohered and then dehydrated by pressurization, mixed with cement, bagged and transferred bysupply boat to an onshore treatment facility. Cuttings aretransferred by vacuum equipment, mixed with cement,bagged and transported ashore. Treatment of cuttings isimportant for maintaining the expected drilling speed.
Therefore, this treatment system was tested on-board using cuttings generated by actual drilling and a maximum
treatment capacity of 20 tons/hour was confirmed.

Rotary Corer
RCB: A system forcore sampling in hardlayers such as rock bed.

Core sample
Thrust Core Barrel into
soil under high pressure.

Extract Core Barrel tosample core.

Core sampling by boring
into soil layer.

6. Conclusion

HPCS: A system forcore sampling in soft
soil layers such asalluvial deposit.

"CHIKYU" is expected to start regular operations in2007 as the principal drill ship in the Integrated Ocean
Drilling Program (IODP). In the future, this ship intends
to drill into the sea bed to a depth of 4 000 meters. To
realize this, it will be necessary to develop deep sea drilling technology incorporating new knowledge obtained
from operational experience, as well as new technology
from the Oil Drilling Industry. The construction of"CHIKYU" is just the first step and further development
will be necessary, in order to reach as yet unexplored
fields of sub-sea research.

Core sample
Fig. 2 HPCS and RCB

4. Core Sampling System
The most important purpose of "CHIKYU" is to obtain the targeted core from deep drilling depth. Sincecontinuous core sampling is required, the Wireline
method has been adopted for the first time in the world
by a riser drill ship. With this method, another container
called a core barrel is placed inside the drill pipe, a bitwith a hollow center drills the well and the container
lifts the core onto the ship. The feature of this method isto retrieve the core without lifting or lowering the drill
pipe, which enables efficient coring. The hydraulic piston coring system (HPCS) to obtain soft sediment, theextended shoe coring system (ESCS) to obtain slightly
harder sediment, the rotary core barrel (RCB) to obtainhard rock, etc. have each been developed for use, depending on the well.

Takashi Ohmura

Eiichi Higashi

Kazuyasu Wada

Tomoya Inoue

Takayuki YamagamiMitsubishi Heavy Industries, Ltd.
Technical Review Vol. 43 No. 1 (Jan. 2006)

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