WISON-APB 50/100/150 kN CPT equipment

This wireline CPT equipment is designed to work within a 4½" API drillpipe. The down-the-hole tools are pushed into the soil beyond the drillbit by means of a hydraulic cylinder. These cylinders are available with 1, 1.6 and 3 meter stroke. They can operate with the three different sampling / logging tools. The 1 meter cylinder pushes up to 100 kN, the 1.6 meter cylinder pushes up to 150 kN and the 3 meter one manages 50 kN. 

The system can operate with:

• 2" and 3" sample tubes.
• Electric cones (c,fs,u,seismic). 
• The offshore vane tester.

The down-the-hole tools are deployed through a special hose umbilical. 

Umbilical

This special design hose umbilical has an average live span of 5 years in the existing system. The oil hydraulics of the winch also takes care for the necessary hydraulic supply to the down-the-hole tools. Reset of the hydraulic cylinders by special high-pressure water pump. The 16 bit down-the-hole data acquisition telemetry system uses only two wires in the umbilical. Depth recording by means of the measuring cylinder integrated in the winch hydraulics. 

WISON-APB Vessel requirements

For testing with the WISON-APB system the vessel needs to meet the following requirements:

- stabilizer for keeping the vessel stationary
- drill rig with heave compensator
- seabed clamp
- bit guide 

Vessel positioning

The vessel has to stay stationary above the proposed testing location. The drill string will only allow a small movement of the vessel, normally a 10% of the water depth as horizontal movement. This can be achieved by a 4-point mooring or with DP facilities.  

Drill rig

The drill rig must run drill tubes of minimum 100 mm inner diameter, for instance 4½IF API. The pulling capacity of the drill rig depends on the test depth and drill tubing size. Approximate figures are: for tests up to 100 metres a minimum capacity of 150 kN is advised. For tests up to 500 metres a minimum capacity of 750 kN is advised. Directly above the bit heavy weights are used in the drill string. During drilling their weight is compensated by the heave compensator to the required bit load. This way the drill tubing is under tension at all times, in order to prevent buckling. 

Seabed clamp

The seabed frame clamp provides the deadweight during the CPT test. The seabed clamp also functions as re-entry frame if the hole needs to be emptied during the drilling process. The bit guide ensures that the bit is able to re-enter the borehole.

Leaflet S19