Geotechnical drilling
Geotechnical marine drill range
A family of marine drilling rigs graded by line pullback – 30, 50, 100 and 150 tonnes, single or twin derrick, drawworks or ram, matched to the campaign.
Rather than one rig stretched to fit every job, we build a range of geotechnical marine drills graded by line pullback, the load the rig can hoist at the power swivel. The right rig depends on water depth, borehole and drill string: the 30 t and 50 t classes cover lighter and mid duties; the 100 t and 150 t classes are deep-water, heavy-string ram rigs. Each is engineered, built and commissioned as a complete system under single-party accountability and they all share the same heave-compensation, handling and control engineering. For the system-level overview and the twin-derrick deployment capability, see geotechnical marine drill solutions.
| Class (pullback) | Derrick | Drive | Typical duty |
|---|---|---|---|
| 30 t | Single mast or twin “goal-post” | Wireline drawworks or ram | Lighter geotechnical drilling; the field-upgrade / retrofit class |
| 50 t | Single mast or twin “goal-post” | Wireline drawworks or ram | Mid-duty geotechnical drilling; twin derrick adds moonpool deployment |
| 100 t | Twin derrick | Pure ram rig | Deep water, heavier drill strings |
| 150 t | Twin derrick | Pure ram rig | Deepest water, heavy-string drilling and deployment |
Two ways to hoist – drawworks or ram
- Wireline drawworks – a roosterbox raised and lowered by a draw-works winch), with the heave compensator separate or combined. Available on the 30 t and 50 t classes.
- Ram rig – hydraulic cylinders do both the hoisting and the heave compensation, with the derrick acting as the guide. An option on the smaller classes and the only configuration on the 100 t and 150 t classes (one combined hoist/compensation cylinder in each derrick leg).
Single or twin “goal-post” derrick
The 30 t and 50 t classes can be supplied with a single derrick mast or a twin “goal-post” derrick. The twin derrick straddles the moonpool, giving the deck space to change tooling out and, crucially, turning the drilling tower into a heavy-lift deployment system that can launch a subsea CPT system (such as a seabed CPT unit) and a seabed drilling system safely through the moon pool. The same compensated heavy-lift arrangement that lowers a seabed frame (SBF) to depth deploys these too.
Heavy-lift interface system – switch modes without re-reeving
Our heavy-lift interface system gives the twin-derrick rig a common lifting interface across its deployment modes, so it switches between subsea drill, SBF (seabed-frame) topside drilling and subsea CPT without re-reeving any wires, a pallet change-out on location rather than a wire-handling campaign. One tower, one heavy-lift system, three modes.
Shared across the range
- Heave compensation – passive heave compensation as standard; Active Heave Assist (AHA/AWOB) available to add controlled weight-on-bit.
- Automation, moving towards fully automatic – iron roughneck, automatic power slips and pipe handling, with a path-to-automation control system. These rigs are driller-operated today; automatic drilling (AWOB + AHA) is the direction of travel – fully realised in our automated geotechnical marine drill.
- Power, fluids & controls – containerised HPUs, automated drilling-fluid mixing and pumping and a PLC/SCADA control system with full drill-data logging.
- Designed to standard – to the recognised offshore lifting, drilling-plant and marine-operations codes (DNV) and API drill-stem standards, with man-riding-rated lifting where required.