ES2759604T3 - Sea bed drilling system - Google Patents

Abstract

Seabed drilling system, comprising a drilling mast module (1) for drill rods (42), said drilling rods (42) piercing the seabed, comprising: - a core tube rack module ( 3) comprising a frame (33) to place the witness tubes (31); - a drilling rack module (4) comprising a frame (41) to place the drilling rods (42) and - a remotely operated arm module (2) provided with an arm (21) to hook and move said bars drilling (42) and / or said core tubes (31) from the rack modules (3, 4) to the drilling mast, or vice versa. characterized in that the system also comprises an acoustic sample verifier module (6) that detects the presence of a sample within a tube holder (31).

Description

DESCRIPTION

Sea bed drilling system

The present invention relates to a seabed drilling system for geotechnical site research for the installation of an offshore wind farm.

Background of the Invention

The towers, cables, and other structures that make up an offshore wind farm (OW) are supported on the seabed. The characteristics of the soils and rocks present in any site are crucial for the design of the OW park: insufficient knowledge of the site can seriously jeopardize the installation and / or operation. The developers have stopped projects at a very advanced stage, alleging poor geotechnical conditions.

Site Geotechnical Investigation (GSI) for OW today involves taking soil and rock samples from expensive and scarce self-lifting platforms and / or specialized geotechnical drilling vessels with a procedure that is slow and highly sensitive to weather conditions. Geotechnical investigation of the site is therefore a bottleneck for OW park developers.

Remotely operated subsea sampling systems make site investigation more resilient to bad weather and use smaller, more affordable supply vessels. Therefore, they can offer a substantial reduction in development costs and extend the time window for GSI.

Developers within the OW field face increasing construction costs. Optimization of the substructure is desirable, but cannot be easily accomplished without sufficient geotechnical investigation of the site.

Improving the acquisition and range of geotechnical data for OWT design helps to reduce safety factors and effectively reduces the cost of overall design. Clients of off-shore land investigations for OW developments are ultimately field developers (utilities, renewables investors). They can act through their internal technical team or through a subcontractor. In some cases, a contractor may be responsible for acquiring soil data, but it is still rare.

There are currently several companies that provide commercial-type subsea drilling for the offshore GSI market in general, but have only briefly entered the offshore wind GSI market. There are several reasons for this: all existing seabed drilling machines have been designed to withstand up to several km of water pressure. While the machines may be conceptually similar, this water depth requirement results in much more expensive components, requiring higher investment and maintenance costs.

Existing seabed drills are restricted to cable line or drill string drilling These procedures are capable of drilling most terrains, but perform optimally in a more restricted set of circumstances (rock wire line competent, drill string on soft ground). In fact, a high complaint at times in previous seabed drilling systems has been a relatively low recovery rate. OW development sites are very large by offshore standards, and there is a likelihood of finding varied terrain.

Existing seabed drills have not been designed with a modular approach that allows for smaller and lighter configurations to be used in circumstances where full depth drilling capacity is not required.

Not all existing seabed drills have the ability to also perform CPT (Cone Penetration Test). Seismic CPT inputs are key to advanced monopillar design, the foundation most OWs opt for.

Not all existing seabed perforations have developed their own internal robotics. Using existing robotics makes it difficult to quickly handle drill strings and samplers.

Because they entail higher construction costs and since the relative profitability of seabed drilling is even higher in deep waters, these machines have targeted the deep water market where more lucrative rates can be obtained than in OW.

In fact, information from market sources indicates that the current daily rates imposed by the most commercially active systems are well above even those for geotechnical drilling vessels. Naturally, they compensate for this with more efficient performance and, crucially, in certain deep-water environments, by their resistance to weather conditions.

It should also be noted that for operators making large investments in geotechnical drilling vessels, there is little incentive to develop cheaper systems that can be considered as a market-wide alternative to geotechnical drilling vessels. From this point of view, expensive deep-sea seabed units are preferred.

US 2013206476 A1 discloses a drilling system that includes a drilling head. The drill head defines a drill head drill and includes a drill head drill closure device. An inner core tube and an inner core tube retrieval device can be passed through the inside of the drill string and drill head drill when the drill head is connected to the drill string and the closure device is actuated the drill head drill to an open position.

EP 2860341 A1 discloses an actuator apparatus for propelling the tubes into the seabed. The actuator apparatus has support spleens that support a drilling rig to propel the tubes into the seabed and a body to support a plurality of tubes in cassettes.

US 2009255728 A1 discloses a device and method for bottom and seabed drilling, matrix sampling and measurement, includes a horizontally and vertically movable cross beam, a winch attached to the cross beam and having a cable wound on it, a drill head arranged on the cross beam, a spindle having a hole formed in it and which is driven by the drill head, and a davit having one end connected to the cable and another end passing through the hole in the spindle to attach and detach from the drill tool of a drill string.

US 374130 A discloses an offshore drilling assembly comprising a main body adapted to be placed on the seabed and including an axially movable drill to rotate a drill string including a core tube provided with a tube assembly removable and replaceable interior to receive and retain a core and a feeding device to move the drill axially.

Therefore, the objective of the present invention is to provide a seabed drilling system designed with a modular approach that allows smaller and lighter configurations to be used in circumstances where full depth drilling capacity is not required.

Description of the invention.

With the seabed drilling system of the invention, said drawbacks can be solved, presenting other advantages that will be described later.

The seabed drilling system according to the invention comprises a drilling mast module for drill rods, said bars piercing the seabed, comprising:

- a tube holder rack module comprising a frame for placing witness tubes;

- a drilling rack module comprising a frame for placing the drilling rods; and

- a remotely operated boom module provided with a boom for hooking and moving said drill rods and / or core tubes from the rack modules to the drill mast, or vice versa, and

an acoustic sample verification module, a module that detects the presence of a sample within a core barrel.

Advantageously, the seabed drilling system according to the invention may also comprise a base comprising a plurality of adjustable feet.

Furthermore, the seabed drilling system according to the invention may also comprise two automated gantry arm modules, one for the core tube rack module and one for the drilling rack module, which also collects and moves the core tubes and drill rods, respectively.

Preferably, the acoustic sample verification module comprises an acoustic probe, such as, for example, a short-range phased array acoustic probe.

In accordance with a preferred embodiment, each automated gantry arm module comprises a latch for engaging a drill rod or core tube.

Preferably, the base can comprise four feet that are independently height adjustable.

Advantageously, the arm of the remotely operated arm module comprises a hook at one of its ends, said hook being rotatable, and the arm of the remotely operated arm module is preferably mounted on a position table, which is rotatable. In accordance with a preferred embodiment, the core of the core tube rack module and / or the core of the drill rod rack module comprise safety latches to secure the core tubes and / or the core bars in position in the frame.

The drilling system according to the disclosure responds to a modular concept, which allows for different drilling hole diameter options and multiple combinations of push- in-place sampling (CPT) testing tools in the same deployment. The main characteristics of the drilling system according to the invention are:

- it is operational in water depths of up to 500 m;

- continuous drilling and / or sampling of soft soils up to 100 m deep below the seabed; - verification of recovery of the acoustic sample on the seabed;

- CPTu continuous thrust unit up to 100 m depth below the seabed;

- seismic measurement unit integrated in CPTu;

- real-time acquisition of drilling and drilling parameters (CPTu);

- selection and installation of the tools used. It can be adapted or modified in each investigation that is carried out;

- the system lands on the seabed and stabilizes. Two twin overhead lines are used for power and lift cables;

- drilling: rotation with reverse mud circulation;

- better daily rates than those currently imposed by drilling vessels or large lifting systems;

- greater flexibility in planning (no need to wait for good weather conditions and / or a specialized drill ship);

- health and safety: there are no drilling operators operating on the ship's floor, resulting in an intrinsically safer operation;

- best adapted to obtain design parameters for use in the design of OW foundations, with the consequent cost savings in infrastructure design.

Brief description of the drawings

For a better understanding of what has been disclosed, some drawings are attached in which, schematically and only as a non-exhaustive example, a practical embodiment is shown.

Fig. 1 is a perspective view of the drilling system according to an embodiment according to the disclosure;

Fig. 2 is a perspective view of the drilling mast module of the drilling system according to the disclosure;

Fig. 3 is a perspective view of the remotely operated boom module of the drilling system according to the disclosure;

Fig.4 is a perspective view of the core tube rack module of the drilling system according to the disclosure;

Fig.5 is a perspective view of the drill rod rack module of the drilling system according to the disclosure;

Fig. 6 is a perspective view of the acoustic sample verification module of the drilling system according to the disclosure;

Fig. 7 is a perspective view of the automated gantry arm module of the drilling system according to the disclosure; and

Figs. 8-12 are perspective views showing how the drilling system according to the present disclosure works.

Description of a preferred embodiment

In Figure 1, the seabed drilling system of the disclosure is shown according to a non-exhaustive embodiment.

The drilling system according to this embodiment comprises the following modules:

- a drilling mast 1;

- a remotely operated arm 2 provided with a hook 22 for hooking and moving drill rods 42 and core tubes 31;

- a tube rack 3 to place the tube tubes 31;

- a drill rock rack 4 to place the drill rods 42;

- a base 5 comprising feet 51;

- an acoustic sample checker 6 that detects the presence of a sample inside a tube holder 31;

- two automated gantry arms 7, one for the tube holder rack 3 and the other for the rock drill rack 4, which also collects and moves the tube holders 31 and the drill rods 41, respectively.

A description of each module is provided below:

- Drilling mast module 1:

As shown in Fig. 2, the drilling mast module 1 according to this embodiment comprises a winch 11, a plurality of clamps 12, a dump head 13, a side-displacement head carriage 14, a head swivel 15, a heavy duty mast 16, a feed cylinder 17 and a base bracket 18.

The height of this drilling mast module 1 is variable, for example, between 3 and 9 meters, and the cylinder section can also be changed to provide more or less force. Also, this module may or may not include winch 11.

- Remotely operated arm module 2:

As shown in Fig. 3, this module comprises a remotely operated hydraulic arm 21, a heavy duty hitch 22 and a positioning table 23.

Hydraulic arm 21 can be programmed to carry out many operations, both manually and automatically. For example, this hydraulic arm 21 can provide a maximum load of 300kg to 2,500mm, and a closed-loop position of each axle allows for easy operator orientation and automation. Heavy duty hitch 22 provides eg 75 ° wrist rotation and 135mm opening, and position table 23 has a fixed height and provides 350 ° rotation.

- Tube holder rack module 3:

This module comprises a plurality of witness tubes 31 and may comprise several outer auger barrels 32, a rack frame 33 for securing barrels 31, 32 and a transportation and mobilization security locking system 34.

This module is configured according to the geotechnical provisions scheme and can include up to 110 barrels per rack and each barrel can be 1,500 mm long.

- Drilling rack module 4:

This module comprises a modular frame 41, a plurality of drill rods 42, a safety lock 44 and a sliding tray 45.

Modular frame 41 comprises several separate sections, each for each bar size, which is an individual locking device, which can be configured according to the expected operations.

- Base module 5:

This module comprises a plurality of adjustable feet and its main functions are to stabilize the perpendicularity of the seabed drill rig drill pipe to the seabed and gently land on the seabed to minimize impact deformation of the drill hole and configure the unit on slopes of the seabed.

- Module 6 of the acoustic sample checker:

This module comprises a support frame 61 to retrieve a tube holder and an acoustic probe 62. This probe is preferably a short-range phased array acoustic probe that detects in a few seconds the presence of a soil sample in the nucleus and at what Recovery height has been possible, and could also be used as a general indicator of soil density and particle size.

The main function of this module is to detect the presence of a physical sample inside the core tube, prior to recovery at the top of the drill hole, so that the quality of each operation of the partial probe can be evaluated and allow thus corrections in the next operation.

With this module, it is possible to obtain the evolution of effective recovery of each sample (which is very important in soft soils) from the first operation to its complete elevation of the cable line inside the drilling hole, the operation of transporting the tubes core holders to the sample rack and the elevation of the entire subsea module to the surface, with variations in temperature, pressure and water.

- Gantry Automated Arm Module 7:

This module comprises a hydraulic system 72 provided with a gearmotor 75 with a closed loop position control mounted on a guided beam 73, and a hitch 74.

The hitch 74 is preferably double and grips a drill rod 42 or a tube holder 31, since the drilling system comprises two automated gantry arm modules, one for the 3 and one core tube rack for drill rod rack module 4.

The hitch 74 can be moved in any direction along the x, y, and z axes to properly position drill rods 42 and core tubes 31 in position.

Next, the operation of the seabed drilling system of the invention according to a preferred embodiment will be described.

- Placement on the seabed

First, the drilling system according to the disclosure should be carefully placed on the seabed. For this purpose, the drilling system comprises the base 5 in which the height of the feet 51 is independently adjustable to compensate for the slopes or obstacles of the seabed.

- Placement of the external barrels of auger

Thereafter, several external auger barrels 32 are first placed by arm 21 into the drill mast module 1 (Fig. 8).

- Drilling

Once in place, the rotating head 15 rotates and the feed cylinder 17 simultaneously pushes the outer barrels of auger 32 (Fig. 9). The rotation speed depends on the type of seabed.

When the outer auger barrels 32 reach the maximum depth, the seabed sample is considered to occupy its position within them.

- Extraction and verification of samples

Once drilled, the rotary head 15 is detached, the hitch 74 catches the barrels 32 with the samples. The hooker 75 moves the barrels 32 with the sample to the sample tester 6 and, once verified, the hooker 75 releases and the arm 21 places them in the modular frame 41 (Fig. 10).

Verification consists of a longitudinal acoustic sweep across different sections and analyzing the acoustic echo that can determine if there is a solid sample or just water.

- Placement of a hollow core tube

Once the sample is in position, the hook 74 will hook the next tube holder 31 to place it in a certain position in the rack frame 33, and then is picked up by the arm 21, which will place it inside the various barrels 32.

Once in place, the core tube 31 slides freely within the barrels 32 to the rotary head 15, where it engages a section of the core 32. It then rotates the rotary head 15 and pushes the core tube 31 again.

- Placement of a drill rod

Next, a drill rod 42 is placed inside the barrels 32 to drill the next span. The gantry arm 7 moves to the first available drill rod 42, grabbing it and placing it in a predetermined external area of the modular frame 41 (Figure 11).

Once in this zone, arm 2 picks up drill rod 42 and is also gripped by gantry hook 74 of gantry arm 7 (Fig. 12) and drill rod 42 rotates to be threaded and drill rod 42 is placed inside barrels 32 to drill a further section.

Recovery of drill rods 42 is performed in the same manner, but with reversed stages.

Although reference is made to a specific embodiment of the invention, those skilled in the art will be able to deduce that the disclosed seabed drilling system is susceptible to variations and modifications, and that all the mentioned details can be replaced by other technically equivalent ones, without depart from the scope of protection defined by the appended claims.

Claims (12)

1. Seabed drilling system, comprising a drilling mast module (1) for drill rods (42), said drilling rods (42) piercing the seabed, comprising: - a tube holder rack module (3) comprising a frame (33) for positioning the witness tubes (31); - a drilling rack module (4) comprising a frame (41) for placing the drill rods (42) and - a remotely operated arm module (2) provided with an arm (21) to hook and move said drill rods (42) and / or said witness tubes (31) from the rack modules (3, 4) to the mast drilling, or vice versa. characterized in that the system also comprises an acoustic sample verifier module (6) that detects the presence of a sample within a tube holder (31). 2. Seabed drilling system according to claim 1, wherein it also comprises a base (5) comprising a plurality of adjustable feet (51). 3. Seabed drilling system according to claim 1, wherein it also comprises two automated gantry arm modules (7), one for the core tube rack module (3) and one for the rack module drill (4), which also collects and moves the core tubes (31) and drill rods (41), respectively. Seabed drilling system according to claim 1, wherein the acoustic sample verifier module (6) comprises an acoustic probe (62). 5. A seabed drilling system according to claim 4, wherein the probe (62) is a short-range acoustic phase array probe. 6. Seabed drilling system according to claim 3, wherein each automated gantry arm module (7) comprises a hook (74) for hooking a drill rod (42) or a core tube (31) . 7. Seabed drilling system according to claim 2, wherein the base (5) comprises four feet (51) that are independently adjustable in height. 8. A seabed drilling system according to claim 1, wherein the arm (21) of the remotely operated arm module (2) comprises a hook (22) at one of its ends. 9. A seabed drilling system according to claim 8, wherein said hook (22) of the arm (21) is rotatable. 10. The seabed drilling system according to claim 1, wherein the arm (21) of the remotely operated arm module (2) is mounted on a positioning table (23). 11. Seabed drilling system according to claim 10, wherein said positioning table (23) is rotatable. 12. Seabed drilling system according to claim 1, wherein the frame (33) of the core tube rack module (3) and / or the frame (41) of the drill rod rack module ( 4) comprises safety closures (33, 34) to fix the witness tubes (31) and / or the drill rods (41) in their position in the frame (33, 41).