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(11) | EP 3 940 191 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | MACHINE AND METHOD FOR UNDERWATER SOUNDINGS |
| (57) The machine for underwater soundings comprises a drilling turret (1), a hose (9)
for injection of water under pressure, a core barrel (11) for taking samples, and
a casing pipe (10) that surrounds said core barrel. (11), and also comprises a rotating
head (7) and jaws (12, 13) for joining and separating sections of the casing pipe
(10). The procedure for underwater soundings comprises lowering a drilling turret (1), a first section of the casing pipe (10) and a core barrel (11); initiating a drilling operation; recovering the hose (9); lowering a second section of the casing pipe (10); screwing the second section of the casing pipe (10) to the first section of the casing pipe (10); and continuing with the drilling operation an additional length, and recovering the core barrel (11) with the sample. |
Background of the invention
[0002] Geotechnical underwater soundings can be carried out in two ways: by using geotechnical ships with a drilling turret, or by rigs that drill directly the seabed.
[0003] Geotechnical soundings, unlike oil or gas soundings, requires recovering the probed sample for further analysis and study, which is why it is a type of sounding that normally requires two processes, sounding and recovering the sample.
[0004] At shallow depths, these soundings can be done by raising and lowering the equipment with a pipe and rod. On the other hand, at great depths this method is not feasible and the core barrel system is used.
[0005] To make a sounding on a ship, the following processes have to be performed:
First, a feed beater is lowered to the seabed. A feed beater is a heavy structure that has a funnel-shaped area and serves to guide the pipe that will be lowered from the ship and thus helps that when the pipe is rotating, it does not move.
[0006] With the feed beater on the seabed, the pipe is lowered from the ship to the feed beater. Depending on the depth, more or less pipe will have to be added.
[0007] Once the pipe is resting on the seabed, a core barrel is lowered inside the pipe. This is just an inner tube that is anchored at the beginning of the pipe and that will store the probed sample (1.5 or 3 meters).
[0008] This core barrel is lowered with a steel cable and when it reaches the bottom and is anchored, it is disconnected from the cable, thus being able to recover that steel cable.
[0009] With the core barrel anchored at the beginning of the pipe, a casing pipe of the same length as the core barrel sampling device is added from the drilling turret and the operation of that pipe is done.
[0010] Once this operation has been completed, the steel cable is inserted to the bottom of the pipe, which will be connected to the core barrel and allow to recover the inner sample.
[0011] With the sample recovered on the ship's deck, another core barrel is lowered that shall be anchored at the beginning of the pipe. The steel cable is recovered and a casing pipe is added with which sounding is carried out.
[0012] This process will be repeated as many times as meters of sample need to be recovered. If we want 60 meters of sounding and the core barrel sampling tube is 3 meters, we will have to repeat it 20 times.
[0013] This is a system that presents several problems:
- Time: Depending on the depth of the sea, we will have to lower a large amount of pipe. We are talking about depths that can reach 2000 meters or even more, which takes an enormous amount of time to reach the seabed by adding 3 or 6 meter pipes.
- Sounding quality: By having the drilling turret on the ship and a large amount of pipe to the bottom, the rotation of the pipe is not perfect, altering the quality of the recovered sample.
- Reduced operational limits if there are waves.
- Cost: The rental of a geotechnical ship is out of reach of most companies, ranging around € 20,000 / € 50,000 per day.
[0014] To solve the problems previously raised, underwater machines have been created that perform sounding from the seabed.
[0015] The operating principle is based on the core barrel system, but in this case the drilling turret is in the machine itself. With these systems, the time spent lowering the pipe to the seabed is eliminated and the poor quality of the recovered samples is eliminated.
[0016] These machines present various problems.
- Cost: They are extremely expensive machines and are not marketed as they are company-owned developments.
- They require very large ships to be able to operate them.
- They require a lot of electronics and hydraulics which causes them to have many failures during their operation.
[0017] Although many machines of this style have been developed, few are 100% functional and hardly find a place on the market, where a balance is sought between the cost of research and the results that are needed, where 6 meters is often enough..
[0018] Here is an important issue and it is that, to perform a sounding, you need to inject water under pressure into the pipe. In a drillship this pressure can be injected from the drilling turret. That is why it is necessary to have the pipeline from the ship to the end of the sounding connected.
[0019] In machines that make soundings from the bottom, this pressure is introduced by a pump that is connected to the top of the pipe, which limits the length of the pipe used to about 3 meters.
Description of the invention
[0020] Therefore, an objective of the present invention is to provide a machine and a method for underwater soundings that solves the above drawbacks, working by using the core barrel from the ship, but introducing the drilling turret in the equipment that is lowered to the seabed and eliminating the obligation to have a pipeline connected from the ship to the seabed
[0021] With the machine and the method for underwater soundings of the invention, it is possible to solve the aforementioned drawbacks, presenting other advantages that will be described below.
[0022] According to a first aspect, the underwater sounding machine according to the present invention comprises:
- a drilling turret, preferably comprising a rotating head and two pistons;
- a pressurized water injection hose that will act as a steel cable at the same time;
- a core barrel for taking samples; and
- a casing pipe where the core barrel will be internally anchored,
- a floating guide to guide the pipe and the core barrel,
- some clamps for the separation of the pipe sections.
[0023] Advantageously, said rotating head is movable, in particular, movable only vertically along the drilling turret, for example, by means of pistons arranged in the drilling turret. Furthermore, said rotating head preferably includes a double jaw to facilitate the operation of reception and coupling of the casing pipes.
[0024] Said pressurized water injection hose is also advantageously a hose for moving the core barrel and the sections of the casing pipe.
[0025] The machine for underwater soundings according to the present invention also comprises a floating guide with an anchoring system that will move between the two steel cables that lift the equipment and will serve to guide the pipes and core barrels that take the samples from the deck of the ship to the feed beater located on top of the equipment.
[0027] Furthermore, the drilling turret comprises one or more cameras, which are arranged in suitable positions to control the actions of the machine.
[0028] According to a second aspect, the present invention refers to a method for underwater soundings, comprising the following steps:
- lowering a drilling turret until it is in contact with a seabed, with a pressurized water hose, a first section of the casing pipe and a core barrel;
- initiating a drilling operation;
- recovering the pressurized water hose;
- lowering a second section of the casing pipe by means of the pressurized water injection hose;
- screwing the second section of the casing pipe to the first section of the casing pipe that is connected to the drilling turret;
- continuing the drilling operation an additional length,
- recovering the core barrel with a sample taken.
[0030] The machine and method for underwater soundings according to the present invention provide the following improvements over current systems:
- The quality of the recovered sample is improved by incorporating the turret in a piece of equipment that is directly on the seabed;
- The need to have as many meters of pipe as the depth of the seabed is eliminated, saving a great deal of time and money;
- The core barrel system is modified where instead of incorporating a steel cable to carry out the operation, we substitute it with a multifunction hose, capable of performing the functions of a steel cable (raising and lowering the casing pipe and the samples of core barrel) while performing the function of a hose to inject water pressure and be able to perform sounding.
Brief description of the drawings
[0031] For a better understanding of what has been stated, some drawings are attached in which, schematically and only as a non-limiting example, a practical case of embodiment is represented.
Figures 1 and 2 are perspective views of the drilling turret of the underwater sounding machine of the present invention;
Figures 3 to 10 are perspective views of the steps of the method for underwater soundings in accordance with the present invention; and
Figure 11 is a perspective view of the drilling turret of the underwater sounding machine of the present invention, according to a second embodiment.
Description of a preferred embodiment
[0032] As shown in Figures 1 and 2, the underwater sounding machine comprises a drilling turret 1, which, in its position of use, is placed on the seabed by moving along cables 3.
[0033] The drilling turret 1 comprises a leveling base 4, which contacts the seabed, which is surrounded by a skirt 5, that is, by a vertical wall.
[0034] The drilling turret 1 also comprises a ballast 6 to provide adequate weight for the drilling turret 1 to be fixed in position and a head 7, the function of which will be described below. This head 7 is vertically movable by means of pistons 8.
[0035] To perform underwater sounding, the underwater sounding machine also comprises a hose 9, which has two functions: a first function of injecting water under pressure to be able to perform underwater sounding, and a second function of allowing the movement of pipe sections 10 and a core barrel 11 (shown in figure 9), which is located inside said pipe 10.
[0036] The function of the head 7 is to join the pipe sections 10 and rotate to carry out the test. As shown in more detail in Figure 5, to separate the pipe sections 10, the turret 1 comprises two jaws 12, 13, said jaws 12, 13 being rotatable relative to each other, one of these jaws being a double one. In this way, the pipe sections 10 can be separated, by, for example, threading and unscrewing.
[0037] As can be seen in figure 2, the drilling turret 1 also includes cameras 14, which allow the process to be controlled remotely. According to this embodiment represented in figure 2, a first camera is located above said head 7, while a second camera is located below the head 7, focusing both cameras towards jaws 12, 13 of the head 7.
[0038] The method for underwater soundings according to the present invention comprises the following steps:
First, the drilling rig 1 is lowered to the seabed with a 3 meter section of pipe and the core barrel already anchored to the first section together with the hose connected to the pipe. When the equipment rests on the seabed, sounding can begin.
[0039] Figure 3 shows the start of drilling, in which an encoder determines a zero position to calculate the drill length, and Figure 4 shows pipe 10 in its drilling position.
[0040] When a penetration of 1.5 meters is reached, from a ship, not shown, and using steel cables 3 and a floating guide 2, the hose 9 is recovered to the deck of the ship, and a second section of pipe is added 10 (figure 6) that is lowered to the drilling turret 10, screwing it into the first section of pipe 10 that is in place (figure 7) and performing the operation (figure 8), by supplying water pressure from that hose 9.
[0041] This hose 9 is in charge of supplying the water pressure to perform the sounding and is strong enough to supply the water pressure and at the same time provide a cable to raise and lower the sections of the casing pipe 10 and the core barrel 11.
[0042] Once the operation is completed, the core barrel 11 sample is recovered to the ship deck (Figure 9) and a new one is lowered. Subsequently, the hose 9 is recovered and another section of pipe 10 is lowered to carry out the following operation (figure 10).
[0043] Figure 5 shows the detail of the jaws 12, 13, which allows the connection and separation of the pipe sections 10 by rotating the jaws 12, 13 with respect to each other.
[0045] In figure 11 a second embodiment of the turret of the machine for underwater soundings according to the present invention is shown.
[0046] For the purpose of simplicity, the same reference numerals are used to indicate the same or equivalent elements.
[0047] The main differences with respect to the first embodiment shown in Figures 1 to 10 is the configuration of the head 7 and of the floating guide 2, and that one of the jaws 13 is double.
[0049] Although reference has been made to a specific embodiment of the invention, it is clear to a person skilled in the art that the machine and the method for underwater soundings described are susceptible of numerous variations and modifications, and that all the mentioned details can be replaced by other technically equivalent ones, without departing from the scope of protection defined by the appended claims.
1. Machine for underwater soundings, comprising:
- a drilling turret (1);
- a hose (9) for injection of pressurized water;
- a core barrel (11) for taking samples; and
- a casing pipe (10) surrounding said core barrel (11),
characterized in that it also comprises a rotating head (7) and jaws (12, 13) for joining and separating sections of the casing pipe (10).2. Machine for underwater soundings according to claim 1, wherein the jaws (12, 13) are
rotatable relative to each other.
3. Machine for underwater soundings according to claim 1 or 2, wherein one of said jaws
(13) is double.
4. Machine for underwater soundings according to claim 1 or 2, wherein said rotating
head (7) is movable.
5. Machine for underwater soundings according to claim 4, wherein said rotating head
(7) is movable along the drilling turret (1).
6. Machine for underwater soundings according to claim 4 or 5, wherein said rotating
head (7) is movable by means of pistons (8) arranged in the drilling turret (1).
7. Machine for underwater soundings according to claim 1, wherein said pressurized water
injection hose (9) is also a hose for moving the core barrel (11) for taking samples
and sections of the casing pipe (10).
8. Machine for underwater soundings according to any one of the preceding claims, which
also comprises a guide (2) to move the drilling turret (1).
9. Machine for underwater soundings according to any one of the preceding claims, wherein
the drilling turret (1) comprises a leveling base (4).
10. Machine for underwater soundings according to any one of the preceding claims, wherein
the drilling turret (1) comprises a ballast (6).
11. Machine for underwater soundings according to any one of the preceding claims, wherein
the drilling turret (1) comprises one or more cameras (14).
12. Method for underwater soundings, characterized in that it comprises the following steps:
- lowering a drilling turret (1) until it is in contact with a seabed, with a pressurized water hose (9), a first section of the casing pipe (10) and a core barrel (11);
- initiating a drilling operation;
- recovering the pressurized water hose (9);
- lowering a second section of the casing pipe (10) by means of the pressurized water injection hose (9);
- screwing the second section of the casing pipe (10) to the first section of the casing pipe (10) that is connected to the drilling turret(1);
- continuing the drilling operation an additional length,
- recovering the core barrel (11) with a sample taken.
13. Method for underwater soundings according to claim 10, wherein a third or more sections
of the casing pipe (10) are lowered depending on the desired depth of the underwater
sounding.