Field of the invention

The invention relates to a directional drilling arrangement comprising a drill head arranged at the end of a drill string, wherein the drill head includes direction means for directing the directional drilling arrangement in a specific direction. The invention further relates to a method for extracting an underground sample by means of a directional drilling arrangement.

Background of the invention

Directional drilling (or slant drilling) is the practice for guided non-vertical drilling in the ground. Different directional drilling machines and methods for making underground holes are known. A typical directional drilling machine is generally configured to drive into the ground a series of drill rods joined end-to-end to form a drill string. At the front end of the drill string is a drill head comprising a drilling tool. Typically, the drilling tool can be rotated by means of a mud motor or by axially rotating the drill string itself and/or it can simply be configured to be pushed through the ground. From WO 2009/052298 Al such a directional drilling machine is known.

In some cased it is necessary to use a directional drill to reach an underground area which e.g. is under suspicion for being contaminated. An object of the invention is therefore to provide for means and method for extracting an underground sample by means of a directional drilling arrangement.

The invention

The invention provides for a directional drilling arrangement comprising a drill head arranged at the end of a drill string, wherein the drill head includes direction means for directing the directional drilling arrangement in a specific direction. The directional drilling arrangement further comprises probe means for extracting a sample of the ground in which the directional drilling arrangement is drilling, wherein the probe means is arranged to be pushed out of the directional drilling arrangement in front of the direction means. The directional drilling arrangement further comprises locking means for locking the position of the probe means in relation to the drill head.

Arranging the probe means so that they can be pushed out of the directional drilling arrangement in front of the direction means and locked in that position is advantageous, in that the means driving the drill head forward hereby can be used to push the probe means into the potentially contaminated area to extract a sample.

Furthermore, the drill head obviously mixes up the soil through which it passes and it inevitably draws at least some gas, air, soil and/or liquid along from one location to another. Thus, pushing only the probe means into the area to be probed is advantageous in that the risk of contaminating the extracted sample hereby is reduced. By the term "direction means" is to be understood any kind of plates, guides, driven or un-driven wheels, conveyers, chains or shovels or any other kinds of direction device suitable for controlling the direction of a directional drill.

By the term "sample" is to be understood any kind of gas, liquid or solid sample or any combination thereof that can be taken from the ground. I.e. the term is in no way limited to only cover dirt/soil samples.

By the term "probe means" is to be understood any kind of probe suitable for extracting a gas, liquid or solid sample from the ground. It should also be understood that the term "probe means" in no way is limited to devices comprising means for analysing the sample. In fact in most cases the "probe means" merely extract the sample, which is then analysed at another location e.g. in the drill head, at the drilling machine above ground or at a specialised laboratory. By the term "locking means" is to be understood any kind of blocking, fastening or fixing device or any other kind of lock suited for locking the relative position of probe means in relation to a drill head

In an aspect of the invention, said direction means comprises a drill plate arranged to be slanting in relation to said drill string.

Arranging a slanting plate at the head of the directional drill enables that the direction in which the drill moves through the ground can be controlled simply by pushing the drill through the ground and then turn the drill and the drill plate to make the drill move in the direction opposite the direction in which the penetrated ground is deflected. Thus, making the direction means comprise a slanting drill plate is advantageous in that it hereby provides simple, durable and inexpensive means for controlling the direction of the directional drill. In an aspect of the invention, said drill string is hollow and wherein said probe means is arranged to extend through at least a part of said drill string.

Forming the drill string hollow is advantageous in that it hereby is possible to transport objects and data through the drill string and making at least a part of the probe means extend through at least a part of hollow drill string is advantageous in that the probe means hereby is protected by the drill string and in that the probe means hereby easily can be moved back and forth through the ground through which the drill string extends. In an aspect of the invention, said drill head comprises a probe opening through which said probe means can be pushed out of.

Pushing the probe means out of a probe opening in the drill head is advantageous in that the probe means hereby can be maintained away from the ground until use hereby reducing the risk of contaminating the probe means and increasing the life of the probe.

In an aspect of the invention, said probe opening is provided with a plug arranged to be pushed out of said drill head by said probe means.

Arranging a plug in the probe opening so that it can be pushed out by the probe means when these are deployed is advantageous in that the probe opening and the inside of the drill head hereby is protected from being filled with soil from the ground being penetrated by the drill. This ensures that the probe means relatively easily can be pushed out of the drill head at all times and it protects the probe means from being contaminated by the ground being penetrated by the drill.

In an aspect of the invention, said probe opening is arranged in said direction means of said drill head.

Arranging the probe opening in the direction means is advantageous in that this enables that the probe means can be push out directly in front of the direction means, which in turn is advantageous in that the risk of the probe means deflecting when pushed forward is reduced.

In an aspect of the invention, said probe means comprises means for extracting a pore gas sample. Sampling pore gas requires that the ground from which the sample is taken is substantially undisturbed when the sample is taken to prevent the sample from being contaminated by outside air or gas. It is therefore particularly advantageous to use a directional drilling arrangement according to the present invention for taking pore gas samples in that the present invention reduces or even eliminates the risk of air or gas drawn down with the drill, or from the ground being penetrated by the drill, contaminating the pore gas sample.

In an aspect of the invention, said directional drilling arrangement comprises means for transporting said pore gas sample to pore gas analysis means arranged above ground.

Analysing pore gas can be a complicated task and the equipment for doing this can be relatively space consuming. It is therefore advantageous to transport the pore gas sample to the ground surface before analysing it. The pore gas sample can either be sucked to the surface by means of vacuum or it can be contained in a container that can be transported to the surface either independently, with the probe means or with the drill head. In an aspect of the invention, said drill head comprises analysing means for analysing said sample.

Bringing the sample to the surface before analysing it can in some cases be time consuming and involve increased risk of sample contamination. If the sample can easily be analysed it is therefore more efficient to analyse it in the drill head.

In an aspect of the invention, said locking means are arranged on said probe means.

Given the relatively small drill head, the space inside the head can easily get a bit crammed. It is therefore advantageous to place the locking means on the probe means so that the locking means is only present in or at the drill head when they are needed i.e. in relation with the probe means.

In an aspect of the invention, said locking means comprises balloon means arranged to locally expand a cross sectional size of said probe means.

To avoid electric power supply to the locking means and to ensure simple and durable locking means, it is advantageous to fix the position of the probe means in relation to the drill head by means of one or more inflatable balloon means.

In an aspect of the invention, said probe means are formed completely independent from said drill string and said drill head.

Forming the probe means independent from the drill string and the drill head is advantageous in that in that the probe means hereby can be moved completely independent from the drill string and the drill head and in that the displacement of the probe means - e.g. when the probe means are pushed out of the drill head into the free space in front of the drill head - can be done manually or by means of push means from above ground so that these means for displacing the probe means in relation to the drill head does not have to be incorporated into the drill string and the drill head.

The invention also provides for a method for extracting an underground sample by means of a directional drilling arrangement having a drill head arranged at the end of a drill string. The method comprises:

• guiding the drill head to the underground area at which a sample must be taken,

• retracting the drill head a predefined distance to create a free space in front of the drill head,

· pushing probe means out into the free space, • locking the position of the probe means in relation to the drill head,

• pushing the drill head forward to make the probe means penetrate the ground in front of the free space, and

• extracting a sample from the ground by means of the probe means.

It takes substantial force to push the probe means into the potentially contaminated ground to be sampled from. I.e. if the probe means was simply pushed out of the drill head and directly into the ground to be tested - when the given area was reached - the directional drilling arrangement would require a massive press dedicated entirely for pushing the probe means forward. However, retracting the drill head before the probe means is pushed out of the drill head enables that the probe means can be pushed out into the free space manually or with very little force. And by locking the position of the probe means in relation to the drill head, the drive means used for driving the drill head forward can now be used for pushing the probe means into the ground from which a sample must be taken.

In an aspect of the invention, said method further comprises pushing a plug out of said drill head by means of said probe means before pushing said probe means out into said free space.

Placing a plug in the drill head is advantageous in that this will ensure that soil does not enter the drill head and block the probe opening when the drill head is being pushed through the ground. And using the probe means for removing the plug is advantageous in that the plug hereby is removed in a simple and inexpensive manner at the time when it is no longer needed.

In an aspect of the invention, said method is a method for extracting an underground sample by means of a directional drilling arrangement according to any of the previously discussed directional drilling arrangements. Figures

The invention will be described in the following with reference to the figures in which illustrates a directional drilling arrangement drilling under a foundation towards a contaminated area under a building, as seen from the side, illustrates a directional drilling arrangement during normal horizontal drilling, as seen from the side, illustrates a directional drilling arrangement being retracted to create a free space, as seen from the side, illustrates a directional drilling arrangement with probe means extending out into the free space, as seen from the side, illustrates a directional drilling arrangement with the probe means pushed into a possibly contaminated area, as seen from the side, illustrates a directional drilling arrangement wherein the probe means have been retracted, as seen from the side, and illustrates a directional drilling arrangement during the mounting of a new plug, as seen from the side. Detailed description

Fig. 1 illustrates a directional drilling arrangement 1 drilling under a foundation 14 towards a contaminated area 12 under a building, as seen from the side. Horizontal directional drilling, commonly referred to as HDD, is a process commonly used when installing utilities underground. Generally the first step in the HDD process includes boring a pilot hole. In this step a bore hole is created that extends underground - generally horizontally or parallel to the surface of the earth - starting at a launch point and ending at a termination point.

The bore hole is created by a drilling machine 17 that rotates and pushes a drill string 3 through the ground. A drill head 2 is attached to the leading end of the drill string 3. The drill string 3 is formed by connecting individual drill rods 16 together end-to-end from a supply of drill rods 16 e.g. stored on the drilling machine 17.

Typically, an operator manually controls the drill string 3 as it is pushed or pulled from the ground. In an embodiment the operator visually monitors the drill string 3 as it advances and retracts and determines when drill rods 3 need to be added (made up) or removed (broken out) from the drill string 3. By means of position detection means 18 arranged in the drill head (see figs. 2-7) the operator can constantly monitor the drill heads actual position and orientation. In an embodiment the drilling machine 17 can include a gearbox that connects to the drill string 3, a carriage on which the gearbox resides, a rack on which the gearbox moves, a vise, a drill rod storage magazine, and a rod loading mechanism. The rod loading mechanism moves the individual drill rods 16 from the storage magazine into alignment with the drill string 3 and the gearbox where the individual drill rod 16 is connected to and made a part of the drill string 3. Rod loading mechanisms typically include a rod transfer mechanism that moves the rod 16 from the storage magazine and positions it with one end in alignment with the drill string 3 and the other end in alignment with the gearbox. In this embodiment the drill rods 16 are long and hollow, and are stored with their longitudinal axes parallel to one another. To push the drill string 3 into the earth, the carriage is moved from a point on the rack that is distal from the vise to a point on the rack that is proximal to the vise.

In this embodiment the directional drilling arrangement 1 is used for taking a pore gas sample from a potentially contaminated area 12 located under a building. The building could e.g. be an old laundry, dry cleaner, service station, chemical plant or other and the only other way to test if the ground under the building is contaminated would be by breaking up the floor and test vertically down from inside the building. But for different reasons this is often not possible or desirable either for financial reasons, because it would be impossible to fit the test equipment inside the building or for other reasons.

In this embodiment the directional drilling arrangement 1 is deployed to test if the potentially contaminated area 12 contains any dangerous or hazardous materials. I.e. in this embodiment the potentially contaminated area 12 is investigated by drawing one or more pore gas samples directly from the potentially contaminated area 12.

In this embodiment the pore gas sample is sucked up to the ground surface where it is analysed by pore gas analysing means. However, in another embodiment the directional drilling arrangement 1 could also or instead include means for sampling and analyzing the condition of soil or water for the presence of hazardous waste such as radioactive waste or toxic chemical in particularly compounds of chlorine, Benzene and other. I.e. in another embodiment the directional drilling arrangement 1 could also or instead comprise means for taking a soil sample or a liquid sample and analysing it on the spot or bringing it to the surface to be analysed either locally or e.g. at a laboratory. In this embodiment the building comprises a foundation 14 which the drill string 3 has to pass under to get to the potentially contaminated area 12. Thus, in this embodiment the drill string 3 is at the front provided with a drill head 2 comprising direction means 4 in the form of a slanting drill plate 7. The slanting plate 7 entails that the head 2 - and thus the drill string 3 - is deflected by the slanting plate 7 in a given direction depending on the orientation of the plate 7. Thus, depending on how the plate 7 is orientated - when the head is pushed through the ground, the head 2 will move up, down, left, right or anything there between as long as the plate 7 is orientated a specific way. To make the head 2 move straight forward the head 2 is rotated continuously while being pushed forward. However, in another embodiment the direction means 4 could be embodied in another way e.g. by small arms that could controllably deployed in different directions, rotating wheels, shovels or chains or in numerous other ways.

Fig. 2 illustrates a directional drilling arrangement 1 during normal substantially horizontal drilling, as seen from the side.

In this embodiment the drill head 2 have arrived just in front of the potentially contaminated area 12. Rotation and forward motion of the drill head 2 have been stopped and above ground probe means 5 are now being introduced into the hollow drill string 3 and pushed towards the drill head 2. In another embodiment the probe means could be present inside the drill string 3 and/or the drill head 2 from the start of the drilling process or at least before the test site is reached.

In this embodiment the drill head 2 comprises position detection means 18 so that the given location and orientation of the drill head 2 - and thereby the drill plate - substantially at all times can be detected and monitored from above ground so that the drilling direction of the drill head 2 substantially at all times can be controlled. In this embodiment and the embodiments disclosed in figs. 3-7 the drill head 2 is drilling substantially horizontally. However, in another embodiment the drill head 2 could be drilling in substantially any other direction in the ground including vertically up or vertically down.

Fig. 3 illustrates a directional drilling arrangement 1 being retracted to create a free space 13, as seen from the side.

In some embodiment at least some of the free space in front of the drill head 2 may collapse but the collapsed material will be so lose that it will not be a problem to push the probe means 5 through it - as illustrated in fig. 4.

In this embodiment the drill head 2 is provided with a plug 9 - arranged in a probe opening 8 arranged in the direction means 4 - to prevent dirt, soil water etc. from entering the inside of the drill head 2 and the drill string 3.

Fig. 4 illustrates a directional drilling arrangement 1 with probe means 5 extending out into the free space 13, as seen from the side. In this embodiment the plug 9 has been pushed out of the of the drill head 2 by the probe means 5. Thus, in this embodiment the pushed out plug 9 is lost and a new one has to be supplied for every test. However, in another embodiment the plug 9 could be formed as a hatch or gate e.g. provided with hinges and e.g. reclosing means so that the plug 9 could be reentered into the probe opening 8 once the probe means 5 have been retracted or at least so that the plug could be reused.

Once the probe means 5 have reached its desired position in front of the drill head 2 locking means 6 is deployed to fix the position of the probe means 5 in relation to the drill head 2. In this embodiment the locking means 6 is arranged on the probe means a given distance behind the probe head 19 but in another embodiment the locking means 6 could be arranged above ground, on the drill head 2 and/or at another location. In this embodiment the locking means 7 are formed as balloon means 11 arranged to expand inside the drill head 2 when a pressurized liquid or gas is supplied either from the drill head itself or more likely from a pressure source arranged above ground so that the liquid or gas would be supplied through a duct in the probe means 5.

In this embodiment the drill head 2 is retracted approximately one meter before the probe means 5 is pushed forward and the position of the probe means 5 is locked when the front end of the probe head 19 is almost one meter in front of the drill head 2. However, in another embodiment the drill head 2 could be retracted more or less before the probe means 5 is pushed forward and the position of the probe means 5 could be locked at another distance from the drill head 2 e.g. dependent on the given equipment, the given soil conditions, the given sample to be taken, the given contamination type or other.

Fig. 5 illustrates a directional drilling arrangement 1 with the probe means 5 pushed into a possibly contaminated area 12, as seen from the side Since the locking means 6 locks the position of the probe means 5 in relation to the drill head 2 the probe means 5 is pressed forward into the potentially contaminated area 12 when the drill head is moved forward. Once in place in the area 12 the probe means 5 will start sucking to extract a pore gas sample. The sample is then transported to the surface where can be analyzed for a number of properties, such as electric conductivity, acidity (pH), redox potential (Eh), oxygen content, pressure, ion content, etc.

In another embodiment of the invention the drill head could comprise analyzing means 10 for analyzing the sample at least in relation to some aspects. Fig. 6 illustrates a directional drilling arrangement 1 wherein the probe means 5 have been retracted, as seen from the side. Once the probe means 5 have extracted the necessary sample the probe means 5 are retracted to the ground surface so that further drill rods 16 can be added to the drill string 3 e.g. if further samples needed to be extracted in the ground ahead of the drill head 2 or so that the drill string 3 can be disassembled as the drill head 2 is pulled back to the drilling machine 17.

Fig. 7 illustrates a directional drilling arrangement 1 during the mounting of a new plug 9, as seen from the side.

If the drill head needs to be moved forward after the probe means 5 have been retracted, a new plug 9 can be mounted in the probe opening 8 while the drill head 2 is in the ground. In this embodiment this is done by providing the plug with expandable means, which is pressed together as the plug 9 is mounted in the drill string 3 above ground, where after the plug is pushed forward to the probe opening 8 - e.g. by means of the probe means as illustrated in fig. 7. The probe opening 8 has a diameter that is larger than the diameter through the drill string 3 so that when the plug 9 reaches the probe opening 8 the expandable means of the plug 9 will expand to ensure that the plug 9 no longer can move backwards in the drill head 2. However, in another embodiment the plug 9 could be locked in position in the probe opening 8 in numerous other ways and it could be brought in position in numerous other ways.

The invention has been exemplified above with reference to specific examples of directional drilling arrangements 1, drill heads 2, probe means 5, locking means 6 and other. However, it should be understood that the invention is not limited to the particular examples described above but may be designed and altered in a multitude of varieties within the scope of the invention as specified in the claims. List

1. A directional drilling arrangement

2. Drill head

3. Drill string

4. Direction means

5. Probe means

6. Locking means

7. Drill plate

8. Probe opening

9. Plug

10. Analysing means

11. Balloon means

12. Possibly contaminated underground area

13. Free space

14. Foundation

15. Pore gas analysis means

16. Drill rod

17. Drilling machine

18. Position detection means

19. Probe head