METHOD FOR LINING BOREHOLES FOR DEEP BORES AND DEVICE FOR CARRYING OUT SAID METHOD
The invention relates to a method for lining boreholes for deep bores. A lining method, which makes a rapid process sequence possible with a substantially uniform borehole diameter, is characterized, according to the invention, in that the borehole is lined directly after boring with a hybrid material consisting of a fibrous material and a hardenable medium. The invention also relates to a device for carrying out the method.
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The invention relates to a method for lining boreholes for deep bores. Furthermore, the invention relates to an apparatus for carrying out said method.
Boreholes for vertical deep bores, that is to say bores which are driven into the ground to a depth of more than 500 m, are formed in practice by the “rotary method”, in which the rock to be penetrated is comminuted with a scraping action by means of a rotating chisel and is continuously removed by a flushing fluid which is pumped downward through the drill rod.
In the case of very deep bores, use is generally made of a drilling turbine which is arranged directly above the drill bit. In this method, the drill rod adjoining the drill bit counter to the drilling direction does not rotate with the drill bit but rather serves only for advancing the bit and for supplying the flushing fluid.
Drill bits with diamond or sintered carbide edging have a durability of 70 to 100 hours in customary ground conditions. In order to exchange and refurbish the drill bit, the entire drill string then has to be pulled out of the borehole and dismantled in order subsequently to be lowered again into the borehole with the new drill bit. In the conventional deep drilling method, the drilling operation therefore proceeds discontinuously.
In order to prevent the borehole from caving in, the borehole has to be supported, which is carried out in the case of the conventional deep bores by casing. This is carried out in stages with a decreasing pipe diameter in such a manner that, for example, in the case of an oil well at a depth of 3000 m, first of all a pipe reaching to a depth of 5 m and having an outside diameter of 473 mm is introduced. After a drilling depth of 150 m, a pipe known as a casing with an outside diameter of 340 mm is pushed as far as the bottom of the bore and the intermediate space between borehole wall and casing is filled with a cement slurry. At a drilling depth of 1500 m and at the final depth of 3000 m, further casing is carried out with casings which each have a smaller outside diameter than the previous casing, and therefore the outside diameter of the final casing after the end depth is reached is only 140 mm.
Although this known deep drilling method has proven successful in practice, the discontinuous lining or casing of the borehole wall is very time-consuming. Furthermore, the borehole inside diameter which decreases in stages is not advantageous for all applications either.
Taking this as the starting point, the invention is based on the object of providing a method for lining boreholes for deep bores, which makes possible a rapid working sequence with a borehole diameter remaining substantially constant.
According to the invention, the achievement of this objective is characterized in that the borehole is lined directly after the drilling with a hybrid material consisting of a fiber material and a curable medium.
By means of the direct lining according to the invention of the borehole after drilling, with a fiber-reinforced hybrid material, it is possible for the first time to provide a lining method which is continuous—if permitted by the drilling operation—and which furthermore permits lining of the borehole having a substantially constant borehole diameter.
According to a practical embodiment of the invention, it is proposed that the curable medium is sprayed onto the fiber material. The spraying method ensures that the fiber material is uniformly and rapidly wetted with the curable medium.
In order to form said hybrid material which serves to line the borehole wall and consists of a reinforcing fiber and a curing medium, use is preferably made of carbon fibers and concrete. Depending on requirements, the borehole can be lined with one layer or with multiple layers.
As an alternative to the mentioned carbon fibers and the concrete as curing medium, it is also possible, of course, to use other fiber materials and other curing media, such as, for example, plastics, for lining the borehole.
An apparatus according to the invention for carrying out the lining method according to the invention is characterized by a borehole lining module which has spraynozzles for applying a curing medium, and a reinforcing fabric laying apparatus.
In order to secure the borehole and also in order to shield the borehole from groundwater-conducting layers, the borehole is continuously lined directly after the drilling. For this purpose, the borehole lining module has spray nozzles for applying a curing medium, such as, for example, concrete, and a reinforcing fabric laying apparatus. In order to form said hybrid material serving for lining the borehole wall and consisting of a reinforcing fiber and a curing medium, use is preferably made of carbon fibers and concrete. The fiber structure can be discharged via a cone, via which the reinforcing fibers can be applied directly onto the borehole wall in order subsequently to be able to be wetted with the curing medium. Depending on requirements, the borehole can be lined with a single layer or with multiple layers.
Of course, as an alternative to the carbon fibers mentioned and the concrete as curing medium, use may also be made of other fiber materials and other curing media, such as, for example, plastics, for lining the borehole.
The borehole lining module according to the invention is advantageously supplied via flexible pipe and/or hose lines, via which the module is connected to supply devices outside the borehole, wherein the pipe and/or hose lines serve for the supply and removal of the materials relevant at least to the borehole lining module and for the feeding in of the electric supply lines. Each individual line of said flexible pipe and/or hose lines is preferably designed here as an endless line which can be kept ready on drums.
In addition to the electric supply lines, the flexible pipe and/or hose lines, via which the borehole lining module is connected to supply devices outside the borehole, also contain data lines, for example a bus system, via which at least the borehole lining module is connected to a workplace outside the borehole.
According to the invention, via the data lines, in addition to the system parameters, such as, for example, feed speed and pumping pressure, all of the ambient parameters in the borehole, such as, for example, temperature, pressure, rock density and the like, can be determined via sensors coupled to the data lines and can be transmitted to the workplace in order to control at least the borehole lining module.
Further features and advantages of the invention emerge with reference to the associated drawings in which an exemplary embodiment of a lining apparatus according to the invention is illustrated merely by way of example without restricting the invention to said exemplary embodiment. In the drawings:
Although vertical deep bores are mentioned, it is possible, with the method described below and the drilling system 1, also to direct the drilling course from the vertical into a horizontal course if this is required. However, the main drilling direction is the deep vertical bore.
As is apparent from the arrangement, illustrated in
The individual pipe and/or hose lines 6 are connected at certain distances to spacers and thus form a feed-in package which is guided into the borehole 5. In order to be able to absorb the tensile forces which occur because of the dead weight of the pipe and/or hose lines 6 and the weight of the drilling system 1, steel cables which are appropriately mounted outside the borehole 5 are preferably entrained. Furthermore, there is the possibility of securing floats to the pipe and/or hose lines 6, said floats absorbing the tensile loading since the borehole 5 is underwater during the drilling operation.
The drilling method and the borehole lining method are described below with reference to a chisel-less drilling method, in which the drill head 2 is configured in such a manner that both high pressure water jet cutting and high frequency rock fragmentation can be carried out therewith.
However, the borehole lining method described is independent of the manner of operation of the drill head 2. It is crucial for the lining method to be able to be active directly after the drilling.
As is apparent from
In order to ensure uniform and substantially extensive processing over the entire borehole diameter of the rock to be penetrated, the entire drill head 2, but at least an end plate 10 of the drill head 2, which end plate is provided with the water outlet nozzles 8 and the sonotrodes 9, is designed so as to be rotatable about the center axis.
For the sucking up of the drilling mud arising during the drilling operation, the end plate 10 is provided with suction openings 17, via which the drilling mud can be sucked off and pumped out of the borehole 5 by the pipe and/or hose lines 6.
In order to generate the high frequency pulses for the high frequency rock fragmentation, piezo elements which are each coupled to an amplifying unit consisting of a sonotrode 9 and an amplitude transformer are arranged in the drill head 2. In order to protect the sonotrode 9 from wear, said sonotrodes are advantageously coated, for example with polycrystalline diamond.
The pumps for the high pressure water jet cutting and for sucking off the flushing medium are arranged on the drill head 2 and/or on the safety module 3. In order to increase the cutting action of the high pressure water jet, an abrasive agent, such as, for example, quartz sand, can be added to the water jet, the abrasive agent being supplied to the drill head 2 via the flexible pipe and/or hose lines 6 and being mixed with the water jet only in the water outlet nozzle 8 in order to keep the wear on the lines as low as possible. The abrasive agent can be added here continuously or else only from time to time.
By means of the combination of the high pressure water jet cutting with the high frequency rock fragmentation, and by means of the sheet-like design of the drill head 2 and the corresponding positioning of the water outlet nozzles 8 and sonotrodes 9, in the illustrated exemplary embodiment it is possible to carry out the drilling operation continuously, that is to say without interruptions for refurbishing a drill bit or for removing a cut-free drill core, as is required in the deep drilling methods known from the prior art.
In order to be able to use a continuously operating drilling method as efficiently as possible, it is advantageous if the borehole 5 can also be secured and lined substantially continuously.
In order to secure the borehole 5 and also in order to shield the borehole from groundwater-conducting layers, the borehole 5 is lined directly after drilling. For this purpose, the borehole lining module 4 according to the invention has spray nozzles 11 for applying a curing medium, such as, for example, concrete, and a reinforcing fabric laying apparatus 12.
Use is preferably made of carbon fibers and concrete in order to produce the hybrid material serving for lining the borehole wall, but other fiber materials and other curing media, such as, for example, plastics, are also usable for producing the hybrid material.
The reinforcing fabric laying apparatus 12 for discharging the fiber structure can take place, for example, via a cone, via which the reinforcing fiber can be applied directly onto the borehole wall in order subsequently to be able to be wetted with curing medium. Depending on the depth and geological conditions, the borehole 5 can be lined with one layer or with multiple layers. The curing time of the concrete can be accelerated by the addition of special additives. In deeper regions with a higher earth temperature, the curing time is reduced simply by the rise in temperature. The concrete supplied via the pipe and/or hose lines is mixed with the additives, which are likewise supplied via the pipe and/or hose lines 6, only at the borehole lining module 4, in order to avoid curing in the supply lines.
A finished borehole lining 18 is illustrated schematically in
The safety module 3 serves, in the event of a sudden rise in pressure in the borehole 5, for example by drilling into a gas bubble, firstly to prevent uncontrolled escape of the gas from the borehole 5 and secondly to prevent the entire drilling system 1 from being able to be pushed upward out of the borehole 5 by the rise in pressure. For this purpose, the safety module 3 has at least one locking element 13 for the form-fitting closing of the inside diameter of the borehole and clamping elements 14 for the force-fitting securing of the drilling system 1 in the borehole 2.
The diameter of the borehole is closed in a form-fitting manner via the locking element 13, for example with an expander ring which closes the borehole 5, in order then to be able to dissipate the positive pressure in a controlled manner via suitable pressure control valves. The clamping elements 14 with which the entire drilling system 1 can interlock in a force-fitting manner in the borehole 5 are designed, for example, as barbs which face radially upward and outward and fix the drilling system 1 in the respective position in the borehole 5 as the need arises.
The drive and also the steering and control apparatus for the drill head 2 are arranged on the drill head 2. In the embodiment illustrated, the drive for the drill head 2 is designed as a crawler drive 15 arranged on the outer side of the drill head 2.
In addition to the electric supply lines, the flexible pipe and/or hose lines 6, via which the drilling system 1 is connected to supply devices 7 outside the borehole 5, also contains data lines, for example a bus system, via which the drill head 2 and/or the safety module 3 and/or the borehole lining module 4 are connected to a workplace 16 outside the borehole 5.
Via said data lines, in addition to the system parameters, such as, for example, feed speed and pumping pressure, all of the ambient parameters in the borehole 5, such as, for example, temperature, pressure, rock density and the like, can be determined via sensors coupled to the data lines and can be transmitted to the workplace 16 in order to control the drilling system 1.
Since, in the illustrated drilling system 1, in particular, the drill head 2 has a larger outside diameter than the fully lined borehole 5, after the end of the drilling operation the entire drilling system 1 remains in the borehole 5 and, after the capping of the supply lines, can be used via the data lines which continue to exist, in order to exchange data with the workplace 16.
Should it be necessary in an alternative drilling method or when an alternative drill head is used for said drill head to be removed from the borehole 5 in the meantime or at the end of the drilling operation, said alternative drill head has to be configured, for example, in a foldable manner, such that the outside diameter thereof can be reduced such that said drill head is moveable through the finished borehole lining 18.
The control of the drilling system 1 can be arranged on only one of the components of drill head 2, safety module 3 or borehole lining module 4, or else can be arranged distributed between a plurality of the components 2, 3 and 4.
The borehole lining method which is described above and is usable for geothermal bores and for opening up natural gas or oil deposits is distinguished in that a virtually continuous lining of the borehole directly after drilling is made possible. Furthermore, the borehole lining 18 has a substantially constant cross-section over the entire length of the borehole.
Claims
1. A method for lining boreholes for deep bores, characterized in that the borehole is lined directly after drilling with a hybrid material consisting of a fiber material and a curable medium.
2. The method as claimed in claim 1, characterized in that the wall of the borehole is continuously lined.
3. The method as claimed in claim 1, characterized in that the curable medium is sprayed onto the fiber material.
4. The method as claimed in claim 1, characterized in that the hybrid material can be applied onto the borehole wall in one layer or in multiple layers.
5. An apparatus for carrying out the method as claimed in claim 1, characterized by a borehole lining module which has spray nozzles for applying a curing medium, and a reinforcing fabric laying apparatus.
6. The apparatus as claimed in claim 5, characterized in that the borehole lining module is connected to supply devices outside the borehole via flexible pipe and/or hose lines, wherein the pipe and/or hose lines serve for the supply and removal of the materials relating at least to the borehole lining module and for the feeding in of the electric supply lines.
7. The apparatus as claimed in claim 5, characterized in that at least the borehole lining module is connected to a workplace outside the borehole via data lines, for example a bus system.
8. The apparatus as claimed in claim 7, characterized in that, via the data lines, in addition to the system parameters, such as, for example, feed speed, all of the ambient parameters in the borehole, such as, for example, temperature, pressure, rock density and the like, can be determined via sensors coupled to the data lines and can be transmitted to the workplace in order to control the borehole lining module.
Type: Application
Filed: Mar 26, 2014
Publication Date: Feb 25, 2016
Applicant: SCHWINDT HYDRAULIK GMBH (Celle)
Inventor: Thomas LUDEWIGT (Buchholz)
Application Number: 14/781,383
