WO2015009213A1

WO2015009213A1 - Method for boring holes and installing collection pipes in holes

Info

Publication number: WO2015009213A1
Application number: PCT/SE2014/000099
Authority: WO
Inventors: Krister Andersson; Mikael Karlsson
Original assignee: Grävinnans Maskintjänst
Priority date: 2013-07-19
Filing date: 2014-07-18
Publication date: 2015-01-22
Also published as: SE1300498A1

Abstract

Method for boring holes and installing collection pipe included in geothermal heating systems. The required equipment and the required material is moved to where the holes for geothermal heating are to be drilled. Initially a required number of casing pipes one after another are connected together and inserted into the ground down to the bedrock and a stretch into the bedrock, after which at least one pressure fluid driven bore hammer (sinker drill) is inserted down through the casing pipe after which the drilling of at least one hole in the bedrock occurs to the required depth. After the hole is drilled to the required depth collection pipe is inserted down in the hole. At least one seal is connected to the collection pipe which when it is inserted into the hole partitions the bored hole into at least one upper section and at least one lower section. After the seal is positioned in the hole, the upper section of the hole in the bedrock is filled (plugged) with sealing material, after which the casing pipe is removed from the hole and the hole is filled after which the collection pipe in the hole is then connected with known art to known above ground geothermal heating equipment.

Description

Method for Boring Holes and Installing Collection Pipes in Holes Field of the Invention

The present invention concerns a method for boring holes and the installation of collection pipes in the bored holes, in accordance with the claims. Background of the Invention

In recent years it has become increasingly more common to install ground source heat pump systems (geoexchange, geothermal heat pump, downhole heat, borehole heat) that utilize geothermal heat for the heating of for example buildings. In conjunction with the installation of a borehole heat pump system one or more holes are drilled in the bedrock at the point of construction of the geothermal heating system. In the bored hole, or holes, at least one collection pipe, or other type of collector, is partially inserted down. After the collection pipe is partially inserted into the hole, it is then connected to a ground heat pump included in the geothermal heating system that is commonly located above ground.

One problem with boring holes for collection pipes and the like in geothermal heating systems is that the holes are usually drilled with drilling equipment powered by compressed-air. The use of existing drilling equipment such as compressed-air drilling equipment, during boring, carries a risk that hazardous substances such as oil enters the borehole and groundwater is thus likely to be contaminated.

Another problem associated with boring holes for geothermal heating systems is caused by the fact that bedrock usually does not reach ground level but is located at a distance below ground level. This means that a section of the hole's length stretches through a looser layer of ground such as clay, sand or the like. In order to prevent ground material from falling into the hole, in the relatively loose layer between bedrock and ground level, lining of the hole with casing or the like is usually performed. One problem with the installation of casing is that it, with existing equipment and methods, takes a long time (relative to the present method) to accomplish. A further problem with the installation of casing and the like is that it consists of pipes which are welded together, resulting in significantly longer time being required for joining of the casing pipes compared with using the method according to the present patent application. A further problem with existing methods for installing geothermal heating and the like, is caused by the casing being left in the ground after the hole in the ground is drilled and the collection pipe is installed (connected) in the hole. The costs for casing pipes, especially if the depth down to the bedrock from the ground surface is great, will therefore be high or very high. There is thus a need for a method that reduces the costs associated with casing pipes.

An additional problem with leaving casing in the ground is that they run the risk of rusting apart with subsequent problems with contaminants in soil (rust, etc.).

Prior Art

Drilling holes in the ground and in bedrock is previously known in a number of different variations of equipment and methods. For example SE527590 describes a drilling device for boring holes in bedrock. The drilling device in accordance with its description differs substantially from the present method and device. For example, the design according to its description does not include a water driven hammer.

SE531106 describes a variant of a sealing member designed to separate sections within an elongated hole. The design differs from the present invention. For example, its description does not describe a method for drilling boreholes in the ground. Further, its description does not include a method for sealing the hole above the seal with concrete in accordance with the present application.

SE429375 describes a variant of a method to utilize heat energy in well water from a drilled borehole. The device and method in accordance with its description differs greatly from the design and method in accordance with the present patent application.

SE391373 describes a variant of a sealing device to close off the connection between parts of bedrock borehole at different levels. The design in accordance with its description differs greatly from the design and method in accordance with the present patent application. For example, its description does not include a similar method drilling boreholes and installing collection pipes.

SE444127 describes a variant of a pressure fluid driven sinker drill that includes a hammer drill bit. Its description does not describe a method in accordance with the present patent application. Purpose of the Invention

The main purpose of the present invention is to create an improved method and device for solving or reducing at least one of the above mentioned problems. The purpose is achieved with a method in accordance with the claims. Detailed Description of the Invention

The present invention relates to a method of boring one or more holes and in the bored hole (or holes) installing at least one collection pipe (collector), in accordance with the present application. The method may preferably be used in the installation of ground source heat pump systems (geoexchange, borehole, geothermal systems) and the like. It is conceivable that the method be used in other types of applications and methods or parts of methods.

The term collector in geothermal applications preferably refers to collection pipe or the like. In alternative embodiments of geothermal applications and in other types of applications, it is conceivable that the collector consists of another suitable for the purpose collector.

Implementation of the method utilizes to a great extent previously known and suitable for the purpose drilling equipment. For example, the drilling equipment may include a drilling rig or similar. Unique to the present equipment is that it is comprised of a percussion (hammer) device and/or vibration generating unit and at least one pressure fluid driven bore hammer (sinker drill or similar) which is preferably driven by pressurized water.

Initially, all or part of the equipment required to implement the method is moved to the location where the installation is to be performed. Initially, all or part of the required amount of material for the geothermal system is also moved to the construction site. The equipment and the materials moved to the construction site are dependent on which of the embodiments of the present method that is to be performed. After the equipment is moved to the location of its intended use, it is set up in a previously known manner and this is why it is not described in more detail in this patent application.

Because bedrock usually does not extend up to the ground surface and is located at a distance from ground surface, the hole usually extends through ground that is by nature looser in character, such as clay, sand or similar. To prevent ground material from falling into the hole, lining of the hole with casing pipe or the like is usually performed. Previous methods of installing casing pipes in the ground have the disadvantage of them taking a long time to perform, and cause clay and the like to be sprayed around the borehole. A unique feature of the present method is that pipe is inserted into the ground by rotation of the casing while the casing is affected by percussion (vibrations) from a hammer (or a vibration generating unit) included in the drilling rig. Preferably, some variant of a drill bit with through holes in the center (reminiscent of a hole cutter bit) is used during insertion of the casing pipe. In connection with the insertion of the casing pipe in the hole, a large part of the material in the borehole is pressed into the surrounding ground.

Preferably, casing pipe which may be connected together and disconnected are used in the method for inserting casing pipe into the ground. In the exemplifying method, this is accomplished by the casing pipes being threaded at their ends. The one end of the casing pipe includes external thread and the other end of the casing pipe includes an internal thread. This allows an internally threaded portion of a casing pipe and an externally threaded portion in another casing pipe to be screwed together. In alternative embodiments, the pipes may be connected together with another for the purpose suitable technique. The required number of casing pipes are connected together and inserted (driven) into the ground until the casing pipe reaches the bedrock. The pipe is also inserted down a stretch into the bedrock. The method also leaves a length, which is suitable for the purpose, of the uppermost casing pipe above the ground surface. After the casing pipe has reached down to the bedrock, and preferably also a distance down into the bedrock, a drill bit is inserted down through the casing pipe down to the bedrock. Thereafter a hole in the bedrock is bored to the desired depth with the drill bit. Unique to the present method is that the rotation of the drill is accomplished with a hydraulic drive and that the percussion function is achieved by a bore hammer, sinker drill, or similar, which for example, includes a hammer drill bit which is preferably powered by pressurized water. This means that the aforementioned problem regarding risk of contamination of the hole with hydraulic fluid, or other inappropriate substances, essentially no longer exists.

After the planned (required) drilling depth is achieved, a suitable length, relative to the borehole depth, of the collection pipe is inserted into the borehole. During insertion of the collection pipe, at least one sealing member is connected to the collection pipe. The seal is inserted with the collection pipe at a level that is suitable for the purpose. The seal is intended to partition the borehole into at least one upper section and at least one lower section. After the collection pipe is inserted into the hole and the seal has partitioned the hole in the bedrock into an upper and lower part the rest is filled with concrete, cement or other for the purpose suitable sealing material.

After the upper part of the hole in the bedrock is sealed, the casing pipe is removed from the hole. The hole by way of the relatively loose material above the bedrock is then filled by the ground around the hole. If needed ground material may be filled into the hole.

After the above sub-operations have been performed, the collection pipe is then connected with known technology to a known heat pump or the like included in the geothermal heating equipment. After the method has been performed, equipment and any surplus material are preferably removed from the site of the borehole and the installation site of the collection pipe.

In the detailed description of the present invention, design details may have been omitted that are apparent to skilled professionals in the field that relates to the device. Such obvious design details are included to the extent necessary so that a proper and full function is obtained for the present invention.

Even if some preferred embodiments have been shown in more detail, variations and modifications of the method and device may become apparent to those skilled in the art of the field that the invention relates to. All such modifications and variations are regarded as falling within the scope of the following claims. Advantages of the Invention

Several advantages are achieved with the present invention. The most important advantage is that at least one of the above disadvantages of known types of methods for boring holes, and installing collection pipes in the bored holes is alleviated. The present method also has the advantage of having low noise emissions and low fuel consumption. The method also has the advantage of the casing pipes being reused and thus the cost for them is avoided.

The method further includes relatively light pipe and hammer, which means that the amount of heavy lifting that needs to be performed is substantially reduced. The method also eliminates or substantially eliminates the risk that pressure accumulates in the cracks under buildings.

Claims

1. Method for boring holes and installing collection pipe or the like, that for example is included in geothermal heating systems characterized by that the required equipment and the required material is moved to where the holes are to be drilled, thereafter a required number of casing pipes one after another are connected together and inserted into the ground down to the bedrock and preferably a stretch into the bedrock, after which at least one pressure fluid driven bore hammer (sinker drill) is inserted down through the casing pipe after which the drilling of at least one hole in the bedrock occurs to the required depth, after the hole is drilled to the required depth in the bedrock collection pipe is inserted down in the hole and at least one seal connected to the collection pipe partitions the bored hole into at least one upper section and at least one lower section and that the upper section of the hole after the seal is positioned in the hole is filled (plugged) with sealing material, after which the casing pipe is removed from the hole and the hole is filled after which the collection pipe in the hole is then connected with known art to known above ground geothermal heating equipment.

2. Method in accordance with claim 1 characterized by that the casing pipe is inserted by rotation and is affected by percussion and/or at least one vibration generating unit included in the drilling rig.

3. Method in accordance with one of the previous claims characterized by that the drill is comprised of a water driven hammer.

4. Method in accordance with one of the previous claims characterized by that at least one seal is inserted down with the collection pipe and partitions the borehole into at least one upper section and at least one lower section.

5. Method in accordance with at least one of the previous claims characterized by that the upper section of the bore hole is completely or partially filled with cement, concrete or similar.

6. Method in accordance with at least one of the previous claims characterized by that the pressure fluid driven bore is water driven.

7. Method in accordance with at least one of the previous claims characterized by that the casing pipes are reused.

8. Method in accordance with at least one of the previous claims characterized by that the casing pipes are connected to each other via threads.

9. Method in accordance with at least one of the previous claims characterized by that sealing is accomplished by concrete or material that contains cement.