US20190169957A1

US20190169957A1 - Installation Of Ground Loops For Geothermal Heating And/Or Cooling Applications

Info

Publication number: US20190169957A1
Application number: US16/206,626
Authority: US
Inventors: Olivia Hatalsky; Howard E. Johnson; Amit Kale
Original assignee: Dandelion Energy Inc
Current assignee: Dandelion Energy Inc
Priority date: 2017-12-06
Filing date: 2018-11-30
Publication date: 2019-06-06
Also published as: CA3026496A1

Abstract

In order to install a ground loop for a geothermal heating and/or cooling system in ground material, a drilling machine having a drill bit connected to an end of first tubing may be used to create an borehole in the ground material. After the borehole is created, grout may be pumped into the borehole through the first tubing as the first tubing is removed from the borehole. This allows the borehole to be grouted from the bottom towards the top. Thereafter, second tubing may be inserted into the grout in order to create the ground loop. This eliminates the need for a “tremie” pipe to insert the ground loop and pump grout into the borehole, while still allowing for the borehole to be grouted from the bottom towards the top to reduce the likelihood of voids.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional Application No. 62/595,315 filed Dec. 6, 2017 for “Installation of Ground Loops for Geothermal Heating and/or Cooling Applications”, which is incorporated herein by reference.

BACKGROUND

Geothermal heating and/or cooling systems include one or more ground loops for exchanging heat with ground material. These ground loops can be arranged horizontally or vertically. Installation of vertical ground loops typically involves drilling an opening or “borehole” in the ground material to a desired depth using a mud material to encase the borehole. Thereafter, inserting a ground loop or heat exchanger and “tremie” pipe are into the borehole. Once in position, grout is deposited into the borehole from the bottom towards the top via the tremie pipe as the tremie pipe is pulled upwards and removed from the borehole. The grout, which is typically selected to enhance thermal conductivity between the ground loop and the ground material, fills the annulus between the borehole and the ground loop and also creates a seal between the ground loop and any underground aquifers, thus preventing aquifers from being contaminated from surface spills and also preventing aquifers with different water qualities from communicating vertically with one another through the borehole.
However, taking the ground loop or heat exchanger down into the borehole can be difficult, especially in the case of a hole that is several hundred feet deep, as both the ground loop (or heat exchanger) and the tremie pipe tend to float in the mud material left during the drilling process. As a result, additional equipment, such as weights and cables to pull down the ground loop towards the bottom of the borehole, is typically used.
In addition, the ground loop (or heat exchanger) may tend to twist during the insertion, causing the tubing of the loop to separate and form a helix. This can make it even more difficult for the grout to fill in the annulus between the borehole and the ground loop, and may even result “channeling” or voids (for example, air pockets). In this regard, the borehole is not properly encased by the grout and there is a risk of underground aquifers from mixing with one another by traveling through such voids in the grout. This is especially problematic when one aquifer is used as potable water and another includes contaminants such as iron, salts, or other materials which should not be consumed by humans. In addition, the voids may affect the efficiency of the thermal connection between the ground loop or heat exchanger and the Earth, reducing the overall effectiveness of the geothermal heating and/or cooling system.

BRIEF SUMMARY

One aspect of the disclosure provides a system for creating a borehole in ground material for installation of a ground loop. The system includes a drilling machine having first tubing at least partially wrapped around a reel and a support equipment apparatus. The support equipment apparatus including a first tank for holding and processing mud material, a second tank for holding a grout component, a pump configured to pump material to the first tubing, and a valve. The valve has a first configuration that allows the mud material to combine with grout component from the second tank in order to form grout such that the pump is configured to pump the grout to the first tubing and a second configuration that allows the pump to pump the mud material without grout component from the second tank.
In one example, the pump is configured to pump the mud material or the grout to a first end of the first tubing, and a second end of the first tubing, opposite of the first end of the first tubing, includes a drill for creating the borehole. In this example, the drill includes an attached mud motor configured to pump mud material and cuttings of ground material from the drill in the borehole towards a ground surface. In addition, the drill is a mud hammer configured to be powered by the pump.
In another example, the drilling machine further includes a tubing injector configured to straighten the first tubing as the first tubing is deployed from the reel into the borehole. In another example, the drilling machine further includes a drill bit attached to an end of the first tubing and a drive system configured to rotate the reel to deploy the first tubing into the borehole and to retract the first tubing from the borehole and coil the first tubing back onto the reel. In this example, the pump is configured to pump the grout into the borehole while the drilling machine retracts the first tubing from the borehole.
In another example, the drilling machine includes two or more outriggers configured to stabilize the drilling machine relative to a ground surface. In another example, the system also includes a pit pump configured to pump a combination of mud material and cuttings of the ground material from the drill from the borehole to the first tank. In addition, the first tank includes a shaker system configured to filter ground material from the combination of mud material and ground material prior to the mud material passing through the valve.
In another example, the system also includes a heat exchanger insertion apparatus including a second reel and second tubing at least partially wrapped on the second reel, the heat exchanger insertion apparatus being configured to insert the second tubing into the borehole after the grout has been pumped into the borehole. In this example, the heat exchanger insertion apparatus includes a drive system configured to force the second tubing into the borehole and through the grout in the borehole. In addition or alternatively, the heat exchanger insertion apparatus further includes a third reel and third tubing at least partially wrapped on the third reel, the drive system being configured to force the third tubing into the borehole and through the grout towards a bottom of the borehole. In addition or alternatively, the third reel is configured to retract the third tubing from the borehole after a predetermined length of the second tubing has been installed in the borehole. In addition or alternatively, the system also includes a pit pump configured to pump grout displaced by the second tubing as the second tubing is inserted into the borehole to the first tank. In addition or alternatively, the first tank includes a shaker system configured to filter the displaced grout prior to the grout reaching the valve.
Another aspect of the disclosure provides a method creating a borehole in ground material for installation of a ground loop. The method includes using a drilling machine having a drill bit attached to a first end of first tubing to create an borehole in ground material, inserting grout into the borehole through the first tubing; and after inserting the grout, installing second tubing into the grout to create a ground loop.
In one example, the method also includes inserting the grout as the first tubing is removed from the borehole such that the borehole is grouted in a direction from a bottom of the borehole towards a ground surface. In another example, using the drilling machine includes pumping a mud material through the first tubing and into the borehole while creating the borehole, and the method further comprises combining the mud material with a grout component to form the grout prior to inserting the grout. In another example, the method also includes pumping grout displaced by the installation of the second tubing to a tank configured to hold the mud material prior to pumping the mud material through the first tubing. In this example, the method also includes using a shaker system to filter the grout at the tank. In another example, the method also includes pumping a combination of mud material and cuttings of ground material from the drill to a tank configured to hold the mud material prior to pumping the mud material through the first tubing. In this example, the method also includes using a shaker system to filter the combination of mud material and cuttings of ground material at the tank.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides an example system for creating a borehole in ground material order to install a ground loop in accordance with aspects of the disclosure.

FIG. 2 provides an example system for both grouting and creating a borehole in ground material in order to install a ground loop in accordance with aspects of the disclosure.

FIGS. 3 and 4 are examples of heat exchanger insertion apparatus in accordance with aspects of the disclosure.

FIG. 5 is an example of drilling a borehole in ground material in accordance with aspects of the disclosure.

FIG. 6 is an example of grouting a borehole in ground material in accordance with aspects of the disclosure.

FIG. 7 is an example of installing a ground loop into a grouted borehole in ground material in accordance with aspects of the disclosure.

FIG. 8 is another example of installing a ground loop into a grouted borehole in ground material in accordance with aspects of the disclosure.

FIG. 9 is an example flow diagram in accordance with aspects of the disclosure.

DETAILED DESCRIPTION

Overview

Aspects of the technology relate installing a ground loop for a geothermal heating and/or cooling system, such as those used to heat and cool various structures. For instance, an example system may include a drilling machine, an equipment support apparatus, and a heat exchanger insertion apparatus. The drilling machine may include a coil of tubing. A first end of the tubing may be configured with a drill such as a downhole drilling mud motor or downhole hammer with an attached drill bit. The drilling machine may also include or be connectable with a tubing injector which can be clamped around the tubing in order to straighten the tubing and to orient the tubing into a borehole created by the hammer.
The drilling machine also includes a drive system configured to control the extension and retraction of the tubing. In this regard, the drive system may rotate a reel upon which the tubing is wrapped. The drive system may also control movement of the drilling machine, for instance by rotating crawler tracks. The drilling machine may also include two or more outriggers to stabilize the drilling machine relative to the ground surface during drilling and prevent tipping of the drilling machine.
The drilling machine may also include operator controls to control the functioning of the drive system, tracks, outriggers, and reel in order to position the drilling machine, place the outriggers, deploy or retract the tubing, and operate the drill.
The support equipment apparatus may include tanks for storing and moving grouting and drilling materials. For instance, a mud tank may store mud material that is used during both the drilling and grouting of a borehole. In addition, the support equipment apparatus may include a grouter having a grout tank. A mud pump of the support equipment may pump the mud material or grout to the tubing depending upon a condition of a valve, manifold with multiple valves, or other directional connection connected to each of the tanks. The support equipment apparatus may include one or more power sources for powering the mud pump, a shaker system attached to the mud pump, and the grouter.
A pit pump may be placed within a small pit to which the mud motor pumps mud material out of the tubing and into the borehole and/or from the borehole towards the ground surface. The pit pump may act to pump the mud and ground material from the pit to the mud tank where the mud and ground material are filtered by the shaker system.
The heat exchanger insertion apparatus may have one or more reels with one or more coils of tubing. The number of reels and/or coils may depend upon the characteristics of the ground loop to be installed in the borehole. For instance, larger-diameter multi-channel tubing may be rigid enough to be inserted using a tubing injector of the heat exchanger insertion apparatus. However, smaller-diameter u-bend tubing may need another more ridged tubing to assist in inserting the smaller diameter u-bend tubing.
Prior to initiating drilling of a borehole, the drilling machine and support equipment apparatus may be positioned in an appropriate location for creating a borehole at a desired location. The drilling machine may be moved so that the tubing injector can be positioned directly over the desired location and tubing is adjacent to the desired location. Once in position, the mud material pumped through the tubing towards the hammer and the drilling can begin using the hammer.
During the drilling, a combination of the mud material and drill cuttings of the ground material may be pumped back from the open via the pit pump to the mud tank where it is filtered by the shaker system. The filtered mud material is then pumped back into the tubing towards the hammer.
After a desired depth has been reached, the condition of the valve may be changed so as to allow grout to flow through the tubing and into the borehole. At the same time, the tubing may be removed from the borehole such that the grout is inserted into the borehole from the bottom of the borehole towards the ground surface. When the end of the tubing reaches the ground surface, the borehole will be completely grouted and the drilling machine may be maneuvered away from the borehole.
Once the drilling machine is removed, the ground loop placement machine may be moved proximate to the borehole in order to install the ground loop into the grouted borehole.
The features described herein provide simplified and lower-cost options for installing vertical ground loops for geothermal heating and/or cooling systems. For instance, by grouting a borehole prior to installing tubing for a ground loop or heat exchanger, this may increase the overall speed of drilling a borehole and installing a ground loop as there is no need to flush the drill prior to removing the drill in order to install the ground loop. In addition, because the grouter is incorporated into the support equipment apparatus including the mud tank, this may actually reduce the complement of heavy machinery needed to drill a borehole, install a ground loop, and grout. As noted above, because the tubing (which will form a ground loop or heat exchanger) is inserted into a borehole after the borehole is grouted, this eliminates the need for a tremie pipe or rather, saves time and logistics of inserting and retrieving a lengthy grout pipe from the boreholes while still allowing the borehole to be grouted from the bottom towards the top to reduce the likelihood of voids.
The use of a single, continuous piece of tubing for the drilling and grouting as opposed to segments of tubing connected together to form the entire length of the tubing, also also simplifies the process of inserting and removing the tubing as well as inserting the grout. For example, there is no need to add or remove segments of tubing during the drilling and grouting. Insertion and removal of the tubing for the drilling is accomplished by a reel with an attached drive system, thereby simplifying the process greatly.
In addition, because no tremie pipe is needed, this can actually reduce the diameter of borehole needed thereby saving drilling time, disposal of drill cuttings, and the amount of grout needed to fill the annulus. In addition, because the grout is pumped through a larger diameter drill tubing, this reduces the pressure that would have been required to pump grout through a small diameter grout tube within the tremie pipe.
In this regard, the method of inserting the tubing for a ground loop or heat exchanger into the grout may prevent mixing of any aquifers drilled through thereby protect underground water sources and satisfying regulatory and environmental concerns. This method also ensures that the heat exchanger is completely surrounded with grout and thermally connected to the Earth while also ensuring that the borehole is sealed off from any surface spills satisfying engineering, regulatory, and environmental concerns.

Example Systems

FIG. 1 provides an example system 100 for creating a borehole in ground material order to install a ground loop. As shown, the system includes a drilling machine 110 on a plane representing the ground surface 120. Below the ground surface 120 is ground material 130. In this regard, part of drill 160 is depicted bellow the ground surface 120, while the drill bit 162 is also below the ground surface.
The drilling machine may include a coil of tubing. In the example of FIG. 1, the drilling machine 110 includes a coil of tubing 140. The tubing may be a single, continuous piece of tubing or segments of tubing connected together to form the entire length of the tubing. The tubing may be made of a metal such as steel. The tubing 140 may include first and second ends, and may have a length sufficient to reach a desired borehole depth. In this regard, the tubing may be as long as 400 feet or even longer. The first end of the tubing 140 may configured with a drill 160 such as a downhole drilling mud motor or downhole hammer with an attached drill bit 162.
The drilling machine may also include or be connectable with a removable tubing injector. For instance, as shown in FIG. 1, the tubing 140 may be run through an injector or tubing injector 150 which can be clamped around the tubing in order to straighten the tubing (in other words, to remove any bends or kinks in the tubing caused by being coiled or wrapped on reel 142) and to orient the tubing into a borehole created by the drill 160. The tubing injector 150 also allows the tubing to remain in a near straight orientation as the tubing is pulled into the borehole during drilling.
Depending upon the characteristics of the ground material, the drill 160 may be an air hammer. For example, the drill may include a downhole drilling mud motor such as a positive displacement Moineau type drilling hammer actuated by mud being pumped within the tubing towards the drill bit 162. Alternatively, the drill may include a pneumatic drill or air jet nozzle powered by compressed air line connected to an air compressor at the ground surface, or a water hammer or a water jet nozzle powered by a water line connected to a pump at the ground surface. The motor may be a small diameter (for instance, less than 4″ in diameter) mud motor that pumps ground material back towards the ground surface 120 as discussed further below.
As noted above, the drill 160 is connected to the drill bit 162. The shape and materials of the drill bit may be selected with attributes suitable for creating a borehole in the particular ground material that is being drilled according the type of drill selected. For instance, different shapes may be required for material such as sand, clay and rock. However, the first drill bit may include at least a drilling portion that can create the borehole.
The drilling machine also includes a drive system. For example, drive system 170 may be a diesel engine, gas engine, electric motor, solar motor, or hydraulic powered drive system that provides sufficient rotational force on the reel to control the extension and retraction of the tubing. For instance, the drive system may rotate a reel 142 upon which the tubing 140 is coiled or wrapped. The drive system may also control movement of the drilling machine, for instance by rotating crawler tracks 180, 182. Alternatively, rather than using tracks, the drilling machine may include pairs of tires, the movement of which would also be controlled by the drive system.
The drilling machine may also include two or more outriggers. Outriggers 190, 192 to stabilize the drilling machine relative to the ground surface during drilling and prevent tipping of the drilling machine. In this regard, an additional pair of outriggers may be located opposite of outriggers 190, 192 (but are not visible in FIG. 1 due to the angle of the view of the drilling machine 110). The outriggers may also help to reduce vibration of the drilling machine caused by operation of the drive system.
The drilling machine may also include operator controls. For example, operator controls 196 may allow an operator to control the functioning of the drive system 170, tracks 180, outriggers 190, and reel 142 in order to position the drilling machine 110, place the outriggers, and deploy or retract the tubing 140.
FIG. 2 provides an example system 200 for both grouting and creating a borehole in ground material in order to install a ground loop that also includes the features of example system 100. In this regard, system 200 includes support equipment apparatus 210 as well as a pit pump 220.
The support equipment apparatus 210 may be arranged on a truck or trailer 230 which allows the support equipment apparatus to be moved as needed. In this regard, the trailer 230 may include wheels (not shown) or tracks 232 similar to those of the drilling machine 110. The support equipment may also include operator controls (not show) which can be used by an operator to control the functioning of the support equipment either locally at the support equipment or remotely via a wired or wireless network connection.
The support equipment apparatus includes tank for storing and moving grouting and drilling materials. For instance, a mud tank 240 may store mud material that is used during both the drilling and grouting of a borehole. This mud material includes a mixture of water, bentonite (for example, a bentonite gel), one or more polymers (to change the pH of the water if needed for the particular ground material), and/or other materials appropriate for drilling in ground material. The mud material is then pumped by a mud pump 260 into the borehole created by the drill bit 162. If the drill 160 is a mud hammer, the mud pump 260 and mud material may also power the drill. The mud material combined with removed ground material may be pumped back into the mud tank 240 by the mud motor attached to the drill 160. In this regard, the mud tank may include an attached shaker system which is configured to shake at least a portion of the contents of the mud tank in order to filter out unwanted ground materials from the mud.
In addition, the support equipment apparatus may include a grouter 250 having a grout tank. The grouter may also include a pump that mixes and/or forces grout within the grout tank towards the mud pump 260 via a valve 270. As an example, the grouter 250 may store grout. As an example, the grout may include a mixture of water, bentonite and graphite. The bentonite may be commercially available bentonite pellets having a polymer coating which slows the setting of the setting time of the grout to allow time for the tubing to be inserted into the grout. Once in the borehole, the grout wells and sets into a flexible but thermally conducting semi-solid that seals of the borehole. This protects any aquifers from surface spill contamination and also prevents different layers of aquifers drilled through from “mixing” or communicating with one another. This avoids aquifers with undesirable constituents, such as salts, iron, or other contaminants from mixing vertically through the borehole annulus (the area between the borehole and the ground loop or heat exchanger tubing) with potable water aquifers.
As noted above, the support equipment apparatus includes a mud pump 260. The mud pump may be a positive displacement pump, such as a triplex pump suitable for high pressure pumping applications. The valve 270 may be a simple three-way directional valve or manifold with a plurality of valves (for instance, 3) that is connected to both the mud tank and the grouter, provides the input material to the mud pump 260. In that regard, depending upon the positioning of the valve or valves of the manifold, input into the mud pump may include mud (for drilling) from the mud tank with or grout from the grout tank. Although not shown in FIG. 2, the output of the mud pump may be connected by a first hose to the second end of the tubing 140.
The support equipment apparatus may include a drive system for powering the mud pump, shaker system, and grouter. For instance, in the example of FIG. 2, the drive system includes an engine 280 and a generator 290. In this regard, mud pump is powered by an engine 280. The engine may include a diesel engine, gas engine, electric motor, solar motor, or hydraulic drive system. The shaker system and grouter may be powered by a generator 290 such as an electric generator set powered natural gas, propane, etc. or diesel or gasoline generator set. Of course, other and/or additional power sources may also be used and/or incorporated into the support equipment apparatus 210.
The pit pump 220 may be a mud pump which is located just at or below the ground surface 120. For instance, the pit pump may be a centrifugal type submersible pump that is either electric hydraulically powered, for instance by hydraulics on the drilling machine 110. In that regard, the pit pump 220 may be placed within a small pit to which the mud motor pumps mud material out of the tubing 140 and into the borehole and/or from the borehole towards the ground surface 120. In this regard, the pit pump may operate while being submerged in the mud. The pit pump may act to pump the mud and drill cuttings from the pit to the mud tank 240 where the mud and drill cuttings are filtered by the shaker system. In this regard, the pit pump and mud tank 240 are connected by a second hose (not shown). By using the pit pump, the amount of pumping power that is needed at the mud motor at the drill.
FIGS. 3 and 4 are examples of heat exchanger insertion apparatuses 300 and 400. Turning to FIG. 3, like drilling machine 110, the heat exchanger insertion apparatus 300 includes a reel 342, a tubing injector 350, a drive system 370, tracks 380 (or wheels, though not shown), outriggers 390, 392, and controls 396 configured the same or similarly to reel 142, tubing injector 150, drive system 170, tracks 380, and outriggers 190, 192. In addition, the heat exchanger insertion apparatus 300 includes a coil of tubing 340.
The tubing 340 may be tubing suitable for use as a heat exchanger. For instance, the tubing 340 may be made of a plastic material such a high density polyethylene (HDPE) suitable for use in ground material applications. The tubing may be configured as a single loop with a concentric interior, a standard u-shaped tubing (as in the example of FIG. 4), or even refrigerant tubing such as where the fluid to exchange heat with the ground material is refrigerant fluid rather than water, water and alcohol, or other mixtures with water. Because of the rigidity of this tubing, the tubing can be inserted into a borehole and moved towards the bottom of the borehole by simply unwinding the tubing from reel 342 and pushing on the tubing 340 at or near the ground surface, for instance using the tubing injector 350. In this regard, no tremie pipe is needed. Alternatively or in addition, a retrievable or non-retrievable weight may be attached to the tubing 340 to assist in the insertion or an additional tube or rod connected to a bottom end of the tubing 340 and used to pull the tubing into the borehole.
In the concentric interior example, the tubing itself may include an interior component configured as an internal divider which creates a multi-channel interior that provides an enclosed path for fluid to move down towards the bottom of the borehole and then back up towards the ground surface within the tubing. As an example, the internal divider may include concentric internal tubing where the fluid is able to flow within the internal tubing and at the bottom of the tubing 340, move between the internal tubing and the tubing back towards the surface. Of course, a reverse path may also be used where the fluid flows downwards between the internal tubing and the tubing 340, and upwards within the internal tubing. To be able to install the internal tubing into the tubing 340, the tubing 340 may be 2.5 inches or more or less in diameter, and the internal tubing may be 1-1.5 inches or more or less in diameter. The multi-channel interior may be inserted into the tubing after the tubing is inserted into the grout as described below.
Turning to FIG. 4, like drilling machine 110 and heat exchanger insertion apparatus 300, the heat exchanger insertion apparatus 400 includes a reel 442, a tubing injector 450, a drive system 470, tracks 480 (or wheels, though not shown), outriggers 490, 492, and controls 496 configured the same or similarly to reel 142, tubing injector 150, drive system 170, tracks 380, and outriggers 190, 192. In addition, the heat exchanger insertion apparatus 300 includes a first coil of tubing 440 as well as a second coil of tubing 444 arranged on a second reel 446 attached to the heat exchanger insertion apparatus 400.
As with tubing 340, the tubing 440 may be made of a plastic material such a high density polyethylene (HDPE) suitable for use in ground material application. The tubing 440 is bent to form a “U” shape or u-bend 448. In this regard, as the tubing 340 is unwound from the reel 342, the tubing 340 is actually a “pair” of tubing connected at the u-bend 448. Because of the use of the bent tubing, tubing 440 may have a smaller diameter than tubing 340, such as 1-1.5 inches or more or less.
Although the tubing is generally ridged, due to the decreased diameter as compared to tubing 340, unwinding the tubing from reel 342 and pushing on the tubing 340 at or near the ground surface, for instance using the tubing injector 350, may not be sufficient to insert the tubing into the grouted borehole. Tubing 440 may be additional metal tubing that can be deployed from reel 446 using drive system 470. Tubing 440 may be a more ridged material than the tubing 340, such as steel, such that the drive system 470 may be used to push on the tubing 440 at the u-bend 448 and force the tubing 440 down into the grouted borehole. Again, however, no tremie pipe is needed.

Example Methods

In addition to the operations described above and illustrated in the figures, various operations will now be described. It should be understood that the following operations do not have to be performed in the precise order described below. Rather, various steps can be handled in a different order or simultaneously, and steps may also be added or omitted.
Prior to initiating drilling of a borehole, the drilling machine 110 and support equipment apparatus 210 may be positioned in an appropriate location for creating a borehole at a desired location. For instance, the desired location may be selected based upon the terrain of the ground surface, location of a heat pump (to which the ground loop will be connected), number of boreholes to be drilled, etc. As an example, two or more boreholes may be drilled at least 10 feet (or more or less) from one another in order to place two ground loops for a single geothermal heating and/or cooling system.
The drilling machine 110 may be moved so that the tubing injector 150 can be positioned directly over the desired location and tubing 140 is adjacent to the desired location. This may involve controlling the tracks 180 and/or extending the outriggers 190, 192 using the controls 196. Because the mud pump 260 and tubing 140 are connected by the first hose and the pit pump 220 and mud tank 240 are connected by the second hose, the location of the support equipment apparatus 210 is limited by the lengths of the first and second hoses and the characteristics of the terrain ground surface only. Thus, if the drilling is to occur at a residential or business location, the trailer 230 may be located at some distance away from the drilling machine 110.
Once in position, the mud material can be mixed (if needed) and the drilling can begin. For instance, FIG. 5 depicts system 200 in a drilling mode. In the drilling mode, as indicated by the path of arrow 510, mud pump 260 pumps mud material from mud tank 240 via valve 270 through the first hose and into the second end of the tubing 140 at the reel 142. The mud material then flows as indicated by arrow 512 through the tubing 140 (around the reel 142) and towards the drill 160.
If the drill is a mud hammer, the drill is actuated by the mud material being pumped through the tubing to the drill 160. Other drills may be actuated by water, compressed air, etc. The drill bit 162 then creates the borehole 500 in the ground material 130. As the drill bit creates the borehole, the drill pulls the tubing into the borehole as indicated by arrow 514. At the same time, the drive system 170 rotates reel 142 to deploy the tubing 140. This allows the tubing 140 to unwind and move through the tubing injector 150. The tubing 140 then moves downward into the borehole. Thus, as the drill bit 162 penetrates the ground material further, the tubing 140 uncoils and is fed down the borehole 500.
The mud material eventually reaches the second end of the tubing and is released into the borehole. The mud motor attached to the drill then pumps the mud material along with some ground material back up through the borehole and on the outside of the tubing 140. The ground material that is pumped upwards includes drill cuttings or ground material that was displaced by the drill bit 162 to create the borehole. Eventually, the mud material and drill cuttings reach the ground surface 120 and enter the pit of the pit pump 220 as indicated by arrows 516 and 518.
The pit pump 220 then pumps the mud material and drill cuttings through the second hose to the mud tank 240 as indicated by arrow 520. At the mud tank 240, the shaker system filters the ground material from the mud material, and the filtered mud material is eventually pumped back into mud pump 260 via valve 270 as indicated by arrow 522. In this way, the mud material moves in a continuous loop through various components of the system 200 following arrows 510-520.
Once the desired depth of the borehole is reached, which may be several hundred feet or more, the grouting may begin. At this point (or some time beforehand) the grouter 250 may mix a pre-determined amount of grout sufficient to fille the borehole which can be readily determined from the diameter of the bore hole and the depth of the borehole. Thereafter, the position of the valve 270 may be changed so as to allow the grout from the grouter 250 to enter the mud pump 260 as indicated by arrow 610 of FIG. 6. The mud pump 260 then pumps the grout through the first hose and to the second end of the tubing 140 as indicated by arrow 612. The grout then moves through the tubing (around reel 142 and into the borehole) until the grout reaches the second end of the tubing at the bottom of the borehole as indicated by arrow 614. Because the grout is denser than the mud, as the grout moves through the first hose and tubing, the grout displaces the mud.
Once a sufficient amount of grout has been pumped into the hose and tubing to reach the second end of the tubing, the controls 196 may be used again to turn the reel 142. This process may take about a minute or more or less depending upon the power of mud pump 260 and the lengths of the tubing 140 and first and second hoses. At this point however, the reel 142 may be rotated by drive system 170 in order to retract the tubing 140 from the borehole and wrap the tubing back around the reel as indicated by arrow 616. At the same time, the second end of the tubing may deposit the grout in the borehole. In this regard, the borehole is grouted from the bottom towards the ground surface 120. The deposited grout then displaces the mud material up towards the ground surface as indicated by arrows 618 and 620 until the mud material reaches the pit pump 220. Again, the pit pump pumps the mud material through the second hose to the mud tank 240 as indicated by arrow 622.
When the second end of the tubing 140 reaches the ground surface 120, the borehole will be completely grouted and the mud material will be removed from the borehole. At this point, the operator may use the controls 196 to move the tracks 180 in order to drive the drilling machine 110 into position for drilling a next borehole as shown in FIG. 7. In this regard, the drilling machine may be set up with another pit pump 720, similar to pit pump 220, in another pit at or below the ground surface 120, and drilling of the next borehole may proceed as described above.
Once the drilling machine is removed, a ground loop placement machine may be moved proximate to the borehole in order to install the ground loop into the grouted borehole. For example, as shown in FIG. 7, an operator may use controls 396 to move tracks 380 in order to position heat exchanger insertion apparatus 300 proximate to borehole 500. The outriggers 390, 392 may then be extended in order to stabilize the heat exchanger insertion apparatus 300 for insertion of the tubing 340.
Tubing 340 may then be inserted into the borehole 500 and through the grout. In this regard, an operator may use controls 396 to rotate reel 342 and deploy tubing 340 through the tubing injector 350. As noted above, the and tubing injector 350 may provide sufficient force on the tubing 340 to insert the tubing into the grout and force the tubing 340 to the bottom of the borehole 500. Alternatively or in addition, a retrievable or non-retrievable weight may be attached to the tubing 340 to allow for the insertion or an additional tube or rod connected to a bottom end of the tubing 340 and used to pull the tubing into the borehole. The insertion may continue until a desired length of the tubing 340 has been inserted into the borehole 500. For instance, the length of tubing may be a predetermined length of tubing, such as 200 feet or more or less. At this point, the tubing 340 may be cut above the borehole, and the inner tubing may be inserted into the tubing 340 to form the ground loop. This ground loop may then be connected as needed to the rest of the geothermal heating and/or cooling system.
As the tubing 340 is inserted into the borehole, this will displace the grout in the borehole. In order to avoid waste, the grout that is displaced will move upwards in the borehole 500 and towards the pit of pit pump 220 as indicated by arrow 730. The pit pump may then pump the displaced grout through a third hose (not shown) to the mud tank 240 as indicated by arrow 732. There, the grout will mix with mud material and drill cuttings pumped by pit pump 720, indicated by arrow 734, as drilling machine 110 drills a new borehole 500′. The mud material, grout, and drill cuttings are then filtered by the shaker system. As in the example of FIG. 5, the filtered mud material then moves through valve 270, as indicated by arrow 736 in FIG. 7 (arrow 522 in FIG. 5), is pumped by mud pump 260 back to the second end of tubing 140, as indicated by arrow 738 (arrow 510 in FIG. 5), moves through the tubing 140 around reel 142, down into the new borehole 500′, and is combined with the drill cuttings. This combination is then pumped by the mud motor attached to the drill 160 back towards the surface as indicated by arrow 740 to the pit of pit pump 640, is pumped by the pit pump 720 back to the mud tank 240, and so on.
Turning to the example of FIG. 8, heat exchanger insertion apparatus 400 may also be used to install a ground loop into the grouted borehole. In this example, an operator may use controls 496 to move tracks 480 in order to position heat exchanger insertion apparatus 400 proximate to borehole 500. The outriggers 390, 392 may then be extended in order to stabilize the heat exchanger insertion apparatus 300 for insertion of the tubing 340.
Tubing 440 may then be inserted into the borehole 500 and through the grout. In this regard, an operator may use controls 496 to rotate reel 442 and deploy tubing 440 through the tubing injector 450. As noted above, the tubing injector 450 may not provide sufficient force on the tubing 440 to insert the tubing 440 into the grout and force the tubing 440 to the bottom of the borehole 500. As such, tubing 444 may be placed at the u-bend 448. While tubing 440 is unwound from reel 442, tubing 444 may also be unwound from reel 446. Thus, tubing 444 can be used to push on the u-bend into the grout and borehole 500 and down towards the bottom of the borehole 500. Alternatively or in addition, a retrievable or non-retrievable weight may be attached to the tubing 444 (for instance, at the u-bend 448) or an additional tube or rod may be connected to the bottom end of the heat exchanger and used to pull the tubing 444 into the borehole.
The insertion may continue until a desired length of the tubing 440 has been inserted into the borehole 500. At this point, the drive system 470 may be used to wind tubing 444 back onto the reel 446 and remove the tubing 444 from the grouted borehole. The tubing 440 may then be cut above the borehole to form the ground loop. This ground loop may then be connected as needed to the rest of the geothermal heating and/or cooling system.
Again, as the tubing 440 is inserted into the borehole, this will displace the grout in the borehole. In order to avoid waste, the grout that is displaced will move upwards in the borehole 500 and towards the pit of pit pump 220 as indicated by arrow 830. The pit pump may then pump the displaced grout through a third hose (not shown) to the mud tank 270 as indicated by arrow 832. There, the grout will mix with mud material and drill cuttings pumped by pit pump 820, indicated by arrow 834, as drilling machine 110 is used to drill a new borehole 500′.
As in the example of FIG. 5, the filtered mud material then moves through valve 270, as indicated by arrow 836 in FIG. 8 (arrow 522 in FIG. 5), is pumped by mud pump 260 back to the second end of tubing 140, as indicated by arrow 838 (arrow 510 in FIG. 5), moves through the tubing 140 around reel 142, down into the new borehole 500′, and is combined with drill cuttings of ground material. This combination is then pumped by the mud motor attached to the drill 160 back towards the surface as indicated by arrow 840 to the pit of pit pump 640, is pumped by the pit pump 820 back to the mud tank 240, and so on.
FIG. 9 is an example flow diagram of only some of the features described herein which may be used to create an borehole in ground material and install tubing to form a ground loop for a geothermal heating and/or cooling system. For example, at block 910, a drilling machine having a drill attached to a first end of first tubing is used to create an borehole in ground material. For instance, this may include pumping a mud material through the tubing and into the borehole while creating the borehole. At block 920, the mud material is combined with a grout component to form the grout prior to inserting the grout. At block 930 a combination of mud material and drill cuttings is pumped to a tank configured to hold the mud material prior to pumping the mud material through the tubing. At block 940 the grout is inserted as the first tubing is removed from the borehole such that the borehole is grouted in a direction from a bottom of the borehole towards a ground surface. After the grout is inserted, second tubing is installed into the grout to create a ground loop at block 950. In addition, grout displaced by the installation of the tubing is pumped to the tank at block 960. Of course, all or some of the above may occur at the same or different times.
The heat exchanger insertion apparatuses 300 and 400 are depicted as stand-alone units. However, one or both of these machines may be incorporated into the drilling machine 110. In this regard, drilling machine 110 could also include one or more reels for tubing 340 and/or tubing 440 and 444. This would allow an operator to use drive system 170 to install the tubing 340 and or 440 into a grouted borehole.
Alternatively, rather than removing the tubing 140 while grouting the borehole 500, the tubing 140 may remain in place until the grout displaces the mud and any drill cuttings to the top of the borehole. At this point, the grout will be visible at the surface (the grout and the mud and/or drill cuttings are readily distinguishable by visible inspection as these materials are typically different in color). Thereafter, the tubing 140 may be removed and the grout level will drop due to the displacement by the removal of the tubing. In this manner, when tubing for the ground loop or heat exchanger is inserted, the grout level will rise to at or close to the ground surface (or in other words, the top of the borehole). This reduces the likelihood of any excess grout being wasted.
In another alternative, rather than using an incorporated drive system, such as drive systems 170, 370, or 470, the features of the drilling machine 110, heat exchanger insertion apparatus 300, and/or heat exchanger insertion apparatus 400 may be powered by any number of different power configurations. For instance, the drive systems may include electric motors powered by an on-board generator set (for instance diesel, gasoline, natural gas, or propane powered) or using an electrical outlet. In another example, one or all of drilling machine 110, heat exchanger insertion apparatus 300, and/or heat exchanger insertion apparatus 400 may be powered by a remote hydraulic pump with a hydraulic supply and return lines extending from a distance away from these features. In this regard, drive systems 170, 370, or 470 may actually include electronic or hydraulic umbilical connections running to the drilling machine 110, heat exchanger insertion apparatus 300, and/or heat exchanger insertion apparatus 400.
Although the technology described herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present disclosure. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present disclosure as defined by the appended claims.

Claims

1. A system for creating a borehole in ground material for installation of a ground loop, the system comprising:

a drilling machine having first tubing at least partially wrapped around a reel; and

a support equipment apparatus including a first tank for holding and processing mud material, a second tank for holding a grout component, a pump configured to pump material to the first tubing, and a valve having a first configuration that allows the mud material to combine with grout component from the second tank in order to form grout such that the pump is configured to pump the grout to the first tubing, the valve further having a second configuration that allows the pump to pump the mud material without grout component from the second tank.

2. The system of claim 1, wherein the pump is configured to pump the mud material or the grout to a first end of the first tubing, and a second end of the first tubing, opposite of the first end of the first tubing, includes a drill for creating the borehole.

3. The system of claim 2, wherein the drill includes an attached mud motor configured to pump mud material and cuttings of ground material from the drill in the borehole towards a ground surface.

4. The system of claim 3, wherein the drill is a mud hammer configured to be powered by the pump.

5. The system of claim 1, wherein the drilling machine further includes a tubing injector configured to straighten the first tubing as the first tubing is deployed from the reel into the borehole.

6. The system of claim 1, wherein the drilling machine further includes a drill bit attached to an end of the first tubing and a drive system configured to rotate the reel to deploy the first tubing into the borehole and to retract the first tubing from the borehole and coil the first tubing back onto the reel.

7. The system of claim 6, wherein the pump is configured to pump the grout into the borehole while the drilling machine retracts the first tubing from the borehole.

8. The system of claim 1, wherein the drilling machine includes two or more outriggers configured to stabilize the drilling machine relative to a ground surface.

9. The system of claim 1, further comprising a pit pump configured to pump a combination of mud material and cuttings of the ground material from the drill from the borehole to the first tank.

10. The system of claim 9, wherein the first tank includes a shaker system configured to filter ground material from the combination of mud material and ground material prior to the mud material passing through the valve.

11. The system of claim 1, further comprising a heat exchanger insertion apparatus including a second reel and second tubing at least partially wrapped on the second reel, the heat exchanger insertion apparatus being configured to insert the second tubing into the borehole after the grout has been pumped into the borehole.

12. The system of claim 11, wherein the heat exchanger insertion apparatus includes a drive system configured to force the second tubing into the borehole and through the grout in the borehole.

13. The system of claim 11, wherein the heat exchanger insertion apparatus further includes a third reel and third tubing at least partially wrapped on the third reel, the drive system being configured to force the third tubing into the borehole and through the grout towards a bottom of the borehole.

14. The system of claim 13, wherein the third reel is configured to retract the third tubing from the borehole after a predetermined length of the second tubing has been installed in the borehole.

15. The system of claim 13, further comprising a pit pump configured to pump grout displaced by the second tubing as the second tubing is inserted into the borehole to the first tank.

16. The system of claim 13, wherein the first tank includes a shaker system configured to filter the displaced grout prior to the grout reaching the valve.

17. A method of creating a borehole in ground material for installation of a ground loop, the method comprising:

using a drilling machine having a drill bit attached to a first end of first tubing to create an borehole in ground material;

inserting grout into the borehole through the first tubing; and

after inserting the grout, installing second tubing into the grout to create a ground loop.

18. The method of claim 17, further comprising inserting the grout as the first tubing is removed from the borehole such that the borehole is grouted in a direction from a bottom of the borehole towards a ground surface.

19. The method of claim 17, wherein using the drilling machine includes pumping a mud material through the first tubing and into the borehole while creating the borehole, and the method further comprises combining the mud material with a grout component to form the grout prior to inserting the grout.

20. The method of claim 19, further comprising pumping grout displaced by the installation of the second tubing to a tank configured to hold the mud material prior to pumping the mud material through the first tubing.

21. The method of claim 20, further comprising using a shaker system to filter the grout at the tank.

22. The method of claim 19, further comprising pumping a combination of mud material and cuttings of ground material from the drill to a tank configured to hold the mud material prior to pumping the mud material through the first tubing.

23. The method of claim 22, further comprising using a shaker system to filter the combination of mud material and cuttings of ground material at the tank.