System and method of treating wells

Abstract

A method of treating a sealed water well is provided. The method comprises injecting air into a pipe arrangement positioned in a sealed water well to increase pressure in the sealed water well and lower a liquid level in the sealed water well thereby forcing liquid into a volume surrounding the water well. The pipe arrangement comprises a telescoping pipe adapted to continuously contact a terminal end of the sealed water well. The method further comprises withdrawing liquid from the sealed water well to at least partially evacuate liquid from the volume surrounding the water well out of the water well.

Description

[0001] System and method of treating wells

[0002] Technical Field

[0003] The subject disclosure relates generally to wells. In particular, the subject disclosure relates to a system and method for treating wells, e.g., water wells.

[0004] Background

[0005] A water well is used to access groundwater in underground aquifers which include underground layers of water-bearing, permeable rock, rock fractures or unconsolidated materials, such as sand or gravel. Water from wells is a necessity in many locations. However, many existing water wells are quite old. Further, high construction costs and potential negative environmental impacts make new water wells difficult to construct. As such there is a need to maintain existing operational wells, and return previously- dormant water wells to operational status. Additionally, there is a need to maximise output of these water wells.

[0006] Further, even new water wells may be negatively impacted by features of underground aquifers. For example, sediment in the environment surrounding a water well may negatively impact water well performance.

[0007] A number of methods and systems of treating, e.g., cleaning and regenerating, water wells are known. For example, the use of acids to clean a well may be dangerous for workers cleaning the well. Further, known methods and systems can be timeconsuming, costly, require significant equipment, and / or require significant human intervention. Alternatives and / or improvements are therefore desired.

[0008] This background serves only to set a scene to allow a person skilled in the art to better appreciate the following description. Therefore, none of the above discussion should necessarily be taken as an acknowledgement that this discussion is part of the state of the art or is common general knowledge. One or more aspects / embodiments of the invention may or may not address one or more of the background issues.

[0009] Summary

[0010] According to an aspect of the disclosure there is provided a method of treating a water well. The method may be more efficient than conventional methods. For example, the method may require less human interaction, may take less time to treat the water well, may require less equipment, may require less water, and may provide higher levels of well performance, e.g., well water output or throughput.

[0011] In the context of the subject disclosure, treating a water well may comprise one or more of measuring well productivity before or after subsequent steps, including measuring parameters associated with the well; cleaning the well, for example by airlifting; and regenerating the well, including surging, hydraulically (hydrostatically) shocking the water well, and air lifting.

[0012] The water well may be a sealed water well. The water well may be sealed such that injected fluid may increase the pressure and / or liquid levels within the sealed water well. The water well may be sealed using various means such as a packer at an opening of the water well.

[0013] As noted above, the method of treating a sealed water well comprises: injecting air into a pipe arrangement positioned in a sealed water well to increase pressure in the sealed water well and lower a liquid level in the sealed water well thereby forcing liquid into a volume surrounding the water well, the pipe arrangement comprising a telescoping pipe adapted to continuously contact a terminal end of the sealed water well; and withdrawing liquid from the sealed water well to at least partially evacuate liquid from the volume surrounding the water well out of the water well.

[0014] Liquid may be withdrawn from the sealed water well concurrently with the injecting. That is to say, while liquid is being withdrawn, air may continue to be injected into the well. The withdrawing may be periodic. In other words, the injecting may be continuous with periodic periods of time during with liquid is withdrawn.

[0015] The injecting and withdrawing may be referred to hydro shocking (or hydraulic shocking) and air lifting. The injecting and withdrawing may form part of a regenerating step of treating a sealed water well. Generally, regenerating may remove dirt, improve water quality, and / or improve water flow of water in the gravel pack surrounding the well. The injecting may force water into the volume surrounding the water well. This area may include a gravel pack surrounding the water well. The gravel pack may have water and dirt therein such that water which flows through the gravel pack into the well may be dirty. Injecting air into the well to force water into this area may be forced into contact with this dirt. Specifically, water may be forced into contact with particles within this volume, e.g., the gravel pack. The particles may dissolve within the water. By then withdrawing the water which is under high pressure due to the injected air, water rushes out of the water well at high speed. This may ensure that the particles which have become entrained in the water are not deposited in the area surrounding the water well, e.g., the gravel pack, but rather the particles are withdrawn along with the water. Thus, particles are removed from the volume thereby regenerating the water well.

[0016] The terminal end of the water well may be at one end of the water well while the open, opposite, end is sealed. The water well may be a generally vertical well in that the sealed end of the water well is at a higher vertical position than the terminal end of the water well. As the pipe arrangement is adapted to continuously contact the terminal end of the sealed water there is no need to reposition the pipe arrangement as the water well is treated. For example, as debris is removed from the area surrounding the terminal end of the water well, the pipe arrangement may extend further down the water well to treat a lower area / volume of the water well. In this way, the entire water well may be treated without the need for human interaction to reposition the pipe arrangement.

[0017] Generally fluid may comprise liquid and / or gas. A liquid may comprise water. A gas may comprise air.

[0018] The pipe arrangement may be positioned within the sealed water well such that liquid, e.g., water, within the water well surrounds the pipe arrangement.

[0019] The injecting may push liquid from the pipe arrangement of the water well. In other words, injecting may comprise forcing liquid from the pipe arrangement to raise or lower a liquid level of the water well depending on where air is injected. For example, liquid may be pushed out of a terminal end of the pipe arrangement into the area surrounding the pipe arrangement. This may raise the liquid level of the water well surrounding the pipe arrangement. A valve (e.g. exhaust valve) which allows for withdrawal of liquid may be open at the same time. In this way, the liquid level of the water well may be increased by injecting air into the pipe arrangement. As a further example, continuing to inject air may fill the area surrounding the pipe arrangement with air thereby lowering the liquid level surrounding the pipe arrangement, i.e., a liquid level in the sealed water well. A valve (e.g. the exhaust valve) which allows for withdrawal of liquid may be closed at the same time air is injected. Liquid may then be forced into the area surrounding the pipe arrangement.

[0020] The volume surrounding the pipe arrangement may be defined by the well, specifically well casing. In other words, the pipe arrangement may be positioned within well casing defining the well. An annulus may be defined as the volume between the pipe arrangement and the well casing. The well casing may be surrounded by a gravel pack. The well casing may be perforated. The well casing may be only partially perforated. That is to say, only certain areas of the well casing may be perforated. The perforated well casing may filter water from the gravel pack. As water is flowing through the gravel pack (or other features surrounding the casing) and then through the perforated well casing, which acts as a filter, the gravel pack surrounding the well casing may defined as a pre-filter zone.

[0021] Injecting may push water into the pre-filter zone. Injecting may facilitate treatment, i.e., cleaning including removal of particles such as dirt, from the pre-filter zone.

[0022] Generally liquid may be withdrawn via a valve arrangement. The valve arrangement may be controlled by a controller. The controller may also control the injecting step.

[0023] The method may further comprise: stopping the withdrawing. The stopping may occur while the injecting is still happening. That is to say, air may be injected into the pipe arrangement and at the same time water may be withdrawn from the water well. Stopping may comprise stopping the withdrawing of water from the sealed water well, but not stopping injecting air into the pipe arrangement.

[0024] As mentioned, the injecting and withdrawing may be referred to hydro shocking and air lifting. The injecting and withdrawing may form part of regenerating the water well. Regenerating may further comprise surging. That is to say, the method may further comprise surging. Surging may be performed prior to the described injecting and withdrawing. Surging may be referred to micro-cracking as surging may cause liquid to create micro-cracks in incrustation surrounding the water well and / or pipe arrangement, e.g., incrustation in the gravel pack surrounding the water well.

[0025] Generally surging may comprise: injecting air to lower a liquid level in the well from a first static or resting level to a second level which is lower than the first level; and injecting air to raise the liquid level from the second level (lower than the first static or resting level) to a third level which is higher than the first level. While the injecting of air of raise the liquid level has been described as such, it could be considered than air is injected to instead form a split water level, or to form a water column separated from the second lower level by a portion of air. As such, surging may alternatively comprise injecting air to form a water column split from the second lower level. The water column may be above the second level. The water column may be separated from the second level by air. The water column may be within the pipe arrangement. The upper level of the water column may be higher than the first static or resting level of liquid in the water well.

[0026] Surging may comprise injecting air into the pipe arrangement to lower the water level. Injecting air into the pipe arrangement may lower the liquid level in the well from the first level to the second lower level. Injecting air to lower the liquid level may comprise injecting air into the pipe arrangement.

[0027] Surging may comprise injecting air into the bottom of the water well, or into the bottom of the pipe arrangement. Surging may comprise injecting air into a volume surrounding the pipe arrangement. Surging may comprise injecting air into a water well column outside of the pipe arrangement. Injecting may comprise injecting air via a controllable valve and conduit, the conduit positioned proximate the volume surrounding the pipe arrangement. Injecting air into a volume surrounding the pipe arrangement may increase the pressure within the well. Injecting may increase the pressure above the water level. The water well may be sealed via a sealing arrangement to facilitate the increase in pressure. Injecting air into the volume surrounding the pipe arrangement may raise the liquid level from the second level to the third level which is above or higher than the first static or resting level.

[0028] By injecting air to lower the liquid level, and then raise the liquid level, liquid is actively forced to the very top of the water well, e.g., proximate a sealing arrangement such as a packer. In particular, a column of liquid is formed with air between the column of liquid at the third level and the remaining liquid in the well. The injected air may be lifting the liquid faster than liquid is coming in from the pre-filter zone through the well casing. This may form an air gap between the lifted water and the water in the well.

[0029] Surging may further comprise: stopping injecting the air to raise the liquid level; and optionally, injecting air to lower the liquid level.

[0030] Surging may further comprise: releasing or withdrawing air from the water well. The releasing / withdrawing may occur concurrently with the stopping and optional injecting. Thus, air may be injected at the top of well, i.e. , into the pipe arrangement. The column of water which has formed may fall down the pipe arrangement not only due to gravity, but also due to the injected air. Thus, the column of air may impact the pre-filter zone (e.g., gravel pack) with tremendous force as a result of the injected air forcing the water down into contact with the pre-filter zone. This may form micro-cracks in the pre-filter zone. This may improve the removal of particles from the pre-filter zone during the subsequent regenerating, i.e., injecting and withdrawing (shocking and air-lifting).

[0031] The releasing may comprise releasing air from the sealed water well to allow the water column to fall down and contact a volume surrounding the water well. The releasing may comprise releasing air from the sealed water well to allow the water column to fall down and form micro-cracks in incrustations in a volume surrounding the water well.

[0032] Further, reagent may be injected into the water well prior to the described steps of surging. Thus, when the water column impacts the pre-filter zone, it may include reagent which goes into pores of incrustation in the pre-filter zone to increase the micro-cracking. Further, the force at which the column of water impacts the pre-filter zone may mean liquid including reagent penetrates further into the pre-filter zone (i.e., a larger radius away from the well casing or pipe arrangement) thereby increasing the effectiveness of the surging. As a result the effectiveness may be improved and the time needed to regenerate the water well may be reduced. The reagent may comprise citric acid.

[0033] Surging may occur prior to the described shocking and air-lifting.

[0034] The method may further comprise: cleaning the sealed water well. Cleaning the water well may comprise a series of steps discussed in more detail below. Cleaning may occur prior to the injecting and withdrawing (i.e., shocking and air lifting) described above.

[0035] Cleaning may comprise: injecting air into the pipe arrangement to entrain sediment proximate the terminal end in liquid in the pipe arrangement; and withdrawing liquid and the entrained sediment from the pipe arrangement.

[0036] The method may further comprise: monitoring or detecting a parameter of the withdrawn liquid, or the withdrawn liquid and entrained sediment.

[0037] The parameter may comprise turbidity. The turbidity may be detected by a detected turbidity sensor proximate the valve arrangement. The turbidity sensor may be within a tank into which water is withdrawn. As such, withdrawing may comprise withdrawing liquid from the sealed water well into a tank.

[0038] The method may further comprise: stopping the injecting and the withdrawing when a threshold value of the parameter is detected. The parameter may comprise a turbidity of the withdrawn liquid. When the withdrawn water reaches a threshold turbidity, this may indicate the water well is sufficiently clean.

[0039] Stopping the withdrawing may comprise controlling a valve arrangement to stop further withdrawing of liquid from the water well. Stopping the injecting may comprise stopping an air compressor from injecting further air into the pipe arrangement. The stopping may be controlled by a controller.

[0040] The step of injecting air into the pipe arrangement and withdrawing water from the sealed water well to clean the water well may be referred to air lifting. Air lifting may clean the dirty water in the water well. The dirty water may be withdrawn into a tank.

[0041] As the turbidity is monitored and the steps of injecting and withdrawing are stopped when a threshold turbidity is reached, the method is optimised to reduce excess injecting and withdrawing. Thus, the method may take less time and require less energy than conventional methods.

[0042] The method may further comprise: injecting a reagent into the sealed water well prior to the withdrawing. The reagent may be a chemical used for cleaning the water well. The reagent may mix with the injected air which may improve the dissolving of the reagent. This may improve the effectiveness of the reagent. The reagent may comprise citric acid.

[0043] As the method may take less time than conventional methods, the amount of reagent injected may be minimised thereby reducing the potential negative effects to the environment.

[0044] The method may further comprise: measuring well productivity. Measuring may comprise measuring parameters associated with the well. Measured parameters may be used in subsequent steps for treating the well. Measuring may occur prior to the described cleaning, and prior to the describing shocking and air lifting, i.e., injecting air and withdrawing liquid. Measuring may also occur after the cleaning, and after the shocking and air lifting. In particular, measuring may occur at the start of the method of treating a well. Subsequently, the cleaning may occur. Subsequent to the cleaning the injecting of air and withdrawing of liquid (shocking and air lifting) may occur. Then the measuring may be repeated. In this way, measuring may determine the effectiveness of the cleaning and regenerating (injecting and withdrawing). Some measuring may also occur during the regenerating. For example, measuring may occur during the injecting. For example, measuring may comprise measuring the time between the commencement of the injecting and the time at which the pressure in the well reaches a particular threshold. Further, measuring may comprise measuring the duration of time water is withdrawn from the well. In this way, the treating of the well may be monitored during treatment rather than at the end of a treatment cycle. This may reduce the time needed to treat a well.

[0045] The method may further comprise: measuring a duration of time between liquid level changes. The duration of time may be the time between the liquid levels. For example, the duration of time for the level to rise from the second level to the first level. The duration of time may be used to determine the effectiveness of the regeneration or when the regeneration is complete. For example, if the duration of time is less than a threshold time, this may indicate regeneration is complete. In this way, unnecessary time may not be spent regenerating the well when it has been sufficiently regenerated. This may improve the efficiency of method compared to conventional methods. The duration of time may alternatively be the time between the liquid level lowering from the first level to the second level.

[0046] The measuring may comprise: injecting air into the sealed water well to increase a pressure in the sealed water well to lower the liquid level.

[0047] The measuring may comprise: withdrawing air from the sealed water well to decrease the pressure in the sealed water well to increase the liquid level.

[0048] The method may further comprise: stopping the regenerating when the duration of time reaches a threshold value.

[0049] The method may further comprise: detecting a pressure of the sealed water well. The pressure of the sealed water well may be detected by a pressure sensor within the water well. The pressure sensor may be associated with the sealing arrangement, e.g., packer, used to seal the water well. For example, the pressure sensor may be within the sealing arrangement and adapted to detect a pressure within the water well. Specifically, a pressure sensor may be adapted to detect a pressure within an uppermost portion of the water well directly below the sealing arrangement.

[0050] Withdrawing may comprise withdrawing liquid from the sealed water well when a threshold pressure is detected. Withdrawing may comprise withdrawing liquid from the sealed water well with negative pressure when a threshold pressure is detected. Withdrawing may comprise withdrawing liquid at velocity (e.g., a high velocity compared to due to negative pressure) from the sealed water well when a threshold pressure is detected. The threshold pressure may indicate that the water well is sufficiently pressurised by the air being injected into the sealing arrangement.

[0051] The method may further comprise: monitoring or detecting a parameter of the withdrawn liquid. The liquid may be withdrawn following the threshold pressure being reached. The pressure may be significant such that liquid rushes from the water well thereby withdrawing liquid from the gravel pack surrounding the water well, not just water within the water well. The water may be withdrawn into a tank.

[0052] The parameter may comprise turbidity. The turbidity may be detected by a turbidity sensor. The turbidity sensor may be within the tank.

[0053] The method may further comprise: stopping the withdrawing when a threshold value of the parameter is detected. The threshold value may indicate that the water is sufficiently clean to stop shocking.

[0054] The method may further comprise: repeating the withdrawing and stopping until the threshold value of the parameter is detected within a pre-set time. The pre-set time may be the time determined during regenerating. When the turbidity, for example, is detected within a pre-set time, e.g., 10 seconds, this may indicate the water from the gravel pack surrounding the water well is sufficiently clean such that further shocking is unnecessary. Thus, the shocking may be stopped. This may reduce the overall time required to treat the well and improve the effectiveness of the method over conventional methods. The method may further comprise: measuring a duration of time for the injecting of air into the pipe arrangement; the withdrawing liquid from the sealed water well; and the surging to determine a yield of the water well. For example, a time which is lower than a threshold value may indicate an acceptable yield of the water well. Additionally, the time may indicate the overall rehabilitation quality of the water well.

[0055] The method may further comprise: measuring a level of liquid in the well. The level may be used during the describing regenerating, i.e., surging, shocking and air-lifting. Measuring the level may ensure that the level is not permitted as a result of injecting or withdrawing, to reach a level at which air may enter the pre-filter zone. Air in the pre-filter zone may result in certain iron ions forming which may result in iron forming in the perforated well casing thereby blocking or restricting flow through the perforated well casing.

[0056] According to another aspect of the disclosure, there is provided a method of treating a sealed water well, the method comprising: cleaning the water well, the cleaning comprising: injecting air into a pipe arrangement positioned in a sealed water well, to entrain sediment proximate a terminal end of the sealed water well in liquid, the pipe arrangement adapted to continuously contact the terminal end of the sealed water well; and withdrawing liquid (the liquid may comprise water and the entrained sediment) from the sealed water well; regenerating the water well, the regenerating comprising: surging; shocking; and air lifting.

[0057] Suring may comprise: injecting air to lower a liquid level in the well from a first static or resting level to a second level which is lower than the first level; injecting air to form a water column separated from the second lower level by a portion of air; and stopping the injecting of air to form the water column, and injecting air to force the water column into a pre-filter zone.

[0058] Shocking and air-lifting may comprise: injecting air into the pipe arrangement to increase pressure in the sealed water well and lower a liquid level in the sealed water well thereby forcing liquid into a volume surrounding the water well; and withdrawing liquid from the sealed water well to at least partially evacuate liquid from the volume surrounding the water well out of the water well.

[0059] The method comprise all of the previously described features and elements.

[0060] According to another aspect of the disclosure there is provided a system for treating a water well. The system may comprise: an air compressor for injecting air into a pipe arrangement positioned in a sealed water well to increase pressure in the sealed water well and lower a liquid level in the sealed water well thereby forcing liquid into a volume surrounding the water well; and a pipe arrangement comprising a telescoping pipe for maintaining contact with a terminal end of the well, the pipe arrangement fluidly connected to the air compressor.

[0061] While an air compressor has been described, one of skill in the art will appreciate an air pump may be used. Additionally, while the term injecting air has been used, one of skill in the art will appreciate the air pump may pump air into the sealed water well.

[0062] The pipe arrangement may be centrally located (radial centre) within the water well, or moved to a lateral side of the water well.

[0063] The air compressor may be located at surface while the pipe arrangement and water well extend below surface.

[0064] The air compressor may be adapted to inject air into the pipe arrangement.

[0065] The air compressor may be adapted to inject air into an end of the water well opposite the terminal end, i.e., the top or topside of the water well. The compressor may be adapted to inject air into an end of the water well uphole of the terminal end which may be the top of the water well proximate the surface.

[0066] The system may further comprise: a valve arrangement for withdrawing a fluid from the sealed water well. The valve arrangement may be adapted for withdrawing fluid from the pipe arrangement of the water well.

[0067] The valve arrangement may comprise: a plurality of valves controllable based on detected measurements. The plurality of valve may comprise: a first valve for withdrawing liquid from the water well, a second valve for withdrawing air from the water well, a third valve for injecting air into the pipe arrangement, and a fourth valve for injecting air into the water well. The first valve may be for withdrawing liquid from the water well and into a tank. The tank may be proximate the water well.

[0068] The system may further comprise: a controller for controlling operation of the air compressor and / or the valve arrangement.

[0069] The system may further comprise: a plurality of sensors for detecting parameters.

[0070] The plurality of sensors may comprise at least one of: a level sensor for detecting a liquid level in the water well; a turbidity sensor for detecting turbidity of liquid withdrawn from the water well; and a pressure sensor for detecting a pressure within the water well.

[0071] The controller may be adapted for controlling the valves based on parameters detected by the sensors. For example, the controller may control the fourth valve to control air injected into the sealing arrangement based on a pressure within the water well detected by the pressure sensor. The controller may control the fourth valve to control air injected into the water well based on a liquid level within the water well detected by the level sensor. The controller may control the first valve to control liquid withdrawn from the water well based on a turbidity detected by the turbidity sensor. The controller may control the second valve to control air withdrawn from the water well based on a level detected by the level sensor. The controller may control the second valve to control air withdrawn from the water well based on a pressure detected by the pressure sensor.

[0072] The controller may operate autonomously according to pre-set parameters, e.g., turbidity, pressure and level values, or may be human operated.

[0073] The system may further comprise: a tank. The tank may be for storing liquid withdrawn from the water well. The turbidity sensor may be located within the tank. The tank may store withdrawn liquid for a temporary period. For example, the tank may store withdrawn liquid solely for the period of time required to detect the turbidity of the withdrawn liquid. The tank may comprise a separator for separating fluid constituents.

[0074] The telescoping pipe arrangement may always be in contact with a terminal end of the water well even when the water well extends further downhole as debris is cleaned and / or removed from the terminal end.

[0075] The system may further comprise: a sealing arrangement for sealing a water well. The air compressor may be proximate the sealing arrangement. The sealing arrangement may comprise a packer. The sealing arrangement may be uphole of a terminal end of the water well. The pipe arrangement may extend downhole of the packer into the water well. The air compressor and / or tank may be uphole of the sealing arrangement.

[0076] The described system may allow for a water well to be treated (e.g., water well yield test) without requiring a pump to be moved into position to remove liquid from the water well, and then removed from an operating position during other steps of water well treatment. This is contrast with conventional systems. Further, components of the system, e.g., valves, compressor, etc., need not be removed between various operating stages, e.g., cleaning, surging, shocking and air-lifting. This may reduce costs and / or improve the speed of well treatment. While the disclosure is described in connection with a water well, one of skill in the art will appreciate the disclosure may be applied to other well types when treatment is required.

[0077] Aspects of the disclosure may include one or more examples, embodiments or features in isolation or in various combinations whether or not specifically stated (including claimed) in that combination or in isolation.

[0078] Brief Description of the Drawings

[0079] A description is now given, by way of example only, with reference to the accompanying drawings, in which:

[0080] Figure 1 is a cross-sectional elevation view of a water well in accordance with an aspect of the disclosure;

[0081] Figure 2 is a cross-sectional elevation view of the water well of Figure 1 during cleaning;

[0082] Figure 3A-3E are cross-sectional elevation views of the water well of Figure 1 during regenerating;

[0083] Figure 4A and 4B are cross-sectional elevation views of the water well of Figure 1 during shocking; and

[0084] Figure 5 is a flowchart of a method of treating a water well in accordance with an aspect of the disclosure.

[0085] Detailed Description

[0086] The foregoing summary, as well as the following detailed description of certain examples will be better understood when read in conjunction with the appended drawings. As used herein, an element or feature introduced in the singular and preceded by the word "a" or "an" should be understood as not necessarily excluding the plural of the elements or features. Further, references to "one example" or “one embodiment” are not intended to be interpreted as excluding the existence of additional examples or embodiments that also incorporate the described elements or features. Moreover, unless explicitly stated to the contrary, examples or embodiments "comprising" or "having" or “including” an element or feature or a plurality of elements or features having a particular property may include additional elements or features not having that property. Also, it will be appreciated that the terms “comprises”, “has”, “includes” means “including but not limited to” and the terms “comprising”, “having” and “including” have equivalent meanings. It will also be appreciated that like reference characters will be used to refer to like elements throughout the description and drawings.

[0087] As used herein, the terms “adapted” and “configured” mean that the element, component, or other subject matter is designed and / or intended to perform a given function. Thus, the use of the terms “adapted” and “configured” should not be construed to mean that a given element, component, or other subject matter is simply “capable of” performing a given function but that the element, component, and / or other subject matter is specifically selected, created, implemented, utilized, and / or designed for the purpose of performing the function. It is also within the scope of the subject application that elements, components, and / or other subject matter that is described as being adapted to perform a particular function may additionally or alternatively be described as being configured to perform that function, and vice versa. Similarly, subject matter that is described as being configured to perform a particular function may additionally or alternatively be described as being operative to perform that function.

[0088] It will be understood that when an element is referred to as being “on”, “attached” to, “connected” to, “coupled” with, “contacting,” etc., another element, it can be directly on, attached to, connected to, coupled with or contacting the other element or intervening elements may also be present.

[0089] It should be understood that use of the word “exemplary”, unless otherwise stated, means ‘by way of example’ or ‘one example’, rather than meaning a preferred or optimal design or implementation.

[0090] Turning now to Figure 1, a water well 8 in a gravel pack 6 is illustrated. A system of treating the water well 8 is also illustrated. The system is used to treat the water well 8 following certain operations which include measuring parameters of the water well 8 (e.g., starting water well yield) cleaning, and regenerating the well. The operations may further include measuring the parameters after the cleaning and regenerating. Cleaning may include airlifting. The system may also be used to inject chemical into the well to clean the well. The system may be used to treat water well in less time, more efficiently, and more effectively than conventional methods and systems of treating water wells.

[0091] The water well 8 is defined by casing (referred to reference sign 8). Certain portions of the casing may be perforated. Such perforations may define a filter. As such liquid flows from the gravel pack 6 through the perforated casing may be filtered by the perforations. As such, the gravel pack 6 surrounding the casing may be referred to as a pre-filter zone.

[0092] As shown, the system comprises a sealing arrangement 10 which in the illustrated arrangement is a well packer, a pipe arrangement 12, a tank 16 for storing fluid withdrawn from the well 8, and an air compressor 18 for injecting air into the water well 8 via one of two conduits 20, 22. The system further comprises a controller 46 for controlling various elements of the system as will be described. The tank 16 may store withdrawn liquid for a temporary period. For example, the tank 16 may store withdrawn liquid solely for the period of time required to detect the turbidity of the withdrawn liquid.

[0093] The water well 8 extends from surface into the gravel pack 6. The gravel pack 6 surrounds the water well 8. The pipe arrangement 12 extends from surface into the water well 8 contacting a terminal end 14 of the water well 8. The pipe arrangement 12 passes through the sealing arrangement 10 which is mounted at a surface end of the water well 8. The sealing arrangement seals the water well 8 such that operation various valves can be used to pressurise the well as will be described.

[0094] The pipe arrangement 12 is telescoping. In the illustrated arrangement, the pipe arrangement 12 comprises a series of telescoping pipes. The telescoping pipes are arranged to contact the terminal end 14 of the water well 8 even as the terminal end 14 extends further downhole as debris is removed from the water well 8.

[0095] The pipe arrangement 12 extends through the sealing arrangement 10 into a tank 16. The tank 16 is used to store liquid withdrawn from the water well 8 as will be described.

[0096] Flow of fluid through the pipe arrangement 12 into or out of the tank 16 is controlled via a first valve 30 associated with the pipe arrangement 12. While not illustrated, the tank 16 comprises separate fluid containing sections. In particular, the tank 16 comprises a section for storing water (potentially only temporarily while detecting the turbidity of the water) withdrawn from the water well 8, one for storing reagent injected into or withdrawn from the water well 8, and one for storing disinfectant injected into or withdrawn from the water well 8.

[0097] An exhaust 24 also extends through the sealing arrangement 10 for withdrawing air from the water well 8. The exhaust 24 is positioned generally above the water level 50. The exhaust 24 is adapted to vent air in the water well 8 which rises or is above the water in the water well 8. A second valve 32 is associated with the exhaust 24 and is controllable to control venting of air from the exhaust 24.

[0098] In the illustrated arrangement, the air compressor 18 and tank 16 are located at the surface. One of skill in the art will appreciate that these may be subsurface. The air compressor 18 is adapted to inject air. Specifically, the compressor 18 is adapted to inject air into the pipe arrangement 12 via a first conduit 20. The compressor 18 is further adapted to inject air into the water well 8 via a second conduit 22. Third and fourth valves 34, 36 are arranged in the respective conduits 20, 22 to control the injection of air.

[0099] The tank 16 may comprise various compartments for storing withdrawn fluid, disinfectant, reagent, etc.; one or more sensors; and a separator for separating the constituent parts of withdrawn fluid.

[0100] Operation of the various valves 30-36 is controlled via the controller 46. The controller 46 may additionally control operation of the compressor 18. The controller 46 may be proximate the tank 16 and / or compressor 18, or may be located remote from the water well 8. In other words, air to be injected and / or withdrawn, and / or liquid to be injected and / or withdrawn may be transported via one or more fluid conduits to the tank 16 and / or compressor 18 located some distance away from the water well 8.

[0101] A number of sensors are also present in the system. A tank level sensor 40 is present within the tank 16 to monitor liquid levels within the tank 16. The tank 16 may include a plurality of level sensors to monitor a water liquid level, a disinfectant liquid level, and a reagent liquid level within the tank 16. A turbidity sensor 42 is located within the tank 16. The turbidity sensor 42 may monitor turbidity of liquid withdraw from the water well 8 via the pipe arrangement 12.

[0102] A well level sensor 44 is located within the water well 8 for measuring a level of liquid within the water well 8. The well level sensor 44 may comprise a hydrostatic pressure sensor for detecting a water level (e.g., water level 50) within the water well 8.

[0103] While not illustrated, the system may also comprise a pressure sensor for detecting a pressure within the water well 8. The pressure sensor may be associated with the sealing arrangement 10. The pressure sensor may monitor pressure within the water well 8 to ensure the sealing arrangement 10 adequately seals the water well 8. Additionally, the pressure sensor may monitor for changes in pressure to control operation of one or more valves 30-36 as will be described.

[0104] The described sensors 40-44 may be connected to the controller 46. The controller 46 controls the valves 30-36 based on signals transmitted from the sensors 40-44 to the controller 46.

[0105] Generally, the controller 46 controls operation of the air compressor 18 to inject air into the pipe arrangement 12 via the first conduit 20 and third valve 34 to clean the water well 8 by airlifting liquid from the water well 8 into the tank 16. Liquid is airlifted pneumatically via the injected air. The controller 46 controls operation of the first valve 30 to allow liquid to enter the tank 16 were the turbidity sensor 42 detects a turbidity of the liquid. Once the liquid reaches a threshold turbidity, i.e., indicating it is sufficiently clean, the controller may close the first valve 30, stop the air compressor 18 from injecting air, and close the third valve 34. The airlifting removes incrustation and sediment at a terminal end 14 of the water well 8 as these are withdrawn into the tank 16. As these are removed, the telescoping pipe arrangement 12 descends downhole into the water well 8 given the terminal end 14 similarly extends downhole. In this way, the telescoping pipe arrangement 12 is always in contact with the terminal end 14 without the need for manually changing the downhole location of the pipe arrangement 12.

[0106] After the airlifting, the controller 46 may also control a valve associated with the reagent section of the tank 16 to inject reagent into the water well 8 to further clean the water well 8. Similarly, disinfectant may be injected into the water well 8 to disinfect the water in the water well 8.

[0107] The controller 46 may also control the valves to regenerate the water well 8. Regenerating includes surging. Suring is performed by manipulating the water level 50 by changing the pressure in the water well 8 to push liquid into the gravel pack 6 and withdraw the liquid back thereby loosening and removing incrustation in the gravel pack 6 surrounding the well 8. Generally, the controller 46 controls operation of the third valve 34 to inject air and increase the pressure, and then open the second valve 32 to withdraw air. The controller 46 may also control the fourth valve 36 and collect certain measurements for a period of the regenerating phase as will described.

[0108] The controller 46 may also control the valves to conduct shocking, e.g., hydraulic shocking, of the water well in a similar manner, i.e., by raising pressure and lowering the liquid level 50, by injected air and removing liquid as will be described.

[0109] Turning now to Figure 2, the system is illustrated in a cleaning phase, i.e., during airlifting of water from the water well 8. During airlifting, the first valve 30 and the third valve 34 are open such that air is injected from the air compressor 18 along the first conduit 20 and into the pipe arrangement 12 via the third valve 34. The pipe arrangement 12 is telescoping such that the terminal end 14 of the water well 8 is in contact with the pipe arrangement 12 as sediment is removed from the water well 14 and the terminal end 14 extends downhole. The air injected into the pipe arrangement 12 is used to entrain sediment from the terminal end 14 of the water well 8 into liquid which is withdrawn by opening the first valve 30 associated with the pipe arrangement 12. The liquid is withdrawn into the tank 16. The turbidity sensor 42 within the tank 16 detects the turbidity of the withdrawn liquid. When the detected turbidity falls to a threshold level, i.e., the water is clean enough, the first valve 30 is closed and liquid stops entering the tank 16.

[0110] As mentioned, following the cleaning, a chemical reagent may be added from the tank 16 to mix with the water. Airlifting of the liquid may assist with mixing the reagent with the liquid to expedite cleaning. Further, the cleaning process stops when the turbidity of the liquid reaches a threshold value. This ensures the cleaning (airlifting) does not continue for longer than required thereby reducing the overall time required to treat the water well 8. The system may monitor a time for the turbidity sensor 42 to detect the threshold turbidity and may repeat the cleaning process until the time is less than or equal to a threshold duration. In this way, the water in the water well 8 may be determined to be sufficiently clean without completing the cleaning cycle an excess number of times.

[0111] Following the cleaning, the system is used to regenerate (specifically surge) the water well 8 which is illustrated in Figures 3A - 3E. Generally, water well 8 regeneration is loosening, dissolving and / or removing encrusting materials from the water well 8 such that water may be pumped from the water well 8. Regenerating may be conducted for wells which have gone through prolonged periods of no or little use. In the illustrated arrangement, the water well 8 is regenerated (specifically surging is performed) by manipulating the liquid level 50 of the water well 8 by changing the pressure inside the water well 8. Liquid (which may or may not include reagent) is pushed into the gravel pack 6 surrounding the water well 8. This pushing with great force loosens incrustation from within the gravel pack 6 thereby allowing the water well 8 to return to a fully operational state. Specifically, micro-cracks may form in the incrustation to allow particles to be removed by the subsequent shocking which will be described.

[0112] Starting with Figure 3A, the controller 46 opens the third valve 34 to inject air from the air compressor 18 into the pipe arrangement via the first conduit 20. As shown in Figure 3B, the injected air rises up into the pipe arrangement 12. As the first valve 30 is closed, the air forces liquid down and out of the pipe arrangement 12 into the surrounding volume within the water well 8. As air continues to be injected into the pipe arrangement 12, eventually all of the liquid is forced out and the air begins to bubble into the volume surrounding the pipe arrangement 12 as shown in Figure 30. The build-up of air forces the water down lowering the liquid level 50 as shown in Figure 3C. The controller 46 then opens the second valve 32 to release the air from the exhaust 24. The liquid level 50 then rises as shown in Figure 3D. Once sufficient air has been withdrawn (i.e., vented or exhausted), the controller 46 closes the second valve 32. While the liquid level 50 has been shown as lowering and rises, in fact a water column forms above water remaining in the well which may be entering from the gravel pack 6 via perforations in casing of the water well 8. When the second valve 32 opens, and the water column may fall down the pipe arrangement 12 and surrounding volume impacting the gravel pack 6. Air continues to be injected into the pipe arrangement 12 starting the process again as shown in Figure 3E.

[0113] By repeating these the raising and lowering of the liquid level 50 within the water well 8, more water (and possibly reagent) acts on incrustation which may be plugging the water well 8. With every new cycle some of the incrustation may be dissolved. In particular, by forcing the column of water down by continuing to inject air at the top of well 8 to force the column of water down when air is released, the column of water impacts the gravel pack with tremendous force not only forming micro-cracks or dissolving the incrustation, but also sending water rushing through the gravel pack to a radius beyond conventional regeneration system. Thus, not only is the well regenerated faster because reach is extended, the water well is regenerated more effectively.

[0114] The controller 46 may determine when to open and close the second valve 32 based on the duration of time determined right before, in the cleaning (airlifting) phase. The controller 46 may determine when to open and close the second valve 32 based on the water level in the water well 8 as detected by the water level sensor 44.

[0115] The controller 46 may also control the fourth valve 36 to inject air via the second conduit 22 into the water well 8 above the liquid level 50. This does not form bubbles in the water in the water well 8, but simply pushes the water level down as injected air above the water increases the pressure in the water well 8. The water level 50 is measured using the well level sensor 44. The second valve 32 is then opened and the liquid level 50 is measured again. The time it takes for the liquid to move between these two levels may be used a duration of time between opening and closing the second valve 32 during the regeneration phase. The describing determination of this time may be conducted in between repeated cycles of the regenerating. Once the time is no longer getting any lower, i.e., the time for the liquid to change between the two levels is constant following regeneration, the regeneration phase may be complete. In this way, regeneration may be efficiently conducted without inefficiently repeating the process without any incrustation being removed. Turning now to Figures 4A and 4B, the process of shocking the water well 8 is illustrated. Shocking is hydraulic shocking of the water well 8 to pull liquid from the gravel pack 6 surrounding the well 8. The liquid may contain water, dirt and / or sediment. The controller 46 opens the third valve 34 to inject air into the pipe arrangement 12 while the other valves 30, 32, 36 are closed. This increases the pressure in the water well 8 as already described. A pressure sensor in the sealing arrangement 10 detects when the pressure is sufficiently high and then opens the first valve 30 to release water and air from the pipe arrangement 12 into the tank 16. Any entrained particles (e.g., dirt, sediment) are also withdrawn into the tank 16. The fluid, e.g., liquid, flows into the tank 16 to the turbidity sensor 42. The turbidity sensor 42 detects the turbidity of the fluid and when a threshold turbidity level is reached, the controller 46 closes the first valve 30 and pressure again builds up in the water well 8. The sudden opening of the first valve 30 creates a hydraulic shock in the water well 8 to remove particles from the well 8 including from the gravel pack 6. The process repeats until the turbidity sensor 42 detects the threshold turbidity level within a threshold period of time.

[0116] The water containing dissolved incrustation particles rushes through the pipe arrangement 12 due to the build of pressure from the injected air, i.e., the water is sucked out by negative pressure. This may only last for several seconds, but the effect may be significant. The water pulls out particles from a pre-filter zone (i.e., the area surrounding the casing of the water well 8 which includes the gravel pack 6) due to the injected air forcing water into the pre-filter zone and then suddenly pulling the water out taking the entrained dissolved particles with the water. The process of injecting the air and withdrawing the liquid repeats such that high pressure is repeatedly creating forcing liquid into the pre-filter zone. As soon as the pressure is sufficiently high liquid is withdrawn via the opening of valve 30.

[0117] Every time water is withdrawn, some amount of “dirt” may remain inside the well and some amount may remain inside the pre-filter zone. However, the amount in the prefilter zone is being reduced with every combination of injection and withdrawal, i.e., with every hydro shock.

[0118] Withdrawing the liquid, i.e., airlifting, is continuously occurring during this hydro shocking. Therefore, you regularly have water going in and out through the pre-filter zone, not giving dissolved particles an opportunity to settle down or react again. As hydro shock subsides with the decrease of pressure, airlifting continues to work by itself and the water gets less dirty with time. This cycle is repeated, i.e. , hydro shocking by increasing the pressure, and air lifting by withdrawing the water including entrained particles until water is sufficiently clean. If one were to utilise only standard airlift without hydro shocking, one may incorrectly presume the well water is sufficiently clean, when it is in fact still significantly dirty.

[0119] As illustrated in Figure 4B, the withdrawn fluid may follow a serpentine flow path 52 within the tank 16. This may promote sediment within the water settling to the bottom of the flow path 52 prior to detection by the turbidity sensor 42. In another arrangement, the withdrawn fluid flows through one or more filters (e.g., grates). The filters may separate large particles, and remove any air within the withdrawn water or fluid. Thus, only liquid or water passes beyond the filter to the turbidity sensor 42.

[0120] While a particular mode of operating the system of treating a water well is described, one of skill in the art will appreciate that variations are possible. For example, the water well 8 may be additionally be disinfected. During disinfection, the controller 46 opens the first valve 30 and injects disinfectant from the tank 16 into the pipe arrangement 12 and into the water well 8.

[0121] Then the controller 46 releases water from a designated part of the tank 16. In this way, the controller 46 may control the amount or volume of disinfectant which enters the water well 8. For example, the controller may ensure all of the disinfectant enters the water well 8 without any disinfectant being left in the pipe arrangement 12.

[0122] Following this, all the valves 30-36 are closed with the exception of the third valve 34. The third valve 34 is opened and the compressor 18 injects air into the pipe arrangement 12 via the first conduit 20. The air improves mixing of the water and the injected disinfectant. After some time, the first valve 30 is opened and disinfectant is withdrawn from the pipe arrangement 12.

[0123] The described system may allow for the water well 8 to be treated without requiring a pump to remove liquid from the water well 8. Further, components of the system need not be removed between various stages, e.g., cleaning, surging, shocking and airlifting. Turning now to Figure 5 a flowchart of a method of treating a water well 8 is illustrated. As shown in Figure 5, the method 58 comprises cleaning 60, regenerating 70, and shocking 80. Cleaning 60 comprises injecting 62 air from the compressor 18 into the first conduit 20 and then into the pipe arrangement 12 via the third valve 34. Liquid is then withdrawn 64 via the first valve 30. The turbidity of the withdrawn liquid is detected 66. The injecting 62, withdrawing 64, and detecting 66 repeat, as indicated by arrow A, until the detected turbidity reaches a threshold level. The method 58 then proceeds to the regenerating 70 phase.

[0124] Regenerating 70 comprises injecting 72 air from the compressor 18 into the first conduit 20 and then into the pipe arrangement 12 via the third valve 34. Air is then withdrawn 74 from the water well 8 via the second valve 32. The time between water level changes as result of the alternating injecting 72 and withdrawing 74 is measured 76. The steps of injecting 72, withdrawing 74, and measuring 76 repeat, as indicated by the arrow B, until the time is less than or equal to a threshold duration. The method 58 then proceeds to the shocking 80 phase. Regenerating 70 also comprises injecting 78 air via the fourth valve 36 into the water well 8 above the liquid level 50. The water level can then be measured in step 76 following the injecting 78 and following the withdrawing 76. During the measurement phase of the regenerating 70, air is not injected 70 via the third valve 34, but only via the fourth valve 36. As such, the injecting 78 is shown in broken lines alongside the injecting 72.

[0125] Shocking 80 comprises injecting 82 air from the compressor 18 into the first conduit 20 and then into the pipe arrangement 12 via the third valve 34. The injected air increases the pressure in the well 8. Liquid is withdrawn 84 from the water well 8 via the pipe arrangement 12 by opening the first valve 30. The withdrawn liquid enters the tank 16 via the serpentine flow path 52. The turbidity is sensed 86 via the turbidity sensor 42.

[0126] The injecting 82, withdrawal 84, and sensing 86 are repeated until the threshold turbidity is sensed within a threshold time duration.

[0127] While regenerating 70 and shocking 80 are described as such they may both form part of a regenerating step. Further, the described regenerating 70 may be referred to as surging. While not illustrated in Figure 5, the method may further comprise conducting a water yield test prior to the cleaning 60, and following the shocking 80. It should be understood that arrangements or embodiments described herein are merely exemplary and that various modifications may be made thereto without departing from the scope of the disclosure as defined by the claims appended hereto.

Claims

CLAIMS:

1. A method of treating a sealed water well, the method comprising: injecting air into a pipe arrangement positioned in a sealed water well to increase pressure in the sealed water well and lower a liquid level in the sealed water well thereby forcing liquid into a volume surrounding the water well, the pipe arrangement comprising a telescoping pipe adapted to continuously contact a terminal end of the sealed water well; and withdrawing liquid from the sealed water well to at least partially evacuate liquid from the volume surrounding the water well out of the water well.

2. The method of claim 1, further comprising: cleaning the sealed water well.

3. The method of claim 2, further comprising: injecting air into the pipe arrangement to entrain sediment proximate the terminal end in liquid in the pipe arrangement; and withdrawing liquid and the entrained sediment from the pipe arrangement.

4. The method of claim 3, further comprising: monitoring a parameter of the withdrawn liquid and the entrained sediment, and optionally wherein the parameter comprises turbidity.

5. The method of claim 4, further comprising: stopping the injecting air into the pipe arrangement to entrain sediment and the withdrawing liquid and the entrained sediment when a threshold value of the parameter is detected.

6. The method of any preceding claim, further comprising: injecting a reagent into the sealed water well prior to the withdrawing.

7. The method of claim 1 , further comprising: repeating the injecting and withdrawing to dissolve incrustation particles in the volume surrounding the water well.

8. The method of any preceding claim, further comprising surging, wherein surging comprises: injecting air to lower a liquid level in the well from a first static or resting level to a second level which is lower than the first level; and injecting air to form a water column separated from the second lower level by a portion of air.

9. The method of claim 8, wherein injecting air to form the water column comprises injecting air at a bottom of the water well.

10. The method of claim 8 or 9, further comprising: stopping the injecting air to form the water column.

11. The method of claim 10, further comprising: releasing air from the sealed water well to allow the water column to fall down and contact a volume surrounding the water well.

12. The method of claim 10 or 11 , further comprising: continuing to inject air to lower the liquid level to force the water column to a volume surrounding the water well.

13. The method of any preceding claim, further comprising: measuring a duration of time between liquid level changes.

14. The method of claim 13 when dependent on claim 8, further comprising: stopping the surging when the duration of time reaches a threshold value.

15. The method of any preceding claim, further comprising: detecting a pressure of the sealed water well.

16. The method of claim 15, wherein withdrawing, following the injecting, liquid from the sealed water well to at least partially evacuate liquid from the volume surrounding the water well out of the water well comprises withdrawing liquid from the sealed water well due to negative pressure when a threshold pressure is detected.

17. The method of any of claims 14 to 16, further comprising: monitoring a parameter of the withdrawn liquid.

18. The method of claim 17, wherein the parameter comprises turbidity.

19. The method of claim 17 or 18, further comprising: stopping the withdrawing when a threshold value of the parameter is detected.

20. The method of claim 19, further comprising: repeating the withdrawing and stopping until the threshold value of the parameter is detected within a pre-set time.

21. The method of claim 8, further comprising: measuring a duration of time for the injecting of air into the pipe arrangement; the withdrawing liquid from the sealed water well; and the surging to determine a yield of the water well.

22. A system for treating a water well, the system comprising: an air compressor for injecting air into a pipe arrangement positioned in a sealed water well to increase pressure in the sealed water well and lower a liquid level in the sealed water well thereby forcing liquid into a volume surrounding the water well; and a pipe arrangement comprising a telescoping pipe for maintaining contact with a terminal end of the well, the pipe arrangement fluidly connected to the air compressor.

23. The system of claim 22, wherein the air compressor is adapted to pump air into the pipe arrangement.

24. The system of claim 22 or 23, wherein the air compressor is adapted to pump air into an end of the water well opposite the terminal end.

25. The system of any of claims 22 to 24, further comprising: a valve arrangement for withdrawing a fluid from the sealed water well, and optionally wherein the valve arrangement comprises a plurality of valves controllable based on detected measurements.

26. The system of claim 25, further comprising: a controller for controlling operation of the air compressor and / or the valve arrangement.

27. The system of any of claim 22 to 26, further comprising: a plurality of sensors for detecting parameters, and optionally wherein the plurality of sensors comprise at least one of: a level sensor for detecting a liquid level in the water well; a turbidity sensor for detecting turbidity of liquid withdrawn from the water well; a pressure sensor for detecting a pressure within the water well.

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