External bypass fluid hammer

Abstract

The present disclosure is directed to a fluid hammer comprising a drill bit defining a drill face; a piston barrel configured to receive a flow of drilling fluid, a piston in the piston barrel operated by a first portion of the drilling fluid, at least one bypass tube disposed exterior to the piston, wherein a second portion of the drilling fluid is diverted in to the bypass tube(s), and wherein the bypass tube is adapted to deliver drilling fluid proximate the drill face.

Description

EXTERNAL BYPASS FLUID HAMMERTECHNICAL FIELD

[0001] The invention is broadly directed to a mud hammer (also known as a fluid hammer), fluid percussion hammer system and method for deep drilling in deep wells.BACKGROUND

[0002] There exists considerable demand in the renewables industry for emission free baseload energy supplies. Geothermal energy production has been the subject of much investment over the recent years, being recognised as a new renewable and environmentally friendly answer to many of the baseload energy supply issues that are being faced worldwide as the world seeks greener alternatives to gas and coal.

[0003] Geothermal energy requires deep wells in order to find sufficient heat for thermal energy production. Much of the cost of drilling is associated with decreased rate of penetration caused by both harder rock and higher mud weights required to counter harder rock. Additionally, over pressurised reservoirs and higher static pressures are inhibitors facing fluid hammers when in use. Typical rotary tricone and PDC drill bit designs and methods encounter obstacles such as slower drilling rate and short drill bit lifetime, increasing costs and decreasing return on investment when exploring geothermal energy alternatives. More recently, the focus of the industry has been increasingly on percussion fluid hammer drilling systems, combining a fluid or f mud percussion hammer with PDC percussion drill bits has shown marked improvement in drilling performance in hard formations.

[0004] Percussion drilling systems convert a portion of the power resident in the drilling fluid to mechanical force that drives the drill bit into the formation. Percussion forces from the piston movement striking the drill bit may improve the rate of penetration in hard rock by more than 500%; however, high flow rates and fluid additives in the drilling fluid required for well control and drill cutting transport to the surface cause a high wear rate on the moving parts of a fluid hammer. This high wear rate on the working components and the limited amount of fluid that can be pumped through a typical fluid hammer to clear drilled cuttings from the bottom of the well are significant drawbacks to a typical fluid hammer system that have been prohibitive to their use for deep well drilling. Accordingly, rotary tricone and rotary PDC drilling methods are generally still the only method used. The low penetration rates and high costs of the typical rotarytricone and rotary PDC methods, however, are at least in part preventing the development of geothermal energy production in most countries where deep hard rock wells are required to reach the required geothermal heat levels for electricity generation, desalination, heating, cooling, hydrogen production, electrolysis and waste water treatment.

[0005] The present invention was conceived with these shortcomings in mind.

[0006] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, a limited number of the exemplary methods and materials are described herein.SUMMARY OF THE INVENTION

[0007] In a first aspect of the present invention, there is provided a fluid hammer comprising: a drill bit defining a drill face; a piston barrel configured to receive a flow of drilling fluid; a piston in the piston barrel operated by a first portion of the flow drilling fluid; and at least one bypass tube disposed exterior to the piston, wherein a second portion of the flow drilling fluid is diverted in to the at least one bypass tube, and wherein an outlet of the at least one bypass tube is positioned to deliver drilling fluid in the proximate the drill face.

[0008] Preferably, the fluid hammer further comprises a valving set positioned at an intake of the bypass tube(s), to divert the second portion of the flow into the bypass tube(s).

[0009] Preferably, the valving set is adjustable to control flow.

[0010] Preferably, the valving set diverts approximately 70% of the drilling fluid into the bypass tube forming the second portion.

[0011] Preferably, the remaining 30% of the drilling fluid forms the first portion for use in the piston barrel for operation of the piston.

[0012] Preferably, the first portion of the drilling fluid is expelled from the piston barrelto the drill bit.

[0013] In some embodiments, all of the flow of drilling fluid is expelled at the drill face, having flowed through the piston barrel and bypass tube(s).

[0014] In some embodiments, the fluid hammer further comprises an exhaust adapted to expel a third portion of the drilling fluid from the piston barrel or bypass tube(s).

[0015] In some embodiments, the expulsion of drilling fluid at the drill face results in vortex around the fluid hammer, flushing cuttings away from the drill face.

[0016] Preferably, the drilling fluid is delivered to the fluid hammer at a rate of approximately 1000 gallons per minute (GPM) at a pressure of 10,000 psi (pounds per square inch).

[0017] Preferably, the drill bit is operating at a pressure of 2,000 psi.

[0018] In some embodiments, the fluid hammer further comprises at least one bypass tube adapted to exhaust fluid in an upward direction, relative to the drill bit when in use.

[0019] In some embodiments, the external bypass tube(s) and valving set are retrofitted to an approved American Petroleum Institute (API) certified drill string.

[0020] In some embodiments, the external bypass tube(s) and valving set are retrofitted to an industry standard fluid hammer.

[0021] In some embodiments, the external bypass tube(s) and valving set are retrofitted to a dual circulation drill system.

[0022] Preferably, the piston has a stroke length of 20 to 60 millimetres.

[0023] The fluid hammer may comprise a plurality of stabilising wings. Each bypass tube may be disposed throughout the length of one of the stabilising wings. Each stabilising wing comprising a bypass tube may comprise a wing body and a face plate extending longitudinally along an outside of the wing body. In such an embodiment, the bypass tube can be formed between the face plate and a longitudinal cavity formed in the wing body.

[0024] In some embodiments, the valving set is positioned above both the intake to thepiston barrel, and the bypass tube(s).

[0025] In some embodiments, the valving set is adapted for diversion of the first portion of the drilling fluid to the piston barrel, and the second position of the drilling fluid to the bypass tube(s).

[0026] In some embodiments, the diversion of the drilling fluid at the valving set is metered.

[0027] In another aspect of the invention, there is provided a system comprising a single flow drill pipe configured to deliver a flow of drilling fluid; and a fluid hammer according to the first aspect of the invention, in fluid communication with the single flow drill pipe.

[0028] A method of modifying a fluid hammer, comprising attaching a valving set and at least one external bypass tube to a body of the fluid hammer.

[0029] Various features, aspects, and advantages of the invention will become more apparent from the following description of embodiments of the invention, along with the accompanying drawings in which like numerals represent like components.BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Embodiments of the invention are illustrated by way of example, and not by way of limitation, with reference to the accompanying drawings, which are briefly described below.

[0031] Figure 1 is a cross-sectional view of the fluid hammer according to an embodiment of the present invention, wherein the bypass tubes are parallel to the piston barrel.

[0032] Figure 2 is a cross-sectional view of the fluid hammer according to an aspect of the present invention, wherein the bypass tube(s) comprise expulsion ports that are bent to face away from the drill bit.

[0033] Figure 3 is an exploded view of the bypass tube according to an aspect of the present invention, wherein a cavity is machined throughout the length of the stabilisation wings, and a face plate welded on to cover the cavity to form a bypasstube.

[0034] Figure 4 is a cross-sectional view of the fluid hammer according to an aspect of the present invention, wherein the bypass tubes comprise expulsion ports facing away from the drill face in addition to the expulsion ports parallel to the piston barrel.

[0035] Figure 5 is top perspective view of Figure 3 according to an aspect of the present invention, where the face plate is shown disassembled and in turn welded to form a bypass tube.

[0036] Figure 6 is an illustration of the fluid hammer according to aspect of the present invention, wherein the bypass tube(s) comprise expulsion ports that are bent to face away from the drill bit.

[0037] Figure 7 is an alternative view of the fluid hammer of Figure 6, showing the whole length of the fluid hammer comprising expulsion ports that are directed to face away from the drill bit.

[0038] Embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which various embodiments, although not the only possible embodiments, of the invention are shown. The invention may be embodied in many different forms and should not be construed as being limited to the embodiments described below.DETAILED DESCRIPTION

[0039] With reference to Figure 1 , there is illustrated a cross-sectional view of a fluid hammer according to an embodiment of the present invention. A flow of drilling fluid 110 is delivered to the fluid hammer 100 via a standard single flow drill pipe (not shown). The standard single flow drill pipe is preferably American Petroleum Institute (API) certified, therefore increasing safety and ease of use for the provided fluid hammer, as opposed to other typical fluid hammers which may require the use of nonAPI certified drill pipes. Although, as a person skilled in the art would appreciate, the present invention is by no means limited to API certified single flow drill pipes, and may be used on a non-approved pipe in some embodiments.

[0040] Following the receipt of the flow of drilling fluid 110 to the fluid hammer 100, the drilling fluid flows to the valving set 120. The valving set 120 controls the flow of drillingfluid within the fluid hammer, and in some embodiments, is also responsible for the diversion of drilling fluid to the piston 130 and bypass tubes 160A, 160B. The fluid hammer 100 includes at least one bypass tube 160A, 160B in fluid communication with the drill bit 190. In some embodiments, the fluid from the bypass tubes 160A, 160B is expelled near the operational end of the fluid hammer at ports 170A, 170B, allowing fluid to be delivered to the drill face of the drill bit 190. The amount of drilling fluid 110 that flows through the bypass tubes 160A, 160B and into the piston 130 is controlled by the valving set 120. The valving set 120 may have a predefined flow, or alternatively, may be adjustable or metered depending on the flow required by each of the fluid passages. When the valving set 120 has a larger diameter, a greater portion of the drilling fluid 110 will be directed into the bypass tubes 160A, 160B, and as such, a lesser volume of the drilling fluid 110 will be directed to the piston 130. Where the valving set 120 has a smaller diameter, a greater volume of the drilling fluid will be directed to the operation of the piston 130 and a lesser volume to the bypass tubes 160A, 160B.

[0041] Reducing the size of the valving set 120 will deliver a greater portion of the drilling fluid into the working components of the hammer 100. At a given pressure and flow rate, for example, 2,000 psi D / T at 6,000 m at 1 ,000 US GPM (US Gallons per minute), reducing the port size will increase the percentage of drilling fluid from 30% to 35% for example and simultaneously reduce the flow rate of drilling fluid to the drill face from 70% to 65%. This reduced diameter of the valving set will increase the strength of the hammer, allowing it to have deliver a greater impact force with a given flow rate. As such, where a drill rig only has the capacity to deliver 1 ,000 GPM and increased piston strike force and / or strike rate is required to break a hard rock formation, then reducing port size (diameter) of the valving set is one means of both improving drill bit life and penetration rates. An increased volume of drilling fluid 110 to the piston 130 via the valving set 120 can also provide a greater cycle rate of the piston 130. Conversely, reducing the flow of drilling fluid 110 to the piston 130 will reduce the piston cycle rate.

[0042] If the geology is softer, it may be advantageous to adjust the flow of the drilling fluid 110 at the valving set 120 to divert more of the flow into the bypass tubes 160A, 160B. This is due to the fact that this will result in more expulsion of drilling fluid at the ports 170A, 170B of the bypass tubes 160A, 160B, such that more fluid is surrounding the drill bit 190. This will result in the hammer hitting with less force (as piston 130 cycles less and with less pressure) and will assist with the flushing of the drill cuttingswhere penetration rates are faster due to soft geology. This results in more drill cuttings in the annulus of the well to push to the surface, needing higher flow rates to flush them back to the surface. The portion directed to the piston 130 is also expelled to the drill face at the drill bit 190 through at least one port 180A, 180B. It will be appreciated that when the flow to the piston 130 is restricted for operational reasons, that the bypass tubes 160A, 160B allow for sufficient drilling fluid to reach the drill face in its absence. At least 95% of all drilling fluid 110 delivered to the fluid hammer 100 is expelled near the drill face near the drill bit 190 after flowing in various capacity through the piston 130 and bypass tubes 160A, 160B.

[0043] In some embodiments, the valving set 120 is set and fitted to the fluid hammer before fixing the fluid hammer 100 in the well, and will remain set until such time the fluid hammer is removed for repairs. Common repairs may include to replace the wear sleeves of the piston (not explicitly shown) and the drill bit 190. At this time, the valving set 120 may be altered to suit the geology encountered through the process of forming the well. In other embodiments, the valving set 120 may be adjustable in nature. This may be advantageous as it will allow for adjustment even in the event that the fluid hammer 100 is not removed from the well. This is particularly advantageous in the present invention, as the repair rate on the fluid hammer as disclosed is likely to require less repair than comparable dual circulation fluid hammers, as well as industry standard API fluid hammers. One disadvantage with the industry standard hammers, is the high wear rate on the internal wear sleeves and drill bit due to the inability to control the flow through the internal components. In some embodiments, the reduction of flow through the valving set 120 may help present a high pressure cushion of drilling fluid at the drill face, a common problem in the industry. This may be yet another advantage.

[0044] In some embodiments, the valving set 120 is a component of the bypass tubes 160A / 160B, thereby capable of directly effectuating flow through the bypass tubes by, for example, having an adjustable diaphragm to selectively increase or decrease flow therethrough.

[0045] In some embodiments, the fluid hammer 100 receives a flow of drilling fluid 110, and delivers a metered portion to the drill bit face 190 and operates on the reaming portion of the drilling fluid, while limiting the drilling fluids degenerating effect on the fluid hammer's internal components, especially the piston 130. This particular embodiment would preferably be used in areas where geology is soft, resulting in themetering of the majority of the water to the bypass tubes 160A, 160B, to flush cuttings, and operating on minimal drilling fluid at the piston 130, which would not need a high strike rate for such a geology.

[0046] In reference to Figure 1 yet again, there is provided a fluid hammer 100 which is adapted to receive a flow of drilling fluid 110 which is passed therethrough to the valving set 120. The valving set 120, as discussed, is adapted to deliver a first portion of the drilling fluid 110 to the piston 130 in the piston barrel 150 and a second portion to the bypass tubes 160A, 160B. As discussed, throughout, the amount of drilling fluid diverted to each component of the fluid hammer 100 will depend on the drilling requirements, surrounding geology, and operational requirements, including strike rate and pressure. The bypass tubes may be disposed throughout the length of the stabilisation wings 210A, 210B. As will be appreciated, there may be any number of bypass tubes, and each bypass tube 160A, 160B would be preferably housed within a stabiliser wing 210A, 210B, allowing the operation of the piston 130 within the piston barrel 150. In other embodiments, the stabiliser wings are absent, and the bypass tubes are disposed throughout the length of the piston barrel, without affecting normal operation of the piston. Disposed around the piston 130 is at least one wear sleeve 200A, 200B. The wear sleeve components 200A, 200B are commonly replaced during drilling operations, as they wear out as the piston 130 performs work and is operated by the drilling fluid 110, which contains fluid and dirty water in some cases. After the operational portion of the drilling fluid 110 is delivered to the piston 130 to perform work, it is then expelled at the drill bit face 190 through at least one port 180A, 180B. Similarly, the second portion delivered to the bypass tubes 160A / 160B is expelled near the drill bit face 190 through a port 170A, 170B. The fluid hammer 100 may be coupled to a standard single flow drill pipe (not shown) through the threading shown near the entry of the drill fluid 110.

[0047] In some embodiments, the drilling fluid 110 may be a water-based fluid, made from water and various additives including clays, polymers, and weighing agents. In another embodiment, the drilling fluid 110 may be freshwater fluid that includes spud, bentonite, natural, phosphate treated fluids, organic fluid and organic colloid treated fluid. It will appreciated by those skilled in the art that the drilling fluid 110 could be any fluid with various additives as defined by the industry standard. This may include, but is not limited to low solid fluid, emulsions, oil based fluid, synthetic-based fluids, air and foam-based fluid, high-density fluids, non-damaging fluids.

[0048] Whilst not explicitly illustrated in the cross-sectional view of the fluid hammer, the body of the fluid hammer 100 may be comprised of a plurality of components. Such components can include a further piston barrel, a top substructure, a drive substructure and other suitable components as understood by those skilled in the art which may increase the operational ability of the fluid hammer 100. The fluid hammer in Figure 1 contains a piston 130 housed within a wear sleeve 200A, 200B which is further housed within a piston barrel 150. The piston 130 is configured to translate in a reciprocating motion, the reciprocating motion defining a stroke length. In various instances, and depending on the portion of drilling fluid 110 diverted to the piston 130 for operation, the piston 130 can operate at about 10-25 cycles (a reciprocated stroke i.e. , 2 strokes) per second. As discussed throughout, the piston cycle rates can be increased with an increase of pressure of the fluid or fluid delivered to the fluid hammer 100.

[0049] In some embodiments, as the piston 130 moves, it strikes the drill bit 190 at an interface on one end of the piston 130. On the opposing end, the piston strikes the valving set 120. In some embodiments, the valving set 120 can be positioned around the piston 130. The valving set 120 is configured to generate the movement of the piston 130 through the injection of drilling fluid 110, as a person skilled in the art of fluid driven hammers and hydraulics would appreciate.

[0050] In some embodiments, one or more wear sleeves 200A, 200B may be positioned between the piston 130 and the piston barrel 150. As the piston 130 moves in its reciprocating motion, friction between the piston 130 and the piston barrel 150 can cause the piston 130 or the piston barrel 150 to degrade over time. Although the operation of the piston 130 with drilling fluid 110 in a controlled way through the valving set 120 reduces this degradation relative to other fluid fluid hammers, it still presents a wear issue regardless, as those skilled in the art would appreciate and understand. To prevent this degradation, a wear sleeve 200A, 200B helps prevent the wear between the two parts, instead transferring the wear to the wear sleeves which can be easily removed and replaced at a marginal cost compared to the piston 130 or piston barrel 150.

[0051] The one or more wear sleeves 200A, 200B may be comprised of any suitable wear material, for example, tungsten, bizaloy, carbon, or diamond impregnated steel. A person skilled in the art will appreciate that this is by no means limiting, and could be extended to any steel material with a high proportion of carbon and manganese in theirmicrostructure. Alternatively, commonly employed wear resistant materials may include tin bronze, leaded bronze, gunmetal, brass and aluminium bronze.

[0052] The wear sleeve 200A, 200B is replaceable upon degrading to a wear limit where the wear sleeve 200A, 200B is unable to prevent contact between the piston 130 and the piston barrel 150. Preferably, the wear sleeve would be constructed from a material which is able to last as long as the drill bit 190 so as to allow maximum operation of the fluid hammer 100 before it must be removed and repaired for further drilling.

[0053] In embodiments where the fluid hammer 100 includes the valving set 120 that strikes the piston 130 for operation, then the fluid hammer may comprise a further wear sleeve in the contact position between the valving set 120 and the piston 130. This helps reduce contact between the piston 130 and the valving set 120 during operation. The fitting of wear sleeves, regardless of between which components, which could also include a further wear sleeve between the piston 130 and the drill bit 190 may reduce degradation-inducing effects of the operation of the fluid hammer 100 and therefore prolong the operational lifetime of the fluid hammer 100.

[0054] In some embodiments, the fluid hammer 100 includes at least one bypass tubes 160A, 160B. This is not limited, and may comprise 3, 6 or 9 bypass tubes in some instances, or 1-2. In some aspects, the bypass tubes 160A, 160B are disposed through the stabiliser wings 210A, 210B. In some embodiments, the bypass tubes 160A, 160B are disposed through the piston barrel. In others, the bypass tube(s) are centred with respect to the axis of the piston 130 thereby creating a flow through the piston in a centre bypass arrangement. The bypass tubes 160A, 160B are in fluid communication with the drill bit 190 through a terminal port 170A, 170B at the end of each of the bypass tubes 160A, 160B. The fluid hammer 100 in some embodiments is configured such that a metered portion of the drilling fluid 110 is delivered to the fluid hammer 100, and diverted to the bypass tubes, while a remaining portion is delivered to the piston 130 for operation. Metering the delivery between the two components may be advantageous, as this allows the control of fluid delivered to the drill bit 190 face, preventing the high pressure cushion problem that can arise when too much drilling fluid 110 is delivered to the drill face.

[0055] In various aspects of the present invention, the valving set 120 can be a singlevalve or adapter or can be multiple valves or adapters and a combination thereof. The valving set 120 can be configured to deliver 80% of the flow of the drilling fluid 110 to the bypass tubes 160A, 160B, and 20% to the piston 130. In other embodiments, the valving set 120 may be set so that only a constant portion of the drilling fluid is delivered to the bypass tubes 160A, 160B and the remainder to the piston 130 or vice versa. The valving set 120 may be adjustable so that the drill operator can adjust the flow depending on the geology encountered during operation. In such aspects, the adjustability provides drill operators with the ability to alter the amount of flow to the drill face.

[0056] The fluid hammer 100 includes a drill bit 190. In some aspects, the drill bit 190 is coupled to the body of the fluid hammer 190 such that it is removable when worn. The drill bit 190 contains a drill face, which has been referred to throughout, and is understood as those skilled in the art would understand. The drill bit 190 may include in most embodiments two or more exit ports 180A, 180B which is in fluid communication with the piston 130. The ports 180A, 180B are adapted to expel the first or operational portion of the drilling fluid 110 which has been directed by the valving set 120 to the piston 130. The fluid expelled from these ports helps, in addition to the fluid expelled from the bypass tubes 160A, 160B ports 170A, 170B to flush away cuttings at the drill face of the drill bit 190. In some embodiments which comprise exhaust ports the exhausted fluid is expelled upward direction away from the drill bit 190.

[0057] The fluid hammer 100 may include one or more exhaust ports along the length of the bypass tubes 160A / 160B to expel drilling fluid 110 close to the surface in the event that the high pressure cushion is starting to form due to an excess of drilling fluid 110 at the drill face of the drill bit 190. These exhaust ports preferably extend from the bypass tubes 160A, 160B and through the stabiliser wings 210A, 210B, such that the fluid would be expelled before it reaches the drill bit 190.

[0058] In various embodiments, the fluid hammer 100 can include any suitable combination of the following components: o-rings, circlips, a distributor, a top barrel or substructure, a check valve or plunger, a y-ring or check valve, a spring, a compression buffer, a bypass tube mount, a bearing bush, one or more bit stop rings and a shroud. The check valve or plunger, t y-ring or check valve, the spring, and / or the compression buffer can comprise the valving set. In some instances, the bearing bush can be cold pressed. In some instances the bit stop ring can be an O-ring.

[0059] The fluid hammer 100 can be positioned in a drilling well. The drilling fluid 110 can be directed to the fluid hammer 100 via the single flow drill pipe (not shown expressly). The single flow drill pipe can be any suitable, standard API-certified drill pipe. In one particular embodiment, the fluid hammer 100 in a drilling well is constructed to operate on drilling fluid, which enables directing the single flow of drilling fluid 110 to the fluid hammer. This is in comparison to at least some typical dual circulation fluid hammers which require a drill pipe system to separate drilling fluid from clean water. At least some of these dual circulation fluid hammers are unable to be adapted to operate via a single drill flow pipe due to high wear of the components, and in some circumstances, complete breakdown of the fluid hammer due to the drilling fluid viscosity. In cases where adaptation has occurred, there is inefficient fluid or fluid hammer requirements as compared to the fluid hammer as described herein.

[0060] Referring to Figure 2, there is provided a fluid hammer 100 as described above and throughout the specification. However, the bypass tubes 160A, 160B comprise expulsion ports that are bent to face away from the drill bit 190. Whilst the drilling fluid 110 is still expelled in the vicinity of the drill bit 190, the reverse facing ports may create a vortex effect, providing an improved method of flushing cuttings. As those skilled in the art would appreciate, the reversal of the direction of the ports may result in an environment where the fluid, curved or straight may form a vortex which revolves around the axis line, being the fluid hammer 100. When the drilling fluids surface is drawn too close to an inlet pipe, it may cause air to enter the system in a suction effect. This suction causes the whirlpool effect that is observed in votex, and generally occurs when there is free surface or air entrainment in the fluid. It is envisaged that the reversal of the direction of ports 170A, 170B from the bypass tubes 160A, 160B may result in such entrainment.

[0061] It may be advantageous to adapt the invention described herein to be retrofitted to an existing standard fluid hammer. In some embodiments, the stabiliser wings 210A, 210B may be pre-fitted with the bypass tubes 160A, 160B and fit over the top of an existing fluid hammer already comprising a fluid or drilling fluid- driven piston 130. In such an embodiment, a person skilled in the art would be required to simply make an adjustment to an existing valving set 120 to pit in fluid communication the input of drilling fluid with the bypass tubes. In some embodiments where a valving set is absent, the person skilled in the art may be required to fit a valving set 120 with the appropriate diversion routes for the drilling fluid.

[0062] Referring now to Figure 3, there is illustrated an exploded view of the bypass tube according to an aspect of the present invention, wherein a cavity is machined throughout the length of the stabilisation wings 210, and a face plate 330 welded on to cover the cavity to form a bypass tube 160. The cavity also comprises an inlet port 300 adapted to receive the flow from the valving set 120 into the bypass tube 160. In this embodiment, once a cavity has been machined, it is envisaged that a face plate 330 may be welded to the stabilisation wing 210 in order to form a bypass tube 160. In some embodiments, the face plate 330 may also contain a plug port 310 adapted to receive a wear plug 320. A person skilled in the art would appreciate that the location of this port may be varied or omitted as required.

[0063] Referring now to Figure 4, there is illustrated a cross-sectional view of the fluid hammer according to an aspect of the present invention, wherein the bypass tube(s) comprise expulsion ports facing away from the drill face in addition to the expulsion ports parallel to the piston barrel. Similarly to the expulsion ports of Figure 1 , this embodiment may still contain an expulsion port 170 parallel to the piston barrel 150. In this particular embodiment, at least one expulsion port may be machined into the stabilisation wings that point away from the drill face. The expulsion ports machined into the stabilisation wings may optionally include a valve 400 to control the flow out, and limit flow away from the drill face in favour of expulsion out of the parallel expulsion port 170.

[0064] Referring now to Figure 5, there is illustrated a top perspective view of Figure 3 according to an aspect of the present invention, where the face plate 160 is shown disassembled and in turn welded to form the bypass tube 160.

[0065] Referring now to Figure 6, there is depicted an alternative illustration of the fluid hammer of Figure 4, wherein the bypass tube(s) comprise expulsion ports facing away from the drill face in addition to the expulsion ports parallel to the piston barrel. Similarly to the expulsion ports of Figure 1 , this embodiment may still contain an expulsion port 170 parallel to the piston barrel 150. In this particular embodiment, at least one expulsion port may be machined into the stabilisation wings that point away from the drill face. The expulsion ports machined into the stabilisation wings may optionally include a valve 400 to control the flow out, and limit flow away from the drill face in favour of expulsion out of the parallel expulsion port 170.

[0066] Referring to Figure 7, there is provided an alternative view of Figure 6, showing the full length of the fluid hammer 100.

[0067] It will be appreciated by persons skilled in the art that numerous variations and modifications may be made to the above-described embodiments, without departing from the scope of the following claims. The present embodiments are, therefore, to be considered in all respects as illustrative of the scope of protection, and not restrictively.

[0068] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present invention, a limited number of the exemplary methods and materials are described herein.

[0069] As used herein and in the appended claims, the singular form of a word includes the plural, unless the context clearly dictates otherwise. Thus, the references "a," "an" and "the" are generally inclusive of the plurals of the respective terms. For example, reference to "a feature" includes a plurality of such "features." The term "and / or" used in the context of "X and / or Y" should be interpreted as "X," or "Y," or "X and Y.

[0070] It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

[0071] In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.LEGENDNo. Description100 Fluid hammer110 Drilling fluid (input)120 Valving set130 Piston150 Piston barrel160A, Bypass tube / s160B170A, Expulsion ports170B180A, Expulsion ports180B190 Drill bit200A, Wear sleeve200B210A, Stabilisation wings210B300 Inlet port310 Stabilisation wing face plate wear plug port320 Wear plug330 Stabilisation face plate400 Adjustable valve

Claims

CLAIMS1. A fluid hammer comprising: a drill bit defining a drill face; a piston barrel configured to receive a flow of drilling fluid; a piston in the piston barrel operated by a first portion of the flow ; and at least one bypass tube disposed exterior to the piston, wherein a second portion of the flow is diverted into the at least one bypass tube, and wherein an outlet of the at least one bypass tube is positioned to deliver drilling fluid proximate the drill face.

2. The fluid hammer of claim 1 , further comprising a valving set positioned at an intake of the at least one bypass tube to divert the second portion of the flow into the at least one bypass tube.

3. The fluid hammer of claim 2, wherein the valving set is adjustable to control flow.

4. The fluid hammer of claim 1 , wherein the valving set diverts approximately 70% of the flow into the bypass tube to form the second portion.

5. The fluid hammer of claim 4, wherein the remaining 30% of the flow forms the first portion for use in the piston barrel for operation of the piston.

6. The fluid hammer of claim 1 , wherein the first portion of the flow is expelled from the piston barrel to the drill face.

7. The fluid hammer of claim 1 , wherein all of the flow of drilling fluid is expelled at the drill face, after flowing through the piston barrel and bypass tube(s).

8. The fluid hammer of claim 1 , further comprising an exhaust adapted to expel some of the drilling fluid from the piston barrel or bypass tube(s).

9. The fluid hammer of claim 1 , wherein the expulsion of drilling fluid at the drill face results in a vortex around the fluid hammer, flushing cuttings away from the drill face.

10. The fluid hammer of claim 1 , wherein the drilling fluid is delivered to the fluid hammer at a rate of approximately 1000 gallons per minute (GPM) at a pressure of 10,000 psi (pounds per square inch).

11. The fluid hammer of claim 1 , wherein the drill bit is operating at a pressure of 2,000 psi.

12. The fluid hammer of claim 1 further comprising at least one bypass tube adapted to exhaust fluid in an upward direction, relative to the drill bit when in use.

13. The fluid hammer of claim 1 , wherein the flow of drilling fluid is delivered through a single flow drill pipe.

14. The fluid hammer of claim 13, wherein the single flow drill pipe is an approved American Petroleum Institute (API) certified drill string.

15. The fluid hammer of claim 1 , further comprising a plurality of stabilising wings.

16. The fluid hammer of claim 15, wherein each bypass tube is disposed throughout the length of one of the stabilising wings.

17. The fluid hammer of claim 15, wherein each stabilising wing comprising a bypass tube comprises a wing body and a face plate extending longitudinally along an outside of the wing body, and wherein the bypass tube is formed between the face plate and a longitudinal cavity formed in the wing body.

18. The fluid hammer of claim 1 , wherein the piston has a stroke length of 20 to 60 millimetres.

19. The fluid hammer of claim 1 , wherein the diversion of the drilling fluid at the valving set is metered.

20. A system comprising: a single flow drill pipe configured to deliver a flow of drilling fluid; and a fluid hammer according to claim 1, in fluid communication with the single flow drill pipe.

21. A method of modifying a fluid hammer, comprising: attaching a valving set and at least one external bypass tube to a body of the fluid hammer.

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