WO2014094125A1

WO2014094125A1 - Methods and devices for filtering

Info

Publication number: WO2014094125A1
Application number: PCT/CA2013/001053
Authority: WO
Inventors: Jason Swist
Original assignee: Jason Swist
Priority date: 2012-12-20
Filing date: 2013-12-19
Publication date: 2014-06-26

Abstract

According to embodiments of the invention a plurality of profiled rods are assembled to provide periodic apertures along the total length of the profiled rods allowing higher fluid extraction rates to be achieved for the same length - diameter of sand screen against those within the prior art. However, the oil sands are not the only application for filtering a fluid to remove particulates. Accordingly, it would be beneficial for the same design principles as applied to the reduction of costs for sand screens to be applied to other filter concepts for fluids. In other applications rather than filtering out particulates it is desirable to reduce the size of the particulates within the fluid such as within waste disposal for example. Accordingly, where the profiled rods are provided with suitable opposing profiles the resultant action of the particulates impacting the profiled rods under pressure is to effectively shred the particulates. Other embodiments provide for separation of fluids with different viscosities but similar densities. It would also be evident that multiple applications within the general processing steps of separating, mixing, drying, and percolating may be envisioned for filters according to embodiments of the invention.

Description

METHODS AND DEVICES FOR FILTERING

FIELD OF THE INVENTION

[001] The present invention relates to filters and more particularly to filters for use in general processing steps of separating, mixing, drying, and percolating.

BACKGROUND OF THE INVENTION

[002] The art of completing wells within the oil and natural gas production industries includes excluding solids particles produced by the well fluids. In many well completions, unwanted formation solids (e.g. sands, fine materials, and other debris) are produced into the well along with the production fluids. These solids are often undesirable and many methods of stopping these solids from flowing into the well whilst producing the fluids are well defined within the prior art.

[003] Within these prior art techniques one common technique is "gravel packing" comprising forming a gravel pack completion, wherein a well screen is lowered into the wellbore and positioned across the interval of the well that is to be completed. Particulate material, collectively referred to as gravel, is then pumped as slurry down the tubing on which the screen is suspended. The slurry exits the tubing above the screen through a "crossover" tool or the like and flows downward in the annulus formed between the screen and the well casing or open hole, as the case may be. The liquid in the slurry flows into the formation and/or the openings in the screen that are sized to prevent the gravel from flowing through them. As the fluid is drawn out of the slurry it dehydrates resulting in the gravel being "screened out" on the screen and in the annulus around the screen where it collects to form the gravel pack. The gravel is sized so that it forms a permeable mass which blocks the flow of any particulates produced with the formation fluids. Whilst gravel packing has benefits in increasing the completion's durability in weak and heterogeneous formations; however, such prior art methods for gravel packing vertical wells are not suited for inclined wells and long horizontal wells, the latter occurring for example within oil sand production environments.

[004] One of the main problems with gravel packing, especially when long horizontal or inclined intervals are completed, is obtaining uniform distribution of the gravel along the entire completion interval and completely packing the annulus between the screen and the casing (in cased hole completions) or between the screen and the wellbore (in open hole completions). Accordingly, within the prior art a number of methods of installing particulate control, commonly referred to as sand control, within such oil sand production wells have been established. Sand control exploits a sand screen to separate sand particles from other materials allowing users to harvest oil products without also collecting the sand nearby. These sand screens are also used on a smaller scale in many industrial and mining applications to separate sand from the material being collected. They are typically made of metal, and can vary in size depending on the application. Whilst one sand screen may be carried by an individual another sand screen may extend for thousands of feet (or meters) below the surface of the earth through the production zone of the oil sand reservoir.

[005] In terms of global oil reserves then these are dominated by a relatively small number of nations as shown below in Table 1. With the exception of Canada the vast majority of these oil reserves are associated with conventional oil fields exploiting vertical drilling into pressurized reservoirs. In contrast, the Canadian reserves which are dominated by the Athabasca oil sands are large geographically distributed deposits of bitumen, or extremely heavy crude oil, within a thin geological layer. The stated reserves of approximately 170,000 billion barrels are based upon approximately 10% of total actual reserves. These being those considered economically viable to recover in 2006.

Table 1 : Top 15 Oil Reserve Nations [006] Accordingly, a number of methods for drilling long horizontal (greater than 200 m) or deviated wells (greater than 80° from vertical) have been developed together with techniques for installing sand control within these wells. However, whilst there are many designs of sand screens within the prior art and multiple manufacturers supporting different tube diameters, typically within the range 3" (75mm) to 6" (150mm), different lengths, typically 10 feet (3m) to 32 feet (10m), and different apertures, typically 0.008" - 0.040" (0.2mm - 1.0mm), one common element is their high cost. Accordingly, it would beneficial to provide sand screens which provide comparable design parameters but with reduced cost.

[007] According to embodiments of the invention a plurality of profiled rods are assembled to provide periodic apertures along the total length of the profiled rods allowing higher fluid extraction rates to be achieved for the same length - diameter of sand screen against those within the prior art. However, the oil sands are not the only application for filtering a fluid to remove particulates. Accordingly, it would be beneficial for the same design principles as applied to the reduction of costs for sand screens to be applied to other filter concepts for fluids.

[008] In other applications rather than filtering out particulates it is desirable to reduce the size of the particulates within the fluid such as within waste disposal for example. Accordingly, where the profiled rods are provided with suitable opposing profiles the resultant action of the particulates impacting the profiled rods under pressure is to effectively shred the particulates. Other embodiments of the invention rather than exploiting stationary elements include the addition of one or more rotary elements.

[009] In other applications rather than filtering out particulates it is desirable to add a fluid to particulates such as mixing and / or drying wherein the particulates should be maintained within a container that allows the fluid or fluids to ingress into the container.

[0010] Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures.

SUMMARY OF THE INVENTION

[0011] It is an object of the present invention to mitigate limitations in the prior art with respect to filters and more particularly to filters for use in general processing steps of separating, mixing, drying, and percolating. [0012] In accordance with an embodiment of the invention there is provided a method comprising:

providing a filter, the filter comprising:

an outer body comprising a tube of predetermined cross-section and at least one opening of a plurality of openings;

a spring having a predetermined cross-section and a predetermined gap between adjacent turns of the spring spiral;

a first end cap retaining a first end of the spring in the outer body at a first predetermined location;

a second end cap retaining a second distal end of the spring in a predetermined relationship to the first end of the spring wherein the gap between adjacent turns of the spring spiral is lower than the predetermined gap; flowing a fluid into the filter inside the spring, the fluid comprising a fluid component and a particulate component through the filter; wherein

the first fluid component and those particulates within the particulate component smaller than the gap may pass from the inside of the spring to the outside of the spring and out through the at least one opening of the plurality of openings.

[0013] In accordance with an embodiment of the invention there is provided a

providing a plurality of profiled rods in a predetermined geometry providing a tube of predetermined cross-section, each profiled rod of the plurality of rods having a surface profile according to a predetermined template;

a first end plate connected to a first end of each of the plurality of rods to retain them in position relative to one another;

a second end plate connected to a second distal end of each of the plurality of rods to retain them in position relative to one another;

wherein adjacent profiled rods define a plurality of holes from the inside of the tube to the outside of the tube, each hole of the plurality of holes being of dimensions determined by the surface profiles of the respect adjacent profiled rods.

[0014] In accordance with an embodiment of the invention there is provided a

providing a filter comprising: providing a plurality of profiled rods in a predetermined geometry providing a tube of predetermined cross-section, each profiled rod of the plurality of rods having a surface profile according to a predetermined template;

wherein adjacent profiled rods define a plurality of holes from the inside of the tube to the outside of the tube, each hole of the plurality of holes being of dimensions determined by the surface profiles of the respect adjacent profiled rods;

moving the filter through a fluid with the upper end higher than the lower end, the fluid comprising first and second fluid components having similar densities but different viscosities, the first fluid component having the higher viscosity;

wherein the first fluid component is preferentially retained by the plurality of profiled rods.

[0015] In accordance with an embodiment of the invention there is provided a

providing a filter comprising:

providing a plurality of profiled rods in a predetermined geometry, each profiled rod of the plurality of rods having a surface profile according to a predetermined template;

an upper end plate connected to a first end of each of the plurality of rods to retain them in position relative to one another;

a lower end plate connected to a second distal end of each of the plurality of rods to retain them in position relative to one another;

flowing through the tube formed by the plurality of profiled rods a fluid comprising first and second fluid components having different viscosities, the first fluid component having the higher viscosity;

rotating the filter at a predetermined rate wherein the first fluid component is preferentially retained within the tube and the second fluid component flows through the holes formed by the plurality of profiled rods.

[0016] Other aspects and features of the present invention will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments of the invention in conjunction with the accompanying figures. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Embodiments of the present invention will now be described, by way of example only, with reference to the attached Figures, wherein:

[0018] Figure 1 depicts slotted sand screens according to the prior art;

[0019] Figure 2 depicts sand screens according to the prior art;

[0020] Figure 3 depicts a spring based sand screen according to the prior art;

[0021] Figures 4A and 4B depicts adjustable filtering particulate dimensions using a spring based sand screen according to the prior art and an embodiment of the invention;

[0022] Figure 5 depicts a profiled rod filter according to an embodiment of the invention;

[0023] Figure 6 depicts perspective views of the profiled rod filter according to the embodiment of the invention in Figure 5;

[0024] Figures 7A and 7B depict a profiled rod filter according to an embodiment of the invention;

[0025] Figure 8 depicts profiled rod filters according to embodiments of the invention;

[0026] Figure 9 depicts profiled rod filters according to embodiments of the invention;

[0027] Figure 10 depicts a profiled rod filter according to an embodiment of the invention;

[0028] Figure 1 1 depicts a profiled rod based rotating filter according to an embodiment of the invention;

[0029] Figure 12 depicts a profiled rod based rotating filter according to an embodiment of the invention;

[0030] Figure 13 depicts examples of profiles for profiled rods for use with profiled rod filters according to embodiments of the invention; and

[0031] Figure 14 depicts an example of a threaded rod filter for filtering fluids according to an embodiment of the invention.

DETAILED DESCRIPTION

[0032] The present invention is directed to filters and more particularly to filters for use in general processing steps of separating, mixing, drying, and percolating.

[0033] The ensuing description provides exemplary embodiment(s) only, and is not intended to limit the scope, applicability or configuration of the disclosure. Rather, the ensuing description of the exemplary embodiment(s) will provide those skilled in the art with an enabling description for implementing an exemplary embodiment. It being understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope as set forth in the appended claims.

[0034] Figure 1 depicts a perspective view 100 of a slotted sand screen according to the prior art wherein the slotted sand screen is defined by a series of parameters. These include inner diameter of the slotted sand screen, the wall thickness, an inner diameter slot dimension, an outer diameter slot dimension, and a column / row count of the number of slots per column and the number of columns. The sand screen body between slots within a column being defined as the rib and the body between adjacent columns being defined as the ring. Referring to first to third patterns 1 10, 120, and 130 it can be seen that different patterns of slots can be employed. In first pattern 1 10 a standard line pattern is depicted wherein the slots 1 12 within the body 1 14 are disposed such that slots within adjacent columns form a row. In second pattern 120 a staggered pattern is depicted wherein the slots 122 within the body 124 are disposed such that they are within a row column to column but the position of slots within the column varies according to a predetermined pattern of offsets. In third pattern 130 a so-called multiple staggered pattern is depicted wherein the pattern is similar to that depicted in second pattern 120 but now the single slots 122 are slot pairs 132 within the body 134.

[0035] Referring to Figure 2 there are depicted sand screens according to the prior art. First sand screen 210 depicts an example of a punched slot screen, also known as a Johnson Screen, which consist of a perforated base pipe 214 and a stainless steel filtration jacket 212 with punched slots in conjunction with end rings 216 allowing them to be cascaded sequentially for the length of the oil well. Second sand ring 220 similarly comprises a perforated base pipe 222 but exploits a series of permeable layers 224 and is protected by a perforated shroud 226. Also depicted is punched screen 230 which is commonly employed to provide protection for a sand screen as is continuous slot screen 240.

[0036] Now referring to Figure 3 there is depicted a spring based sand screen 300 according to an embodiment of the invention comprising an outer shell 310 and spring 320. As depicted in Figure 4A the outer shell 310 has first and second opening sets 440A and 440B respectively and threaded portions 410 allowing first and second end caps 450A and 450B respectively to be attached. As depicted first end caps 450A result in a first compression of the spring 320 resulting in gaps of width G_t whilst second end caps 450B result in a second compression of the spring 320 resulting in gaps of width G₂ . Alternatively, common end caps may be applied and according to the extent they are applied at the ends of the outer shell 310 the gaps between the coil of the spring may be adjusted. Optionally, the spring 320 may be attached to a linear drive allowing the gap to be dynamically adjusted such that should the particulates within the fluid being filtered are large the spring 320 can be set for wider gaps and faster fluid flow and conversely where the particulates are small the spring 320 can be set for smaller gaps. Particulate dimensions may be established from one or more techniques known within the prior art.

[0037] Now referring to Figure 4B there is depicted a variation of the spring based sand screen according to an embodiment of the invention. Unlike spring 320 in Figure 4A where constant cross-section of the spring coil was employed in the prior art the spring 480 in Figure 4B has a an outer surface that is profiled, e.g. the spring 480 had a thread applied or other repeating profile to the coil material prior to the spring 480 being formed. As depicted first end caps 450A again result in a first compression of the spring 480 resulting in gaps of width G_x - FN(L) + Th_GAP such that the gap is a variable element, FN(L), with a constant element, Th_GAP , whilst second end caps 450D result in a second compression of the spring 480 such that it is fully compressed such that G₂ = Th_GAP . Alternatively, a common end cap may be applied and according to the extent they are applied at the ends of the outer shell 310 the gaps between the coil of the spring may be adjusted. Optionally, the spring 480 may be attached to a linear drive allowing the gap to be dynamically adjusted such that should the particulates within the fluid being filtered are large the spring 480 can be set for wider gaps or where faster fluid flow is required through the filter. Conversely where the particulates are small the spring 480 can be set for smaller gaps. Full compression of the spring 480 results in the gap being set to the minimum value G₂ = Th_GAP which may be under some circumstances be defined as normal operating condition with maximum particulate dimension established by G₂ = Th_GAP . Subsequently, should pressure relief be required the end caps can be moved allowing the spring gap to increase and higher fluid flow to occur albeit with increased particulate dimensions allowed. In expanded view 4000F first and second spring coil sections 460A and 460B are depicted at full compression with the gap 470 defined by the profiled cross-section of the spring coil 480.

[0038] Now referring to Figure 5 there is depicted a profiled rod filter 500A according to an embodiment of the invention comprising a plurality of profiled rods 520 arranged in a circular pattern and coupled at either end to threaded flanges 510. End view 500B shows the arrangement of rods 520 in a circular pattern with the threaded flange 510 whereas cross- section 500C along section X-X similarly shows the rods 520 and threaded flange 510. As evident the rods 520 are disposed in a circular pattern touching each other but as the rods have a profile then there are a plurality of gaps along the region where two rods 520 touch allowing liquid to flow and restricting particulates. Accordingly the depth of the profile, the width of the profile, and the profile shape itself on the rods 520 contribute to defining the maximum particulate dimension fitting through the gaps between the rods 520.

[0039] Referring to Figure 6 there is depicted a first perspective view 600A of the profiled rod filter according to the embodiment of the invention depicted in Figure 5 showing the plurality of rods 520 and two threaded flanges 510. An example of profiled rod 520 being depicted in second perspective view 600B which is a threaded rod of pitch P . As depicted in third perspective 600C a pair of profiled rod filters 600 are joined together with a flange 630 allowing a long sand screen to be formed from a plurality of profiled rod filters 600. It would be evident to one skilled in the art that where the profiled rod 520 is a threaded rod that the thread may be selected from one of the standard threads, including but not limited to, ISO metric, BSP, ASME B l . l Unified Inch Screw Thread, Unified Thread Standard, National Pipe Standard, British Standard Whitworth, British Standard Buttress, Aerospace Threads. However, other non-standard threads may be employed according to their pitch, lead distance, number of starts, thread angle, thread depth, profile etc. Alternatively, profiled rod 520 may be profiled without employing a spiral thread with the rod defined by similar characteristics such as effective pitch, depth, side wall profile, overall profile, etc.

[0040] Now referring to Figure 7A there is depicted a profiled rod filter 700A according to an embodiment of the invention comprising a plurality of profiled rods 720 arranged in a circular pattern and coupled at either end to threaded flanges 710. End view 700B shows the arrangement of rods 720 in a circular pattern with the threaded flange 710 whereas cross- section 700C along section X-X similarly shows the rods 720 and threaded flange 710. As evident the rods 720 are disposed in a circular pattern touching each other but as the rods have a profile then there are a plurality of gaps along the region where two rods 720 touch allowing liquid to flow and restricting particulates. Accordingly the depth of the profile, the width of the profile, and the profile shape itself on the rods 720 contribute to defining the maximum particulate dimension fitting through the gaps between the rods 720. Referring to Figure 7B there are depicted first to third perspective views 700B through 700D respectively of the profiled rod filter according to the embodiment of the invention depicted in Figure 7A.

[0041] Referring to Figure 8 there is depicted a profiled rod filter 800A according to an embodiment of the invention comprising a plurality of profiled rods 820 arranged in a circular pattern and coupled at either end to flanges 810. End view 800B shows the flange 810 with arrangement of mounting holes 830 allowing the each flange 810 to either be bolted to another flange 810 for joining two profiled rod filters 800A or joining the profiled rod 800A to another element of the fluid system. First cross-section 800C represents a cross- section along section X-X showing the rods 820 in a circular pattern with the flange 810 whereas second cross-section 800D shows a design variation wherein thick rods 830 of a larger dimension than those depicted in first cross-section 800C are disposed around a plain flange 840 of similar diameter to flange 810. In each instance the rods 820 and thick rods 830 are disposed in a circular pattern touching each other but as the rods have a profile then there are a plurality of gaps along the region where two rods touch allowing liquid to flow and restricting particulates. Accordingly the depth of the profile, the width of the profile, and the profile shape itself on the rods contribute to defining the maximum particulate dimension fitting through the gaps between the rods. Rods with standard thread, non-standard thread, and non-thread profiles such as described above in respect of Figure 5 and 6 may be employed with varying pitch, lead, and profile to define profiled rod filters with different maximum particulate dimensions passing through the holes (or alternatively specified as minimum particulate dimension filtered out).

[0042] Referring to Figure 9 there are depicted first to third profiled rod filter cross-sections 900A through 900C respectively according to embodiments of the invention. As depicted first cross-section 900A shows a square array of rods whereas second cross-section 900B whilst depicting a similar square array but with alternating large and small diameter rods. Third cross-section 900C depicts circular arrays of rods of constant dimension but now with two circular arrays symmetrically disposed. It would be evident to one skilled in the art that other geometric configurations of rods may be deployed with one, two, or more different rod diameters. Alternatively, rods of constant diameter may be employed but with different profiles on different combinations / sub-sets of rods.

[0043] Figure 10 depicts a profiled rod filter 1000 according to an embodiment of the invention wherein a plurality of rods 1020 are disposed in a configuration such as described above in respect of Figures 5 through 9 respectively which are coupled at either end to flange 1010 which has a central opening 1030 and bolt holes 1060A. Also disposed between each flange 1010 around the plurality of rods 1020 is outer shell 1040 which is attached to the flange 1010 via shell bolt holes 1060B that mate with bolt holes 1060A (the bolts being omitted for clarity). Outer shell 1040 having holes 1050 allowing fluid flowing into the profiled rod filter 1000 via central opening 1030 that has been passed through the openings provided by the plurality of rods 1020 to flow through these holes 1050.

[0044] Now referring to Figure 1 1 there is depicted a profiled rod rotating filter 1 100 according to an embodiment of the invention comprising an outer shell 1 130 with holes 1 140. Disposed within the outer shell 1 130 and axially aligned with it are inner profiled rod filter comprising a plurality of first profiled rods 1 1 10 mounted to first flange 1 180 and outer profiled rod filter comprising a plurality of second profiled rods 1 120 mounted to second flange 1 160. Disposed between first and second flanges 1 180 and 1 160 respectively is first rotary joint 1 170, e.g. a ball bearing race, and similarly disposed between second flange 1 160 and outer shell 1 130 is second rotary joint 1 150. Accordingly, each of the first and second profiled rod rotating filters may rotate freely within the outer shell 1 130 under mechanical drive from a driver mechanism, e.g. a motor, not shown for clarity. Optionally, first rotary joint 1 10 may be a fixed joint such that the first and second profiled rod rotating filters are coupled and rotate under a single drive mechanism. Alternatively, first and second profiled rod rotating filters are coupled to a drive mechanism comprising a driver mechanism, e.g. motor, and a gearbox such that there is predefined ratio of rotation rates between the first and second profiled rod rotating filters. This may be configured for the inner profiled rod rotating filter to be rotating faster than the outer profiled rod rotating filter or vice-versa. It would be further evident that first and second profiled rods 1 1 10 and 1 120 respectively may be of the same design or different designs including rod diameter, profile, pitch, lead, profile depth etc. Potentially one or both of first and second profiled rod rotating filters may also exploit multiple rod profiles / diameters within it or may comprise multiple sets of radially positioned rods. Optionally, the number of profiled rod rotating filters may be increased where filters follow a predetermined rotation rate profile from the innermost to the outermost.

[0045] Now referring to Figure 12 there is depicted a profiled rod rotating filter 1200 according to an embodiment of the invention of similar design to that discussed supra in respect of Figure 1 1 comprising inner profiled rod filter, comprising first profiled rods 1210 and first flange 1280, and outer profiled rod filter, comprising second profiled rods 1220 and second flange 1260, first and second rotary joints 1250 and 1270 all housed within outer shell 1230 with holes 1240. However, unlike profiled rod rotating filter 1 100 the profiled rod rotating filter 1200 has the first and second profiled rods 1210 and 1220 in close proximity to one another. Accordingly, material within the fluid flowing within the inner bore of the profiled rod rotating filter 1200 may, where these inner and outer profiled rod filters are rotating at different rates, be sheared or cut by the action of the first and second profiled rods 1210 and 1220 acting in conjunction with one another.

[0046] In another deployment of the profiled rod rotating filter 1200 the rod assembly or assemblies may be rotated at a high angular rotation rate wherein if a fluid mix comprising different fluid components is contained within the inner region of the profiled rod rotating filter 1200 then the resulting motion induced within the fluid results in those fluid components with low viscosity flowing through the gaps between the profiled rods whereas those fluid components with high viscosity cannot such that the fluid mix, with time for a fluid mix with zero or low flow along the axis of the profiled rod rotating filter 1200 or distance along the profiled rod rotating fluid 1200 for a fluid mix with flow along the axis of the filter, changes with low viscosity fluid elements being dispelled and the higher viscosity elements being retained to the centre. It would be evident to one skilled in the art that the concept may be extended such that multiple rings of rod filters separate fluid elements by viscosity or that the fluid mix may be flowed through a sequential series of rod filters with different designs and / or rotational characteristics.

[0047] Now referring to Figure 13 there are depicted first to ninth exemplary profiled rod profiles 1310 through 1390 respectively, representing British Standard Whitworth, I.S.O. Taper Pipe, U.S. Pipe Taper, Trapezoidal, I.S.O. Unified, I.S.O. Metric, British Standard Cycle, B.A. and U.S. Pipe Straight profiles. These in addition to others discussed supra and designs particular to the manufacturer of the profiled rod filters may be employed singly or in combination upon profiled rods within one or more of the designs discussed supra in respect of Figures 3 through 12. Accordingly profiles with flat tops, flat bottoms, pointed tips, sharp grooves, etc may be employed. In some configurations of the profiled rod filters the profile may be applied on only a portion of the outer surface of the rod with smooth or flattened regions to the remainder of the rod surface such that, for example, the inner bore through the profiled rod filter is free of contours allowing eased access for tools within the bore in some applications such as drilling. In others the outer surface may be smooth such that the profiled rod filter can be easily inserted into an external jacket or into a drilled bore for example.

[0048] Referring to Figure 14 there are depicted first and second threaded rod filters 1400A and 1400B respectively according to embodiments of the invention. In each of the first and second threaded rod filters 1400A and 1400B a plurality of threaded rods 1420 are disposed between an upper plate 1410 and a lower plate 1430. Lower plate 1430 comprises a plurality of feed-through 1440 accessing a container element 1450. Accordingly first and second threaded rod filters 1400A and 1400B respectively may be employed either statically with a flow comprising mixed fluids or dynamically within a pool comprising mixed fluids. Where the mixed fluids are of comparable density, such as some oils and water for example, but different viscosities conventional separation based filtering techniques cannot be applied an alternative technique is required. With first and second threaded rod filters 1400A and 1400B respectively the mixed fluid component with higher viscosity will become attached to the threaded rods 1420 whereas the mixed fluid component with low viscosity would flow around the threaded rods 1420. Once attached to the threaded rods 1420 the high viscosity component would tend to remain attached but flow down the threaded rods 1420 to the lower plate 1430 wherein it will flow through the feed-throughs 1440 into the container element 1450. First and second threaded rod filters 1400A and 1400B respectively differ in separation of the threaded rods 1420 but it would be evident to one skilled in the art that they may equally differ in rod diameter, thread pitch, thread lead, etc such as described supra in respect of other embodiments of the invention exploiting threaded rods.

[0049] It would be evident to one skilled in the art that the discussions supra in respect of Figures 5 through 14 have been discussed primarily with respect to profiled rods of circular cross-section and assembled geometries that are similarly predominantly circular. However, rods that are square, rectangular, hexagonal, regular polygons, and irregular polygons may also be employed with profiled geometries. Additionally, profiled rods may be alternated with non-profiled rods or rods of different dimensions, profile, cross-section etc may be alternated. Similarly, the overall cross-section may comprise a single circular geometry or a single square, rectangular, hexagonal, regular polygonal, and irregular polygonal geometry. Optionally, multiple geometries may be disposed radially with respect to one another of common rod configurations of varying rod configurations with and without gaps between sequential geometries. It would also be evident that the material of each rod may be selected from the group comprising metals, glasses, ceramics, and plastics for example. Rods may be solid cross-section or hollow cross-section and have the profiles on the entire cross-section or only those portions of the cross-section that will be disposed adjacent neighbouring rods.

[0050] When considering the development of sand screens then during the 1970s we find that so-called wire-wrapped screens, such as depicted by continuous slot screen 240 in Figure 2, became dominant as they offered keystone slots (i.e. slots wider on the inside of the screen to the outside) with high manufacturing efficiency whilst allowing stainless steel materials. However, these suffer from inaccurate wire spacing as well as potential for damage due to the wrapped wires with perpendicularly disposed support rods. Additionally, a design issue is the transfer of forces applied to the wrapped wire screen to the overall pipe assembly. Hence, in the 1980s variations with stainless steel mesh evolved with a base pipe, layered filtration jacket with an uneven pore structure with an outer shroud. These were then superseded by sintered (diffusion bonded) stainless steel mesh introduced in the 1990s. Accordingly, prior art sand screen filters have evolved to an increasing number of layers to provide the desired functionality with the necessary mechanical integrity.

[0051] Whilst a screen should be selected with consideration to formation particle size distribution an important consideration is the projected rate of recovery and the resistance presented by the screen to the fluid being recovered and separated from the particulate contamination. Equally, it is important to consider the fluid injection aspects of such screens where the particulate is one the other side of the screen to the fluid being injected rather than in production wherein the particulates are within the fluid.

[0052] Accordingly, embodiments of the invention offer a reduced drag when compared to the square leading edges of slotted liners, perforated pipe and wire wrapped screens. This is a very important characteristic to consider on both the injection and production side of thermal/EOR/heavy oil/natural/shale gas etc. recovery projects. Basically, drag in these examples can be equated to friction, the higher the friction or drag coefficient (CD) the lower the flow rate potential and the greater the pressure drop potential. This can be easily seen when consider a square screen versus a circular cross-section screen to a fluid flow perpendicular to the axis of the screen. A square cross-section screen yields a CD of approximately 2.2 whilst a circular cross-section screen yields a CD of approximately 0.3.

[0053] It would also be evident that where a screen liner is seamed, this actually presents a very small and sharp leading edge towards inflow (during production), which will create tremendous turbulence in the "slot" which will dramatically increase erosion of both the edge and the slot, leading to premature slot failure. Accordingly, an important design factor for efficient fluid flow is minimizing turbulence and have the fluids part on the leading edge and then merge on the trailing edge, which is one reason aeroplane wings are tapered. It would be evident that the cross-section of the rods allows this to be easily accomplished but is difficult to achieve with square slots. In fact the opposite occurs generally with prior art screens in that turbulence is also created at the exit point and that further contributes to pre-mature slot erosion.

[0054] In fact, when simulating a threaded rod screen it is important to consider essentially that it is actually comprised of two surfaces, the rod and the wedge (thread). Accordingly, the CD of the rod is in the 0.03 range but as fluid velocity increases the threads should actually work, assist, in the laminar flow of the fluid as it will assist in both separation at the point of contact and then merging after contact.

[0055] Within the embodiments of the invention described above in respect of Figures 5 through 14 these have been described as relating to particulates and fluids to be separated away from these particulates, such as sand and particulates from oil for example, or separating one fluid from another, such as oil from water for example. However, it would be evident to one skilled in the art that the filter designs described with respect to embodiments of the invention may be applied to a variety of applications including, but not limited to those, separating, mixing, drying, and percolating one or more first components which include, but are not limited to, fluids, particulates, slurries, and powders with one or more second components which include, but not limited to, fluids, particulates, slurries, and powders. For example, harvested materials such as grain require drying wherein filters according to embodiments of the invention would allow hot air to be passed into a flowing stream of grain for drying as well as separating the subsequent moisture laden air from the grain. A similar application exists for example in some mining and minerals applications such as the drying of potash after mining as well as filtering the potash to remove any particulates. Accordingly, it would be evident that multiple applications within the general processing steps of separating, mixing, drying, and percolating may be envisioned for filters according to embodiments of the invention.

[0056] The foregoing disclosure of the exemplary embodiments of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many variations and modifications of the embodiments described herein will be apparent to one of ordinary skill in the art in light of the above disclosure. The scope of the invention is to be defined only by the claims appended hereto, and by their equivalents.

[0057] Further, in describing representative embodiments of the present invention, the specification may have presented the method and/or process of the present invention as a particular sequence of steps. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible. Therefore, the particular order of the steps set forth in the specification should not be construed as limitations on the claims. In addition, the claims directed to the method and/or process of the present invention should not be limited to the performance of their steps in the order written, and one skilled in the art can readily appreciate that the sequences may be varied and still remain within the spirit and scope of the present invention.

Claims

CLAIMS What is claimed is:

1. A method comprising:

providing a filter, the filter comprising:

2. The method according to claim 1 wherein,

at least one of the first end cap and second end cap are adjustable allowing the gap to be adjusted.

3. The method according to claim 1 wherein,

at least one of the first end cap and second end cap are adjustable whilst fluid is flowing within the filter, the adjustment of the at least one of allowing the gap in the spring to be adjusted during filtering.

4. A method comprising:

5. The method according to claim 4 further comprising;

flowing a fluid into the inside of the tube formed by the plurality of profiled rods, the fluid comprising a fluid component and a particulate component through the filter; and filtering the first fluid component and those particulates within the particulate component smaller than the plurality of holes gap from the fluid.

6. The method according to claim 4 wherein,

the tube of predetermined geometry is essentially circular, square, rectangular, hexagonal, a regular polygon, and an irregular polygon.

7. The method according to claim 4 wherein,

adjacent profiled rods are at least one of identical in design, identical in profile but different diameters, and constant diameter with different profiles.

8. The method according to claim 4 wherein,

the predetermined template may be a thread selected from the group comprising British Standard Whitworth, I.S.O. Taper Pipe, U.S. Pipe Taper, Trapezoidal, I.S.O. Unified, I.S.O. Metric, British Standard Cycle, B.A. Pipe Straight, U.S. Pipe Straight, BSP, Unified Inch Screw Thread, Unified Thread Standard, National Pipe Standard, British Standard Buttress, and Aerospace Thread.

9. A method comprising:

providing a filter comprising:

10. The method according to claim 9 wherein;

the plurality of profiled rods are threaded such that the first fluid component flows down the plurality of profiled rods allowing it to be collected.

1 1. A method comprising:

providing a filter comprising:

a lower end plate connected to a second distal end of each of the plurality of rods to retain them in position relative to one another; flowing through the tube formed by the plurality of profiled rods a fluid comprising first and second fluid components having different viscosities, the first fluid component having the higher viscosity;