Abstract:
Apparatus used for the transport of fluids, the apparatus being suitable for use in oil-well production pipelines and pipelines and pipelines connectors used in oil fields or other applications where fluid contains a solid or where a solid is readily precipitated from the fluid. The apparatus comprises a conduit provided with at least one circumferentially discontinuous profiled turbulence inducing means formed around an inner diameter surface of the conduit. The turbulence inducing means may be formed integrally with the inner diameter surface of the conduit. The invention creates turbulent flow thereby preventing the build up of blockages in the conduit which can occur if solid masses form in the conduit.

Description:
[0001]    The present invention relates to components used for the transport of fluids and, more specifically, to components such as oil-well production pipelines and pipeline connectors used in oil fields.  
           [0002]    The transmission of oil-field fluids is undertaken through conduits such as pipelines and liners. By the very nature of the origin of these fluids, they can also carry solids in various forms which can be suspended in the fluids or easily precipitated from the fluids. Over a period of time, the solids will be deposited on to the internal bore of the pipe-work where they will adhere to this surface. The resulting effect, known as waxing or scaling, can reduce production rates, ultimately reducing productivity.  
           [0003]    Furthermore, such pipe-work and the connectors that are used to conjoin them are slick or smooth in internal profile. As the fluid passing through the pipes travels at specific speeds, the lack of turbulence in the flow regime of the fluid encourages the deposition of solids. Such a lack of turbulence is maintained and assisted by the smooth profile on the internal diameter.  
           [0004]    A number of prior art documents have been identified including GB2127581A, WO95/18923A1, WO92/19898A1, U.S. Pat. No. 4,487,510, U.S. Pat. No. 3,835,015 and GB1375908. All of these documents disclose devices which encourage turbulent flow in a conduit by placing a physical obstruction of some kind in the flow path of the conduit. However, where it is necessary to provide a substantially clear path through the conduit to allow the transport or deployment of solid objects such as probes, pigs or cable, any structure which even partially blocks the conduit will impede the transport or deployment of these objects and cannot be used.  
           [0005]    It is therefore an object of the present invention to address the problems outlined above whilst maintaining the productivity rates of the pipeline or whichever type of pipe-work is being used.  
           [0006]    It is further an object of the present invention to enable prevention of the build-up of solids on the internal bore surface of the pipe-work without having to close down the pipe-line or add further pieces of apparatus to the pipe-work.  
           [0007]    Furthermore, it is independently an object of the present invention to improve upon existing types of apparatus used for the prevention and removal of solids build-up from the internal surface of pipe-work in terms of the production time lost by having to close off the pipe-work to enable cleaning apparatus to be inserted, the time, cost and effort involved in this, the cost of the cleaning apparatus itself and the associated risks with inserting apparatus into pipe-work.  
           [0008]    According to the present invention, there is provided a conduit member for use in the transportation of fluids, wherein said conduit is provided with at least one circumferentially discontinuous profiled turbulence inducing means formed in a fluid contacting inner diameter surface of the conduit.  
           [0009]    Preferably, the profiled turbulence reducing means are formed integrally with the fluid contacting inner surface of the conduit.  
           [0010]    Preferably, the conduit is provided with a recess to accommodate an insert shaped to fit the inner diameter surface of the conduit and forming the fluid contacting inner surface of the conduit, said insert being provided with a plurality of circumferentially discontinuous profiled turbulence inducing means formed integrally therewith.  
           [0011]    Preferably, the conduit is provided with a recess to accommodate an insert shaped to fit the inner diameter surface of the conduit and forming the fluid contacting inner surface of the conduit, said insert being provided with a plurality of circumferentially discontinuous profiled turbulence inducing means formed integrally therewith.  
           [0012]    Preferably, said profiled turbulence inducing means may be provided by at least one indentation. Preferably, a plurality of indentations are arranged at a variety of angles to an axis to the conduit. Optionally, said profiled turbulence inducing means may be provided by at least one blade formed in the indentation. Optionally, said means may be a combination of indentations and blades.  
           [0013]    Preferably, said profile may be curved or angular. Optionally, said profile may be shaped to suit the inner diameter and an internal flow regime.  
           [0014]    Preferably, said means may be self-cleaning.  
           [0015]    Preferably, said means may be arranged radially, longitudinally or randomly to suit the flow regime anticipated. Optionally, means may be arranged helically. In such circumstances the helix is not continuous.  
           [0016]    Preferably, said curved profile may be shaped generally in the form of an aerofoil, which will vary according to anticipated flow regime. Preferably, said profile may be provided with a leading edge and a trailing edge. Preferably, said indentations may be arranged at a variety of angles to an axis normal to the longitudinal axis of said conduit. Preferably, said indentations may be arranged so that the fluid is deflected at an angle normal to an impact surface of said profile, the impact surface may be convex or concave.  
           [0017]    Preferably, said conduit may be a pipe connector. Optionally, said conduit may be a pin or a box connector. Optionally, said conduit may be an insert. Said connector may be provided with a threaded portion at either end. The threaded portions may be separated by said inner diameter surface. The tubular member may be provided with a recess to accommodate a suitably sized insert. Said threaded portions may be separated by an insert. Said insert may be provided with said inner diameter surface. Said insert may be provided with said turbulence inducing means.  
           [0018]    The conduit may be provided with a male threaded portion on at least one end. The pipe may be provided with a male threaded portion at either end of said pipe. The pipe may be provided with a female threaded portion at one end and a male threaded portion at the other end. The male threaded portion is provided with said inner diameter surface. The male threaded portion surrounds said inner diameter surface.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0019]    Embodiments of the invention will now be described, by way of example only, by reference to the accompanying drawings, in which:  
         [0020]    [0020]FIG. 1 shows a cross-sectional view of a tubular member in accordance with an embodiment of the present invention;  
         [0021]    [0021]FIG. 2 shows a cross-sectional view of a tubular member in accordance with a further embodiment of the present invention;  
         [0022]    [0022]FIG. 3 shows a cross-sectional view of a tubular member provided with an insert in accordance with yet a further embodiment of the present invention; and  
         [0023]    [0023]FIGS. 4 a  and  4   b  are cross sectional views of indentations in a pipe and FIG. 4 c  is a plan view of the indentation; and  
         [0024]    [0024]FIG. 5 is a cross sectional view of a further embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0025]    Referring to FIG. 1 of the drawings, there is shown the general arrangement of a conduit, in this case a hollow pipe connector  10  having a through bore  40  which extends longitudinally through the connector and defines an internal diameter surface of the connector. In this embodiment, the pipe connector  10  has a female threaded portion  30  provided at either end of the through bore. Each of the internally threaded portions  30  extend inwardly from the end face  35  at either side of the connector and continue towards the middle of the connector  10  along a portion of the connector bore  40 . However, the threaded portions do not meet in the middle of the connector and are separated by a portion of the inner bore diameter surface  40 .  
         [0026]    This bore surface  40  is the fluid contacting inner surface and has one or more series of profiles  20 , dependant upon the anticipated flow regime, cast or machined into the bore surface  40  at regular intervals. In an alternative embodiment the profiles are randomly around the circumference of the inner bore surface  40 . In this example, the profiles  20  are shaped in the general form of an aerofoil and are formed parallel with the longitudinal axis of the bore. However, the profiles may be arranged angled, staggered or helical.  
         [0027]    Referring now to FIG. 2 of the drawings, there is shown a tubular member  10 , which, in this embodiment, is a conduit having an outer diameter  85  and an external threaded portion. The conduit  10  shares many of the same features as the pipe connector shown in FIG. 1 and the same reference numerals will be used for these. The threaded portion in this embodiment is an external thread formed on a diameter of a size suitable for mating with another pipe or connector. This outer diameter of the threaded portion  30  is terminated by a chamfered shoulder  80 , which is formed on the outer diameter  85  of the conduit. The outer diameter  85  is larger in size than the diameter of the threaded portion  
         [0028]    This threaded portion  30  extends from the end face  35  of the conduit along a portion of the conduit  10  for a length suitable for connection to a pipe connector similar to that shown on FIG. 1. The profiles are formed in the same manner as described previously. Furthermore, the profiles are positioned in that portion of the internal diameter of the conduit that is surrounded by the threaded portion  30  on the external diameter. This positioning of the profiles  20  alters the flow of the fluid upon entry into the conduit.  
         [0029]    [0029]FIG. 3 of the drawings shows another embodiment wherein the tubular member  10  is provided with an insert  90  in the form of a snap-ring which fits into a pre-formed recess in the internal bore of the body  10 . The snap-ring is provided with an internal bore  40 ′ which provides a fluid contacting inner surface. Furthermore, the ring is provided with the turbulence inducing means  20 . It is important to note that the internal diameter  40 ′ of the insert should not project into the main bore  40  of the tubular member as this creates restricted access to the inner diameter for cleaning tools and the like. The snap ring embodiment described herein is applicable to the embodiments of both FIGS. 1 and 2.  
         [0030]    [0030]FIGS. 4 a ,  4   b  and  4   c  show an example of a suitable indentation  100  that can be provided in the fluid contacting inner surface of a conduit. FIGS. 4 a  and  4   b  show the cross section of a conduit containing the indentation. FIG. 4 c  is a plan view of the indentation which is substantially triangular in shape. As is apparent, the indentation is substantially triangular and has a curved inner surface  115  that is substantially concave in shape such that the edges  110  of the indentation are at the normal circumference of the conduit, whereas the indentation is further from the centre of the conduit. The overall dimensions are illustrated by reference numerals  140  and  150 , the indentation can be sized appropriately depending upon pipe size, fluid flow and other parameters. The maximum depth  130  of the indentation  100  is located towards the base of the indentation  100  towards ‘B’. The depth decreases towards ‘A’. It is also apparent in this example that the edges  110  of the indentation are substantially straight or angular.  
         [0031]    The indentation  100  can be located on the fluid contacting inner surface at any point thereon and a plurality of the indentations can be positioned thereon as previously described. The representation of the indentation  100  is a flat surface representation of the indentation. In most cases, the conduit to which the indentation is applied will be cylindrical and therefore the indentation will be applied to a curved surface and the edges of the indentation will be curved. In addition, other shapes of indentation may be used, for example a square or rectangular indentation can be applied to the fluid contacting the inner surface of the conduit. Also, the indentations may be angled towards or away from the direction of fluid flow in order to create turbulence.  
         [0032]    [0032]FIG. 5 shows a cross sectional view of an indentation  100  similar to that of FIGS. 4 a ,  4   b  and  4   c . In addition this embodiment shows a pair of blades  125  extending from the surface of the indentation to assist in providing turbulent flow. The blades do not extend into the space enclosed by the normal surface shape of the inner surface of the cylinder and are provided in the indentation only.  
         [0033]    In use, as fluids are transported through the connector, and come into contact with the profiles, the flow regime of these fluids is changed from laminar to turbulent. This change reduces the deposition of solids on the bore surface  40  and the bore surface of any pipes connected thereto as the speed of flow of the solids is increased and does not allow them to travel slowly enough to be deposited on the bore surface. As previously stated this would impact upon the economics of any transport system and effectively increase the period of time between remedial clean out operations.  
         [0034]    The internal profile of the turbulence inducing means will change the flow regime of the fluid passing through it. The shape of the internal profile will vary to suit the fluid type, flow rate and solids encountered. The profile will not reduce the internal diameter at the pipe connection but will be machined as a repeated recess around the internal circumference, a number of times. Additionally, by the nature of the flow regimes induced, the means would be self-cleaning.  
         [0035]    It should be noted at this stage that by the very nature of the connector means, there may be a part of the threaded portion left exposed, whether male or female. In this instance, it should be understood that the helical nature of this threaded portion is not to be construed as circumferentially discontinuous for the purposes of this invention.  
         [0036]    The present invention may be suitable for use in a range of industries for example food processing, heat exchange, chemical production and sewerage treatment.  
         [0037]    While certain modifications and variations have been described above, the invention is not restricted thereto, and other modifications and variations can be adopted without departing from the scope of the invention.