Abstract:
A system and method of sensing fluid in a wellbore, where fluid along a range of radial locations in the wellbore is diverted along a flow path that runs adjacent a fluid sensor. Diverting the fluid from the range of radial locations provides a representative sample of the fluid flowing in the wellbore. Further, the diverted fluid forms a continuous volumetric flow past the fluid sensor to avoid fluid stagnation adjacent the fluid sensor. Diverting the fluid flow can be accomplished by elongate diverter wings attached at discrete circumferential locations around an outer surface of a fluid sensor and that project at oblique angles to the direction of flow. Elongate members can be used for diverting flow, where the distal ends of the elongate members attach to a downhole tool, and vane members span across selected adjacent members for directing flow to the sensor.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of Invention 
         [0002]    The present disclosure relates to a method and system of sensing fluid downhole, and more specifically, relates to a method and system of diverting a continuous stream of wellbore fluid past the sensor. 
         [0003]    2. Description of Prior Art 
         [0004]    Downhole sensors are often used for sensing properties in a flow of fluid produced from hydrocarbon producing wellbores. The sensors may be deployed downhole within a producing wellbore, a jumper or caisson used in conjunction with a subsea wellbore, or a production transmission line used in distributing the produced fluids. Monitoring fluid produced from a wellbore is useful in wellbore evaluation and to project production life of a well. In some instances transmission lines may include fluid produced from wells having different owners. 
         [0005]    The produced fluid may include water and/or gas mixed with liquid hydrocarbon. Knowing the water fraction is desirable to ensure adequate means are available for separating the water from the produced fluid. Additionally, the amount and presence of gas is another indicator of wellbore performance, and vapor mass flow impacts transmission requirements. Fluid sensors can be employed that provide information regarding total flow, water cut amount, and gas fractions. However, in some flow conditions a single phase (e.g. oil or water) of the wellbore fluid flowing past the sensor can remain adjacent the sensor, so that the measurements taken by the sensor do not fully represent the fluid flowing in the wellbore. Moreover, when in a deviated or horizontal portion of a wellbore, multi-phase fluids can stratify so that sampling fluid in one axial location of the wellbore may not accurately represent the entire volume of fluid flowing in the wellbore. SUMMARY OF THE INVENTION 
         [0006]    Disclosed herein is an example of a downhole tool for monitoring fluid in a wellbore and which includes a housing, a fluid sensor in the housing, and a fluid diverter having a surface that extends along a path that intersects the fluid sensor and which extends along a portion of a circumference of the housing. The fluid diverter can include an elongate member oriented generally oblique to an axis of the housing. The downhole tool can further include additional fluid diverters that are spaced around the circumference of the housing, wherein the additional fluid diverters have surfaces that extend along paths that intersect with the fluid sensor. In this example, the fluid diverters project radially outward into an annular space circumscribing the housing and at angularly spaced locations from one another, so that when a volume of fluid flows in the annular space, a representative portion of the volume of fluid is diverted to the fluid sensor by the fluid diverters. In one example, further included are elongate spring members having ends that couple wife the housing, and wherein the fluid diverter mounts between the spring members. Optionally, the sensor is disposed in a cavity within the housing. In this example, an inlet is formed through a side of the housing and adjacent a downstream end of fee fluid diverter, and wherein an outlet is formed through a side of the housing on an end of the cavity distal from the inlet. Further in this example, the fluid sensor is optionally disposed proximate the outlet. A strainer can be included in the cavity and upstream of the fluid sensor. 
         [0007]    Also disclosed herein is an example of a downhole tool for monitoring fluid in a wellbore and which includes a housing having a sidewall, an inlet formed in the sidewall, and an outlet formed in the sidewall and spaced axially away from the inlet, a cavity in the housing in communication with the inlet and the outlet, a fluid sensor in the cavity disposed proximate the outlet, a planar fluid diverter having an upstream end spaced radially outward from the housing, a downstream end disposed proximate the inlet, and a diverter surface that faces the housing, so that when the downhole tool is disposed in the wellbore and a volume of wellbore fluid flows past the housing, at least some of the volume of wellbore fluid flows along the diverter surface and to the fluid sensor. Elongate spring members can be included and that have ends coupled to the housing at axially spaced apart locations, and wherein lateral sides of the fluid diverter mount to the spring members. Additional fluid diverters can be included that each have an upstream end spaced radially outward from the housing, a downstream end disposed proximate the inlet, and a diverter surface facing the housing, so that when the downhole tool is disposed in the wellbore and a volume of wellbore fluid flows past the housing, at least some of the volume of wellbore fluid flows along the diverter surface and to the fluid sensor, and wherein the fluid diverters are angularly spaced around the housing so that the fluid being diverted to the fluid sensor is representative of the volume of fluid flowing in the wellbore. The upstream end of the fluid diverter can be disposed adjacent an outer radius of an annulus that circumscribes the housing. 
         [0008]    A method of sampling fluid within a wellbore is disclosed herein and that includes disposing a fluid sensor in the wellbore and in the path of a volume of flowing fluid, diverting an amount of the volume of flowing fluid to the fluid sensor from a space that extends along a portion of the circumference of the wellbore, and sensing the amount of the volume of the flowing fluid with the fluid sensor. The amount of the volume of the flowing fluid can be representative of the entire cross section of fluid flowing in the wellbore. The sensor can be provided in a cavity of a downhole tool, and the method can further include directing the amount of the volume of the flowing fluid to an inlet on the downhole tool that is in fluid communication with the cavity and the fluid sensor. In an alternative, the amount of the volume of the flowing fluid is taken at multiple locations in the wellbore and that are angularly spaced apart from one another. The fluid sensor can be disposed in a horizontal portion of the wellbore. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0009]    Some of the features and benefits of the present invention having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which: 
           [0010]      FIG. 1  is a side sectional view of art example of a downhole tool for sensing fluid flowing in a wellbore. 
           [0011]      FIG. 2  is a side sectional view of an example of fluid flowing past an example of a fluid sensor in the downhole tool of  FIG. 1 . 
           [0012]      FIG. 3  is a side sectional view of an alternate example of a downhole tool for sensing fluid in a wellbore. 
           [0013]      FIG. 4  is an axial sectional view of the downhole tool of  FIG. 3  and taken along lines  4 - 4 . 
           [0014]      FIG. 5  is a side sectional view of an example of the downhole tool of  FIG. 1  in a horizontal portion of the wellbore. 
           [0015]      FIG. 6  is a side sectional view of an alternate example of a downhole tool for sensing fluid flowing in a wellbore. 
           [0016]      FIG. 7  is an axial sectional view of the downhole tool of  FIG. 6  and taken along lines  7 - 7 . 
           [0017]    While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims. 
       
    
    
     DETAILED DESCRIPTION OF INVENTION 
       [0018]    The method and system of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. The method and system of the present disclosure may be in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout. In an embodiment, usage of the term “about” includes +/−5% of the cited magnitude. In an embodiment, usage of the term “substantially” includes +/−5% of the cited magnitude. 
         [0019]    It is to be further understood that the scope of the present disclosure is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation. 
         [0020]      FIG. 1  shows in a side sectional view one example of a downhole tool  10  that is disposed in a wellbore  12 , which as illustrated intersects a formation  14 . In the example, a string of casing  16  lines the wellbore  12  which selectively isolates portions of formation  14  from wellbore  12 . In the example of  FIG. 1 , an optional string of tubing  18  is shown inserted within casing  16  and which circumscribes downhole tool  10 . Downhole tool  10  is shown made up of an elongate housing  20  and in which is disposed a fluid sensing unit  22 . Fluid produced from formation  14  enters into tubing  18 , and flows upward within tubing  18 , where it can be sensed by fluid sensing unit  22 . Examples of fluid sensing unit  22  include flow meters, tuning forks, capacitance type, and radioactive. Shown coupled on the outer surface of housing  20  is a flow diverter  24 , which as illustrated extends into an annulus  25  that is defined between housing  20  and tubing  18 . As illustrated by arrows, a flow of fluid F makes its way up tubing  18 , enters annulus  25 , and then is directed radially inward against housing  20  by flow diverter  24 . An advantage of diverting flow to the fluid sensing unit  22  is that the flow velocity of fluid F is increased when passing by sensing unit  22 , thereby eliminating the possibility of fluid stagnation. Because the fluid properties may change over time with the fluid F flowing over the sensing unit  22 , it is important that no fluids linger proximate the fluid sensing unit  22  that may give results that are not fully representative of the fluid F within wellbore  12 . Examples of a representative sample include a fluid sample having properties that reflect the flow of fluid F within tubing  18  as a whole, and not skewed by fluid that may concentrate in one portion or zone of tubing  18  and have properties that differ from the overall flow of fluid F. 
         [0021]    In the embodiment of  FIG. 1 , downhole tool  10  is shown supported by a wireline  26  which threads through a wellhead assembly  28  shown at the opening of the wellbore  12  and at surface  30 . An end of wireline  26  opposite from its attachment to downhole tool  10  extends into a surface truck  32  shown on surface  30 . Operation and control of downhole tool  10  within wellbore  12  may take place within surface truck as well as the recording of any data sensed by downhole tool  10  within wellbore  12 . Alternatively, a controller  34  separate from surface truck  32 , may be included and which communicates with downhole tool  10  via a communication means  36 . Controller  34  can be on surface  30  or remote from wellbore  12 . Example communication means  36  include hard wire, fiber optics, telemetry, combinations thereof, and the like. 
         [0022]    Referring now to  FIG. 2 , a portion of downhole tool  10  is shown in a side sectional view. In this example, fluid sensing unit  22  is shown equipped with a sensor element  38  that is disposed within a cavity  40 ; where cavity  40  is formed within housing  20 . An inlet  42  is formed through a sidewall of housing  20  that is in fluid communication with cavity so that the flow of fluid F within annulus  25  may flow into housing  20  via inlet  42 , through cavity  40 , and into contact with sensor element  38 . Providing fluid at or proximate to sensor element  38  allows sensor element  38  to monitor intonation about the fluid. Examples of information may include fluid composition, fluid density, fluid viscosity, fluid pressure, fluid temperature, water, gas, and oil percentage (i.e. fluid, phase holdup). Adjacent sensor element  38  is an exit  44  shown through a sidewall of housing  20 . Accordingly, a flow path of fluid F can make its way along a surface of flow diverter  24  into cavity  40  via inlet  42 , and exit cavity  40  through outlet  44  and return into annulus  25  and continue flowing uphole. In the example of  FIG. 2 , a downstream end of flow diverter  24  connects proximate the inlet  42 . In the illustrated embodiment the flow diverter  24  can be an elongate element and which is disposed at an angle oblique to an axis A X  of the housing  20 . In one example, the flow diverter  24  is made up of a number of elongate planar elements. Further, the upstream ends of the elements may project proximate to an outer radius of annulus  25  and adjacent to or in contact with an inner surface of tubing  18  (or any other tubular in which downhole tool  10  is inserted). Further examples exist wherein the downhole tool  10  is disposed within a wellbore  12  which is sometimes referred to as an open hole, and that is not lined with casing or does not have tubing. In this example, the outer or upstream ends of the flow diverter  24  would be adjacent walls of the wellbore  12  ( FIG. 1 ). Further in the example of  FIG. 2 , a strainer  46  is shown spanning radially across cavity  40  and is designed to capture particles or other unwanted material and prevent such particles from impending or otherwise coming into contact with sensor element  38 . Although shown as a planar element, examples of the strainer  46  include conically shaped elements with its apex directed upstream so that any debris entrained within the flow of fluid F is directed radially outward when it impinges the strainer  46  and is guided out of the primary path of the flow by the conical shape of the strainer  46 . 
         [0023]    Shown in  FIG. 3  is one alternate example of a downhole tool  10 A disposed in wellbore  12  and for sensing fluid sampled from a flow of fluid F flowing within wellbore  12 . In this example a series of elongate elements  47 A are shown having their opposite ends coupled to an outer surface of housing  20 A. Here the downstream ends  48 A of the elements  47 A couple to the housing  20 A proximate where the fluid sensing unit  22 A is provided within housing  20 A. Upstream ends  49 A of the elements  47 A couple to housing  20 A an axial distance upstream from the fluid sensing unit  22 A. Examples exist where the elongate elements  47 A resemble bow springs that are used typically for measuring devices, or for centralizing tools within wellbores or tubulars. Accordingly, the elongate elements  47 A can be flexible and bend when coming into contact with the wall of tubing  18 A or other solid surface encountered within wellbore  12 A. Vane elements  50 A are shown provided between adjacent elongate elements  47 A and extending axially from about a midsection of the elements  47 A and up to proximate the downstream ends  48 A of the elongate elements  47 A. As shown, the vane elements  50 A have upstream ends  52 A that are proximate the outer radial area of annulus  25  (and proximate the midsection of elements  47 A), so that the flow of fluid F can impinge upon surfaces of vane elements  50 A facing towards housing  20 A, and be directed radially inward towards the fluid sensing unit  22 A. The portion of the flow of fluid F that is diverted by the flow diverter  24 A extends along a path that intersects with fluid sensing unit  22 A when flowing along the inner surface of the vane elements  50 A. The fluid exits the vane elements  50 A al downstream ends  54 A of the vane elements  50 A. The location and positioning of the vane elements  50 A provides for the diverting of fluid at multiple radial locations within annulus  25 A, and thus provides the ability to obtain a representative sample of the flow of fluid F flowing within wellbore  12 A. 
         [0024]    In the example of  FIG. 3 , multiple vane elements  50 A are illustrated disposed at angularly spaced apart locations that circumscribe housing  20 A. As will be described in more detail below, this provides an advantage of obtaining a sample that is representative of the flow of fluid F when stratification can occur in the flow of fluid F, such as in a deviated or a horizontal wellbore. In stratified conditions, sampling at a single location in the wellbore will not yield representative results. 
         [0025]    Still referring to  FIG. 3 , optional flow channels  56 A are shown formed within housing  20 A and proximate the downstream ends  54 A of vane elements  50 A. The flow channels  56 A provide a flow path of the fluid flowing past the upstream end of main elements  50 A to enter into housing  20 A and flow past a sensing element (not shown) disposed within fluid sensing unit  22 A. Although some flow is projected radially inward by interaction with vane element  50 A as shown in  FIG. 3 , the flow F may then expand radially outward when downstream of the flow sensing unit  22 A. 
         [0026]      FIG. 4  shows an axial sectional view of the downhole tool  10 A of  FIG. 3  and taken along lines  4 - 4 . Here, vane elements  50 A are shown at equidistant angles Θ, spaced apart from one another and circumscribing access A X  of housing  20 . Thus flow along the surface S that laces radially inward on the vane elements  50 A can be directed towards the flow sensing unit  22 A ( FIG. 3 ) which is downstream of the downstream end  54 A of the vane elements  50 A. In one example, the surface S extends along the path of the flow of fluid F flowing from within wellbore  12  and on its way to the sensing unit  22 A. Optionally, a strainer  46 A is shown provided within tool  10 A and upstream of fluid sensing unit  22 A. 
         [0027]      FIG. 5  shows one example of downhole tool  10  in a deviated horizontal portion  54  of wellbore  12 . Here, housing  20  is shown roughly coaxial with an axis A X  of wellbore  12  and held in place by optional centralizers  58  that support housing  20  in wellbore  12  and away from walls of the wellbore  12 . Thus an annulus  25  remains between the housing  20  and tubing  18 . As is known, in horizontal wellbores the flow of fluid F within wellbore  12  may stratify so that portions of fluid in the lower regions of wellbore  12  may contain a higher percentage of water than fluid in an upper region. One of the examples of the selective sampling of fluid at different angular locations within wellbore  12  is the ability to obtain a samples at multiple angular locations about the wellbore  12 , that are then mixed, so that a representative sample of fluid from the wellbore is sent towards fluid sensing unit  22 , and where the representative sample of fluid has properties and/or characteristics that are the same or substantially similar to an entire cross section of the flow of fluid F flowing in the wellbore  12 . In one example, the representative sample of fluid has properties/characteristics that are the same or substantially similar to an average of the properties/characteristics of the cross section of the flow of fluid F flowing the wellbore  12 . 
         [0028]    An additional advantage of the flow diverter  24  described herein is that unlike some diverters that fully circumscribe a downhole tool, flow diverter  24  provides elongate elements that are at strategic locations angularly spaced around the housing  20 . As such, the flow of fluid F can make its way between adjacent ones of the elongate elements making up the flow diverter  24  and significantly reduce overall fluid factional drag across the tool  10 . Additionally, the embodiment discussed herein improves wettability characteristics of a tool in the sensor surface which discourages affinitive of different fluid phases. Referring back to  FIG. 4 , although four different vane elements  50 A are shown, the number of vane elements  50 A can range from about two to about ten. An advantage of using the bow spring type material is that the tool  10  can be used in tubulars of varying diameters. 
         [0029]    Shown in a side sectional view in  FIG. 6  is another alternate example of a downhole tool  10 B for sensing fluid flowing within a tubular. Here elongate elements  47 B which in an example include bow springs, have ends that pivotingly attached to the housing  20 B with pins  60 . The opposite ends of the elements are equipped with rods  62  that slidingly fit into slots  64  shown formed into the housing  20 B. Thus the downhole tool  10 B can be disposed into tubulars having a wide range of diameters, with any change in diameter, the elongate members  47 B can pivot about pins  60 , while the distal end can slidingly reciprocate within slots  64 . Also shown in  FIG. 6  are flow diverters  24 B that have ends mounted to the housing  20 B adjacent both the inlet  42 B and outlet  44 B. As shown, the configuration of the flow diverters  24 B accounts for flow of fluid F in axial directions wherein the fluid flows into cavity  40 B via inlet  42 B, and from cavity  40 B via outlet  44 B. Conversely, the direction of fluid flow F can be reversed, so that fluid flows into cavity  40 B via the outlet  44 B and flows from cavity  40 B via inlet  42 B. Further in this example, the ends of the flow diverters  24 B that mount to housing  20 B are equipped with pins  66  so that the flow diverters  24 B can pivot and their outer ends move radially inward and outward depending on a diameter of tubing  18 . Further, the ends of flow diverters  24 B distal from housing  20 B have rods  68  that slidingly fit into slots  70  form axially within portions of the elongate members  47 B. Thus as the elongate members  47 B flex radially inwardly arid outwardly, the flow diverters  24 B can pivot about their pinned connections to the housing  20 B to account for the flexing of the elongate members  47 B. 
         [0030]      FIG. 7  is an axial sectional view of an example of the downhole tool  10 B and taken along lines  7 - 7  of  FIG. 6 . Here a pair of flow diverters  24 B project radially outward from housing  20 B, and at substantially opposing sides of housing  20 B. However, alternate embodiments exist wherein more than two flow diverters  24 B are provided on housing  20 B. Moreover, the flow diverters can be spaced at equidistant angular distances from one another, or staggered and set apart at different angular distances. Shown in dashed outline are slots  70  in the elongate members  47 B and in which rods  68  can slidingly move. It should be pointed out that the bi-directional flow feature is not limited to the embodiments of  FIGS. 6 and 7 , but can be employed to all other embodiments disclosed herein for operation in tubulars where fluid flows in more than one direction. 
         [0031]    The present invention described herein, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While a presently preferred embodiment of the invention has been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the present invention disclosed herein and fee scope of the appended claims.