Patent Publication Number: US-2020300681-A1

Title: Gas bypass meter system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present document is based on and claims priority to U.S. Provisional Application Ser. No. 62/557,527, filed Sep. 12, 2017, which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     In a variety of applications, wedge meters are used to provide flow measurements with respect to a fluid flowing through the meter. A wedge meter has a tubular flow body and a smooth wedge-shaped restriction in the tubular flow body to create a pressure drop as fluid flows past the restriction. Wedge meters may be used to establish and measure differential pressures in gases, steam, or liquids, including highly viscous liquids. However, wedge meters tend to provide unreliable, e.g. erratic, measurements when mixed fluids flow through the tubular flow body. For example, wedge meters tend to provide erratic measurements regarding flow of liquids mixed with gas. Sufficient gas void fractions (GVFs) in the fluid can substantially affect the accuracy of the wedge meter. 
     SUMMARY 
     In general, a system and methodology provide a meter for accurately monitoring fluid flow of a liquid even if gas is present in the liquid. The meter system may comprise a tubing with an internal flow passage and a wedge or other restriction extending into the internal flow passage. A first port may be located upstream of the restriction and a second port may be located downstream of the restriction to enable monitoring of a differential pressure across the restriction. The differential pressure can be used to determine the desired flow parameter, e.g. volumetric flow. The system facilitates separation of gas from the liquid and utilizes a gas bypass. The gas bypass routes the separated gas past the restriction, e.g. wedge, before directing the gas back into the fluid flow path. 
     However, many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Certain embodiments of the disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood, however, that the accompanying figures illustrate the various implementations described herein and are not meant to limit the scope of various technologies described herein, and: 
         FIG. 1  is an orthogonal view of an example of a gas bypass meter system, according to an embodiment of the disclosure; 
         FIG. 2  is a partial cross-sectional view of the gas bypass meter system illustrated in  FIG. 1 , according to an embodiment of the disclosure; 
         FIG. 3  is a left end view of the gas bypass meter system illustrated in  FIG. 1 , according to an embodiment of the disclosure; 
         FIG. 4  is a cross-sectional view taken generally along line  4 - 4  of  FIG. 2 , according to an embodiment of the disclosure; and 
         FIG. 5  is a flowchart providing an example of a methodology for implementing a gas bypass meter system, according to an embodiment of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, numerous details are set forth to provide an understanding of some embodiments of the present disclosure. However, it will be understood by those of ordinary skill in the art that the system and/or methodology may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible. 
     The present disclosure generally relates to a system and methodology for facilitating a more accurate monitoring of flowing liquid even if gas is present in the liquid. The system and methodology utilize a meter system which may be used in a variety of well related applications and other fluid flow applications. By way of example, the meter system may be used in oil and gas industry applications to measure flows of liquid produced by a progressive cavity pumping system, electric submersible pumping system, or other pumping system used to pump oil up through a wellhead. 
     According to an embodiment, the system utilizes a meter having a tubing with an internal flow passage and a wedge or other restriction extending into the internal flow passage. The restriction/wedge creates a reduction in the flow area within the internal flow passage and thus establishes a differential pressure between the regions upstream and downstream of the restriction. The meter may further comprise a first port located upstream of the restriction and a second port located downstream of the restriction to enable monitoring of the differential pressure. 
     This differential pressure can then be used to determine the desired flow parameter, e.g. volumetric flow. For example, wedge type restrictions may be used to create a differential pressure which can be correlated with volumetric flow. In some embodiments, the differential pressure may be correlated with a volumetric flow rate of the liquid by utilizing standard flow equations. However, calibration curves also may be used in determining correspondence between the differential pressure measured across the restriction/wedge and the volume flow rate. In some applications, the differential pressure created by the restriction can be correlated with a mass flow rate or with other flow parameters of the liquid. 
     To reduce inaccuracies which may result from gas mixed within the liquid, the system is constructed to facilitate separation of gas from the liquid and to then route the gas past the restriction. According to an embodiment, a gas bypass may be used to route the separated gas from the internal flow passage and past the restriction, e.g. wedge, before directing the gas back into the fluid flow path. By way of example, the separation of gas may be encouraged by a flow straightening section or other suitable gas separation section. The gas bypass routes gas past the restriction/wedge and may comprise a conduit coupled to the tubing upstream and downstream of the restriction/wedge. Additionally, various types of differential pressure monitors/transmitters may be coupled with the first and second ports to enable continued monitoring of the differential pressure across the restriction. 
     Referring generally to  FIG. 1 , an embodiment of a gas bypass meter system  20  is illustrated. In this example, the gas bypass meter system  20  comprises a meter  22  which will be described as a wedge meter for purposes of explanation. However, the wedge meter  22  may utilize various styles of restrictions which have wedge shapes or other types of shapes able to establish a suitable differential pressure. In the illustrated example, the wedge meter  22  comprises a tubing  24  having an internal flow passage  25 . The wedge meter  22  is constructed for coupling into a variety of fluid flowing systems, such as a well system  26 . By way of example, the wedge meter  22  may comprise connectors  27 , e.g. flange connectors or other suitable connectors, by which the tubing  24  may be coupled into a fluid flow path of the well system  26  or other fluid flow system. 
     With additional reference to  FIG. 2 , the meter  22  further comprises a restriction  28 , e.g. a wedge, which extends into the internal flow passage  25  to establish a reduced flow area region  30 . For example, the restriction/wedge  28  may extend into internal flow passage  25  from a wall of tubing  24 . The meter  22  may further comprise a first port  32  located upstream of the restriction  28  and a second port  34  located downstream of the restriction  28 . In some embodiments, a plurality of first ports  32  and/or a plurality of second ports  34  may be used. The ports  32 ,  34  are formed through the wall of tubing  24  to enable monitoring of the pressure differential between the region upstream of the restriction  28  and the region downstream of the restriction  28 . 
     In the embodiment illustrated, the gas bypass meter system  20  also comprises a gas separating section  36 , e.g. a flow straightening section, which may be coupled along tubing  24  at a position upstream of the restriction/wedge  28 . By way of example, the flow straightening section  36  may comprise a plurality of flow straightening vanes  38  which serve to straighten a flow of fluid, represented by arrow  40 , as the fluid moves through tubing  24 . In some applications, the flow straightening vanes  38  may be in the form of perforated tubes  42  stacked side-by-side, as further illustrated in  FIG. 3 . 
     The flow straightening section  36  straightens the flow of fluid represented by arrow  40  and also generates a constant flow profile. Additional effects on the fluid flowing through flow straightening section  36  include separation of gas from the liquid portion within fluid flow  40 . Following separation, the lighter gas migrates to an upper portion of the tubing  24  which enables removal of the gas from internal flow passage  25  via a gas bypass  44 . 
     In the embodiment illustrated, gas bypass  44  comprises a conduit  46  extending from the flow straightening section  36  and into communication with the internal flow passage  25  downstream of the restriction  28 . By way of example, the conduit  46  may be placed in fluid communication with the internal flow passage  25  above and below restriction  28  via a pair of bypass conduit connectors  48  which couple the conduit  46  to tubing  24 . The conduit connectors  48  may comprise various types of connectors. By way of example, each connector  48  may comprise a male tube fitting end  50  which is threadably received in a corresponding receptacle  52  welded or otherwise affixed to tubing  24 . 
     Additionally, a valve  54  may be positioned along the gas bypass  44  and may be in the form of a needle valve or other suitable gas flow valve. In the illustrated example, the valve  54  is positioned along conduit  46  and is adjustable to enable control over the gas flow rate along gas bypass  44 . 
     Depending on parameters of a given application, various types of differential pressure monitors  56  may be used to monitor the differential pressure across the restriction/wedge  28 . By way of example, the differential pressure monitor  56  may comprise a differential pressure sensor and transmitter for sensing and transmitting the differential pressure data to a suitable processing system, e.g. a computer-based processing system. The processing system may then be used to automatically determine the desired flow parameter, e.g. volumetric flow rate, of the flowing liquid based on standard flow equations, calibration curves, or other suitable correlation/modeling techniques. The differential pressure data provided by monitor  56  also may be compared manually to appropriate calibration curves or other pressure/flow correlation data to estimate the volumetric or mass flow rate of the liquid. 
     With additional reference to  FIG. 4 , the differential pressure monitor  56  may be placed in fluid communication with first and second ports  32 ,  34  via appropriate flow conduits, flow manifold, or other suitable flow circuit. In some embodiments, a valve  58 , e.g. a three-way valve, may be coupled with tubing  24  via a suitable mounting fixture  60  and placed in fluid communication with the differential pressure monitor  56  as well as with first and second ports  32 ,  34 . The valve  58  may be used as a flow isolation device as well as a device for zeroing the differential pressure monitor  56 . 
     Referring generally to  FIG. 5 , a flow chart is provided to illustrate a methodology for implementing gas bypass meter system  20 . In this operational example, restriction  28  is provided along the internal flow passage  25  of tubing  24 , as indicated by block  62 . In a variety of embodiments, the restriction  28  may be in the form of wedge  28  as described above. 
     The flow straightening section  36  is placed along tubing  24  at a position upstream of the restriction  28 , as indicated by block  64 . Fluid flowing along internal flow passage  25  of tubing  24  is directed through the flow straightening section  36  and past the restriction  28 , as indicated by block  66 . As the fluid flows through the flow straightening section  36 , gas is separated from the fluid, as indicated by block  68 . 
     The gas moves upwardly into the upstream end of gas bypass  44  via the upstream connector  48 . The separated gas is then able to move separately through gas bypass  44 , e.g. through conduit  46 . The separated gas may then be reintroduced into the internal flow passage  25  downstream of the restriction  28 , as indicated by block  70 . As described above, gas bypass  44  may comprise conduit  46  which is coupled into fluid communication with internal flow passage  25  upstream and downstream of restriction  28  via bypass conduit connectors  48  so as to enable flow of the gas around the restriction  28 . 
     The “lower gas content” fluid/liquid continues to flow past restriction  28  and establishes a differential pressure between regions of the internal flow passage  25  upstream and downstream of restriction  28 . This differential pressure can be measured via monitor  56  and used to determine a desired flow parameter, as indicated by block  72 . Effectively, tubing  24 , restriction  28 , flow straightening section  36 , and gas bypass  44  cooperatively function to establish a gas bypass meter system  20  able to accurately determine the desired flow parameter, e.g. a volumetric flow rate of the liquid phase of the fluid. 
     The gas bypass meter system  20  may be used in cooperation with a variety of systems to obtain data on the desired flow parameter as fluid flows through the system. For example, the tubing  24  may be coupled with a well system tubing of well system  26  to provide a flow parameter meter  22  able to measure the desired flow parameter with respect to fluid flow through the well system tubing, as indicated by block  74 . At least a portion of the fluid flow moving through the well system tubing (or other system tubing) is able to flow through the tubing  24  so that appropriate well system fluid flow parameter data may be determined via gas bypass meter system  20 . 
     It should be noted the well system tubing may be part of a variety of well systems  26  having corresponding fluid flows. Examples of well systems  26  which may be combined with gas bypass meter system  20  include progressive cavity pumping systems, electric submersible pumping systems, other pumping systems, or various fluid flow control or directing systems. The gas bypass meter system  20  also may be used to measure selected fluid parameters with respect to fluid flows through non-well related systems. 
     Accordingly, the gas bypass meter system  20  may be used in many types of well applications and also in non-well applications. In a variety of such operations, the gas separating section  36  is a flow straightening section used to smooth the fluid flow thus enabling gas to break out from the liquid. However, other types of gas separating sections  36  may be employed. The gas bypass  44  provides a path for the gas to exit from the internal flow passage  25  of the tubing  24  and to flow around the restriction/wedge  28 . By removing the gas, the flow of liquid past restriction  28  establishes a more consistent and accurate differential pressure which can be monitored and transmitted via differential pressure monitor  56 . Consequently, reliable differential pressure data is available to provide accurate monitoring of liquid flow  40  through meter  22 . 
     Depending on the specific usage of gas bypass meter system  20 , the components and features of the gas bypass meter system  20  may be adjusted. For example, various types of differential pressure monitors  56  may be used to measure and utilize the differential pressure established on upstream and downstream sides of the restriction  28 . Additionally, the gas bypass  44  may comprise tubing or a variety of other conduits, e.g. passages, for directing the gas around the restriction  28 . The restriction  28  may be formed as a wedge extending internally from the wall forming tubing  24 , or the restriction  28  may have other suitable shapes and configurations. The restriction  28  is constructed to create the desired differential pressure as the liquid (lower gas fluid) moves past the restriction. The size, shape, and materials of the various components of gas bypass meter system  20  may be selected according to the characteristics of a given system and/or environment. 
     Although a few embodiments of the disclosure have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims.