Patent Publication Number: US-9416657-B2

Title: Dual flowline testing tool with pressure self-equalizer

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present disclosure claims the benefit of U.S. Provisional Patent Application 61/726,872, filed Nov. 15, 2012, the entirety of which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     Aspects generally relate to evaluation of a subterranean formation. More specifically, aspects relate to downhole formation fluid sampling techniques apparatus for accomplishing formation fluid sampling with an equalizer. 
     BACKGROUND INFORMATION 
     Underground formation testing is performed during drilling and geotechnical investigation of underground formations. Testing of such underground formations is important as the results of such examinations may determine, for example, if a driller proceeds with drilling and/or extraction. Since drilling operations are expensive, excessive drilling impacts the overall economic viability of drilling projects. There is a need, therefore, to minimize the amount of drilling and to obtain accurate information from the underground formations. 
     Different types of information may be obtained from the underground formations. One of the primary forms of information is obtained using actual samples of fluid from underneath the ground surface. Such samples, when they are obtained, are analyzed to determine constituents of the underground formation. 
     Determination of the underground fluid constituents is important in the exploration for trapped hydrocarbon reserves. Determination of oil, gas or mixtures of oil and gas are of importance in many areas of the world, and correct determination of the presence of the constituents is valuable. 
     Obtaining fluid samples from a formation requires a great deal of precision. This precise sampling is referred to as focused sampling. Focused sampling techniques are described in detail in U.S. Pat. No. 8,210,260 to Milkovisch et al. and U.S. Patent Publication No. 2010/0071898 to Corre et al., the contents of which are herein incorporated by reference. In focused sampling, fluid is pumped from a formation through a peripheral zone and/or a central zone of a wellbore wall. The fluid is drawn and/or pumped into two or more flowlines of a downhole tester. Oftentimes, the pumping pressure is desired to be adjusted at the peripheral or guard zone relative to the pumping pressure of the fluid at the central or sample zone. However, adjusting of pumping pressure results in increased complexity, weight and cost of the downhole tester. The increased weight and complexity are due to the existence of a second pump because each flowline is required to be coupled to a pump. 
     SUMMARY 
     The present summary should not be considered limiting and provides but one arrangement for accomplishing the aspects described. A tool, is described having a body configured to expand from a first outer diameter to a second outer diameter; at least one sample port in the body configured to accept a fluid in an environment; at least one guard port in the body configured to accept the fluid in the environment; at least one flow line configured to extend from each of the sample port and the guard port to transport fluid; and a pressure equalizer configured between at least two flowlines. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a side view of a drill rig system that prepares a wellbore in a geotechnical subsurface environment. 
         FIG. 2  shows a schematic view of a downhole tool that may be used in the geotechnical environment to carry out embodiments of the present disclosure. 
         FIG. 3  shows a cross sectional diagrammatic view of a pressure equalizer between two flowlines in accordance with one or more aspects of the present disclosure. 
         FIGS. 4 and 5  show cross sectional diagrams of pressure equalizers between two flowlines in accordance with one or more aspects of the present disclosure. 
         FIG. 6  shows a schematic view of an interchangeable flow routing valve module between two flowlines in accordance with one or more aspects of the present disclosure. 
         FIG. 7  shows a perspective view of a valve plug that may be used on the interchangeable flow routing valve system of  FIG. 6 . 
         FIGS. 8A, 8B, 9A, 9B, 10A, 10B, 11A, 11B, 12A, 12B, 13A, 13B, 14A, 14B, 15A and 15B  show schematic views of various flow routing configurations that may be employed by the flow routing module and plug of  FIGS. 6 and 7 . 
     
    
    
     DETAILED DESCRIPTION 
     Certain examples are shown in the above-identified figures and described in detail below. In describing these examples, like or identical reference numbers are used to identify common or similar elements. The figures are not necessarily to scale and certain features and certain views of the figures may be shown exaggerated in scale or in schematic for clarity and/or conciseness. 
     The example pressure equalizer apparatuses, systems, and/or methods described herein may be used on a downhole tester, such as, for example, a packer, to sample fluids in a subterranean formation. More specifically, the example pressure equalizers described herein may regulate and/or adjust pressures in flowlines of a downhole tester by controlling the flow of fluid in at least one of the flowlines. After flowing from the pressure equalizer, the flow may be further diverted by a flow routing module with adjustable routing components. 
     The present disclosure illustrates an apparatus, a system, and/or a method for focused collection of formation fluid through two or more ports of a downhole tool. The downhole tool may be, for example, a packer. When sampling with a packer, the collected formation fluid may be conveyed along an outer layer of the packer to flowlines and then directed to a desired collection location. 
     The packer may be expandable across an expansion zone to collect formation fluids from a position along the expansion zone, i.e., between axial ends of the outer sealing layer. Formation fluid may be collected through one or more ports or drains having fluid openings in the packer for receiving formation fluid into an interior of the packer. The drains may be positioned at different radial and longitudinal distances. For example, separate drains may be disposed along the length of the packer to establish collection intervals or zones that enable focused sampling at a plurality of collecting intervals, e.g., two or three collecting intervals. 
     The collected formation fluid may be directed along flowlines having a sufficient inner diameter to transport the formation fluid. Separate flowlines may be connected to different drains to enable the collection of unique formation fluid samples. Different flowlines may serve different ports. For example, a sample port may be served by one flowline, and a guard port may be served by a separate flowline. Depending on the composition of the sampled fluid and conditions, the pressure in the flowlines may be desired to be regulated. A pressure equalizer may be provided in communication with the two flowlines. The pressure equalizer may use an equalizing chamber and an equalizing piston. Further, one or more pressure equalizers may be interchangeable to change the flow scheme between the flowlines. Different plugs may house various pressure equalizer configurations such that the plugs may be changed in the downhole tool by a technician or a user. 
     In accordance with the present disclosure, a wellsite with associated wellbore  110  and apparatus is described to exhibit a typical, but not limiting, environment in which an embodiment of the application may be installed. To that end, the apparatus at the wellsite may be altered, as necessary, due to field considerations. The apparatus may be installed using various techniques described hereinafter. 
     Referring now to the drawings wherein like numerals refer to like parts,  FIG. 1  shows one embodiment of a rig  101  as deployed in the wellbore  110 . The rig/well system  101  has a conveyance  105  employed to deliver at least one packer  200  (hereinafter referred to as “packer” or “focused sampling module”) into the wellbore  110 . In many applications, the packer  200  is used on a modular dynamics formation tester (MDT) tool deployed by the conveyance  105  (hereinafter referred to as “conveyance” or “tool string”) in the form of a wireline. However, the conveyance  105  may have other forms, including tubing strings, such as a coiled tubing, tool strings, production tubing, casing or other types of conveyances depending on the required application. In the embodiment illustrated in  FIG. 1 , the packer  200  is an inflatable packer or an extendable packer that may be used to collect formation fluids from a surrounding formation  115 . The packer  200  is selectively expanded in a radially outward direction to seal across an expansion zone. For example, the packer  200  may be inflated by fluid, such as wellbore fluid, hydraulic fluid or other fluid. When the packer  200  is expanded to seal against the wellbore  110 , formation fluids may flow into the packer  200 . The formation fluids may then be directed to a tool flow line and produced to a collection location, such as a location at a well site surface. 
     As shown in  FIG. 1 , the conveyance  105  may extend from a rig/well system  101  into a zone of the formation  115 . In an embodiment, the packer  200  may be part of a plurality of tools  125 , such as a plurality of tools forming a modular dynamics formation tester. The tools  125  may collect the formation fluid, test properties of the formation fluid, obtain measurements of the wellbore, formation about the wellbore or the conveyance  105  or perform other operations as will be appreciated by those having ordinary skill in the art. The tools  125  may be measuring while drilling (“MWD”) and/or logging while drilling (“LWD”) tools, for example such as shown by numerals  6   a ,  6   b . In an embodiment, the downhole tools  6   a  and  6   b  may be a formation pressure MWD tool. 
     In an embodiment, the tools  125  may include LWD tools having a thick walled housing, commonly referred to as a drill collar and may include one or more of a number of logging devices. The LWD tools may measure, process, and/or store information therein, as well as communicate with equipment disposed at the surface of the well site. As another example, the MWD tools may include one or more of the following measuring components: a modulator, a weight on bit measuring device, a torque measuring device, a vibration measuring device, a shock measuring device, a stick slip measuring device, a direction measuring device, an inclination measuring device and\or any other device. As yet another example, the tools  125  may include a formation capture device  170 , a gamma ray measurement device  175  and formation fluid sampling tools  61 ,  71 ,  81  which may include a formation pressure measurement device  6   a  and/or  6   b . The signals may be transmitted toward the surface of the earth along the conveyance  105 . 
     Measurements obtained or collected may be transmitted via a telemetry system to a computing system  185  for analysis. The telemetry system may include wireline telemetry, wired drill pipe telemetry, mud pulse telemetry, fiber optic telemetry, acoustic telemetry, electromagnetic telemetry or any other form of telemetering data from a first location to a second location. The computing system  185  is configurable to store or access a plurality of models, such as a reservoir model, a fluid analysis model, a fluid analysis mapping function. 
     The rig  101  or similar functioning devices may be used to move the conveyance  105 . Several of the components disposed proximate to the rig  101  may be used to operate components of the overall system. For example, a drill bit  116  may be used to increase the depth of the wellbore. In an embodiment where the conveyance  105  is a wireline, the drill bit  116  may not be present or may be replaced by another tool. A pump  130  may be used to lift drilling mud  135  from a tank  140  or pits. The mud  135  may be discharged under pressure through a standpipe  145 , a flexible conduit  150  or hose, through a top drive  155  and into an interior passage inside the conveyance  105 . The mud  135 , which may be water-based or oil-based, exits the conveyance  105  through courses or nozzles (not shown) in the drill bit  116 . The mud  135  may cool and/or lubricate the drill bit  116  and lift drill cuttings generated by the drill bit  116  to the surface of the earth through an annular arrangement. 
     After the wellbore  110  has been drilled to a selected depth, the tools  125  may be positioned at the lower end of the conveyance  105  if not previously installed. The tools  125  may be coupled to an adapter sub (not shown) at the end of the conveyance  105  and may be moved through, for example in the illustrated embodiment, a highly inclined portion  165  of the wellbore  110 . 
     During well logging operations, the pump  130  may provide fluid flow to operate one or more turbines in the tools  125  to provide power to operate certain devices in the tools  125 . When tripping in or out of the wellbore  110 , the pumps  130  may be turned on and off to provide fluid flow. As a result, power may be provided to the tools  125  in other ways. For example, batteries may be used to provide power to the tools  125 . In one embodiment, the batteries may be rechargeable batteries and may be recharged by turbines during fluid flow. The batteries may be positioned within the housing of one or more of the tools  125 . Other manners of powering the tools  125  may be used including, but not limited to, one-time power use batteries. 
     An apparatus and system for communicating from the conveyance  105  to the surface computer  185  or other component configured to receive, analyze, and/or transmit data may include a second adapter sub  190  that may be coupled between an end of the conveyance  105  and the top drive  155 . The top drive  155  may be used to provide a communication channel with a receiving unit  195  for signals received from the tools  125 . The receiving unit  195  may be coupled to the surface computer  185  to provide a data path therebetween that may be a bidirectional data path. 
     The conveyance  105  may alternatively be connected to a rotary table (not shown), via a kelly, and may suspend from a traveling block or hook (not shown) and a rotary swivel (not shown). The rotary swivel may be suspended from the drilling rig  101  through the hook, and the kelly may be connected to the rotary swivel such that the kelly may rotate with respect to the rotary swivel. The kelly may be any mast that has a set of polygonal connections or splines on the outer surface type that mate to a kelly bushing such that actuation of the rotary table may rotate the kelly. An upper end of the conveyance  105  may be connected to the kelly, such as by threadingly reconnecting the tool string  105  to the kelly. The rotary table may rotate the kelly to rotate the tool string  105  connected thereto. 
       FIG. 2  shows a schematic diagram view of a tool string  105  that may be used in the geotechnical environment to carry out embodiments of the present disclosure. For example, the packer  200  may be deployed into a wellbore  110  for other uses. The packer  200  may be used to fluidly isolate one portion of a wellbore  110  from another portion of a wellbore  110 . The packer  200  is conveyed to a desired downhole location and, in the non-limiting embodiment provided, inflated or expanded to provide a seal between the packer  200  and the well  100 . For example, the packer system may prevent fluid communication from two portions of the wellbore  110  by expanding or inflating circumferentially to abut the wellbore  110 . 
     The packer  200  may have one or more ports or sampling drains  204 ,  206  (the terms “drains” or “ports” are used herein interchangeably, and no inference should be drawn from use of one term without the other) for receiving fluid from the formation or the wellbore into the packer  200 . In an embodiment, the packer  200  has one or more guard ports  204  located longitudinally from one or more sample ports  206 . In the illustrated embodiment, the guard ports  204  are illustrated at a closer longitudinal distance from ends of the packer  200  than a longitudinal distance of the one or more sample ports  206  to the ends of the packer system  200 . The ports  204 ,  206  may be located at distinct radial positions about the packer system  200  such that the ports  204 ,  206  contact different radial positions of the wellbore. 
     The ports  204 ,  206  may be embedded radially into a sealing element of an outer layer of the packer  200 . By way of example, the sealing element may be cylindrical and formed of an elastomeric material selected for hydrocarbon based applications, such as nitrile rubber (NBR), hydrogenated nitrile butadiene rubber (HNBR), and fluorocarbon rubber (FKM). The packer  200  may be expanded or inflated, such as by the use of wellbore fluid, hydraulic fluid, mechanical arrangement or otherwise positioned such that one or more of the sample ports  206  and one or more of the guard ports  204  may abut the walls of the formation  115  to be sampled. The packer  200  may be expanded or inflated from a first position to a second position such that the outer diameter of the packer  200  is greater at the second position than the first position. In an embodiment, the second position may be the position in which the ports  204 ,  206  abut the formation, and the first position may be an unexpanded or deflated position. The packer  200  may move to a plurality of positions between the first position and the second position. The packer  200  may expand in the relative areas around the one or more guard ports  204  and the one or more sample ports  206 . A tight seal may be achieved between the exterior of the packer  200  and the wellbore, a casing pipe or other substance external to the packer  200 . 
     Operationally, the packer  200  is positioned within the wellbore  110  to a sampling location. The packer  200  is inflated or expanded to the formation through the expansion of the body of the packer  200  until the packer  200  abuts the formation  115 . A pump  208  may be utilized to draw fluid from the ports  204 ,  206  and/or to transport fluid within or out of the packer  200 . Flowlines  201 ,  202  may transfer the fluid drawn from the drains  204 ,  206  to other portions of the packer  200  and/or the downhole tool. The pump  208  may be incorporated into the packer  200 , may be external to the packer  200  and/or may be incorporated into each of the individual drains  204 ,  206 . The fluid removed through the sample drain  206  and/or guard drains  204  may then be transported through the packer  200  to a downhole tool, such as, for example, the tools  125  shown in  FIG. 1 . 
     The tool string may be configured in “reverse low shock” mode with a single pump  208  pumping fluid from a focused sampling module. The focused sampling module may be a single packer module as illustrated in  FIG. 2 . To achieve efficient separation of mud filtrate from formation fluid in respectively the guard ports  204  and the sample ports  206 , the pressure at the guard ports  204  may be less than or equal to the pressure in the sample ports  206 . While the pressures in the flowlines  201 ,  202  may be similar in and/or near the flow routing module  220 , the pressure levels are not guaranteed to be the same at the guard ports  204  and the sample ports  206 . For example, differences in flow rates and/or viscosities of the fluids flowing in the flowlines  201 ,  202  may cause pressure drops along the flowlines  201 ,  202 . Moreover, during sampling, the pressure may be higher at the guard port  204  than at the sample port  206 . In alternative configurations, alternative focusing sampling tools may be used, including a focused probe or quad packer configured to interface with the aforementioned systems and components. 
     To regulate pressures at the guard ports  204  and the sample ports  206 , a pressure equalizer  210  may be provided between the two flowlines  201 ,  202 . The pressure equalizer  210  may be closer to the focused sampling module  200  than a merging point  222  of the flowlines  201 ,  202  in a flow routing module  220 . For example, the pressure equalizer  210  may be implemented in a field joint between the focused sampling module  200  and the next module, such as shown in  FIG. 2 . However, the pressure equalizer  210  may also be implemented as part of the focused sampling module  200 , a multi-sample chamber module  240 , and/or in other locations in the conveyance  105 . The next module, may be, for example, a fluid analyzer module  230  for measuring properties of formation fluid drawn into the flowlines  201 ,  202 . The fluid analyzer module  230  may have a first optical fluid analyzer  231  and a second optical fluid analyzer  232 . In an alternative configuration, the pressure equalizer  210  may be an active flow restrictor, such as a throttling valve. 
     The first flowline  201  may be in fluid communication with a first intake valve  211  of an equalizing chamber  213  of the fluid pressure equalizer  210 . The second flowline  202  may be in fluid communication with a second intake valve  212  of the equalizing chamber  213 . The second flowline  202  may have a pilot relief valve  215  disposed on the second flowline  202  before the second intake valve  212  of the equalizing chamber  213 . A pump  216  may be in communication with the second intake  212  of the equalizing chamber  213 . The pump  216  may be configured to pressurize the equalizing chamber  213  by pumping fluid through the pilot relief valve  215 . 
       FIG. 3  shows a cross-sectional diagram of the pressure equalizer module  210  between the flowlines  201 ,  202  in accordance with one or more aspects of the present disclosure. The first flowline  201  may be in communication with one or more of the sample ports  206  of the focused sampling module  200 . The second flowline  202  may be in communication with one or more of the guard ports  204  of the focused sampling module  200 . The pressure equalizer  210  may have an actuator. The position of the pressure equalizer  210  is contingent on the pressures in the guard flowline  202  and the sample flowlines  201 . The actuator may be a piston  214 , a diaphragm (not shown), or any other pressure induced mechanism. In the example shown in  FIG. 2 , the actuator is an equalizing piston  214  sized to slide in the equalizing chamber  213 . The equalizing piston  214  may have an o-ring  219  disposed around a circumference thereof. 
     The equalizing chamber  213  may have two pressure passage holes  217 ,  218 . Each of the two pressure passage holes  217 ,  218  connect one of the flowlines  201 ,  202  to the equalizing chamber  213 . The pressure equalizer  210  may also have at least one intake valve that may progressively obstruct at least one of the sample flowline  201  or the guard flowline  202 , or, as shown in  FIG. 2 , both of the flowlines  201 ,  202 . The intake valves  211 ,  212  may be, for example, poppet valves, globe valves, butterfly valves or any other type of valve which may be known to one of ordinary skill in the art. The valves  211 ,  212  may be located downstream of the pressure passage holes  217 ,  218 . 
     The piston  214  may be displaced based on the comparative pressure in the flowlines  201 ,  202 . For example, if the pressure in the guard flowline  202  is larger than the pressure in the sample flowline  201 , the equalizing piston  214  is biased toward the sample flowline  201  thereby closing the valve  211  disposed on the sample flowline  201 , and/or opening the valve  212  disposed on the guard flowline  202 . As a result, the flow rate in the sample flowline  201  may decrease, or the flow rate in the guard flowline  202  may increase, or both. When the flow rate in the sample flowline  201  decreases, the pressure at the port  206  increases towards the formation pressure. When the flow rate in the guard flowline  202  increases, the pressure in the sample flowline  201  decreases below the formation pressure. Thus, the piston  214  may stabilize at a position that ensures the same pressure level in both flowlines  201 ,  202 . 
       FIG. 4  shows a cross-sectional diagram of another pressure equalizer  400  between the flowlines  201 ,  202  in accordance with one or more aspects of the present disclosure that may be used. As illustrated, the pressure equalizer  400  has an equalizing chamber  413  and an equalizing piston  414 . The flowlines  201 ,  202  have a corresponding intake  411 ,  412  into the equalizing chamber  413 . The piston  414  may be affixed to a reciprocating rod  415  with a valve and/or sealing mechanism disposed on each end thereof. In the example shown, male cone valve plugs  417 ,  418  may be disposed on the ends of the rod  415 . The male cone valve plugs  417 ,  418  may be associated with corresponding female cone valve inlets  421 ,  422 . Thus, when the male cone plugs  417 ,  418  are abutted to the corresponding female inlets  421 ,  422 , the corresponding flowlines  201 ,  202  become obstructed. The equalizing piston  414  may be biased by a spring  416  toward restricting the sample flowline  201  and/or opening the guard flowline  202 . The bias may also be provided by a pressurized chamber, and/or any other biasing mechanism that may be used to apply a force on the equalizing piston  414  when the piston  414  is in a central/resting position as shown. Thus, the piston  414  of the equalizer  400  shown may stabilize in a position that ensures that the pressure in the sample flowline  201  is higher than the pressure in the guard flowline  202 . The equalizer  400  may be disposed in the tool string  105  further away from the focused sampling module  200  and may still ensure that the pressure at the guard ports  204  is less than or equal to the pressure at the sample ports  206 . 
       FIG. 5  shows a cross sectional diagram of yet another pressure equalizer  500  between the flowlines  201 ,  202  in accordance with one or more aspects of the present disclosure. The equalizer  500  is biased toward restricting the sample flowline  201  and/or opening the guard flowline  202 . The bias is provided by stepped pistons  514 ,  516  disposed in an equalizing chamber  513 . The first piston  514  on the side of the sample flowline  201  has a larger surface area than the second piston  516  on the side of the guard flowline  202 . The arrangement of the pistons  514 ,  516  may also be reversed depending on the application. The flowlines have respective corresponding intakes  511  and  512 . 
     The pistons  514 ,  516  are affixed on a reciprocating rod  515  with cone valve plugs  517 ,  518  on each end thereof. The cone valve plugs  517 ,  518  are insertable into corresponding female valve inlets  521 ,  522  to restrict flow in the corresponding flowlines  201 ,  202 . The equalizing chamber  513  has a first intake  211  and a second intake  212  which correspond to the first flowline  201  and the second flowline  202 , respectively. 
       FIG. 6  shows a schematic view of an interchangeable flow routing valve module  600  between the flowlines  201 ,  202  in accordance with one or more aspects of the present disclosure. The flow routing module  600  may be used as the flow routing module  220  of the tool string  105  shown in  FIG. 2 . In alternative configurations, the flow routing module  600  may be a flow routing valve incorporated into a tool in the drillstring. The flow routing module  600  may have a cavity  610  through which a flow routing plug  700  may be inserted.  FIG. 7  shows a perspective view of the plug  700  that may be used on the flow routing module  600  of  FIG. 6 . The plug  700  may have an exterior shape that is adaptable to conform to the cavity  610  of the flow routing module  600 . The cavity  610  has intakes  601 ,  602  and outflows  603 ,  604  for the flowlines  201 ,  202 . The plug  700 , when inserted, routes the flow through the flowlines  201 ,  202 . The plug  700  may be shaped such that the plug  700  may be plugged into place on the tool string  105 . Multiple ones of the plugs  700  are interchangeable such that different ones of the plugs  700  may be inserted and/or removed from the module  600  with relative ease. The changing of the plugs  700  may be carried out automatically or manually by a user. 
     Multiple ones of the plugs  700  may be provided having different exterior shapes and/or interior configurations which correspond to different flow routing configurations. Grooves  701 ,  702  may be disposed about the valve for routing the flow. The grooves  701 ,  702  essentially form canals  701 A,  702 A through which the fluid flow is routed. The fluid is restricted to flowing through the canals  701 A,  702 A due to the plug  700  being flush within the cavity  610 . O-rings  705  or rubber may be disposed about the grooves  701 ,  702  to prevent leakage of fluid. The interior surface of the cavity  610  is abutted by the raised grooves  701 ,  702  to restrict the movement of fluid. Therefore, in the exterior configuration shown in  FIG. 7 , the plug  700  restricts the flow from the flowline  201  to continue from the intake  601  through the outflow  604 . Likewise, the grooves  702  rout the flow from the flowline  202  to continue from the intake  602  through the outflow  603 . Thus, the example plug  700  shown diverts the flow from the flowline  201  to the flowline  202 , and the flow from the flowline  202  to the flowline  201 . It should be noted that, in the example shown, the intake  601  is the inflow from the flowline  201 , and the outflow  603  is the outflow to the flowline  201 . Likewise, the intake  602  is the inflow from flowline two  202 , and outflow  604  is the outflow to the flowline  202 . The plug  700  may also divert flow through an interior (not shown) thereof. Pipes and/or passages (not shown) may route the incoming flow. 
     Referring still to  FIG. 7 , an adapter port  710  may extend from the plug  700 . The port  710  may be used to attach a resistor or other identifying pin-connector to the plug  700 . For example, the port  710  may have a resistor of a specific resistance such that measurement of the resistance identifies the flow routing configuration of the plug  700 . When installed in the flow routing module  600 , the port  710  may be connected to a resistance measuring device (not shown). The resistance measuring device may interpret the resistance measured, identify the plug configuration and/or relay the information to a user. Moreover, a symbol  720  may be disposed on the exterior of the plug  700  for purposes of identifying the flow regime. 
       FIGS. 8A, 8B, 9A, 9B, 10A, 10B, 11A, 11B, 12A, 12B, 13A, 13B, 14A, 14B, 15A and 15B  show schematic views of various flow routing configurations that may be employed by the flow routing module and plug of  FIGS. 6 and 7 . Each plug may have the two inlets  601 ,  602  for inflow from the flowlines  201 ,  202 , respectively. Likewise, each plug may have the two outlets  603 ,  604  for outflow to the flowlines  201 ,  202 . Each plug of  FIGS. 8A through 15A  has a different flow routing configuration as indicated by corresponding  FIGS. 8B through 15B , respectively. For example,  FIG. 10A  shows a criss-crossing configuration by which the inflow from the guard flowline  202  is routed to the sample flowline  201 , and the inflow from the sample flowline  201  is routed to the guard flowline  202 .  FIGS. 8A and 8B  show a separated configuration in which the flowlines  201 ,  202  are closed.  FIGS. 9A and 9B  show a straight flow configuration in which the flows in the flowlines  201 ,  202  are kept segregated.  FIGS. 11A and 11B  show a return flow configuration in which the flow from the flowline  201  is returned via the flowline  202 .  FIGS. 12A, 12B, 13A, 13B, 14A, 14B, 15A and 15B  show a plurality of configurations in which two flowlines are co-mingled into a single flowline. 
     The preceding description has been presented with reference to present embodiments. Persons skilled in the art and technology to which this disclosure pertains will appreciate that alterations and changes in the described structures and methods of operation can be practiced without meaningfully departing from the principle and scope of the disclosure. Accordingly, the foregoing description should not be read as pertaining only to the precise structures described and shown in the accompanying drawings, but rather should be read as consistent with and as support for the following claims, which are to have their fullest and fairest scope. 
     Although exemplary systems and methods are described in language specific to structural features and/or methodological acts, the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as exemplary forms of implementing the claimed systems, methods, and structures.