Patent ID: 12259093

DETAILED DESCRIPTION

Referring toFIG.1, a system100for analyzing a multiphase production fluid according to the present disclosure may comprise fluidic piping10, a production fluid supply valve20a fluidic separation chamber30, an inert gas exhaust valve40, a separation chamber pressure sensor50, a fluidic separation detector60, and a fluidic supply and analysis unit70. The production fluid supply valve20can be used to divert multiphase production fluid25from a surface production conduit of, for example, an oil or gas production operation.

The fluidic piping10is configured to supply multiphase production fluid25from the production fluid supply valve20to the fluidic separation chamber30. The inert gas exhaust valve40is configured to exhaust inert gas45from the fluidic separation chamber30. The inert gas45, which may be supplied via an inert gas supply valve42, has a lower density than the gaseous phase of the multiphase production fluid. For example, the inert gas may comprise helium, neon, or combinations thereof.

The fluidic supply and analysis unit70is in communication with the production fluid supply valve20, the inert gas exhaust valve40, the separation chamber pressure sensor50, and potentially, other components of the system100, as will be described in further detail below. The fluidic supply and analysis unit70communicates with the production fluid supply valve20to supply multiphase production fluid25to the fluidic separation chamber30. The fluidic supply and analysis unit70also communicates with the separation chamber pressure sensor50, which is configured to provide an indication of gas pressure in the fluidic separation chamber30, and the inert gas exhaust valve40, to stabilize gas pressure within the fluidic separation chamber30. Additionally, the fluidic supply and analysis unit70communicates with the fluidic separation detector60to monitor a growth rate QCof a gaseous phase column25G of the multiphase production fluid25in the fluidic separation chamber30, and convert the growth rate QCof the gaseous phase column25G to a production fluid gas flow rate QG.

In one embodiment of the present disclosure, the growth rate QCof the gaseous phase column25G is converted to the production fluid gas flow rate QGby accounting for a gravitational separation rate QSof the gaseous phase column25G resulting from gravitational forces in the fluidic separation chamber30. This gravitational separation can be optimized by ensuring that the fluidic separation chamber30is vertically oriented, and can be represented as QG=QC=QS.

Although the growth rate QCof the gaseous phase column25G can be converted to the production fluid gas flow rate QGin a variety of ways, in one embodiment, it is converted by (i) measuring a change of height Δh of the gaseous phase column25G over a time Δt, (ii) calculating an increase in gaseous volume ΔV as a function of Δh and a cross sectional area of fluidic separation chamber30, and (iii) calculating the production fluid gas flow rate QGas a function of ΔV and a gravitational separation rate QS. The gravitational separation rate QScan be a predetermined value that is obtained from a sample of the multiphase production fluid and helps account for volumetric growth of the gaseous phase column25G resulting from gravitational forces in the fluidic separation chamber30. To ensure the accuracy of this conversion, it can be helpful to ensure that a complete gaseous phase column25G resides within the fluidic separation chamber30over the time Δt. In other words, a sufficient volume of multiphase production fluid should be introduced into the system100, via the production fluid supply valve20, to ensure that a complete gaseous phase column25G resides within the fluidic separation chamber30over the time Δt.

In some embodiments, it may be preferable to include a baseline liquid supply valve80in the system100. In such embodiments, a heavy water, or heavier-than-water, baseline liquid85can be used to move a fixed volume of the multiphase production fluid25into the fluidic separation chamber30, as is illustrated inFIG.1. More specifically, the supply and analysis unit can be configured to supply sufficient volumes of the multiphase production fluid25and the baseline liquid85to the fluidic separation chamber30via the production fluid supply valve20and the baseline liquid supply valve80to ensure that a complete gaseous phase column25G resides within the fluidic separation chamber30over the time Δt.

The present inventors have recognized distinct diagnostic improvements if laminar flow in the multiphase production fluid25is preserved in the fluidic piping10. For example, with laminar flow, it is contemplated that gravitational separation in the fluidic separation chamber30will be enhanced, and may occur more rapidly, if laminar flow is maintained. This also helps keep the required height of the fluidic separation chamber30from becoming too large because particular diagnostic modes of the present disclosure require extended active flow regimes where a specific degree of separation is required. To this end, it may be preferable to configure the fluidic supply and analysis unit70to maintain a preferred pressure drop across the multiphase production fluid flow in the fluidic piping10and the fluidic separation chamber30. This pressure drop can be measured with the aid of the separation chamber pressure sensor50. Although a wide range of suitable pressure drops are contemplated by the present disclosure, e.g., up to about 1000 kPa, in practice, the pressure drop will depend on the length of the fluidic separation chamber30, particularly where it is vertically oriented. For example, and not by way of limitation, with a fluidic separation chamber30having a length in the range of 30 m to 100 m, suitable pressure drops may be between 500 kPa and 1000 kPa, as this would be more likely to maintain the average velocity of the multiphase production fluid low enough to keep the flow laminar (Re<3000). If, for logistical reasons, the length of the fluidic separation chamber is shorter, e.g., about 10 meters in height, then a smaller pressure drop would be required to reduce the velocity even more and give time for the phases to have measurable separation in the fluidic separation chamber. For example, a 10 meter fluidic separation chamber may require a pressure drop of less than 10 kPa. Longer fluidic separation chambers, e.g., about 50 meters in height may require pressure drops of about 700 KPa.

The aforementioned pressure drop can be maintained by controlling the inert gas exhaust valve40, the production fluid supply valve20, or both. Depending on the fluid content, the average velocity of the multiphase fluid in the fluid analysis system100is maintained so that it is less than about 0.5 m/s. In some embodiments, it will be sufficient to ensure that the fluidic supply and analysis unit70is configured to keep multiphase production fluid flow in the fluidic piping10and the fluidic separation chamber30slow enough to ensure that at least 50% of the volumetric growth of the gaseous phase column25G in the fluidic separation chamber30is a result of gravitational forces.

To help stabilize the pressure drop, the separation chamber pressure sensor50can be positioned in the fluidic separation chamber30to sense gas pressure of the inert gas45in the fluidic separation chamber30. The fluidic supply and analysis unit70is placed in communication with the pressure sensor50and can be configured to stabilize gas pressure within the fluidic separation chamber30by controlling the inert gas exhaust valve40. Pressure can also be stabilized by controlling the rate at which multiphase production fluid25is supplied via the production fluid supply valve20. In any case, it is contemplated that the pressure can be stabilized by holding the gas pressure constant, or by controlling the pressure in some other diagnostically recognizable way, to enable analysis. In other words, a “stabilized” pressure need not be a constant pressure.

In embodiments where a baseline liquid85is available for introduction via the baseline liquid supply valve80, the fluidic supply and analysis unit70can be configured to stabilize gas pressure within the fluidic separation chamber by further controlling a rate at which the baseline liquid85is supplied to the fluidic piping10via the baseline liquid supply valve80. Depending on the particular control scheme used to control gas pressure within the fluidic separation chamber30, the various valves described herein, i.e., the production fluid supply valve20, the inert gas exhaust valve40, and the baseline liquid supply valve80, may be continuously variable valves defining a wide range of admissible flow rates, or more simple valves that merely transition between “on” and “off” states.

The fluidic supply and analysis unit70can be configured to provide volume fraction data by transitioning the fluidic separation chamber30to a static state after a complete gaseous phase column25G and a complete oil phase column250are formed within the fluidic separation chamber30. Once formed, the fluidic supply and analysis unit70communicates with the fluidic separation detector60to measure the absolute or relative sizes of the complete gaseous phase column25G and the complete oil phase column250. Oil/gas volume fractions can be calculated as a function of the measured sizes of the gaseous phase and oil phase columns25G,25O in the fluidic separation chamber30.

In some cases, the complete oil phase column25O may comprise an oil/water emulsion, particularly if the properties of the multiphase production fluid are such that complete separation of the oil and water phases by gravity is not practical. In such cases, it may be advantageous to configure the fluidic supply and analysis unit70to calculate the oil/gas volume fraction as a function of an emulsification factor that can be used to estimate the respective volumetric proportions of the oil and water phases of the oil/water emulsion forming the complete oil phase column25O. This emulsification factor can be obtained experimentally using demulsifiers.

Those practicing the concepts of the present disclosure will appreciate that a number of different factors can be used to determine if the gas and oil columns25G,25O are “complete.” For example, in some embodiments, the fluidic supply and analysis unit70will calculate the oil/gas volume fraction after a growth rate of the gaseous phase column25G, the oil phase column25O, or both, drops below a growth rate threshold. In other embodiments, the oil/gas volume fraction will be calculated after a threshold separation time has elapsed, or after the oil phase column25O and the gaseous phase column25G have reached between about 50% and about 80% of their fully separated sizes. More specifically, although it may be advantageous to ensure substantially complete separation of the oil and gas phases of the production fluid25in the fluidic separation chamber30, because of time constraints, in many embodiments, where the volume of a water/oil emulsion is not expected to be considerable, it may be sufficient to ensure that the oil phase column25O and the gaseous phase column25G have merely reached a degree of separation that is diagnostically significant.

It is also noted that the calculated oil/gas volume fractions according to the present disclosure may represent absolute or proportional volumes of oil and gas in the fluidic separation chamber30. More specifically, embodiments are contemplated where the oil/gas volume fraction represents respective oil and gas volumes relative to each other, or relative to a total volume of the multiphase production fluid in the fluidic separation chamber.

Given a calculated volume fraction, the fluidic supply and analysis unit70can be configured to calculate a production fluid oil flow rate QOas a function of at least the production fluid gas flow rate QGand the volume fraction VO/VG. More specifically, as QO=QG(VO/VG).

The fluidic supply and analysis unit70can be configured to transition the fluidic separation chamber30to a static state by stopping the supply of multiphase production fluid25via the production fluid supply valve20. In embodiments where the system100further comprises a baseline liquid supply valve80, and the fluidic piping10supplies baseline liquid85from the baseline liquid supply valve80, the fluidic supply and analysis unit70can be configured to transition the fluidic separation chamber30to a static state by replacing the supply of multiphase production fluid25with baseline liquid85and subsequently stopping the supply of baseline liquid85.

In additional embodiments, oil/gas/water volume fractions can be calculated as a function of the measured sizes of the gaseous phase, oil phase, and water phase columns25G,25O,25W in the fluidic separation chamber30. More specifically, The fluidic supply and analysis unit70can be configured to transition the fluidic separation chamber30to the aforementioned static state after a complete gaseous phase column25G, a complete oil phase column250, and a complete water phase column25W are formed within the fluidic separation chamber30, as is illustrated inFIG.1. Once formed, the fluidic supply and analysis unit70communicates with the fluidic separation detector to measure the absolute or relative sizes of the complete gaseous phase column25G, the complete oil phase column250, and the complete water phase column25W, and calculate a volume fraction VO/VG/VH2Oas a function of the measured sizes of the gaseous phase, oil phase, and water phase columns25G,25O,25W in the fluidic separation chamber30. In such embodiments, the fluidic supply and analysis unit70can be configured to calculate a production fluid oil flow rate QOand a production fluid water flow rate QH2Oas a function of at least the production fluid gas flow rate QGand the volume fraction VO/VG/VH2O. For example, in one embodiment, where a 2-3 meter column of the multiphase production fluid25is supplied at a rate of approximately 0.2 m/s, through supply and separation pipe of about 4 inches in diameter, given a separation time of about 2 minutes, a 30 meter fluidic separation chamber30will be large enough to accommodate the necessary entry and separation of the multiphase production fluid25in the fluidic separation chamber30. Shorter chamber lengths will be suitable for lower flow rates, or if less time is needed to ensure sufficient separation.

As is implied above, in embodiments where a baseline liquid85is supplied via a baseline liquid supply valve80, the fluidic supply and analysis unit70can be configured to communicate with the baseline liquid supply valve80to replace the supply of multiphase production fluid25with baseline liquid85. In this manner, the baseline liquid85can be used to ensure that a complete gaseous phase column25G, a complete oil phase column25O, and/or a complete water phase column25W will resides within the fluidic separation chamber30.

As is illustrated inFIG.1, the system100may further comprise a production fluid drain valve55, and the fluidic piping10may be configured to drain production fluid from the fluidic separation chamber30through the production fluid drain valve55. In this manner, separated fluids may be returned to the production system through the production fluid drain valve20. Alternatively, it is contemplated that separated fluids may be returned through the baseline liquid supply valve80.

Although the fluidic piping10and the fluidic separation chamber30are merely illustrated schematically inFIG.1, it is contemplated that the fluidic piping10and the fluidic separation chamber30may comprise cylindrical piping of matching cross sectional dimensions. In many embodiments, it will also be preferable to ensure that the fluidic separation chamber30comprises an optically transparent cylindrical pipe, as this will enhance the ability of particular types of fluidic separation detectors60, like an optical vision system defining a field of view encompassing the transparent pipe, to provide meaningful separation data. It will also be advantageous, in many embodiments, to ensure that the fluidic separation chamber30is vertically oriented and the system is configured such that the multiphase production fluid25assumes a vertical orientation in the fluidic separation chamber30, as this will enhance gravitational phase separation.

As will be appreciated by those familiar with fluidic control systems and fluidic detection, the fluidic supply and analysis unit70may be presented in a variety of configurations. For example, and not by way of limitation, the fluidic supply and analysis unit70may comprise a fluidic separation detection module72, a fluidic metering module74, and a programmable controller76. In such embodiments, the fluidic separation detection module72would be in communication with the fluidic separation detector60. In addition, the fluidic metering module74would be in communication with the production fluid supply valve25, the inert gas exhaust valve40, and the separation chamber pressure sensor50. Collectively, the fluidic separation detection module72and the fluidic metering module74would be in communication with the programmable controller76. In these types of implementations, it is contemplated that the stated modules would comprise memory and other electronic components suited to complement the functionality of the corresponding detector(s), valve(s), and sensor(s) with which they communicate. Alternatively, the functionality of the stated modules and controller could be accommodated in a single, programmable unit or control hub.

Those practicing the present invention, and familiar with fluidic detection will appreciate that the system100may comprise a plurality of fluidic separation detectors60, as is illustrated inFIG.1, where a plurality of fluidic separation detectors60are arranged along a longitudinal dimension of the fluidic separation chamber30. In addition, it is contemplated that a variety of detectors60will be suitable for providing useful phase movement and separation data to the fluidic supply and analysis unit70. Contemplated detectors may be presented as passive or active sensors. For example, and not by way of limitation, a non-illuminating vision system or a temperature/gas sensor array could be used as passive sensors to observe the multiphase production fluid to facilitate the aforementioned growth rate monitoring. Active sensors include, but are not limited to, microwave or acoustic transceivers, or an illuminating vision system including one or more high speed cameras. Depending on the sensing technology utilized, these detectors60can be arranged along the fluidic separation chamber by positioning them outside of the chamber body, or may be embedded in the chamber body, in contact, or non-contact, with the fluid receiving space of the fluidic separation chamber30.

For the purposes of describing and defining the present invention, it is noted that reference herein to a characteristic of the subject matter of the present disclosure being a “function of” a parameter, variable, or other characteristic is not intended to denote that the characteristic is exclusively a function of the listed parameter, variable, or characteristic. Rather, reference herein to a characteristic that is a “function” of a listed parameter, variable, etc., is intended to be open ended such that the characteristic may be a function of a single parameter, variable, etc., or a plurality of parameters, variables, etc.

It is noted that recitations herein of a component of the present disclosure being “configured” in a particular way, to embody a particular property, or to function in a particular manner, are structural recitations, as opposed to recitations of intended use. More specifically, the references herein to the manner in which a component is “configured” denotes an existing physical condition of the component and, as such, is to be taken as a definite recitation of the structural characteristics of the component.

It is noted that terms like “preferably,” “commonly,” and “typically,” when utilized herein, are not utilized to limit the scope of the claimed invention or to imply that certain features are critical, essential, or even important to the structure or function of the claimed invention. Rather, these terms are merely intended to identify particular aspects of an embodiment of the present disclosure or to emphasize alternative or additional features that may or may not be utilized in a particular embodiment of the present disclosure.

For the purposes of describing and defining the present invention it is noted that the terms “substantially” and “approximately” are utilized herein to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement, or other representation. The terms “substantially” and “approximately” are also utilized herein to represent the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.

Having described the subject matter of the present disclosure in detail and by reference to specific embodiments thereof, it is noted that the various details disclosed herein should not be taken to imply that these details relate to elements that are essential components of the various embodiments described herein, even in cases where a particular element is illustrated in each of the drawings that accompany the present description. Further, it will be apparent that modifications and variations are possible without departing from the scope of the present disclosure, including, but not limited to, embodiments defined in the appended claims. More specifically, although some aspects of the present disclosure are identified herein as preferred or particularly advantageous, it is contemplated that the present disclosure is not necessarily limited to these aspects.

It is noted that one or more of the following claims utilize the terms “in which” and “wherein” as transitional phrases. For the purposes of defining the present invention, it is noted that these terms are introduced in the claims as an open-ended transitional phrase that is used to introduce a given number of claim elements and should be interpreted in like manner as the more commonly used open-ended preamble term “comprising.”