NO338808B1 - Modular Hydrocarbon Fluid Taskbar - Google Patents

Description

Modularized process line for hydrocarbon fluid

Technical field of the invention

The present invention relates to processing equipment which is useful in the production of hydrocarbons. The invention relates in particular to a process line comprising a modularized processing unit that can be utilized in the process of extraction, treatment and transport of multiphase fluid produced from a hydrocarbon well.

Background of the invention and prior art Extraction and production of oil and gas from hydrocarbon wells involves a majority of process steps which are carried out at the production site before the product is delivered to a recipient on the surface. A process line for processing multiphase well fluid will generally involve processing units designed and dedicated for use as a separator, pump or compressor, etc. The complexity of a hydrocarbon process line for multiphase well fluid is obvious, considering that individual separators for separating f .ex. sand/liquid, gas/liquid and liquid/liquid may be required in the process line. In addition to the active processing units, the process line needs appropriate manifolds, bridging/piping and valves, which contributes to a complicated structure.

US 6811382 B2, US 2009/0200035 A1, US 2013/0236341 A1 and US 6527521 B2 can be mentioned from prior art.

Summary of the Invention

The present invention aims to provide a process line which avoids complexity in structure and installation, which is usually associated with processing multiphase hydrocarbon fluid.

A key to the solution presented here is a power and flow module that, without significant modification, can be used to generate flow and pressure in most, if not all, of the process steps where required.

The proposed solution reduces qualification costs for different and specialized equipment, increases operational efficiency and experience, and allows flexibility in a standardized solution for production of hydrocarbon well fluid on the seabed as well as

as on land.

An overview of the potential of the present invention for modularization and standardization is given in the following brief explanation of a possible implementation and example of implementation of the invention: Multiphase fluid from the well is led to a first set of power and flow modules that act as a gas/liquid separator. The gas is separated into a side pipe while the fluid moves forward through the rotating power and flow modules into a second set. The second set acts as an oil/water separator, where the water is separated into a side pipe while oil moves forward through the rotating power and flow modules and into a third set. The third set acts as a pressure boosting pump and increases the pressure of oil and gas for further transport. A fourth set of power and flow modules may be arranged to operate as a water treatment module and receive water from the side pipe from the second set. Waste water is recycled upstream back to the third set. Clean water runs downstream to a fifth set of power and flow modules that serve as one

water injection pump.

Among the advantages that can be achieved by implementing such a modular processing unit are, for example, the following: • a uniform power and regulation system for all units

• active separation becomes possible

• problems with waste water flows can be avoided

• better reliability due to redundancy

• a singular well distribution system is achieved.

The objective of the present invention is achieved by providing a process line configured for the extraction, treatment and transport of hydrocarbon well fluid, comprising processing units arranged and required to perform at least one of the following process steps:

• separation of fluid/solid

• homogenization of multiphase fluid

• separation of gas/liquid

• liquid/liquid separation

• pumping

• increase in flow or pressure

• compression of gas

• water treatment

• water injection

• wax treatment

• gas-hydrate handling,

wherein flow through the processing line is achieved by a power and flow module which essentially generates an axial flow through an annular annular flow passage, wherein the power and flow module comprises:

- a rotor supported for rotation on a rotor shaft,

- the rotor has rotor blades which extend essentially in radial directions from a rotor center axis, - permanent magnets mounted at the outer ends of the rotor blades, - electromagnets and stator windings mounted on an enclosure that encloses the rotor, the enclosure having coupling means for connecting the power and flow module to an adjacent power and flow module in a stacked configuration. In the stacked configuration, the rotors of the power and flow module are individually mounted on the outside of a stationary through shaft to rotate about it separately from other rotors in a set of power and flow modules.

The power and flow module is preferably an electrically driven machine which can be realized in various designs.

The rotor is designed for axial movement of fluid through the power and flow module. Embodiments of the invention include a power and flow module where the rotor blades have an angle of attack against the direction of flow which serves to generate an essentially axial flow, without any significant radial component, through the processing unit. Other embodiments include a rotor designed to add a significant radial component to the flow through the processing unit.

The power and flow module can be used in a processing unit if configured for separation. In one embodiment, the power and flow module is operationally connected in line with a separate screw or paddle wheel that generates separation of the fluid phases by centrifugal or cyclonic action. In another embodiment, the power and flow module is integrated with a cylindrical drum which may be internally designed with vanes which impart a rotary motion to the flow through the drum.

In yet another embodiment, the force and flow module, as a result of a compound curvature in the radial vanes, generates the rotary motion in the flow required to achieve separation of fluid phases by centrifugal action.

In all cases, the processing unit acting as a separator may be arranged for lateral/radial discharge of a heavier fluid phase separated from an incoming multi-phase flow, while a lighter fluid phase passes through the processing unit in the axial direction.

Routing of the separated fluid phases from and between the processing units can be accomplished with a stationary transition piece having internal passages as well as upstream and downstream interfaces suitable for connected processing units. The transition piece typically has an upstream interface comprising an outer annular inlet for the heavier fluid phase and a central inlet, annular or circular, for the lighter fluid phase radially within the outer annular inlet. The downstream interface has either an annular outlet for heavier fluid phase or a central outlet for lighter phase fluid.

The power and flow module can be used in a processing unit configured for pressure boosting. In one embodiment, the power and flow module is multiplexed and forms a package of axially stacked PM motors and rotors that serve to accelerate and compress the flow through the pressurization unit. Each power and flow module in a stacked configuration can be operated separately and controlled individually via dedicated frequency converters (Variable Speed Drives - VSD), one for each motor stage or rotor.

Similarly, in one embodiment, the power and flow module is an electrically driven flow machine, where permanent magnets are mounted along the circumference of a rotor while electromagnets and stator windings are mounted in a stationary enclosure that encloses the rotor.

In one embodiment, the rotor blades are provided with an angle of attack against the direction of flow which serves to generate an essentially axial flow, without a significant radial component, through a power and flow module which is integrated into a processing unit which acts as a pump, pressure booster or separator.

In other embodiments, the rotor blades are curved to impart a significant radial component to the flow through a power and flow module integrated into a processing unit that acts as a pump, booster, or separator.

In one embodiment, the power and flow module is operationally connected in line with a screw or paddle wheel in a processing unit leading to the separation of the fluid phases by means of centrifugal or cyclonic action.

The power and flow module is in one embodiment integrated with a cylindrical drum which is internally designed with vanes which impart a rotary movement to the flow through a processing unit leading to the separation of the fluid phases by means of centrifugal or cyclonic action.

In one embodiment, the rotor comprises turbine wheels in a power and flow module that is integrated into a processing unit that acts as a wet gas compressor.

Embodiments of the invention comprise a stationary transition piece which is designed to connect successive processing units in a process line, the transition piece being designed internally with separate runs for heavier and lighter fluid phases.

In one embodiment of the present invention, a first processing unit comprises a power and flow module that operates as a separator or as a fluid homogenizer and in a second processing unit a power and flow module operates as a pressure boosting pump or compressor, and so on as the processing units are connected and assembled in sequence and assembled for axial flow through the first and second processing units.

Another embodiment of the present invention comprises in-line separators where the first and second processing units each comprise a power and flow module which operates as a separator, while a third processing unit comprises a power and flow module which operates as a pressure boosting pump or compressor, and so on as the separators and booster pump/compressor are connected and assembled in sequence for axial flow through first, second and third processing units.

Yet another embodiment of the present invention comprises a first transition piece that connects the first and second separators which are arranged for the discharge and feeding of a separated gas phase to the pressure boosting pump or the compressor, and where a second transition piece, which connects the second separator to the pressure boosting pump/compressor, is designed for the discharge of a separated water phase to a water treatment unit.

In one embodiment, the first water treatment unit comprises the power and flow module which acts as a separator, and where waste water is led from the first water treatment unit to the pressure boosting pump.

In one embodiment, the second water treatment unit comprises the power and flow module which acts as a water injection pump.

Implementations of the present invention include designs where cold well flow is enabled through a hydrocarbon solids precipitation chamber where the power and flow module drives a rotary scraper in the precipitation chamber.

From the following detailed description of embodiments, it will be apparent that processing units acting on the power and flow module may be included in many types and configurations of hydrocarbon well fluid process lines, subsea as well as onshore, although only a few such are mentioned in this description.

Brief description of the drawing figures

Embodiments of the invention will be explained below with reference to the attached drawings, which show as follows: Figure 1 shows a longitudinal section through a set of power and flow modules which are adapted for incorporation in the processing units that follow from the present invention. Figure 2 is a corresponding section illustrating the power and flow module used in a processing unit configured for separation, Figure 3 is a corresponding section illustrating the power and flow module used in a processing unit configured for pressure boosting, Figure 4 is a corresponding section illustrating the power and flow module used in a processing unit configured for pressure boosting, Figures 5a-5c illustrate the power and flow module used in alternatively configured processing units for separation, Figure 6 is a schematic illustration of a first subsea process line composed of processing units dependent of the power and flow module for its operation, Figure 7 is a schematic illustration of a second subsea process line composed of processing units that rely on the power and flow module for its operation, and Figure 8 is a schematic illustration of a third subsea process line composed of processing units that depend on the power and flow module for their operation.

Detailed description of preferred designs

Although explained and illustrated below with reference to a subsea implementation, it must be emphasized that the embodiment provided herein can equally be used in the process of hydrocarbon production from onshore hydrocarbon wells.

With reference to Figure 1, a set of power and flow modules 1 is shown in longitudinal section. Each power and flow module 1 comprises a rotor 2 which is supported for rotation on a rotor shaft 3. The rotors 2 can be individually supported in radial/axial bearings 4 on the outside of a stationary rotor shaft to rotate about this separately from other rotors in a set with power and flow modules.

Each rotor 2 comprises a set of rotor blades or rotor blades 5 which extend essentially in radial directions from a rotor center axis C. At least some of the rotor blades 5 have a permanent magnet 6 at the outer circumferential end of the rotor blade. The permanent magnets 6 can be integrated into a ring element 7 which connects the outer ends of the rotor blades in the rotor circumference 8.

The rotor 2 is enclosed by an enclosure 9 which has coupling means, such as flanges 10, for connection to adjacent power and flow modules 1. Seals, not shown in the drawings, are arranged as required in the meeting interfaces between enclosures to coupled power- and flow modules. Mounted in housing 9 is a set of electromagnets with associated stator windings, marked in the drawings with the same reference number 11. The electromagnets 11 form an outer ring around the inner ring of permanent magnets, and the housing 9 may have the shape of a cylinder.

The rotor 2 is thus set in rotation by the permanent magnets moving in the magnetic field which is generated when current is supplied to the stator windings to activate the electromagnets.

During rotation, the power and flow module 1 primarily forms an axial flow through an annular flow passage which is defined by the rotor(s) in the power and flow module/set of power and flow modules. The rotor blades 5 are designed with an angle of attack or pitch angle against the flow F and in relation to the axial center axis C. In a set of power and flow modules, at least one of the rotors can have blades with a different pitch angle than the other rotors in the set, pitch angle can increase or decrease successively from the first to the last rotor in the set, in order in this way to change the flow and/or pressure in the fluid.

To further customize the operation of the set of power and flow modules 1, the power and flow modules can have individual power supplies and be controlled separately via dedicated frequency converters, as illustrated by the VSD boxes in Figure 1.

Embodiments of the force and flow module 1 can be modified to add a radial component in the direction of flow. For this purpose, modified rotor blades (see the rotor blades 5' in Figure 2) can be shaped with an angle of attack or curvature in the radial plane, the rotor blades being bent backwards in relation to the rotor's direction of rotation. In a set of power and flow modules, some of the rotors may be designed to generate a predominantly axial flow, while other rotors are designed to generate rotation in the flow to subject the fluid to centrifugal force and cyclonic action.

Figure 2 illustrates the power and flow module 1 implemented in a processing unit acting as a separator 12. Note that although the drawing in Figure 2 shows only two power and flow modules, the actual number of power and flow modules 1 can be multiplied and adapted to operational legal requirements. For example, the separator 12 may comprise an upstream group of force and flow modules configured to generate axial flow, while a downstream and downstream group of force and flow modules are configured to impart rotary motion to the flow by means of the radially curved or doubly curved rotor blades 5'.

In the separator 12, the rotary motion imparted to the flow causes the fluid phases to separate due to cyclonic action, because the heavier fluid phase is driven by centrifugal force to collect in a peripheral area in the annular passage through the force and flow modules.

A stationary transition piece 13 is connected to the downstream end of the separator and provides passages 14 and 15 for conveying the heavier fluid phase 0 to a radial or lateral outlet, as well as passages 16 and 17 for conveying the lighter fluid phase G to an axial, central outlet. In the upstream interface, the transition piece 13 has an annular outer inlet 18 for the heavier phase and an annular inner inlet 19 for the lighter fluid phase. The inlets 18 and 19 can be separated upstream by a cylindrical partition 20. A pipe fitting 21 without moving internal parts can be inserted between the power and flow modules 1 and the transition piece 13, if suitable.

The power and flow module 1 can be implemented in separation units in other and alternative configurations. With reference to Figure 5a, there is illustrated a processing unit which acts as a separator 12', which comprises a cylindrical drum 22 which is rotatably mounted inside a stationary cylinder 23. The drum can be rotatably stored in bearings 24 and 25 which are arranged at the ends of drum and cylinder. The drum is installed in a multiphase fluid flow F to receive mixed fluid phases via an inlet end 26 and to discharge separated fluid phases 0, G via an outlet end 27. Separation of the fluid phases is achieved by introducing rotary motion in the fluid after passing through the drum 22.

Rotating movement is generated by one or more power and flow modules 1 which are integrated into the separator 12' and installed above the fluid flow through the separator. More specifically, the electromagnets 11 are mounted on the stationary cylinder 23, while the permanent magnets 6 are mounted on the drum 22. The drum is thus set in rotation by the permanent magnets moving in the magnetic field that is generated when current is fed to the stator windings to activate the electromagnets.

Rotating movement can be supplied to the flow via one or more vanes 28 which are arranged so that they point inwards from the wall of the drum, the vanes lying mainly in the longitudinal direction of the drum. The wings 28 may be of any suitable shape. The internal wings can be oriented parallel to the longitudinal axis of the drum, as illustrated by the straight dotted line in Figure 5b. Alternatively, the wings can be oriented at an angle a in relation to the center line, as illustrated by line 28 in Figure 5b. The wings can also have a design that follows a helical curve in the inner periphery of the drum 22, as illustrated by the curved dotted line in Figure 5b.

Yet another alternative implementation of the power and flow module 1 in a processing unit acting as a separator is described with reference to Figure 5c. The separator 12'' in figure 5c comprises a stationary outer cylinder 29 in ambient conditions about a stationary inner cylinder or drum 30. The inner drum 30 has a perforated wall in which openings or slots 31 are designed to allow the transfer of a heavier fluid phase from the drum to an annular region 32 defined between the drum and the outer cylinder. A side outlet 33 is connected to the annular area 32 in the radial direction.

A screw 34 is stored for rotation internally in the drum. The internal screw 34 has a radial blade 35 which runs in a spiral around a screw shaft 36. The screw shaft 36 is drive-connected to the rotor shaft of one or more stacked power and flow modules 1. The non-driven end of the screw is stored in a bearing housing 37 arranged at the downstream end of the separator.

The processing unit acting as a separator 12, 12' or 12'' is connected to a downstream processing unit in the process line via an intermediately connected transition piece, such as the stationary transition piece 13 in Figure 2. While the transition piece 13 shown in Figure 2 is arranged to carry the heavier the phase out of the axial flow which continues through the coupled processing units is, however, another and alternative transition piece 13', see Figure 3, adapted to carry the lighter phase G out of the axial flow while the heavier phase 0 continues axially along an annular passage 38 into the next processing unit in the line. The transition piece 13' can be followed in the process line by a unit configured to act as an axial pump or pressure boosting unit 39. In the pressure boosting unit 39, power and flow modules 1 are driven to accelerate the fluid and thereby increase flow and/or pressure towards an outlet end of pump or pressure boosting unit. An outlet element 40 is connected to the downstream end of the pressure boosting unit and leads the flow out of the process line. In that way, the outlet element 40 terminates the process line or at least an upstream part of the process line.

Figure 4 illustrates a modified power and flow module 1' built into a processing unit that acts as a wet-tolerant gas compressor 41. The power and flow module 1' of Figure 4 differs from the power and flow module 1 in terms of the shape of the rotor blades. Instead of the blades forming rotor 2 in the power and flow module 1, rotor 42 in the power and flow module 1' comprises a set of stacked turbine wheels 43 which rotate about a shaft 44. Stationary transition pieces 45 lead the fluid to the subsequent turbine stage.

In a subsea process line, compressor 41 can be connected in line with the separator 12 and an intermediate transition piece 13 which leads wet gas to the compressor and oil and water out of the axial flow, for further processing downstream.

Processing units for subsea process lines can thus be based on the same rotary power and flow module essentially without modification. Besides the illustrated integration in separators, in axial pumps or booster units and wet gas compressors, the power and flow module will be suitable for implementation in multiphase fluid homogenization units, water treatment units, water injection pumps, wax and gas hydrate handling devices, etc., where required rotating force.

The concept of a modular power and current unit to generate the rotation and current required in processing units in a subsea process line provides great flexibility in the layout of process lines. A few examples will be briefly reviewed below with reference to the drawings in Figures 6 to 8.

Thus Figure 6 shows a subsea process line 100 where in a first processing unit 101 the power and flow module is implemented as a centrifugal separator, or as a multiphase fluid homogenizer and in a second processing unit 102 the power and flow module is configured to act as a pressure boosting unit or a wet gas compressor , and further where the processing units 101 and 102 are connected via a stationary transition piece 103 which ensures axial flow between the processing units 101, 102.

Figure 7 shows a subsea process line 200 comprising process units 201 and 202 which act as separators. In the first separator 201, the power and flow module is used to separate gas and fluid. Gas is led from the first separator 201 via a pipeline 203 to a third processing unit 204 which acts as a pressure booster pump, while oil and water continue with the axial flow into the second separator 202. The first and second separators 201 and 202 can be connected via a stationary transition piece 13'. In the second separator 202, the power and flow module is used to separate oil and water. Oil continues with the axial flow into the pressure increase pump 204, while water W is led out of the axial flow via a pipeline 205. The second separator 202 and the pressure increase pump 204 can be connected via a stationary transition piece 13.

A blind flange 206 terminates the axial flow through the processing units 201, 202 and 204. The blind flange can be designed like the outlet element 40 mentioned with reference to Figure 3, which ensures that recombined oil and gas can be discharged from a booster pump 204 with increased pressure and/or flow.

Process line 200 can be extended beyond the booster pump 204. In a fourth processing unit 207, the power and flow module is used as a separator for treating water received from pipeline 205. Waste water W{1) is carried out by the axial flow as the heavier phase , while pure water W(2) as the lighter phase continues to flow axially into a fifth processing unit 208. In the fifth processing unit 208, the power and flow module is used as a water injection pump. In contrast, the waste water can be led back to the pressure increase pump 204 via a pipeline 209 for further transport.

The general design of process line 300 in Figure 8 is essentially as described with reference to Figure 7, and corresponding units are marked with the same reference numbers. However, Process Line 300 in Figure 8 differs from Process Line 200, among other things, in regard to the flow path for separated gas which in the embodiment 300 runs outside the pressure boosting pump 304 and is led via pipeline 303 to be reintroduced into the increased fluid flow that flows out of the pressure boosting pump 304.

Process line 300 further comprises a function for treating wax and gas hydrate. More specifically, a processing unit 310 is upstream of a booster pump 304 adapted to operate to enable cold well flow, where the power and flow module is used to generate rotation of a scraper 311 which is stored for rotation in a hydrocarbon solids precipitation chamber. In the precipitation chamber, the temperature of the fluid is lowered to below the temperature for the formation of hydrates and solids, which cause precipitation and deposition of solids on the walls of the precipitation chamber. The precipitation chamber can be cooled by natural or forced convection, or by other cooling techniques.

Above, it is explained and illustrated in drawings of examples of executions, that a significant modularized and standardized process line for the extraction, treatment and transport of hydrocarbon well fluids can be achieved by carrying out the descriptions given here.

It will nevertheless be obvious that modifications of the embodiments described are possible without deviating from the scope and spirit of the invention as described above and defined in the attached patent claims.

Claims (14)

1. Process line configured for extraction, treatment and transport of hydrocarbon well fluid, comprising processing units designed and required to perform at least one of the following process steps: - fluid/solid separation, - multiphase fluid homogenization, - gas/liquid separation, - liquid/ liquid separation, - pumping, - current or pressure increase, - gas compression, - water treatment, - water injection, - wax treatment, - gas hydrate treatment, flow through the process line is achieved by a power and flow module (1, 1') which essentially generates an axial flow through an annular flow passage, where the power and flow module (1, l<f>) comprises: - a rotor {2, 42) supported for rotation on a rotor shaft (3, 44), - the rotor has rotor blades (5, 43) extending essentially in radial directions from a rotor center axis (C), - permanent magnets (6) mounted at the outer ends of the rotor blades (5, 43) , - electromagnets and stator windings (11) mounted on an enclosure (9) which encloses the rotor (2, 42), the enclosure (9) having coupling means for coupling the power and flow module (1, 1' ) to an adjacent power and flow module (1, 1') in a stacked configuration, characterized in that in a stacked configuration the rotors (2, 42) of the power and flow module are individually supported on the outside of a stationary through shaft (3, 44 ) to rotate about this separately from other rotors in a set of force and flow m odules. 2. Process line according to claim 1, in that the power and flow modules (1, 1') are individually driven and separately controlled via dedicated frequency converters. 3. Process line according to claim 1 or 2, the rotor blades (5) being given an angle of attack against the direction of flow (F) which serves to generate an essentially axial flow, without a significant radial component, through a force and flow module (1 ) which is integrated into a processing unit that operates as a pump, as a pressure boosting unit or as a separator. 4. Process line according to any one of claims 1-3, the rotor blades (5') being curved to impart a significant radial component to the flow through a power and flow module (1) integrated into a processing unit acting as a pump, as a pressure boosting unit or as a separator. 5. Process line according to claim 3 or 4, in that the power and flow module (1) is operationally connected in line with a screw or paddle wheel (34) in a processing unit (12") which performs separation of the fluid phases by centrifugal action or cyclone action. 6. Process line according to any one of claims 1-4, wherein the power and flow module (1) is integrated with a cylindrical drum (22), internally formed with vanes (28) which imparts a rotary motion to the flow through a processing unit (12'') which performs separation of the fluid phases by centrifugal action or cyclone action. 7. Process line according to claim 1, in that the rotor (42) comprises turbine wheels (43) in a power and flow module (1') integrated in a processing unit (41) which acts as a wet gas compressor. 8. Process line according to any preceding claim, comprising a stationary transition piece (13, 13') arranged for connecting successive processing units in the process line, the transition piece being internally designed with separate paths (0, G) for heavier and lighter fluid phases . 9. Process line according to any preceding claim, in that in a first processing unit (101) the power and flow module (1) operates as a separator or as a fluid homogenizer, in a second processing unit (102) the power and flow module (1) operates , 1') as a pressure boosting pump or compressor, and further as the processing units are connected and assembled successively for axial flow through the first and second processing units. 10. Process line according to any one of claims 1-8, comprising in-line separators, the first and second processing units (201, 202) each comprising the power and flow module (1) operating as a separator, while a third processing unit ( 204) comprises the power and flow module (1) which acts as a booster pump or compressor, and further as the separators (201, 202) and booster pump/compressor (204) are connected and assembled successively for axial flow through the first, second and third processing unit. 11. Process line according to claim 10, in that a first transition piece (13') which connects the first (201) and second (202) separators is arranged for outlet and feeding of a separated gas phase to the pressure increase pump or compressor (204), and in that a second transition piece (13), which connects the second separator (202) and the pressure boosting pump/compressor (204), is arranged for the discharge and feeding of a separated water phase to a water treatment unit (207). 12. Process line according to claim 11, in that the first water treatment unit (207) comprises the power and flow module (1) which acts as a separator, and in that waste water W{1) is transferred from the first water treatment unit (207) to the pressure increase pump (204) . 13. Process line according to claim 12, in that the second water treatment unit (208) comprises the power and flow module (1) which acts as a water injection pump. 14. A process line according to any preceding claim, wherein cold well stream is opened through a hydrocarbon solids precipitation chamber (310) comprising the power and flow module (1) driving a rotatable scraper (311) in the precipitation chamber.