WO2016074950A1

WO2016074950A1 - A modularized hydrocarbon fluid process line

Info

Publication number: WO2016074950A1
Application number: PCT/EP2015/075269
Authority: WO
Inventors: Luciano Emanuel PATRUNO; Espen Hauge; Jose Luis PLASENCIA CABANILLAS
Original assignee: Vetco Gray Scandinavia As
Priority date: 2014-11-10
Filing date: 2015-10-30
Publication date: 2016-05-19
Also published as: NO338808B1; NO20141342A1

Abstract

A process line (200) is disclosed, configured for recovery, treatment and transportation of hydrocarbon well fluid, comprising processing units (201, 202), wherein the processing units are arranged and required for carrying out at least one of separation, homogenization, pumping, pressure boosting, compression, water treatment, water injection, wax or gas hydrate handling in a hydrocarbon production process, wherein any two or more processing units operate on basically the same power and flow module to generate flow through the processing units.

Description

A MODULARIZED HYDROCARBON FLUID PROCESS LINE

TECHNICAL FIELD OF THE INVENTION

The present invention relates to processing equipment useful in hydrocarbon production. The invention particularly relates to a process line comprising a modularized processing unit which can be applied in the process of recovery, treatment and transportation of multiphase fluid produced from a hydrocarbon well.

BACKGROUND AND PRIOR ART

Recovery and production of oil and gas from hydrocarbon wells involves several processing steps which are carried out at the production site before the product is delivered to a topside recipient. A process line for processing of multiphase well fluid generally involves processing units which are designed and dedicated for use as separator, pump or compressor etc. The complexity of a hydrocarbon process line for multiphase well fluid is readily understood, considering that individual separators for sand/liquid separation, gas/liquid separation and liquid/liquid separation, e.g., may be required in the process line. In addition to the active processing units the process line needs appropriate manifolds, jumpers/pipings and valves which add to the complexity in structure.

SUMMARY OF THE INVENTION

The present invention aims at providing a process line that avoids the complexity in structure and installation which is usually connected with the processing of multiphase hydrocarbon fluid.

A key to the solution presented herein is a power and flow module which can be used, without substantial modification, to generate flow and pressure in most if not all of the processing applications required. The proposed solution reduces qualification costs of different and specialized equipment, increases operational efficiency and experience, and enables flexibility in a standardized solution for hydrocarbon well fluid processing, on seafloor as well as on land.

An overview of the potential of the present invention for modularization and standardization is provided in the following brief explanation of a possible embodiment and exemplifying implementation of the invention:

Multiphase fluid from the well is supplied in a first set of power and flow modules that acts as a gas/liquid separator. The gas is extracted to a side pipeline while the liquid 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 extracted to a side pipeline while oil moves forward through the rotating power and flow modules into a third set. The third set acts as a boosting pump increasing the pressure of oil and gas for further transport. A fourth set of power and flow modules can be arranged to operate as a water treatment module, receiving water from the side pipeline out of the second set. Water reject is recirculated back to the third set, upstream. Clean water moves downstream to a fifth set of power and flow modules acting as a water injection pump.

Among the benefits which are achievable by implementation of such a modular processing unit are, e.g.:

• a uniform power and control system for all units · active separation is enabled

• issues with reject streams can be avoided

• provides increased reliability through redundancy

• a singular well distribution system accomplished.

The aim of the present invention is achieved by providing a process line configured for recovery, treatment and transportation of hydrocarbon well fluid, comprising processing units arranged and required for carrying out at least one of the following processing steps:

• fluid/solids separation

• multiphase fluid homogenization · gas/liquid separation

• liquid/liquid separation

• pumping

• flow or pressure boosting

• gas compression · water treatment

• water injection

• wax handling

• gas hydrate handling, wherein any two or more processing units operate on basically the same power and flow module to generate flow through the processing units.

In one advantageous embodiment the two or more processing units are connectable in line.

The power and flow module is preferably an electrically powered machine which can be realized in different embodiments. Common to all embodiments is an integrated permanent magnet (PM) motor wherein permanent magnets are carried in the periphery of a rotor whereas electromagnets and stator coils are supported on a stationary casing that surrounds the rotor. Embodiments of the invention comprise a power and flow module wherein the rotor is formed with radial blades or vanes which attach to a central rotor shaft that is journalled for rotation. Other embodiments comprise a rotor with vanes that are journalled for rotation on the exterior of a stationary shaft. The rotor is designed for axial displacement of fluid through the power and flow module. Embodiments of the invention comprises a power and flow module wherein the rotor vanes are provided a pitch angle against the flow direction which is applied to generate a mainly axial flow, without a significant radial component, through the processing unit. Other embodiments comprise a rotor designed to apply a significant radial component to the flow through the processing unit.

The power and flow module can be applied in a processing unit configured for separation. In one embodiment the power and flow module is drivingly connected in line with a separate screw or impeller which generates separation of fluid phases through centrifugal or cyclonic action. In another embodiment the power and flow module is integrated with a cylindrical drum which may internally be formed with wings that impart a rotational motion to the flow through the drum.

In yet another embodiment the power and flow module generates, in result of a composite curvature in its radial vanes, the rotational motion in the flow which is required to accomplish separation of fluid phases through centrifugal action. In all cases the processing unit operating as separator can be arranged for lateral/radial discharge of a heavier fluid phase which is separated out from an incoming multiphase flow, whereas a lighter fluid phase passes through the processing unit in axial direction.

Routing the separated fluid phases from and between the processing units can be accomplished through a stationary transition piece having internal passages as well as upstream and downstream interfaces which mate with the connecting processing units. The transition piece typically has an upstream interface comprising an outer annular entrance for the heavier fluid phase and a central entrance, annular or circular, for the lighter fluid phase radially inside of the outer annular entrance. The downstream interface has either an annular exit for heavier phase fluid or a central exit for lighter phase fluid.

The power and flow module can be applied in a processing unit configured for pressure boosting. In one embodiment the power and flow module is multiplied, forming a package of axially stacked PM motors and rotors which are operated for acceleration and compression of the flow through the booster unit. Each power and flow module in the stacked configuration may be separately powered and individually controlled via dedicated variable speed drives (VSD), one for each motor stage/rotor.

Accordingly, in one embodiment the power and flow module is an electrically powered flow machine wherein permanent magnets are carried in the periphery of a rotor whereas electromagnets and stator coils are supported on a stationary casing that surrounds the rotor.

In one embodiment the rotor vanes are provided a pitch angle against the flow direction which is applied to generate a mainly axial flow, without a significant radial component, through a power and flow module integrated in a processing unit operating as pump, as booster or as separator.

In other embodiments the rotor vanes are curved to apply a significant radial component to the flow through a power and flow module integrated in a processing unit operating as pump, as booster or as separator. In one embodiment the power and flow module is drivingly connected in line with a screw or impeller in a processing unit which effects separation of fluid phases through centrifugal or cyclonic action.

The power and flow module is in one embodiment integrated with a cylindrical drum which is internally formed with wings that impart a rotational motion to the flow through a processing unit which effects separation of fluid phases through centrifugal or cyclonic action.

In one embodiment the rotor comprises turbine wheels in a power and flow module integrated in a processing unit operating as wet gas compressor. Embodiments of the invention comprise a stationary transition piece arranged for interconnection of successive processing units in a process line, the transition piece internally formed with separate routes for heavier and lighter fluid phases.

In one implementation of the present invention a first processing unit comprises the power and flow module operating as separator or as fluid homogenizer, in a second processing unit the power and flow module operates as booster pump or compressor, and further wherein the processing units are connected and assembled in succession for axial flow through the first and second processing units.

Another implementation of the present invention comprises in-line separators wherein first and second processing units each comprises the power and flow module operating as separator, whereas a third processing unit comprises the power and flow module operating as booster pump or compressor, and further wherein the separators and the booster pump/compressor are connected and assembled in succession for axial flow through the first, second and third processing units. Still another implementation of the present invention comprises a first transition piece connecting the first and second separators arranged for discharge and routing of a separated gas phase to the booster pump or compressor, and wherein a second transition piece, connecting the second separator and the booster pump/compressor, is arranged for discharge and routing of a separated water phase to a water treatment unit.

In one embodiment the first water treatment unit comprises the power and flow module operating as separator, and wherein reject water is transferred from the first water treatment unit to the booster pump.

In one embodiment the second water treatment unit comprises the power and flow module operating as water injection pump.

Implementations of the present invention comprise embodiments wherein cold flow is enabled through a hydrocarbon solids precipitation chamber comprising the power and flow module driving a rotatable scraper in the precipitation chamber. From the following detailed description of embodiments it will be understood that processing units operating on the power and flow module can be incorporated in hydrocarbon well fluid process lines of many different configurations, subsea as well as on land, only a few of which will be named in this disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will be explained below with reference made to the accompanying schematic drawings, wherein

Fig. 1 is a longitudinal sectional view through a set of power and flow modules adapted for incorporation in the processing units provided by the present invention, Fig. 2 is a corresponding sectional view illustrating the power and flow module applied in a processing unit configured for separation,

Fig. 3 is corresponding sectional view illustrating the power and flow module applied in a processing unit configured for pressure boosting,

Fig. 4 is a corresponding sectional view illustrating the power and flow module applied in a processing unit configured for pressure boosting,

Figs. 5a-5c illustrate the power and flow module applied in alternatively configured processing units for separation,

Fig. 6 is a schematic illustration of a first subsea process line composed of processing units relying on the power and flow module for their operation, Fig. 7 is a schematic illustration of a second subsea process line composed of processing units relying on the power and flow module for their operation, and

Fig. 8 is a schematic illustration of a third subsea process line composed of processing units relying on the power and flow module for their operation. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Although explained and illustrated below with reference to a subsea implementation it should be pointed out that the teachings provided herein are likewise applicable in the process of hydrocarbon production from land based hydrocarbon wells. With reference to Fig. 1 a set of power and flow modules 1 is shown in longitudinal sectional view. Each power and flow module 1 comprises a rotor 2 which is journalled for rotation on a rotor shaft 3. The rotors 2 can be individually journalled in radial/axial bearings 4 onto the exterior of a stationary rotor shaft for rotation thereabout separately from other rotors in a set of power and flow modules. The rotors may alternatively be non-rotationally attached to a common rotor shaft which is journalled to rotate in bearings arranged on a bearing support (not shown).

Each rotor 2 comprises a set of rotor blades or rotor vanes 5 that extend mainly in radial directions from a rotor centre axis C. At least some of the rotor vanes 5 carry a permanent magnet 6 in the outer, peripheral end of the rotor vane. The permanent magnets 6 can be integrated in a ring member 7 which interconnects the outer ends of the rotor vanes in the rotor periphery 8.

The rotor 2 is surrounded by a casing 9 which has coupling means, such as flanges 10, for coupling to adjacent power and flow modules 1. Seals, not shown in the drawings, are arranged as required in the meeting interfaces between casings of coupled power and flow modules. Supported in the casing 9 is a set of electromagnets with associated stator coils, in the drawings commonly referred to by reference no. 11. The electromagnets 11 form an outer ring about the inner ring of permanent magnets, and the casing 9 can take the shape of a cylinder.

The rotor 2 is thus brought in rotation as the permanent magnets move in the magnetic field which is generated when current is fed to the stator coils for energizing the electromagnets.

In rotation the power and flow module 1 effects basically an axial flow through an annular flow passage defined by the rotor(s) of the power and flow module/set of power and flow modules. The rotor vanes 5 are designed with an angle of attack or pitch angle against the flow F and relative to the axial entre axis C. In a set of power and flow modules at least one of the rotors may have vanes with other pitch angle than the other rotors in the set. The pitch angles can be successively increased or decreased from the first to the last rotor in the set, in order this way to change flow and/or pressure in the fluid.

In order to further customize the operation of the set of power and flow modules 1 the power and flow modules can be individually powered and separately controlled via dedicated variable speed drives as illustrated through the VSD boxes in Fig.1. Embodiments of the power and flow module 1 can be modified to impart a radial component to the flow direction. To this purpose modified rotor vanes (see rotor vanes 5' in Fig. 2) can be shaped with an angle of attack or curvature in the radial view, the rotor vanes being swept backwards with respect to the rotational direction of the rotor. In a set of power and flow modules some of the rotors may be designed to generate axial flow mainly, whereas other rotors are designed to generate rotation in the flow in order to subject the fluid to centrifugal force and cyclonic action.

Fig. 2 illustrates the power and flow module 1 implemented in a processing unit operating as separator 12. It should be noted that even if the drawing of Fig. 2 depicts two power and flow modules only, the actual number of power and flow modules 1 can be multiplied and adapted to operational requirements. For example, the separator 12 may comprise an upstream group of power and flow modules configured for generation of axial flow, whereas a successive and downstream group of power and flow modules are configured to impart rotational motion in the flow by means of the radially curved or double-curved rotor vanes 5 ' . In the separator 12 the rotational motion that is imparted to the flow causes separation of fluid phases due to cyclonic action, as the heavier fluid phase is urged by centrifugal force to accumulate in a peripheral region of the annular passage through the power and flow modules. Coupled to the downstream end of the separator, a stationary transition piece 13 provides the passages 14 and 15 for routing the heavier fluid phase O to a radial or lateral discharge, as well as passages 16 and 17 for routing the lighter fluid phase G to an axial, central discharge. In the upstream interface the transition piece 13 has an annular outer entrance 18 for the heavier phase and an annular inner entrance 19 for the lighter fluid phase. The entries 18 and 19 can be separated upstream by a cylindrical divider ring 20. A spool piece 21 with no moving internals can be inserted between the power and flow modules 1 and the transition piece 13, if appropriate.

The power and flow module 1 can be implemented in separation units of other and alternative configuration. With reference to Fig. 5a, a processing unit operating as separator 12' is illustrated, comprising a cylindrical drum 22 which is supported rotationally inside a stationary cylinder 23. The drum can be rotationally journalled in bearings 24 and 25 arranged in the ends of the 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 O, G via an outlet end 27. Separation of the fluid phases is accomplished by imparting rotational motion in the fluid upon passage through the drum 22.

Rotational motion is generated by one or several power and flow modules 1 which is/are integrated in the separator 12' and installed across the fluid flow through the separator. More precisely, the electromagnets 11 are supported on the stationary cylinder 23, whereas the permanent magnets 6 are supported on the drum 22. The drum is thus brought in rotation as the permanent magnets move in the magnetic field which is generated when current is fed to the stator coils for energizing the electromagnets. Rotational motion can be imparted to the flow via one or more wings 28 which is/are arranged projecting inwards from the wall of the drum, the wings running mainly in the longitudinal direction of the drum. The wings 28 can have any suitable sectional shape. The internal wings may be oriented in parallel with the longitudinal centre of the drum, as illustrated by the straight dotted line in Fig. 5b. The wings may alternatively be oriented at an angle a relative to the centre line as illustrated through the line 28 in Fig. 5b. The wings may also be shaped to follow a helical curve in the inner periphery of the drum 22 as illustrated through the curved dotted line in Fig. 5b.

Yet an alternative implementation of the power and flow module 1 in a processing unit operating as a separator is disclosed with reference to Fig. 5c. The separator 12" of Fig. 5c comprises a stationary outer cylinder 29 in surrounding relation about a stationary inner cylinder or drum 30. The inner drum 30 has a perforated wall wherein openings or slits 31 are formed to permit transfer of a heavier fluid phase from the drum to an annular space 32 defined between the drum and the outer cylinder. A lateral discharge 33 is connected to the annular space 32 in radial direction. A screw 34 is journalled for rotation internally in the drum. The internal screw 34 has a radial blade 35 running helically about a screw shaft 36. The screw shaft 36 is drivingly connected to the rotor shaft of one or several stacked power and flow modules 1. The non-driven end of the screw is journalled in a bearing support 37 arranged in the downstream end of the separator. The processing unit operating as separator 12, 12' or 12" is connected to a downstream processing unit in the process line via an inter-coupled transition piece, such as the stationary transition piece 13 of Fig. 2. However, whereas the transition piece 13 depicted in Fig. 2 is arranged to route the heavier phase out of the axial flow that continues through the coupled processing units, another and alternative transition piece 13', see Fig. 3, is arranged to route the lighter phase G out of the axial flow while the heavier phase O continues axially along an annular passage 38 into the successive processing unit in the line.

The transition piece 13' may be succeeded in the process line by a processing unit configured to operate as an axial pump or booster 39. In the booster 39, power and flow modules 1 are powered to accelerate the fluid, thus increasing flow and/or pressure towards a discharge end of the pump or booster. A discharge piece 40 is coupled to the downstream end of the booster, routing the flow out of the process line. In that sense, the discharge piece 40 terminates the process line or at least an upstream portion of the process line. Fig. 4 illustrates a modified power and flow module 1 ' incorporated in a processing unit operating as a wet tolerant gas compressor 41. The power and flow module 1 ' of Fig. 4 differs from the power and flow module 1 with respect to the shape of the rotor vanes. Instead of the blades forming the rotor 2 in the power and flow module 1, the rotor 42 in the power and flow module 1 ' comprises a set of stacked turbine wheels 43 rotating about an axle 44. Stationary transition pieces 45 route the fluid to the successive turbine stage.

In a subsea process line, the compressor 41 is connectable in line with the separator 12 and an inter-positioned transition piece 13 that routes 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 rotating power and flow module substantially without modification. Besides the illustrated integration in separators, in axial pumps or boosters and wet gas compressors, the power and flow module is suitable for implementation in multiphase fluid homogenization units, water treatment units, water injection pumps, wax and gas hydrate handling devices, etc., where rotational power is required.

The concept of a modular power and flow unit to generate the rotation and flow required in processing units of a subsea process line provides great flexbility in the layout of process lines. A few examples will be briefly discussed below with reference made to the drawings of Figs. 6-8.

Fig. 6 thus shows a subsea process line 100 wherein in a first processing unit 101 the power and flow module is implemented as a centrifugal separator, or as a multiphase fluid homogenizer, in a second processing unit 102 the power and flow module is configured to operate as a booster or a wet gas compressor, and further wherein the processing units 101 and 102 are interconnected via a stationary transition piece 103 providing axial flow between the processing units 101, 102.

Fig. 7 shows a subsea process line 200 comprising processing units 201 and 202 operating as separators. In the first separator 201 the power and flow module is used for separation of gas and liquid. Gas is routed from the first separator 201 via a pipeline 203 to a third processing unit 204 operating as booster pump, whereas oil and water continue with the axial flow into the second separator 202. The first and second separators 201 and 202 may be interconnected via a stationary transition piece 13'. In the second separator 202 the power and flow module is used for separation of oil and water. Oil continues with the axial flow into the booster pump 204, whereas water W is routed out of the axial flow via a pipeline 205. The second separator 202 and the booster pump 204 may be interconnected 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 realized as the discharge piece 40 mentioned with reference to Fig. 3, through which the recombined oil and gas can be discharged from a booster pump 204 at elevated pressure and/or flow.

The 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 in the treatment of water which is received via the pipeline 205. Reject water W(l) is routed out of the axial flow as the heavier phase, whereas clean water W(2) as the lighter phase continues the flow in axial direction into a fifth processing unit 208. In the fifth processing unit 208 the power and flow module is used as water injection pump. The reject water on the other hand can be routed back to the booster pump 204 via a pipeline 209 for further transport. The general layout of the process line 300 of Fig. 8 is substantially as described with reference to Fig. 7, and corresponding units are defined by the same reference numbers. The process line 300 of Fig. 8 however differs from the process line 200 with respect, inter alia, to the flow path for separated gas which in the embodiment 300 by-passes the booster pump 304 to be routed via pipeline 303 for reintroduction into the boosted fluid stream that is discharged from the booster pump 304.

The process line 300 further incorporates a wax and gas hydrate handling functionality. More precisely, a processing unit 310 upstream of a booster pump 304 is arranged to operate as cold flow enabler, wherein the power and flow module is used to generate rotation of a scraper 311 that is journalled for rotation in a hydrocarbon solids precipitation chamber. In the precipitation chamber the temperature in the fluid is lowered below a hydrate and solids formation temperature, which causes precipitation and deposition of solids on the wall of the precipitation chamber. The precipitation chamber can be cooled through natural convention, forced convection or through other refrigeration technology.

It has been explained above and illustrated in the drawings of exemplifying embodiments, that a highly modularized and standardized process line for recovery, treatment and transportation of hydrocarbon well fluids can be achieved by implementation of the teachings presented herein.

Still, it will be appreciated that modifications of the disclosed embodiments are possible without leaving the scope and spirit of the invention as disclosed above and defined in appended claims.

Claims

CLAIMS:

1. A process line configured for recovery, treatment and transportation of hydrocarbon well fluid, comprising processing units arranged and required for carrying out at least one of the following processing steps: fluid/solids separation, multiphase fluid homogenization, gas/liquid separation, liquid/liquid separation, pumping, flow or pressure boosting, gas compression, water treatment, water injection, wax handling, gas hydrate handling, wherein any two or more processing units (12, 12', 12", 39, 41) operate on basically the same power and flow module (1, 1 ') to generate flow through the processing units.

2. The process line of claim 1, wherein any two or more processing units (12, 12', 12", 39, 41) are connectable in line.

3. The process line of claim 1 or 2, wherein the power and flow module (1, 1 ') is an electrically powered flow machine wherein permanent magnets (6) are carried in the periphery of a rotor (2, 22, 30, 42) whereas electromagnets (11) and stator coils are supported on a stationary casing that surrounds the rotor.

4. The process line of any previous claim, wherein rotor vanes (5) are provided a pitch angle against the flow direction (F) which is applied to generate a mainly axial flow, without a significant radial component, through a power and flow module (1) integrated in a processing unit operating as pump, as booster or as separator.

5. The process line of any of claims 1-3, wherein rotor vanes (5') are curved to apply a significant radial component to the flow through a power and flow module (1) integrated in a processing unit operating as pump, as booster or as separator.

6. The process line of claim 4 or 5, wherein the power and flow module (1) is drivingly connected in line with a screw or impeller (34) in a processing unit (12") which effects separation of fluid phases through centrifugal or cyclonic action.

7. The process line of any of claims 1-5, wherein the power and flow module (1) is integrated with a cylindrical drum (22) which is internally formed with wings (28) that impart a rotational motion to the flow through a processing unit (12') which effects separation of fluid phases through centrifugal or cyclonic action.

8. The process line of any of claims 1-3, wherein the rotor (42) comprises turbine wheels (43) in a power and flow module ( ) integrated in a processing unit (41) operating as wet gas compressor.

9. The process line of any previous claim, comprising a stationary transition piece (13, 13') arranged for interconnection of successive processing units in the process line, the transition piece internally formed with separate routes for heavier and lighter fluid phases.

10. The process line of any previous claim, wherein in a first processing unit (101) the power and flow module (1) operates as separator or as fluid homogenizer, in a second processing unit (102) the power and flow module (1, ) operates as booster pump or compressor, and further wherein the processing units are connected and assembled in succession for axial flow through the first and second processing units.

11. The process line of any of claims 1-9, comprising in-line separators wherein first and second processing units (201, 202) each comprises the power and flow module (1) operating as separator, whereas a third processing unit (204) comprises the power and flow module (1) operating as booster pump or compressor, and further wherein the separators (201, 202) and the booster pump/compressor (204) are connected and assembled in succession for axial flow through the first, second and third processing units.

12. The process line of claim 9, wherein a first transition piece (13') connecting the first (201) and second (202) separators is arranged for discharge and routing a separated gas phase to the booster pump or compressor (204), and wherein a second transition piece (13), connecting the second separator (202) and the booster pump/compressor (204), is arranged for discharge and routing a separated water phase to a water treatment unit (207).

13. The process line of claim 12, wherein the first water treatment unit (207) comprises the power and flow module (1) operating as separator, and wherein reject water W(l) is transferred from the first water treatment unit (207) to the booster pump (204).

14. The process line of claim 13, wherein the second water treatment unit (208) comprises the power and flow module (1) operating as water injection pump.

15. The process line of any previous claim, wherein cold flow is enabled through a hydrocarbon solids precipitation chamber (310) comprising the power and flow module (1) driving a rotatable scraper (311) in the precipitation chamber.