WO2008136680A1 - Method and apparatus for a pump - Google Patents

Method and apparatus for a pump Download PDF

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Publication number
WO2008136680A1
WO2008136680A1 PCT/NO2008/000152 NO2008000152W WO2008136680A1 WO 2008136680 A1 WO2008136680 A1 WO 2008136680A1 NO 2008000152 W NO2008000152 W NO 2008000152W WO 2008136680 A1 WO2008136680 A1 WO 2008136680A1
Authority
WO
WIPO (PCT)
Prior art keywords
vessel
outlet
solids
opening
inlet opening
Prior art date
Application number
PCT/NO2008/000152
Other languages
French (fr)
Inventor
Knut Nyborg
Steinar ØYULVSTAD
Richard Arntzen
Original Assignee
Aker Kvaerner Subsea As
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Aker Kvaerner Subsea As filed Critical Aker Kvaerner Subsea As
Publication of WO2008136680A1 publication Critical patent/WO2008136680A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D35/00—Filtering devices having features not specifically covered by groups B01D24/00 - B01D33/00, or for applications not specifically covered by groups B01D24/00 - B01D33/00; Auxiliary devices for filtration; Filter housing constructions
    • B01D35/02—Filters adapted for location in special places, e.g. pipe-lines, pumps, stop-cocks
    • B01D35/027—Filters adapted for location in special places, e.g. pipe-lines, pumps, stop-cocks rigidly mounted in or on tanks or reservoirs

Definitions

  • the present invention relates to a method and apparatus for ensuring start-up and operation of a pump downstream a vessel containing solids. More particularly the invention relates to a method that ensures the liquid flow to a downstream pump from a vessel containing solids, where the solids would normally block the liquid outlet of the vessel and thereby prevent a liquid flow to the pump.
  • the production well-stream from an oil well may contain a mixture of oil, water, gas, and solids.
  • the solids production is typically controlled by so-called sand screens installed in the well. These sand screens may however fail due to mechanical or other failure, and large amounts of solids may be released into the well-stream. This phenomenon is often termed accidental solids production.
  • This well-stream may then flow in a flow-line or pipe to a production facility, where the well-stream often enters a pressure vessel, such as a separator or slug catcher. Solids released from the well may, if no particular action has been put in motion to prevent this (such as shutting out the well), end up inside the vessel.
  • the vessel can be equipped with a flushing system, based on available water or other liquid.
  • a flushing system based on available water or other liquid.
  • the production fluid e.g. the well-stream, possibly minus separated gas.
  • the liquid and solid phases can be processed by a downstream pump to boost these phases to a topside facility.
  • the liquid processed by the pump can be provided for by fluidizing and flushing the solids, and the system can be started up from a shut-down coinciding with accidental solids production.
  • an apparatus for preventing large amounts of solids from blocking a liquid outlet, and for providing a path substantially free of solids for supply to the downstream pump so that this can be started.
  • a method for preventing large amounts of solids from blocking a liquid outlet and for providing a path substantially free of solids for supply to the downstream pump so that this can be started.
  • a third aspect of the present invention there is provided a method for preventing large pieces of solids from reaching a liquid outlet, and potentially damage downstream equipment.
  • a fourth aspect of the present invention there is provided a method for using pressurized liquid to remove the solids from the vicinity of an outlet of a vessel, after the downstream pump has been started.
  • a fifth aspect of the present invention there is provided a method for preventing solids from blocking or piling up and thereby covering an outlet of a vessel.
  • a hollow apparatus in form of a cone, cylinder, tube or similar is placed on top of the liquid outlet, so that solids settling during a shut-down mainly fall on the side of the cone until it reaches the bottom of the vessel.
  • the hollow apparatus has an opening in the tip, extending above the zone where solids may accumulate, and through this opening the downstream pump has access to liquid during start-up.
  • the vessel and apparatus must be sized so that the volume on the outside of the apparatus is sufficient to contain the full volume of solids present in the vessel at the time of shut-down, without the solids accumulating above the level of the opening in the tip.
  • the opening in the tip should be large enough to provide a liquid flow to the downstream pump without creating pressure drop impairing the operation of the pump for example with regards to NPSH requirements, but at the same time so small that the amount of solids flowing through the opening can be handled by the pump during start-up.
  • the bottom of the apparatus should preferably be larger than the liquid outlet, to an extent where the amount of solids able to creep below the bottom of the apparatus, between the apparatus and the bottom wall of the vessel, during a shut-down can be handled by the pump during start-up.
  • Fig. 1 shows the apparatus according to the invention inside a vertical vessel.
  • Fig. 2 shows the apparatus fitted with grating, mesh, or a hat, at or above the top opening of the apparatus.
  • Fig. 3 shows the apparatus fitted with grating, or mesh, along the bottom.
  • Fig. 4 shows the apparatus fitted with a pipe segment at the top or at the bottom of the conical part of the apparatus.
  • Fig. 5 shows the apparatus with side walls of a variable angle, or in the form of a pipe.
  • Figure 1 shows the apparatus in the shape of a cone 1 inside a vertical vessel 2.
  • the cone has an opening in the tip 3 allowing liquid to flow through the liquid outlet 4 and to a downstream pump (not shown), even though large amounts of solids are accumulated on the outside of the cone 1.
  • liquid can be re-circulated through a fluidizing/flushing system 5 which will flush fluidized solids to the liquid outlet 4 if desirable. Solids will settle down by gravity and impact with the cone 1, and fall down along the side of the cone 1 to the bottom of the vessel 2.
  • the solids will form a pile 6 around the cone 1 at the bottom of the vessel 2, near the lower end of the cone wall, as there is no net transport to the outlet 4, and the angle in the bottom of the vessel 2 is not sufficient for solids to move under gravity.
  • the inside of the cone 1 will have a solids content that is negligible with respect to the downstream pump.
  • Fig. 2 shows three various embodiments of the apparatus or cone tip 3, having a grating 7a, mesh 7b, a hat 7c, or similar at or directly above the top of the cone 1. These embodiments prevent objects larger than a certain size from entering through the opening in the tip 3 of the cone 1, and potentially damage downstream equipment.
  • This grating 7a, mesh 7b , hat 7c, or similar might also have a conical shape, so that such objects will fall along the side of this to the bottom of the vessel 2.
  • Fig. 3 shows an embodiment where the apparatus or cone 1 is equipped with grating 8a, mesh 8b or similar along the bottom of the apparatus 1 to prevent objects larger than a certain size from moving in the gap below the apparatus 1, between the apparatus 1 and the bottom of the vessel 2, to the outlet 4 of the vessel 2.
  • Fig. 4 shows one embodiment where the conical part of the apparatus or cone 1 is equipped with a pipe segment 9 at the top 3, extending the effective height of the apparatus 1 and allowing for a larger solids volume.
  • Fig. 4 also shows an embodiment where the apparatus 1 is equipped with a pipe segment 10 at the bottom of the conical part, extending the effective height of the apparatus 1 and allowing for a larger solids volume.
  • Fig. 5 shows one embodiment where the wall of the apparatus 1 has variable angle, and another embodiment where it has an angle of 90° (i.e. a vertical pipe).
  • the angle of the apparatus 1 is not required to be constant or to have any pre-defined value, although the most efficient design will be with an angle between 30° and 90°.
  • the only requirements are that the opening in the top 3 is small enough to limit the amount of solids being able to pass through and towards the outlet 4, and that the opening in the bottom is larger than the liquid outlet 4 of the vessel 2, so that the solids accumulated outside the apparatus 1 does not flow into the liquid outlet 4 naturally in the case of a shut-down.

Abstract

Apparatus for preventing solids from blocking or piling up at an outlet of a vessel, adapted to be arranged inside and covering the outlet (4) of the vessel (2), and having an inlet opening and an outlet opening.

Description

Method and apparatus for a pump
The present invention relates to a method and apparatus for ensuring start-up and operation of a pump downstream a vessel containing solids. More particularly the invention relates to a method that ensures the liquid flow to a downstream pump from a vessel containing solids, where the solids would normally block the liquid outlet of the vessel and thereby prevent a liquid flow to the pump.
The production well-stream from an oil well may contain a mixture of oil, water, gas, and solids. The solids production is typically controlled by so-called sand screens installed in the well. These sand screens may however fail due to mechanical or other failure, and large amounts of solids may be released into the well-stream. This phenomenon is often termed accidental solids production. This well-stream may then flow in a flow-line or pipe to a production facility, where the well-stream often enters a pressure vessel, such as a separator or slug catcher. Solids released from the well may, if no particular action has been put in motion to prevent this (such as shutting out the well), end up inside the vessel.
The vessel can be equipped with a flushing system, based on available water or other liquid. For subsea applications where oil/water separation is not implemented, the only readily available fluid in significant quantity is the production fluid (e.g. the well-stream, possibly minus separated gas). The liquid and solid phases can be processed by a downstream pump to boost these phases to a topside facility.
If a shut-down coincides with accidental solids production, the solids in the vessel will settle down and potentially block the liquid outlet. When it is desired to start the system again, this may then not be possible due to lacking liquid feed to the pump, and therefore lack of pressurized liquid to fluidize and flush out the accumulated solids.
It is the aim of the present invention to provide a method and apparatus for providing the pump with a liquid phase under these conditions, so that liquid can be processed by the pump or other downstream equipment. The liquid processed by the pump can be provided for by fluidizing and flushing the solids, and the system can be started up from a shut-down coinciding with accidental solids production.
According to a first aspect of the present invention there is provided an apparatus for preventing large amounts of solids from blocking a liquid outlet, and for providing a path substantially free of solids for supply to the downstream pump so that this can be started.
According to a second aspect of the present invention there is provided a method for preventing large amounts of solids from blocking a liquid outlet, and for providing a path substantially free of solids for supply to the downstream pump so that this can be started.
According to a third aspect of the present invention there is provided a method for preventing large pieces of solids from reaching a liquid outlet, and potentially damage downstream equipment.
According to a fourth aspect of the present invention there is provided a method for using pressurized liquid to remove the solids from the vicinity of an outlet of a vessel, after the downstream pump has been started.
According to a fifth aspect of the present invention there is provided a method for preventing solids from blocking or piling up and thereby covering an outlet of a vessel.
According to the invention, a hollow apparatus in form of a cone, cylinder, tube or similar is placed on top of the liquid outlet, so that solids settling during a shut-down mainly fall on the side of the cone until it reaches the bottom of the vessel. The hollow apparatus has an opening in the tip, extending above the zone where solids may accumulate, and through this opening the downstream pump has access to liquid during start-up. The vessel and apparatus must be sized so that the volume on the outside of the apparatus is sufficient to contain the full volume of solids present in the vessel at the time of shut-down, without the solids accumulating above the level of the opening in the tip. The opening in the tip should be large enough to provide a liquid flow to the downstream pump without creating pressure drop impairing the operation of the pump for example with regards to NPSH requirements, but at the same time so small that the amount of solids flowing through the opening can be handled by the pump during start-up. The bottom of the apparatus should preferably be larger than the liquid outlet, to an extent where the amount of solids able to creep below the bottom of the apparatus, between the apparatus and the bottom wall of the vessel, during a shut-down can be handled by the pump during start-up.
Embodiments of the invention will now be described with reference to the drawings, in which
Fig. 1 shows the apparatus according to the invention inside a vertical vessel. Fig. 2 shows the apparatus fitted with grating, mesh, or a hat, at or above the top opening of the apparatus.
Fig. 3 shows the apparatus fitted with grating, or mesh, along the bottom.
Fig. 4 shows the apparatus fitted with a pipe segment at the top or at the bottom of the conical part of the apparatus. Fig. 5 shows the apparatus with side walls of a variable angle, or in the form of a pipe.
Figure 1 shows the apparatus in the shape of a cone 1 inside a vertical vessel 2. The cone has an opening in the tip 3 allowing liquid to flow through the liquid outlet 4 and to a downstream pump (not shown), even though large amounts of solids are accumulated on the outside of the cone 1. After the pump has been started, liquid can be re-circulated through a fluidizing/flushing system 5 which will flush fluidized solids to the liquid outlet 4 if desirable. Solids will settle down by gravity and impact with the cone 1, and fall down along the side of the cone 1 to the bottom of the vessel 2. If no liquid flows through the outlet 4, the solids will form a pile 6 around the cone 1 at the bottom of the vessel 2, near the lower end of the cone wall, as there is no net transport to the outlet 4, and the angle in the bottom of the vessel 2 is not sufficient for solids to move under gravity. The inside of the cone 1 will have a solids content that is negligible with respect to the downstream pump.
Fig. 2 shows three various embodiments of the apparatus or cone tip 3, having a grating 7a, mesh 7b, a hat 7c, or similar at or directly above the top of the cone 1. These embodiments prevent objects larger than a certain size from entering through the opening in the tip 3 of the cone 1, and potentially damage downstream equipment. This grating 7a, mesh 7b , hat 7c, or similar might also have a conical shape, so that such objects will fall along the side of this to the bottom of the vessel 2.
Fig. 3 shows an embodiment where the apparatus or cone 1 is equipped with grating 8a, mesh 8b or similar along the bottom of the apparatus 1 to prevent objects larger than a certain size from moving in the gap below the apparatus 1, between the apparatus 1 and the bottom of the vessel 2, to the outlet 4 of the vessel 2.
Fig. 4 shows one embodiment where the conical part of the apparatus or cone 1 is equipped with a pipe segment 9 at the top 3, extending the effective height of the apparatus 1 and allowing for a larger solids volume.
Fig. 4 also shows an embodiment where the apparatus 1 is equipped with a pipe segment 10 at the bottom of the conical part, extending the effective height of the apparatus 1 and allowing for a larger solids volume.
Fig. 5 shows one embodiment where the wall of the apparatus 1 has variable angle, and another embodiment where it has an angle of 90° (i.e. a vertical pipe). The angle of the apparatus 1 is not required to be constant or to have any pre-defined value, although the most efficient design will be with an angle between 30° and 90°. The only requirements are that the opening in the top 3 is small enough to limit the amount of solids being able to pass through and towards the outlet 4, and that the opening in the bottom is larger than the liquid outlet 4 of the vessel 2, so that the solids accumulated outside the apparatus 1 does not flow into the liquid outlet 4 naturally in the case of a shut-down.

Claims

Patent claims P3071PC00
1.
Apparatus for preventing solids from blocking or piling up at an outlet of a vessel, c h a r a c t e r i z e d i n that
- the apparatus (1) is adapted to be arranged inside the vessel (2) and covering the outlet (4) of the vessel (2) in proximity of the outlet (4) of the vessel (2), and that
- the apparatus (1) has an inlet opening and an outlet opening, through which material in the vessel (2) is capable of flowing.
2.
Apparatus according to claim 1, c h a r a c t e r i z e d i n that the apparatus (1) has the shape of a cone which is tapered towards the inlet opening.
3.
Apparatus according to claim 1 or 2, c h a r a c t e r i z e d i n that the apparatus (1) is provided with a filtering device (7a, 7b, 7c), such as a grating, mesh, or a hat at the inlet opening.
4.
Apparatus according to any one of the preceding claims, c h a r a c t e r i z e d i n that the apparatus (1) is provided with a filtering device, such as a grating (8a) or a mesh (8b) at the outlet opening.
5.
Apparatus according to any one of the preceding claims, c h a r a c t e r i z e d i n that the apparatus (1) is provided with an extension tube (9) at the inlet opening, enhancing the distance between the inlet opening and the outlet opening of the apparatus (1). Ip, Apparatus according to any one of the preceding claims, c h a r a c t e r i z e d i n that the apparatus (1) is provided with a pipe segment (10) at the outlet opening.
7.
Apparatus according to any one of the preceding claims, c h a r a c t e r i z e d i n that the side walls of the apparatus (1) exhibit a curved shape.
8.
Apparatus according to any one of the preceding claims, c h a r a c t e r i z e d i n that the apparatus (1) has a cylindrical shape.
9.
Apparatus according to any one of the preceding claims, c h a r a c t e r i z e d i n that the dimension of the apparatus (1) at the end of the apparatus (1) intended to face the outlet
(4) of the vessel (2), is adapted in such way that solid material piled up at the bottom of the vessel (2), outside the apparatus (1), is not capable of free flowing through a clearance between the apparatus (1) and the vessel (2), to the outlet (4) of the vessel (2).
10.
Method for preventing solids from blocking or piling up at an outlet of a vessel, c h a r a c t e r i z e d i n arranging an apparatus according to any one of the claims 1-8 inside the vessel and in proximity to the outlet of the vessel and covering this outlet.
11. Method for preventing large pieces of solids from entering an outlet of a vessel, c h a r a c t e r i z e d i n arranging an apparatus according to claim 2 or 3 inside the vessel and above the outlet of the vessel.
12.
Method for fluidizing solids into liquid in a vessel, whereby a pump is connected to the outlet of the vessel c h a r a c t e r i z e d i n re-circulating liquid from the vessel through a flushing system which will flush fluidized solids to the vessel outlet.
13.
Method for preventing solids from blocking or piling up and thereby covering an outlet of a vessel, c h a r a c t e r i z e d i n arranging an apparatus with an inlet opening and an outlet opening in the vessel, whereby the outlet opening of the apparatus is covering the outlet of the vessel in proximity of this outlet, in such way that a space for accumulating solids is created in proximity to the outlet of the vessel, however outside the apparatus.
PCT/NO2008/000152 2007-05-02 2008-04-29 Method and apparatus for a pump WO2008136680A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NO20072266A NO20072266L (en) 2007-05-02 2007-05-02 Method and apparatus for securing the start-up and operation of a pump downstream of a container containing solids
NO20072266 2007-05-02

Publications (1)

Publication Number Publication Date
WO2008136680A1 true WO2008136680A1 (en) 2008-11-13

Family

ID=39596340

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/NO2008/000152 WO2008136680A1 (en) 2007-05-02 2008-04-29 Method and apparatus for a pump

Country Status (2)

Country Link
NO (1) NO20072266L (en)
WO (1) WO2008136680A1 (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3653638A (en) * 1970-06-18 1972-04-04 Union Oil Co Method and apparatus for dispersing a solid material in a liquid
US4801333A (en) * 1983-03-24 1989-01-31 Mosell Carl G Method of cleaning articles in a tank
US5425882A (en) * 1991-05-03 1995-06-20 Boco Gmbh & Co. Apparatus for removing dirt particles from water

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3653638A (en) * 1970-06-18 1972-04-04 Union Oil Co Method and apparatus for dispersing a solid material in a liquid
US4801333A (en) * 1983-03-24 1989-01-31 Mosell Carl G Method of cleaning articles in a tank
US5425882A (en) * 1991-05-03 1995-06-20 Boco Gmbh & Co. Apparatus for removing dirt particles from water

Also Published As

Publication number Publication date
NO20072266L (en) 2008-11-03

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