OA21986A - Equipment for the conveying and recovery of hydorcarbons from an underwater well for the extraction of hydrocarbons under uncontrolled release conditions. - Google Patents

Abstract

The present invention relates to equipment for the conveying and recovery of hydrocarbons from an underwater well for the extraction of hydrocarbons under uncontrolled release conditions, comprising a chamber (23) for the separation of the hydrocarbon stream leaving the well, into a heavy phase (23a) and a light phase (23b), means (15,16,17,24,25,26) being envisaged, in connection with the separation chamber (23), for conveying the heavy phase (23a) and light phase (23b) towards the surface, characterized in that it comprises a directioning body (18) of the hydrocarbon stream, having a substantially cylindrical shape, or as a truncated paraboloid with both ends open, wherein a first end is an inlet of the hydrocarbon stream leaving the well, and a second end, distal with respect to the inlet of the hydrocarbon stream (20), is in fluid connection with the separation chamber (23) with the interpositioning of a perforated spherical cap (22).

Description

EQUIPEMENT FOR THE CONVEYING AND RECOVERY OF HYDROCARBONS FROM AN UNDERWATER WELL FOR THE EXTRACTION OF HYDROCARBONS, UNDER UNCONTROLLED RELEASE CONDITIONS

The présent invention relates to equipment for the conveying and recovery of hydrocarbons from an underwater well for the extraction of hydrocarbons under uncontrolled release conditions.

The constant increase in the worldwide demand for fluid hydrocarbons has led to a growing activity in the underwater or offshore exploration and production.

Underwater environinents, in addition to making production more difficult, create an increased risk of environmental damage in the case of blowout events, i.e. uncontrolled release of hydrocarbons from the extraction wells, and/or other uncontrolled leakages of hydrocarbons into the sea, for example as a conséquence of fractures of underwater piping.

These events, even if rare, not oniy cause a loss in tenns of energy, but can also create severe conséquences in terms of personnel safety, environmental pollution and well restoration costs.

Various attempts hâve been made in the past to guarantee an effective recovery of uncontrolled leakages of hydrocarbons in deep water.

In this respect, hollow containers hâve been produced, for example, such as that described in patent US 4,318,442 which is essentially equipped with a chimney controlled by a valve, a gas outlet configured so as to maintain a gas stratification in the upper part of the container and a liquid discharge in correspondence with the oil stratification in the lower part of the container.

This container is positioned above the well outlet in blowout so as to capture the outgoing stream of hydrocarbons, also called plume, in order to convey its fluid part to the surface in a controlled manner, removing the gaseous part.

Altematively, the use of dome-shaped protection shields is known, such as that proposed in the USA patent US 4,405,258.

Ihis patent describes a method for the containment of hydrocarbons inside a domeshaped shield equipped with safety valves on its upper part which, positioned above an underwater well in blowout, entraps the hydrocarbons in its interior.

-121986

Structures positioned above the well outlet, however, whether they be hollow or dome-shaped container, hâve proved to be unsuitable for an effective containment of the blowout phenomenon, in particular of wells from which there is a great outflow of hydrocarbons. The power of these phenomena, in fact, tends to induce the hydrocarbons to 5 exit not from the spécifie upward ducts but from the base of the stiucturc.

The dôme shape, moreover, is not effective in deviating high-rate streams.

Other equipment known for the containment or recovery of hydrocarbons in gaseous and/or liquid form is described in American patent US 4,324,505.

This equipment comprises a cône containing suitable slits. When the apparatus is 10 positioned at the well head, as far as is possible, it drives and directs the fluid through a duct connected to the upper portion of the cône, up to the surface where the hydrocarbons can be separated from the other fluids.

In this equipment, particularly for high-rate blowout streams, the impact of theplume inside the cône can generate turbulent motions which can cause the émission of the jet from 15 the cône with a conséquent reduced efficiency in the recovery of hydrocarbons coming out of the well.

The necessity is therefore felt, in the case of offshore blowout events, to efficiently intercept, contain and convey the outgoing hydrocarbons in order to reduce their uncontrolled dispersion in the environment tô the minimum.

0 An objective of the présent invention is to overcome the drawbacks mentioned above, and in particular to provide equipment for the conveying and recovery of hydrocarbons from an underwater well, under uncontrolled release conditions, which allow to carry out an effective and substantially complété recovery of hydrocarbons exiting in an uncontrolled manner.

5 Another objective of the présent invention is to provide equipment for the conveying and recovery of hydrocarbons from an underwater well under uncontrolled release conditions, which is capable of reducing to the minimum the dispersion into the environment of hydrocarbons exiting in an uncontrolled manner.

A further objective of the présent invention is to provide equipment for the conveying 30 and recovery of hydrocarbons from an underwater well under uncontrolled release

-221986 conditions, which allows the hydrocarbons exiting in an uncontrolled manner to be effectively intercepted, contained and conveyed.

Yet another objective of the présent invention is to provide equipment for the conveying and recovery of hydrocarbons from an underwater well under uncontrolled release conditions, which is capable of separating the hydrocarbons coming from the well into a heavy phase consisting of water and liquid hydrocarbons and into a light phase mainly consisting of gas and liquid hydrocarbons and conveying said heavy phase to the surface.

These and other objectives according to the présent invention are achieved by providing equipment for the conveying and recovery of hydrocarbons from an underwater well under uncontrolled release conditions as explaincd in the independent daims.

Further characteristics of the equipment for the conveying and recovery of hydrocarbons from an underwater well under uncontrolled release conditions are object of the dépendent daims.

The characteristics and advantages of equipment for the conveying and recovery of hydrocarbons from an underwater well under uncontrolled release conditions, according to the présent invention, will appear more évident from the following illustrative and nonlimiting description referring to the enclosed schematic drawings in which Figure l is a sectional schematic view of the equipment for the conveying and recovery of hydrocarbons from an underwater well under uncontrolled release conditions, according to a preferred embodiment of the présent invention.

With reference ta the figure, this shows equipment for the conveying and recovery of hydrocarbons from an underwater well under uncontrolled release conditions, indicated as a whole as 10.

The equipment 10 for the conveying and recovery of hydrocarbons, comprises a chamber 23 for the séparation of the flow of hydrocarbons coming from the well 21 into a heavy phase 23a and a light phase 23b.

In particular, means 15, 16, 17, 24, 25, 26 for the conveying of the heavy phase 23a and light phase 23b towards the surface, are envisaged in connection with the séparation chamber 23.

-321986

According to the présent invention, the equipment for the conveying and recovery of hydrocarbons also comprises a directioning body 18 of the hydrocarbon stream, having a substantially cylindrical shape, or as a truncated paraboloid with both ends open, wherein a first end is an inlet of the hydrocarbon stream coming from the well 21, and a second end, distal with respect to the inlet of the hydrocarbon stream 20, is in fluid connection with the séparation chamber 23 with the interpositioning of a perforated spherical cap 22.

In the preferred embodiment illustratcd, the séparation chamber 23 is defined inside a hollow tubular body 11 comprising two hollow cylindrical portions l la, l Ib connected by a portion having a tapered conformation l le.

A first cylindrical portion lia is connected to the tapered portion lie in correspondcnce with the enlarged end 11 c' of the same 11 c.

The first cylindrical portion l la of the hollow body 11 ends with an annular base 12 defming an opening of the hollow tubular body 11 with reduced diameter with respect to the diameter of the first cylindrical portion l la.

A second cylindrical portion l Ib is connected to the tapered portion lie in correspondence with the narrower end 11 c” of the same 11 c.

The tapered portion l le preferably bas a truncated- conical shape with the smaller diameter coinciding with the diameter of the portion of the second cylindrical portion l Ib and the larger diameter coinciding with the diameter of tHé first cylindrical portion 11 a of the tubular body 11.

The second cylindrical portion l Ib ends, in correspondence with its free end, with an upper base 13, so as to definea closed containment space.

The séparation chamber 23 is delimited in the perimeter and extemally by the tubular body 11 and intemally and centrally by the perforated cap 22 and by the hollow body 18 for directing the incoming flow so as to hâve a substantially annular conformation.

For this purpose, the directioning body 18 is arranged coaxially with the tubular body 11 and extends intemally to the same.

The directioning body 18 preferably lias, at least in correspondence of its own inlet end of the hydrocarbon flow, a diameter coinciding with the inner diameter of the annular base 12 and an extension substantially equal to the development of the first cylindrical

-421986 portion 11 a of the tubular body 11.

The directioning body 18 is open in correspondence with both its ends, thus allowing, once positioned in correspondence with the outflow of hydrocarbons, the plume 20 coming from the wcll 21 to be conveyed into its interior 19.

The hollow perforated spherical cap 22 is situated. however, in correspondence with the end of the directioning body 18, distal with respect to the inlet of the hydrocarbon flow 20, preferably in a position distant from the directioning body 18.

The geometry of the directioning body 18 and perforated cap 22 is such as to attenuate the momentum of the plume of the multiphase stream at the inlet.

The gravitational séparation of the incoming mixture into dense or heavy phase 23a and light 23b phase takes place inside the séparation chamber 23.

The séparation chamber 23 is in fluid connection with the means 15, 16, 17, 24, 25, 26 for conveying the heavy phase 23a and light phase 23b towards the surface.

In particular, the lower part of the séparation chamber 23a, in which the dense phase 23a is stratified, is in fluid communication with pumping means 16 situated inside the second cylindrical portion l Ib of the hollow tubular body 11.

The fluid connection takes place by means of a plurality of conveying pipes 24, angularly spaced, preferably equispaced, consisting of a first vertical section and subsequently converging into a common collecter 25 overlying the perforated cap 22.

The collecter 25 is arranged centrally with respect to the tubular body 11 and is, in tum, connected with the pumping means 16 through a first section 15a of a conveying duct 15 situated inside the hollow tubular body 11, between the tapered portion 11c and the second cylindrical portion 11 b of the hollow tubular body 11, coaxially with respect to the same.

A second section 15b of the conveying duct 15, again situated inside and coaxially to the second cylindrical portion 11b, puis the pumping means 16 in fluid communication with an éjection System 17, inside the second cylindrical portion 11b, also equipped with suction doors 17a for the suction of the light phase 23b.

A third and last section 15c of the conveying duct 15 is inserted on the upper base 13 of the second cylindrical portion 11b and puis the multiphase stream produced inside the

-521986 éjection System 17 in fluid communication with suitable treatment and collection Systems situated on the sea surface (not illustrated).

The upper part of the séparation chamber 23, in which the light phase is stratified, is in fluid communication with the surface by means of a vent duct 26 intercepted by a régulation valve (not illustrated) in the collection point on the sea surface.

A fluid connection duct 27 with the surface is also envisaged, which extends for a first section extemally and parallel to the tubular body 11 and is inserted for a subséquent section on the directioning body 18 passing through the wall of the first cylindrical portion 11 a of the tubular body l l.

Said duct 27 for fluid connection with the surface is suitable for feeding a methanol distribution System (not illustrated), positioned in correspondence with the lower end of the directioning body 18.

The functioning of the equipment 10 for conveying and recovering hydrocarbons from an underwater well for extraction is as follows.

In operative condition, the plume 20, consisting of a mixture of gas and oil, leaves the well at high pressure 21, thus englobing seawater in its interior.

The inlet of seawater inside the equipment for the conveying and recovery of hydrocarbons 10 favours the formation of the heavy liquid phase 23a. The quantity of seawater entering the equipment for the conveying and recovery of hydrocarbons 10 can be controlled by varying the height at which the equipment 10 is positioned with respect to the sea bottom, together with the dimensions and rotation rate of the pumping means 16.

The multiphase stream at the inlet 20, generaliy consisting at least of oil, gas and seawater, enters the equipment for the conveying and recovery of hydrocarbons 10 through the hollow directioning body 18.

The geometry of said directioning body 18, together with that of the perforated cap 22, is such as to attenuate the momentum of the ingoing stream 20, preventing a downward reflux of the plume 20 and consequently its outflow.

Passing through the holes of the perforated cap 22, the multiphase stream 20 enters the séparation chamber 23.

In its interior, the oil-gas-water mixture tends to separate and become stratified into

-621986 two phases: a light phase 23b, consisting of a mixture of gas and liquid hydrocarbons, is formed on the upper part of the séparation chamber 23, and a dense phase 23a, consisting of a mixture of water and liquid hydrocarbons containing limited quantities of dispersed gas, is formed on the lower part of the séparation chamber 23.

The dense phase 23a is directed from the séparation chamber 23, through the plurality of conveying pipes 24, towards the collecter 25, due to the pumping means 16, and is conveyed at high pressure into the éjection System 17.

A part of the light phase 23b separated in the séparation chamber 23, is sucked at low pressure by the suction doors 17a of the éjection System 17.

The multiphase stream produced in the éjection System 17 is then conveyed through the third section 15c of the conveying duct 15 in the direction of the sea surface towards spécifie conveying and recovery means.

The remaining portion of light phase 23b is extracted through the vent duct 16.

The distribution between the light phase 23b sucked by the éjection System 17 and that extracted through the vent duct 26, is regulated by the régulation valve situated on the vent duct 26.

The régulation valve also has the function of keeping the vent duct 26 full of air, guaranteeing the correct functioning of the System during the initial conveyance and recovery phases of the hydrocarbon mixture.

During the recovery of the hydrocarbons, the methanol is also distributed from the surface by means of the fluid connection duct 27 with the surface to the methanol distribution system in correspondence with the inlet of the plume 20 in order to prevent the formation of hydrates.

The characteristics of the equipment for the conveying and recovery of hydrocarbons from an underwater well for extraction, object of the présent invention, as also the relative advantages, are évident from the above description.

The particular conformation of the directioning body of the flow, in addition to the perforated spherical cap at its end, allows the momentum of the multiphase stream at the inlet to be attenuated, thus preventing a downward reflux of the same and consequently its outflow.

-721986

Furthermore, the passage through the perforated cap facilitâtes an effective séparation of the multiphase stream into a light phase and heavy phase, favouring its conveyance towards the surface.

Finally, the equipment thus conceived can obviously undergo numerous modification 5 and variants, ail included in the invention; ail the details, moreover, can be substituted by technically équivalent éléments. In practice the materials used, as also the dimensions, can vary according to technical requirements.

Claims (10)

1. . Equipment (10) for the conveying and recovery of a stream of hydrocarbons from an underwater well under uncontrolled release conditions, comprising a chainber (23) for the séparation of said hydrocarbon stream leaving said well, into a heavy phase (23a) and a light phase (23b), means (15,16,17,24,25,26) being envisaged, in connection with said séparation chamber (23), for conveying saîd heavy phase (23a) and said light phase (23b), towards the surface, characterized in that it comprises a directioning body (18) of said hydrocarbon stream, having a substantially cylindrical shape, or as a truncated paraboloid with both ends open, wherein a first end is an inlet of said hydrocarbon stream leaving said well, and a second end, distal with respect to the inlet of said hydrocarbon stream (20), is in fluid connection with said séparation chamber (23) with the interpositioning of a pcrforated spherical cap (22).

2. The equipment (10) for the conveying and recovery of a stream of hydrocarbons from an underwater well under uncontrolled release conditions according to claîm I, characterized in that said perforated spherical cap (22) is positioned at a distance with respect to said distal end of said directioning body (18).

3. The equipment (10) for the conveying and recovery of a stream of hydrocarbons from an underwater well under uncontrolled release conditions according to claim 1 or 2, characterized in that said séparation chamber (23) is defined inside a hollow tubular body (11), said séparation chamber (23) being perimetrically and extemally delimited by said tubular body (11), and intemally and centrally by said perforated cap (22) and said directioning body (18) so as to hâve a substantially annular configuration.

4. The equipment (10) for the conveying and recovery of a stream of hydrocarbons from an underwater well under uncontrolled release conditions according to any of the previous daims, characterized in that said hollow tubular body (11) comprises a first (lia) and a second (11b) cylindrical portion interlinked by means of a portion having a tapered conformation (11c), said first cylindrical portion (lia) being connected to said tapered portion (1 le) in correspondence with an enlarged end (11c’) of the same (1 le) and said second cylindrical portion ( 11b) being connected to said tapered portion (11c) in

-921986 correspond ence with a narrowed end (l le) of the same (lie), the lower part of said first cylindrical section (lia) ending with an annular base (12) defining an opening of said hollow tubular .body (11) having a reduced diameter with respect to the diameter of said first cylindrical portion (lia) and the upper paît of said second cylindrical portion (I Ib) 5 ending with an upper base ( 13).

5. The equipment ( 10) for the conveying and recovery of a stream of hydrocarbons from an underwater well under uncontrolled release conditions according to claim 4, characterized in that said directioning body (l 8) is coaxially arranged with respect to said tubular body (11) and extends inside the same, said directioning body (18) having a 10 diameter coinciding with the inner diameter of said annular base (12) at least in correspondence with said first end, is an inlet, and an extension substantially the same as the expansion of said first cylindrical section (lia) of said tubular body (11).

6. The equipment (10) for the conveying and recovery of a stream of hydrocarbons from an underwater well under uncontrolled release conditions according to any of the 15 previous daims, characterized in that a lower part of said séparation chamber (23), in which said heavy phase (23a) is stratified, is in iluid communication with pumping means ( 16) by means of a plurality of conveying pipes (24) angularly spaced and interlinked in a collector (25) overlying said perforated cap (22), said collector (25) being connected to said pumping means (16) through a first section (15a) of a conveying duct (15) towards the surface.

20

7. The equipment (10) for the conveying and recovery of a stream of hydrocarbons from an underwater well under uncontrolled release conditions according to claim 6, characterized in that said pumping means (16) are situated in fluid communication with an éjection system (17) by means of a second section (15b) of said conveying duct (15) towards the surface.

25

8. The equipment (10) for the conveying and recovery of a stream of hydrocarbons from an underwater well under uncontrolled release conditions according to any of the previous daims, characterized in thaï an upper portion of said séparation chamber (23), in which said light phase (23b) is stratified, is in fluid communication with the surface by means of a vent duct (26).

30

9. The equipment (10) for the conveying and recovery of a stream of hydrocarbons

-1021986 from an underwater well under uncontrolied release conditions according to any of the previous daims from 6 to 8, characterized in that said pumping means (16) and said ejector ( 17) are positioned inside said second cylindrical portion ( 11 b) of said hollow tubular body (H), said conveying duct (15) towards the surface passing coaxially through said second cylindrical portion (l Ib).

10. The equipment (10) for the conveying and recovery of a strcam of hydrocarbons trom an underwater well under uncontrolied release conditions according to any of the previous daims, characterized in that it comprises a duct (27) for fluid connection with the surface, and extends for a first section extemaîly and parallel to said tubular body (l l) and for a subséquent section is inserted on said directioning body ( 18), passing through the wall of said first cylindrical section (lia) of said tubular body (l l).