HUE034468T2 - Arrangement used in oil field wells for lifting hydrocarbons - Google Patents

Description

Description

FIELD OF THE INVENTION

[0001] The present invention is directed to an arrangement used in oil field wells for lifting hydrocarbons, and more particularly it is directed to a new arrangement of elements placed within production wells for safely lifting liquid or gaseous hydrocarbons, avoiding gas venting and thus allowing for an increase in productivity of the facility, among other important advantages.

BACKGROUND OF THE INVENTION

[0002] Lifting of hydrocarbons from oil fields involves introducing into the well a casing that extends down sufficiently to reach the hydrocarbon-containing strata, so that any oil, gas and water found therein may flow upwardly to the surface through the casing to be then separated, stored or channeled to its next destination. The oil, gas and water from the strata enter the casing and, because of their different densities, they segregate from each other so that water remains at the bottom of the casing, while oil floats over it and gas flows up through the casing.

[0003] Conventional oil lifting requires the use of pumping units disposed on the surface of the field ground and on the wellhead, which include, among other components used for fluid extraction, a pump lever, a suction rod and a pump placed downhole within thecasing at the deepest possible production position. For operating the suction rod, its lowerend is connected to the pump, while its upper end is connected to the pump lever disposed on the ground surface. By means of a mechanical arm lever, the pump lever drives the upwards and downwards reciprocating movement of the suction rod, thus performing the pumping work in the production well.

[0004] Another widely known type of pumping system, such as disclosed by W02007/084927, consists in using a bailing system disposed on the ground surface adjacent to the production well, using a bailer mechanism disposed on the ground surface adjacent to the production well, comprising a bailer type (tube and hose) system, a pulling strip or cable which extends along an admission tube or arm, and a hoist mechanism. In this system for lifting hydrocarbons, the bailing system is operated by spooling and unspooling a pulling cable from a hoisting mechanism, to which one end of the wireline is attached, while the other end is attached to the upper end of the bailer-type mechanism placed within the well casing. During operation of the hoist mechanism by spooling and unspooling the wireline or cable, the latter makes a reciprocating movement and undergoes considerable stresses when it is spooled to lift the bailer or unspooled for lowering it to the oil-containing section of the well casing. When the bailer is submerged into the oil-containing section, it collects some oil and gets filled with it. Then, the bailer is lifted up to the surface and the oil is poured into a storage dam.

[0005] In these conventional systems for lifting hydrocarbons, fluid discharge from the hose that extends along the borehole is achieved by the action of gravity. These systems have disadvantages that must be overcome. In fact, during the lowering operation, the hose may stick to the tube due to the presence of viscous or paraffin hydrocarbons. These conditions may be affected by external temperatures and the tubes may be worn off by friction with the hose, which may cause ecological damage. In addition, the hose must have thickerwalls in order to withstand the strain caused by the rollers over the curvature of the header when entering into the PVC tube. Furthermore, the hose diameter is limited by the header’s entrance hole and the recovery capacity of the hose is limited by the length of the tubes, all of which leads to a reduction in productivity. Another disadvantage is that the hose detection system is external and has no protection. In addition, harsh environmental conditions (temperatures, wind, sunlight), the presence of animals, mishandling, etc. can damage the tube joints and cause leaks. The presence of gas pockets may damage PVC tubes and cause environmental damage. In addition, the horizontal tube where the fluid is discharged is made of plastic and can only withstand low gas pressure. Consequently, the gas cannot be transferred by its own pressure and requires permanent venting.

[0006] In order to solve the above mentioned drawbacks of conventional hydrocarbon-lifting facilities, the inventors have developed the arrangement of the present invention, which provides outstanding improvements over the prior art. In fact, the arrangement to be used in oilfield wells for lifting hydrocarbons is capable of capturing gas from the well and thus avoid venting, which increases productivity of the lifting equipment. One of the most important factors favoring productivity is the use of the gas pressure from inside the casing for draining the hose. The hose length may be made proportional to gas pressure at a ratio of 10 mt per 1 kg/sq. cm. of gas pressure, without modifying the length of the surface equipment. In addition, there will be less tubing on the surface and all the moving elements of the arrangement will remain within the casing, thus avoiding possible leaks of fluid at surface level and providing greater safety to the lifting process. It should also be underlined that equipment, mounting and operation costs are lower than those of conventional arrangements, no "pulling" is needed, it is easily maintained and consumes less power, among other advantages.

SUMMARY OF THE INVENTION

[0007] The present invention discloses an arrangement for the lifting of hydrocarbons, which is used in oil field wells, and comprises a lifting assembly having a fluid collecting hose and a fluid suction tube within the well casing. The suction tube extends along the collecting hose, which has an open upper end, through which pass- es the upper section of the suction tube having an end attached to the pulling cable of the "collecting hose /suction tube" assembly, and a lower end closed by means of a one-way check valve, through which the fluid flows into a space comprised between the hose and said tube. The upper section extending beyond the open upper end of the collecting hose has a laterally-conformed fluid dischargeopening. When the "hose/suction tube" assembly is risen by action of the pulling cable to reach the end of its travel, said discharge hole is positioned within a sealed chamber in the wellhead, which is defined between a pair of sealing rings, and in this way the fluid is discharged with the assistance of the suction pump and/or the inner gas pressure from the casing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]

Figures 1A to 1C are schematic side elevation views showing the arrangement of the present invention positioned in a production well, which as a whole represents the lifting operation sequence for the fluid contained in the field.

Figure 2 is a schematic overall view showing a hydrocarbon lifting facility including the arrangement of the present invention.

Figure 3 is a schematic overall view showing a facility for lifting hydrocarbons comprising the arrangement of the present invention, where said facility includes a device for lowering gas pressure within the casing.

DETAILED DESCRIPTION OF THE INVENTION

[0009] Figures 1A to 1C show that the hydrocarbon lifting arrangement placed within oil field wells of the invention comprises a lifting assembly formed by a suction tube 1 and a fluid collection hose 2, said assembly extending along the well casing 3. The hose 2 has an open upper end 4 and a lower end 5 closed by means of a oneway check valve 6 which opens into the hose 2 to let the fluid flow into it. In turn, the suction tube 1, which extends from the proximity of the check valve 6 and beyond the upper end 4 of the collecting hose 2, has a lower section 7 and an upper section 8 having a laterally positioned discharge opening 10 for the fluid being lifted. The upper section 8 of the suction tube 1 has a closed end 9, to which the pulling cable 11 is connected to cause the upwards and downwards movement of the lifting assembly defined by the suction tube 1 and the collecting hose 2.

[0010] The upper section 8 of the suction tube 1 is of a length such that, during operation of the facility, when the "tube-hose" assembly reaches the end of its upwards travel, the discharge hole 10 is positioned between a pair of sealing rings - a lower ring 12 and an upper ring 13 -which are placed in the lower section 15 of the wellhead 14, a sealed chamber 16 being formed between said rings, where said chamber has a discharge opening coupled to a fluid outlet duct 17 connected to a suction pump 18.

[0011] The pulling cable 11, attached to the upper end 9 of the suction tube 1, passes through a cable guide bushing 19 and an actuating device that senses the sealed chamber 16. The bushing 19 is part of a member having a lower section 20, which defines the bushing itself and an upper section 21 having a larger diameter than said lower section 20 and defining a guide and an abutment on the sealing ring 13 within the upper section 22 of the header 14. As shown in the drawing, the bushing 19 passes through said pair of sealing rings 12 and 13 during the travel ofthe "tube-hose" assembly. In addition, the pulling cable 11 passes though a cable seal 23 positioned next to the upper section 22 of the wellhead 14.

[0012] As shown in the operation sequence represented in Figures 1A to 1C, when the "tube-hose" assembly is pulled up by the cable 11 until it reaches the end of the travel, the upper section 8 ofthe suction tube 1, and consequently the discharge opening 10, are positioned within the sealed chamber 16 defined between sealing rings 12 and 13. Immediately after the discharge opening 10 connects with the sealing chamber 16, the suction pump 18 begins to force the circulation of the fluid contained in the collecting hose 2 towards the outlet duct 17, passing through the discharge opening 10. Liquid flow, and consequently, oil production, is maintained during the parts ofthe cycle comprising ascending and descending ofthe "tube-hose" assembly, as long as the discharge opening 10 is in communication with the sealed chamber 10 and until the hose 2 is drained. In this part of the lifting process the check valve 6 remains closed.

[0013] During the descending travel ofthe "tube-hose" assembly, when the end 5 of hose 1 is submerged again into the fluid content of the well, the check valve 6 is opened by the pressure exerted thereon by the fluid, and consequently the hose 2 is filled again until the "tube-hose" assembly reaches the end of its descending travel, to be subsequently discharged in each "up/down" cycle ofthe "tube-hose" assembly. In gas-containing wells, the pressure exerted by the gas, depending on its intensity, will cause discharging ofthe hose 2, thus contributing to an increase inthefluidflowratefromthesuction pump 18.

[0014] Figure 2 shows an exemplary embodiment of the present invention, in which the outlet duct 17 comprises a flow-rate control 24, which, by means of a one way check valve 25, is fluidly connected to the corresponding flow line, together with the outlet duct of pump 18, so that the produced gas will be driven to the storage facilities under its own pressure.. The figure also shows that the pulling cable 11 goes through a pulley mechanism 26 and extends along a tube 27 to enter a motor driven equipment 28 where it is spooled on a drum 29.

[0015] Figure 3 shows a further embodiment of the present invention, which includes a device 30 designed to lower gas pressure within the well casing 3 whenever it is deemed convenient. Said device 30 comprises a storage tank 31 having an inlet 32 connected to the suction pump 18 outlet, a first outlet 33 connected to a screw pump 34, and a second outlet connected to the corresponding fluid transportation line. The outlet of the screw pump 34 is connected to an auxiliary inlet of the suction pump 18. In addition, in this exemplary embodiment the sealed chamber 16 of the wellhead 14 has an attached pressure switch 36 and a positioning sensor 37.

[0016] When the tube-hose assembly is in its discharge position as detected by sensor 37, the device 30 suctions the fluid to discharge hose 2. On the other hand, when the tube-hose assembly is not in position - during the upwards and downwards movements - if gas pressure is higher than desired, the pressure switch 36 actuates the device 30, allowing only gas to flow out.

Claims 1. An arrangement for lifting hydrocarbons placed within oil field wells, the oil field well having a wellhead assembly and a bailer device disposed along a well casing (3) and connected to a pulling cable (11) attached to the bailer, said pulling cable (11 ) extending up to a drum which forms part of the driving mechanism of the lifting arrangement, wherein the lifting arrangement extends along the well casing and wherein the lifting arrangement comprises: • a fluid collecting hose (2), the hose having an open upper end (4) and a lower end (5); • a fluid suction tube (1) extending along said hose, said suction tube (1) comprising an upper section (8) projecting beyond the upper end (4) of the collecting hose in which a hole (10) is formed fordischarching thefluid to be suctioned by a suction pump (18) connected to the wellhead (14), the end of said upper section (8) being attached to the end of the pulling cable (11) which drives the lifting arrangement; characterized in that, said open upper end (4) and a lower end (5) of the hose is closed by means of a one-way check valve (6) which opens into the hose to let the fluid flow into it, so that the fluid can also enter through the upper end (4) of the hose. 2. The arrangement according to claims 1 , wherein lower end (5) of the suction tube (1) is open and reaches the proximity of the lower end (5) of the fluid collecting hose (2), while its upper end (4) is closed and said fluid discharge hole (10) is laterally conformed in the upper section (8) of said suction tube (1). 3. The arrangement according to claims 1 .wherein the length of the upper section (8) of the suction tube (1) is such that, when the hose-tube assembly reaches the end of the ascending travel, the discharge opening is placed between a pair of sealing rings - an upper ring (13) and a lower ring (12) - which are positioned in a section of the wellhead (14) where a sealed chamber (16) is defined to which a fluid suction pump (18) is connected. 4. The arrangement according to claim 3, wherein a cable attached to the upper end (4) of the suction tube (1) passes through a bushing (19) through said pair of sealing rings (12,13) during the descending travel of the hose-tube assembly until it reaches the end of said travel, where said bushing is positioned as a guide for the cable. 5. The arrangement according to claim 4, wherein said bushing (19) forms part of a member having a lower section (20) and an upper section (21), said lower section (20) defining the bushing itself, while the upper member - which has a larger diameter than the lower member- defines a guide for the displacement of the bushing, and, in addition, defines a sensor detecting the final position of the hose for its discharge, and an abutment on the upper sealing ring (13).

Patentansprüche 1. Anordnung fürdie Extraktion von Kohlenwasserstoffen bei Ölfeldbohrungen, wobei die Ölfeldbohrung eine Bohrungskopfeinheit und eine Fördervorrichtung aufweist, die entlang einer Bohrlochummantelung (3) angeordnet und mit einem Zugseil (11) an der Fördervorrichtung verbunden ist, wobei sich das Zugseil (11) bis zu einer Trommel erstreckt, die Teil des Antriebsmechanismus der Extraktionsanordnung ist, wobei sich die Extraktionsanordnung entlang der Bohrlochummantelung erstreckt und wobei die Extraktionsanordnung - einen Schlauch (2) zum Aufnehmen eines Fluids, wobei der Schlauch ein offenes oberes Ende (4) und ein unteres Ende (5) aufweist, - ein Rohr (1) zum Ansaugen des Fluids, das sich entlang des Schlauches erstreckt, wobei das Saugrohr (1) einen überdas obere Ende (4) des Aufnahmeschlauchs hinausgehenden oberen Abschnitt (8) aufweist, in dem ein Loch (10) zum Ablassen des von einer mit dem Kopf (14) der Bohrung verbundenen Säugpumpe (18) anzusaugenden Fluids ausgebildet ist, wobei das Ende des oberen Abschnitts (8) am Ende des Zugseils (11) befestigt ist, das die Extraktionsanordnung antreibt, aufweist, dadurch gekennzeichnet, daß das offene obere Ende (4) und ein unteres Ende (5) des Schlauchs mittels eines Einweg-Sperrventils (6) verschlossen sind, das sich zum Schlauch hin öffnet, um das Fluid hinein fließen zu lassen, so daß das Fluid auch durch das obere Ende (4) des Schlauchs eintreten kann. 2. Anordnung gemäß Anspruch 1, dadurch gekennzeichnet, daß das untere Ende (5) des Saugrohrs (1 ) offen ist und die Nähe des unteren Endes (5) des Fluidaufnahmeschlauchs (2) erreicht, während das obere Ende (4) geschlossen ist und das Fluidablaßloch (10) seitlich im oberen Abschnitt (8) des Saugrohrs (1) ausgebildet ist. 3. Anordnung gemäß Anspruch 1, dadurch gekennzeichnet, daß die Länge des oberen Abschnitts (8) derart ist, daß sich die Ablaßöffnung, wenn die Schlauch-Rohr-Einheit am Ende des Aufwärtswegs ankommt, zwischen einem Paar Dichtringen - einem oberen Ring (13) und einem unteren Ring (12) - befindet, die in einem Abschnitt des Kopfs(14)der Bohrung abgeordnet sind, in dem eine abgeschlossene Kammer 16) eingerichtet ist, an die die Fluidsaugpumpe (18) angeschlossen ist. 4. Anordnung gemäß Anspruch 3, dadurch gekennzeichnet, daß ein mit dem oberen Ende (4) des Saugrohrs (1) verbundenes Seil während des Aufwärtswegs der Schlauch-Rohr-Einheit durch eine Durchführung (19) durch das Paar Dichtringe (12, 13) verläuft, bis es am Ende des besagten Wegs ankommt, wo die Durchführung als Seilführung angeordnet ist. 5. Anordnung gemäß Anspruch 4, dadurch gekennzeichnet, daß die Durchführung (19) Teil eines Elements ist, das einen unteren Abschnitt (20) und einen oberen Abschnitt (21 ) aufweist, wobei der untere Abschnitt (20) die Durchführung bildet, während der obere Abschnitt - der einen größeren Durchmesser als der untere Abschnitt hat - eine Führung für das Versetzen der Durchführung und zusätzlich einen Sensor zum Feststellen der Endposition des Schlauchs für dessen Entleerung sowie einen Anschlag am oberen Dichtring (13) bildet.

Revendications 1. Arrangement pour extraire des hydrocarbures en place à l’intérieur de puits de champ pétrolifère, le puits de champ pétrolifère ayant un ensemble de têtes de puits et un dispositif de tube à clapet disposé le long d’un tubage de puits (3) et raccordé à un câble de remontée (11) fixé au tube à clapet, ledit câble de remontée (11) s’étendant jusqu’à un tambour qui forme une partie du mécanisme d’entraîne ment de l’arrangement d’extraction, l’arrangement d’extraction s’étendant le long du tubage de puits, et l’arrangement d’extraction comprenant : - un flexible (2) collecteur de fluide, le flexible ayant une extrémité supérieure ouverte (4) et une extrémité inférieure (5) ; - un tube (1 ) d’aspiration de fluide s’étendant le long dudit flexible, ledit tube d’aspiration (1) comprenant une section supérieure (8) dépassant au-delà de l’extrémité supérieure (4) du flexible collecteur, dans laquelle un trou (10) est formé pour refouler le fluide destiné à être aspiré par une pompe d’aspiration (18) raccordée à la tête de puits (14), l’extrémité de ladite section supérieure (8) étant fixée à l’extrémité du câble de remontée (11) qui entraîne l’arrangement d’extraction ; caractérisé en ce que ladite extrémité supérieure ouverte (4) et une extrémité inférieure (5) du flexible sont fermées au moyen d’un clapet de retenue antiretour (6) qui s’ouvre dans le flexible pour permettre au fluide de s’écouler dans celui-ci, de telle sorte que le fluide puisse aussi pénétrer par l’extrémité supérieure (4) du flexible. 2. Arrangement selon la revendication 1, dans lequel l’extrémité inférieure (5) du tube d’aspiration (1) est ouverte et atteint la proximité de l’extrémité inférieure (5) du flexible (2) collecteur de fluide, tandis que son extrémité supérieure (4) est fermée et que ledit trou (10) de refoulement du fluide a une forme latéralement adaptée dans la section supérieure (8) dudit tube d’aspiration (1). 3. Arrangement selon la revendication 1, dans lequel la longueur de la section supérieure (8) du tube d’aspiration (1) est telle que, quand l’ensemble flexible-tube atteint l’extrémité du parcours ascendant, l’ouverture de refoulement soit placée entre une paire de bagues d’étanchéité - une bague supérieure (13) et une bague inférieure (12) - qui sont positionnées dans une section de la tête de puits (14) dans laquelle une chambre étanche (16) est définie, à laquelle une pompe d’aspiration de fluide (18) est raccordée. 4. Arrangement selon la revendication 3, dans lequel un câble fixé à l’extrémité supérieure (4) du tube d’aspiration (1) passe à travers une douille (19) à travers ladite paire de bagues d’étanchéité (12, 13) pendant le parcours descendant de l’ensemble flexible-tube jusqu’à ce qu’il atteigne l’extrémité dudit parcours, où ladite douille est positionnée en tant que guide pour le câble. 5. Arrangement selon la revendication 4, dans lequel ladite douille (19) forme une partie d’un élément ayant une section inférieure (20) et une section supérieure (21), ladite section inférieure (20) définissant la douille proprement dite, tandis que l’élément supérieur - qui a un diamètre supérieur à celui de l’élément inférieur - définit un guide pour le déplacement de la douille et, en outre, définit un capteur détectant la position finale du flexible pour son refoulement, et une butée sur la bague d’étanchéité supérieure (13).

REFERENCES CITED IN THE DESCRIPTION

This list of references cited by the applicant is for the reader’s convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description • WO 2007084927 A [0004]

Claims (4)

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