FR2710946A1 - System for generating and transferring power - Google Patents

Abstract

The present invention relates to a system and a method for generating and transmitting power from a power-generator device to a pumping unit positioned at a certain height above the power generator. It includes at least one means (8) for withdrawing a certain quantity of a fluid from a fluid coming from the said deposit, the said withdrawn fluid making it possible to generate power from the said power-generator device, at least a first connection means (7) located between the said withdrawal means (8) and the power-generator device, and at least one means (14) for transmitting the power generated by the said power-generation device (3) from the device to the pumping unit (11).

Description

 The present invention relates to a device and a method for generating and transferring energy.

 The present invention makes it possible in particular to transmit to a pumping assembly situated in conditions of difficult or uneasy access to power and energy so as to make it operate under optimum conditions.

 The device according to the present invention is particularly well suited in the context of oil production. Indeed, the exploitation of oil deposits implements pumping systems requiring an energy supply located between a deposit to be exploited and a treatment or transfer platform receiving the effluents compressed by a pump. For reasons of technology and reliability, the pump and its associated drive equipment are preferably positioned above the surface of the water, this arrangement thus allowing easy maintenance. Thus, when it rises to the surface, the effluents from the deposit undergo a pressure drop before entering the pumping system, which restricts the range of transportable effluents by the pumping system.

 To overcome these drawbacks, the pump is then positioned in the vicinity of the deposit to be exploited and at the bottom of the sea, the transfer of effluents being through a pipe connecting the pump to a main processing platform or directly to the coast. The pumping system is powered by an electric cable located at the bottom of the sea or positioned between two waters, from the main platform of treatment. For important distances between the energy source and the pumping system, for example a few kilometers and beyond twenty kilometers, this arrangement causes disturbances of the electric supply current, including dissipation of the power supply. electrical energy not insignificant. In addition, the length of the cables and their installation lead to a significant increase in the costs of the oil exploitation facility.

 The purpose of the present application is to overcome the aforementioned drawbacks and to provide a device and a method, at a cost lower than that of the devices generally used, for supplying power to a pumping system located under controlled conditions. difficult access, and / or located at a great depth, especially for water heights greater than 200 meters.

 It may also be used in fields other than marine production where the work environment has an impact on a pump's power supply systems and which requires positioning these systems at a distance. feeding, especially in the case where there is a significant difference in altitude between the location where the pump is located and that where the energy generator is located.

 Thus, the present invention uses an original arrangement of the elements necessary for the exploitation of a deposit, and more particularly of the energy supply system, the pumping system, the various cables and lines of arrival of the energy and effluent transfer, and a platform for the transfer and / or treatment of effluents.

 The system for generating and transmitting energy or power to a pumping assembly located beneath a layer of water and connected to a fluid reservoir according to the invention, comprises in combination a possibly floating support equipped with at least one energy generating device, at least one means for taking a certain quantity of fluid from the fluid coming from said deposit for generating energy via the energy generator, at least one first means connecting link between said sampling means and said floating support, at least one means for transmitting the energy generated by said energy generating device connecting said floating support to said pumping assembly.

 Said sampling means is preferably located between the deposit and the pumping assembly.

 The energy generating device can be composed of a gas turbine associated with a hydraulic pump.

 It may comprise a pipe for returning energy from said pump assembly to said floating support.

 The first connecting means located between the floating support and the sampling means is, for example, a flexible pipe, such as a riser.

 The energy transmission means is, for example, an electrical cable connecting the floating support and the pump, it can also be in the form of a flexible or semi-rigid pipe adapted to the transfer of gas.

 The pumping assembly comprises, for example, a pump associated with a drive device.

 In an exemplary embodiment of the system according to the present invention, the pump is a multiphase type pump associated with a drive turbine.

 In addition, the system comprises, for example, control and control means. These means make it possible to control the pumping assembly and all the equipment usually employed in the context of oil production.

 It may also comprise means for anchoring said floating support to the bottom of the sea.

 The system makes it possible, for example, to generate and transmit energy from an energy generating device (3) to a pumping assembly positioned at a certain altitude with respect to a pumping assembly. For example, it comprises, in combination, at least one means (8) for withdrawing a certain amount of a fluid from the fluid coming from said deposit, said withdrawn fluid making it possible to generate energy from the energy generating device at least one first connecting means (7) located between said sampling means (8) and the energy generating device, at least one transmission means (14) of the energy generated by said energy generating device ( 3) from the device to the pumping assembly (11).

 The present invention also relates to a method for generating and transferring energy from an energy generating device positioned on a possibly floating support to a pumping assembly located below a layer of water and connected to a a reservoir of fluid. It is characterized in that it comprises the following steps - positioning said support above and in the vicinity of said reservoir and the pumping assembly, - a certain amount of fluid is taken from said fluid from said reservoir to the reservoir. With the aid of a sampling means, said withdrawn fluid is transferred to said energy generating device, and the energy from said energy device is transferred to the pumping assembly.

 Gas is preferably used as fluid taken off and a turbine located in said energy generating device is actuated, said gas turbine driving a hydraulic pump compressing a fluid coming from a reservoir and in that one sends the compressed fluid to the pumping assembly.

 The fluid used, for example, is seawater. This procedure has the advantage of having an open energy circulation circuit comprising only a compressed seawater injection line.

 The device and the method are particularly well suited to the transfer of a multiphase fluid.

 The device and the method are particularly well suited to the transfer of a petroleum effluent.

 The system of generation and transfer of energy makes it possible, thanks to the original disposition of the various elements constituting it, to widen the field of effluents from transportable oilfields whatever the depth of water to which they are located, by obtaining a higher pressure value at the suction of the pump, because the effluent no longer undergoes the loss of hydrostatic pressure of the fluid column, usually observed when it rises to the surface, that when the pump is placed on the surface. By this advantageous arrangement, it also offers a greater pumping efficiency, since the volume of gas from the effluent to the suction is lower, the gas being more compressed than it would be on the surface. The maintenance of such a system is facilitated, the most fragile equipment being positioned on the surface. In addition, such a system offers the possibility of using simpler pump drive equipment of currently known technology. In addition, the device thus formed proves to be less expensive than the devices usually used, by reducing the lengths of the supply lines of the energy.

Other features and advantages of the present invention will appear more clearly on reading the description given below of a non-limiting example of the embodiment of the invention given with reference to the accompanying drawings in which - FIG. set showing an application of
the invention for the exploitation of a deposit in which the
device is positioned downstream of the pumping assembly, - Figures 2A, 2B and 2C show in detail different circuits
of injecting energy to the pumping assembly according to the
nature of this energy, FIG. 3 schematizes an embodiment in which the
fluid sampling device is positioned upstream of
the pump assembly, and - in FIG. 4 the sampling device consists of a
regulating balloon and damping fluctuations.

 The principle used in the present application consists in arranging the energy and power generating means on a floating support located near a reservoir to be exploited, in order firstly to eliminate energy supply cables of constraining length. and, on the other hand, to subtract certain elements from environmental conditions that diminish their reliability.

The following description given by way of non-limiting example concerns the application of the system to the transfer of effluents from, for example, a petroleum deposit producing multiphase effluents or fluids, comprising at least one liquid phase and at least one a gaseous phase, the liquid phase consisting of water and oil, the value of the volumetric ratio, usually referred to as
GLR varies unpredictably.

 The system for generating and transmitting energy or power according to the present invention (FIG 1) comprises a floating support 1, such as a buoy located on the surface of the water 2, equipped with means for generating energy 3 consisting, for example, of a gas turbine 4 (FIG 2A) associated with a hydraulic pump 5 (FIG 2A) and a reservoir 6 (FIG 2A) containing fluid used as energy producer connected to the hydraulic pump in a manner described in connection with FIG. 2A. The floating support 1 is connected by a pipe 7, for example a riser, to a sampling means or separation device 8 located on the sea floor and positioned in this example before the pump. This device is used to collect a certain amount of fluid, for example and preferably gas, from the effluent from the exploited deposit used for the generation of energy. The separation device 8 is connected by effluent transfer pipes 9 to several well heads T, each connected to the deposit to be exploited, and by a pipe 10 allowing the transfer of the remainder of the effluents from the deposit to a pumping assembly 11 comprising a pump 12 and its associated drive device 13, for example a drive motor, preferably hydraulic. For a gas turbine, part of the gaseous phase or gas is taken from the effluents from the deposit. By a power transmission means 14 such as a pipe, the hydraulic fluid pressurized by the pump 5 and serving as hydraulic energy is transmitted to the driving motor of the pump 12, and is then returned to the pump. reservoir 6 by a line 15 for returning the fluid. The effluents at which the pump has communicated a pressure increase by passing through the pump are then sent via a transfer line 16 to a main treatment station or directly to the coast.

 Such a system can operate, for example, as follows, the effluent from the deposit passes through the separator 8 in which a portion of the gas is withdrawn and directed to the gas turbine 4 by the transfer pipe 7. The The gas actuates the gas turbine driving the hydraulic pump 5. This then communicates to the hydraulic fluid from the tank 6 a sufficient pressure value so that it can serve as hydraulic energy actuating the hydraulic drive motor 13 of the pump 12 .

 This way of proceeding offers, in particular, the advantage of avoiding the use of electric cables coming from a processing platform or the coast over long distances and moreover to keep in an easily accessible zone, for example, over the sea all the drive devices such as electric motors whose current technology does not provide infrequent maintenance or put internal combustion engines at the bottom of the sea.

 Nevertheless, electric motors can, without departing from the scope of the invention, be used.

 In this way, the effluents are transferred directly from the pump to a treatment platform, without having to go up to the surface. This widens the field of deposits to be exploited, particularly in deposits located at great depths of water. Thus, the depths of water for which the process is particularly most advantageous, are water depths greater than 200 meters.

 FIGS. 2A, 2B and 2C describe various embodiments for the energy generating systems and the associated energy transfer circuit. The following table (I) is a non-limiting example of the fluids taken from the effluents coming from a petroleum deposit, associated devices making it possible to generate energy and the type of energy obtained.

Energy generating devices and associated fluid

<tb> fluid <SEP> sampled <SEP> device <SEP> associated <SEP> energy <SEP> produced <SEP> and <SEP> fluid
<tb><SEP> Intermediate <SEP> Associate
<tb><SEP> turbine <SEP> to <SEP> gas <SEP> + <SEP> hydraulic <SEP> pump <SEP> (oil, <SE> water <SEP>)
<tb><SEP> sea, <SEP> fluid, <SEP> water <SEP> from
<tb><SEP> Gas <SEP> Deposit) <SEP> Open <SEP> Circuit Open
<tb><SEP> or <SEP> closed
<tb><SEP> turbine <SEP> to <SEP> gas <SEP> + <SEP> electric
<tb><SEP> alternator
<tb><SEP> engine <SEP> diesel <SEP> + <SEP> hydraulic <SEP> (oil, <SE> water <SEP>)
<tb><SEP> pump <SEP> sea, <SEP> fluid, <SEP> water <SEP> from
<tb> oil <SEP> or <SEP> crude <SEP> deposit) <SEP> circuit <SEP> open
<tb><SEP> or <SEP> closed
<tb><SEP> engine <SEP> diesel <SEP> + <SEP> electric
<tb><SEP> alternator
<Tb>
In FIG. 2A, the gas taken from the effluents from the reservoir during operation is brought to the gas turbine by the pipe 7. The gas drives the turbine which actuates the pump 5. The pump communicates with the intermediate fluid (see table above) from the tank 6 through a pipe 17, a pressure value sufficient for it to serve as a source of hydraulic energy. This hydraulic energy (in the form of compressed hydraulic fluid) is transmitted to the driving motor of the pump via line 14.

 The hydraulic fluid after passage in the pump assembly 1 1 is then returned to the reservoir 6 by a pipe 15. This circuit is called closed circuit.

 When seawater is used as the hydraulic fluid, the closed-circuit operation described above is no longer necessary, since seawater can be discharged directly without causing pollution problems.

 Thus, FIG. 2B schematizes a circuit for generating energy, called an open circuit, in which seawater is used as an intermediate fluid.

 The seawater arrives via a pipe 18, communicating with the sea or ocean, at the pump 5 which transfers a pressure value sufficient for use as hydraulic energy. This compressed seawater is then sent to the drive motor 13 of the pump included in the pump assembly 11. This assembly is equipped with a conduit 19 allowing the evacuation of the seawater used for the treatment. pump operation.

 Another variant described according to FIG. 2C consists in using instead of the pump 5 an alternator 20. In this embodiment, the alternator is controlled in the same way as the descriptions referring to FIGS. 2A and 2B by the turbine. 4. The energy generated by the alternator 20 is then sent by an electric cable 21 to the pump assembly 1 1 for which it serves to actuate the drive motor 13 of the pump 12.

 It is understood that one can use as fluid taken, oil or crude. In these cases, the associated devices comprise for example a diesel engine associated with either a pump or an alternator (Table I).

 Of course, any other device for generating energy from a fluid can be used without departing from the scope of the invention.

 According to one embodiment of the invention, the floating support is held in place with respect to the pumping assembly 1 1 using the energy transmission means 14 and the pipe 7 whose structures are calculated depending on the most adverse weather conditions and the stresses exerted to keep the floating structure in place. It can also be anchored to the seabed using cables or flexible lines 22, such as catenary chains commonly used in offshore operations, and an anchor 23. Any other available means providing the anchor A floating support unit may, without departing, of the present invention be used.

 A buoy is used whose floatation characteristics are such that one part of its body is submerged, the other emerging sufficiently far above the surface of the sea, so as to install the means necessary to generate the energy.

 The floating support is, for example, a buoy, of the type used to moor offshore oil tankers or a buoy type "pencil".

 It can be equipped with a porous element acting as a damper such as that described in application FR-90 / 15,749 to minimize all heave movements due in part to the swell.

 The floating support 1 comprises1, for example, means for controlling and controlling equipment located on the floating support and on the seabed, for example the pumping assembly. The remote control signals are sent for example by a hardware link not shown in the figure or by satellite link from the coast or a main processing platform to the floating support and the floating support to the underwater equipment. via cables (not shown in the figure) to equipment located on the sea floor.

 During the operation of such a system, the conventional operation control and measurement operations are performed automatically and make it possible to manage the production and transfer of energy, for example the regulation of fluid flow, the position of valves equipping the power transmission lines, not shown in the figures. This equipment is known specialists in the field of offshore operation, or offshore, are not detailed later.

 In another embodiment shown diagrammatically in FIG. 3, the separation device 8 is positioned after the pump and takes a certain quantity of fluid from the effluent compressed by the pump. This embodiment is better suited when the amount of fluid required for power generation is low.

 Such an arrangement of the different elements with each other has the advantage of using a fluid, for example gas, having a higher pressure, which thus makes it possible to obtain a higher energy for the drive motor of the pump.

 This system operates in a substantially identical manner to that described with reference to Figure 1, the effluent from the deposit being sent directly through a pipe 24 to the pumping assembly in which it is compressed.

 The compressed effluent is then transmitted via a pipe 25 to the separation device 8 in which a certain quantity of fluid is taken and sent via a pipe 26, of a type identical to the pipe 7, to the energy generating device. 3. The remainder of the effluent is transferred to the coast directly or to a main treatment platform via a pipe 27.

 The generation and transmission of energy is identical to that described above with reference to FIGS. 1 to 2.

 FIG. 4 describes another possibility in which the separation device or separator 8 consists of a regulating and damping flask of the effluents, such as that described in the patent application FR-2,642,539 and the application for Applicant's patent FR-2,669,559.

 In this case, the flask is equipped with a gas sampling tap 28 or outlet port connected to the gas transfer line 7 to the gas turbine 4. The outlet pipe 29 of the effluent control flask having a controlled GLR value is directly connected to the pipe 16 through which the transfer of the effluents to be compressed to the pump is ensured.

Any device making it possible to take a part of the effluent from the exploited deposit, such as dividers in the form of
T or Y known to specialists, in particular by patent application GB-2,239,679 can be used without departing from the invention.

 Figures 1, 3 and 4 described above relate more particularly to the use of a portion of the gaseous phase of an effluent to operate a gas turbine, and produce hydraulic or electrical energy. The mode of operation described with reference to these figures remains valid, without departing from the invention, for any fluid taken from the effluent from a deposit capable of operating a device, performing a function identical to that of a gas turbine, namely the driving of a pump capable of producing from an auxiliary fluid hydraulic energy or from an alternator directly electric power. Table I lists, in a non-exhaustive way, a list of fluids, the devices associated with them and the energy produced.

 The pump included in the pumping means arranged at the bottom of the sea is for example a multiphase pump described in patents FR-2,333,139 and FR-2,665,224 of the applicant.

 The drive motor associated with this pump is preferably a hydraulic motor. Any drive device for reliable operation of the pump may also be used.

 Without departing from the scope of the invention described above, with reference to the figures, the invention naturally encompasses any other modification within the scope of those skilled in the art.

Claims (17)

1) System for generating and transmitting energy to a pumping assembly located below a layer of water and connected to a fluid reservoir, comprising in combination a possibly floating support (1) equipped with at least one energy generating device (3), at least one means (8) for taking a certain quantity of a fluid from the fluid from said reservoir, said withdrawn fluid making it possible to generate energy from the generating device of energy, at least a first connecting means (7) located between said sampling means (8) and said floating support (1), at least one transmission means (14) of the energy generated by said generating device of energy (3) connecting said floating support (1) to said pump assembly (11). 2) System according to claim 1, characterized in that said sampling means (8) is located between said deposit and said pumping assembly (11). 3) System according to claims 1 and 2, characterized in that said energy generating device (3) is a gas turbine (4) associated with a hydraulic pump (5). 4) System according to claims 1 to 3, characterized in that it comprises a return pipe of the energy of said pump assembly to said floating support (1). 5) System according to claims 1 to 4, characterized in that said first connecting means (7) between said floating support and said sampling means is a flexible pipe, such as a riser. 6) System according to claims 1 and 2, characterized in that said energy transmission means (14) is a flexible pipe, rigid, or semi-rigid for transferring gas. 7) System according to claims 1 and 2, characterized in that said energy transmission means (14) is an electric cable. 8) System according to one of the preceding claims, characterized in that the pump assembly comprises a pump (12) associated with a drive device (13). 9) System according to claim 8, characterized in that said pump is a pump (12) of the multiphase type associated with a drive turbine (13). 10) System according to one of the preceding claims, characterized in that said floating support comprises control means and control. 11) System according to one of the preceding claims, characterized in that it comprises anchoring means (22, 23) of said floating support at the bottom of the sea. 12) System for generating and transmitting energy from an energy generating device (3) to a pumping assembly positioned at an altitude relative to a pumping assembly comprising in combination at least one sampling means (8) a certain quantity of a fluid from the fluid coming from said deposit, said sampled fluid making it possible to generate energy from the energy generating device, at least a first connecting means (7) located between said sampling means (8) and the energy generating device, at least one transmission means (14) of the energy generated by said energy generating device (3) from the device to the set of pumping (11). 13) A method for generating and transferring energy from an energy generating device positioned on a possibly floating support to a pumping assembly located below a layer of water and connected to a fluid reservoir , characterized in that it comprises the following steps - positioning said support above and in the vicinity of said reservoir and the pumping assembly, - a certain amount of fluid is taken from said fluid from said reservoir to the reservoir. by means of a sampling means, - said sample fluid is transferred to said energy generating device, and - the energy from said energy device is transferred to the pumping assembly. 14) A method according to claim 13, characterized in that gas is used as fluid taken and actuated a turbine located in said energy generating device, said gas turbine driving a hydraulic pump compressing a fluid from a reservoir and in that said compressed fluid is sent to the pumping assembly. 15) A method according to claim 14, characterized in that it uses as fluid compressed seawater. 16) Application of the system according to one of claims 1 to 12 and / or the method according to one of claims 13 to 14 to the transfer of a multiphase fluid. 17) Application of the system according to one of claims 1 to 12 and / or the method according to one of claims 13 to 14 to the transfer of a petroleum effluent.