Classifications

• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B33/00—Sealing or packing boreholes or wells
  • E21B33/02—Surface sealing or packing
  • E21B33/03—Well heads; Setting-up thereof
  • E21B33/035—Well heads; Setting-up thereof specially adapted for underwater installations
  • E21B33/0355—Control systems, e.g. hydraulic, pneumatic, electric, acoustic, for submerged well heads
• • E—FIXED CONSTRUCTIONS
  • E21—EARTH OR ROCK DRILLING; MINING
  • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
  • E21B33/00—Sealing or packing boreholes or wells
  • E21B33/02—Surface sealing or packing
  • E21B33/03—Well heads; Setting-up thereof
  • E21B33/035—Well heads; Setting-up thereof specially adapted for underwater installations
  • E21B33/038—Connectors used on well heads, e.g. for connecting blow-out preventer and riser
  • E21B33/0385—Connectors used on well heads, e.g. for connecting blow-out preventer and riser electrical connectors
• • E—FIXED CONSTRUCTIONS
  • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
  • E02B—HYDRAULIC ENGINEERING
  • E02B17/00—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor
  • E02B17/02—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor placed by lowering the supporting construction to the bottom, e.g. with subsequent fixing thereto
  • E02B17/021—Artificial islands mounted on piles or like supports, e.g. platforms on raisable legs or offshore constructions; Construction methods therefor placed by lowering the supporting construction to the bottom, e.g. with subsequent fixing thereto with relative movement between supporting construction and platform

Definitions

• the present invention relates to a plant for exploiting underwater reservoirs of natural fluids, such as for example, oil, natural gas or other hydrocarbon-based extracted fluids. More specifically, the invention relates to an extraction plant through a horizontal production cross.
• the control umbilical is therefore substantially a bundle of tubes comprising the duct for the passage of the hydrocarbons extracted, two or more pipes for the supply and return of the oil of the hydraulic actuation circuits and a bundle of electric feeding and signalling wires for the electric instrumentation of the production cross.
• the hydraulic actuation circuit is fed by a unit comprising a pump, the relative actuation motor and the tank for the oil or other hydraulic fluid; this unit is normally situated on the master platform 3.
• the control of the production cross becomes complicated and the costs of the known control umbilical become excessively high, making the development of the satellite well economically inconvenient .
• An objective of the present invention is therefore to overcome the drawbacks of the known systems described above for exploiting hydrocarbon reservoirs through a control umbilical and submersed production cross, in particular allowing a reduction in the costs of the control umbilical and increasing the maximum horizontal distance and/or maximum depth of the well for which the exploitation of the latter is economically convenient.
• this and other objectives are achieved by providing a plant for exploiting reservoirs of natural fluids, such as for example oil, natural gas or other hydrocarbon-based extracted fluids, having the characteristics according to claim 1.
• natural fluids such as for example oil, natural gas or other hydrocarbon-based extracted fluids
• the invention relates to a method according to claim 11.
• FIG. 1 shows, in a vertical section, a plant of the known type for exploiting an underwater hydrocarbon reservoir ;
• Figure 2 shows, in a vertical section, a plant for exploiting an underwater hydrocarbon reservoir, according to a preferred embodiment of the invention
• Figure 3 shows, in a side view, a functional electric and fluid scheme of the plant of Figure 2 ;
• Figure 4 shows a section, according to a longitudinal plane, of the production cross of the plant of Figure 2;
• Figure 5 shows a functional electric and fluid scheme of the production cross of Figure 4.
• Figure 6 shows a protection structure that can be used for installing and protecting the production cross of Figure 4 on the installation seabed;
• Figure 7 shows a step of a method for installing a production cross according to an aspect of the invention .
• Figures 2-6 relate to a plant for exploiting underwater reservoirs of oil, natural gas or other hydrocarbon-based extracted fluids, according to a preferred embodiment of the invention.
• Said plant indicated with the overall reference number 10, can comprise a first surface part and a second underwater part.
• the first surface part can comprise an oil platform 3' on which the following are preferably positioned ( Figure 3): an electrical distribution unit or EDU 101;
• a topside umbilical termination unit or TUTU of the surface system 102 a topside umbilical termination unit or TUTU of the surface system 102;
• MCS 104 a master control station or MCS 104.
• the oil platform 3' can be sustained for example by pylons or anchored to fixed cables on the seabed.
• the second underwater part comprises a well head unit 1' situated on a seabed ( Figure 2) .
• the first surface part and the second underwater part are connected by a control umbilical or another connection cord 5 ' .
• the well head unit 1' can be like that shown in Figure 4, and comprise a production completion unit of the well, in turn comprising for example:
• cementation vent systems 6 (shallow water devices ) ;
• casing hanger surface casing 9 also called seal ring or VX gasket
• a cross support 20 also called conductor pipe housing 20.
• the well head unit 1' also comprises a so-called production cross or Christmas tree indicated with the reference number 21.
• the production cross 21 rests on and is connected to the production completion unit of the well with the necessary hydraulic seal by means of the casing hanger surface casing 9.
• the production cross 21 comprises:
• valve body 25 suitable for being fixed to the production completion unit of the well and in which there is a first 27 and second extraction duct 29, suitable for the outflow of the oil, natural gas or other fluid extracted from the reservoir G, outside the reservoir itself;
• the first extraction duct 27 extends coaxially, or in any case longitudinally, with respect to the axis AP of the well section closest to the surface of the sea bottom on which the production cross is situated.
• the second extraction duct 29 branches out from the first extraction duct 27 and extends transversally with respect to the latter, for example perpendicularly.
• the first 31 and second extraction control valve 33 are suitable for reversibly allowing, preventing or regulating the flow of oil, natural gas or other fluid extracted through the second extraction duct 33 towards the outside of the production cross 21 itself.
• the production cross 21 is a so-called horizontal production cross, i.e. at least one of the extraction control valves 31, 33 is positioned along the second extraction duct 29, and along the first extraction duct 27 there is no valve suitable for reversibly allowing, preventing or regulating the flow of oil, natural gas or other fluid extracted; this allows secondary interventions to be effected on the well for example with slick line, coiled tubing or wire line operations (rigless, i.e. without any plant) and always for example for connecting a BOP (Blow Out Preventer) on the well head without having to completely remove the production cross 21 - or at least its valve body 25 - from the production completion unit of the well, unlike a production cross of the vertical type.
• BOP Second Out Preventer
• the upper end of the first extraction duct 27 is substantially straight for a suitable length.
• At least one of the first 31 and second extraction control valve is an intercepting valve, i.e. only capable of completely opening and closing the duct along which they are positioned, or a regulation or control valve, i.e. capable of varying the flow-rate passing through it with continuity or at different levels .
• the two extraction control valves and possible other valves suitable for reversibly allowing, preventing or regulating the flow of oil, natural gas or other fluid extracted through the production cross itself 21, are activated by electric actuators 35, 37, which can be assembled for example inside or in any case on the valve body 25.
• the electric actuators 35, 37 can for example be rotating motors, linear motors or solenoids depending on the type of valve to be activated ( Figure 4) .
• the first 31 and second extraction control valve 33 and the other possible valves suitable for allowing, preventing or regulating the flow of extracted fluid through the production cross itself, are advantageously not activated by fluid actuators, such as for example, hydraulic or pneumatic actuators, but only by electric actuators preferably combined with manual activations according to the redundancy principle; the manual actuators can be in turn activated for example by scuba-divers, skin-divers or mechanical arms of robots or bathyscaphes.
• fluid actuators such as for example, hydraulic or pneumatic actuators, but only by electric actuators preferably combined with manual activations according to the redundancy principle
• the manual actuators can be in turn activated for example by scuba-divers, skin-divers or mechanical arms of robots or bathyscaphes.
• the control umbilical 5' can be known per se, and for example can be of the type currently supplied by the companies Technip, Oceaneering or Saipem Energy System.
• valves suitable for reversibly allowing, preventing or regulating the flow of oil, natural gas or other fluid extracted through the production cross itself 21 are advantageously activated by electric actuators, , which can be assembled for example inside or in any case on the valve body 25.
• the production cross 21 can be significantly lightened, allowing its installation on the well head by means of a fixed drill plant (jack up) with the derrick of the plant, for example. This allows to use plants at a lower cost - indicatively with a daily installment about a third of that of a floating plant - and with a greater diffusion.
• the actuators of the production cross 21 advantageously guarantee the redundancy principle which is part of the safety system of the production cross.
• the redundancy system envisages the activation of the valve with a redundant electric system, if a breakage in the primary system is recorded.
• the two systems should be considered completely independent and are applied not only to 5 inch valves but also, for example, to 2 inch valves.
• the production cross 21 is advantageously equipped with a manual mechanical control system of the production cross valves in the case of contemporary damage of the two actuator systems.
• a secondary electric power unit is advantageously automatically activated, which is capable of supplying electric current to the whole underwater system.
• the secondary electric power unit is situated on the oil platform 3' or in any case on the above first surface part of the exploitation plant and can comprise a continuity group or a suitable UPS (Universal Power Supply) such as for example an electrogen group with a thermal combustion motor or accumulator battery.
• UPS Universal Power Supply
• the various subsystems on the oil platform 3' or in any case on the first surface part of the exploitation plant are advantageously constructed applying the redundancy principle.
• the production cross 21 preferably comprises a watertight casing (not shown) which encloses and seal separates from the outside water the extraction control valves 31, 33, the possible other valves suitable for allowing, preventing or regulating the flow of the extracted fluid through the production cross 21 itself and the relative electric actuators.
• the production cross 21 is suitable for being installed and operating on a seabed, ocean, lake, or river .
• the well head unit 1' is preferably equipped with a well bottom safety valve, or a Surface Controlled Subsurface Safety Valve (SCSSV) 45, of the known type and is exclusively activated and controlled electrically - and possibly also manually - by the production cross 21 through appropriate electric penetrators or in any case electric cabling ( Figures 4, 5) .
• Said feeding and control cabling of the well bottom safety valve 45 is preferably interfaced with the underwater electrical control module 47 through one or more suitable connectors 49 which can be exposed to a sea environment (wet-mate) , of the known type, for example one or more DigiTRON wet-mate connectors commercialized by the company EXPRO/TRONIC .
• the well bottom safety valve 45 is currently hydraulically activated but the production cross according to a preferred embodiment of the invention only has electric penetrations. This standardization allows greater simplicity in the engineering phase of the components, production of the system, operations onboard the drilling plant. Furthermore, the insertion of the electric safety valve 45 allows to remove a valve, elsewhere important, on the body of the production cross. This favours the weight and compactness of the system itself.
• the underwater electrical control module 47 also called SEM (subsea electrical module) comprises an appropriate logic unit and a plurality of signal or power input and/or output gates to control the various electric actuators of the production cross 21' and/or exchange data with these.
• the underwater electrical control module 47 is preferably assembled on the production cross 21' itself, for example on its valve body 25, and separated from the water of the sea environment by a suitable watertight casing.
• control umbilical 5' is preferably suitable for being reversibly coupled with the underwater electrical control module 47 by means of an umbilical termination unit 51, for the sake of brevity also called UTA, which can comprise one or more electric connectors of the wet-mate type and possible rapid couplings 53 for connecting the feeding lines of particular auxiliary chemical substances, such as for example methanol, glycol or other water-based chemical inhibitors for preventing the formation of hydrates.
• UTA umbilical termination unit 51
• UTA can comprise one or more electric connectors of the wet-mate type and possible rapid couplings 53 for connecting the feeding lines of particular auxiliary chemical substances, such as for example methanol, glycol or other water-based chemical inhibitors for preventing the formation of hydrates.
• the reference 54 indicates a plurality of electric data or signal lines directed towards the inside of the production cross 21
• the references 55 indicate the group of electric data or power lines which connect the underwater electrical control module 47 and the electric safety valve 45
• the references 57, 59 indicate the feeding lines through which the umbilical termination unit 51 supplies the production cross 21 with the above auxiliary substances.
• Figure 6 shows a side view of an example of a protection structure 61 that can be used for installing and protecting the production cross 21 on the seabed.
• the protection structure 61 comprises:
• trunk 65 suitable for protecting the production cross for example from fishing nets, anchors, waste products or pieces of wreckage coming from the surface;
• cap 67 also called debris cap, suitable for protecting the production cross from any debris or other objects falling from above.
• the protection structure 61 rests on the cross support 20 by means of the connection frame 69.
• the production cross 21 To allow the production cross 21 to be installed on the seabed by means of a jack-up, it preferably has a weight equal to or less than 35 tons; more preferably the combination of production cross 21 + protection structure 61 has a weight equal to or less than 35 tons .
• the present invention relates to a method for installing, maintaining or running the plant 10 comprising the following steps:
• a jack up that is a platform 50 comprising a buoyant hull 52 and one or more extendable legs 54 fixed to the hull 52;
• the extendable legs 54 can be for example retractable columns or pillars, for example having reticulated or tubular structures.
• the extendable legs are kept preferably lifted and retracted while the platform 50 sails carrying the production cross 1 ' towards the destination place.
• the extendable legs 54 can be lifted and retracted again, and the platform can sail away and be used in other locations.
• the platform -i.e. jack up- is provided with a derrick 56 or other drilling tower or mobile tower, and the production cross is lowered from the buoyant hull 52 down to the installation seabed SB is made by hanging the production cross 1 ' to the derrick 56 or other drilling tower or mobile tower, and hauling the production cross 1' from the derrick 56 or other drilling tower or mobile tower down to the installation seabed SB.
• the production cross 1' is lowered from the platform down to a well head. This way the production cross 1 ' can be installed on a well head at particularly low costs.
• the previously described platform 50 that is a jack up, is a relatively cheap apparatus for installing, running or maintaining electric production crosses 1 ' according to the invention.
• the device thus conceived can obviously undergo numerous modifications and variants, all included in the invention.
• the oil platform 3' for example, can be substituted by a support ship, a floating platform or other surface control unit.
• a production cross according to the invention can be suitable for being installed and operating underwater not only on a seabed but also on the bed of an ocean, lake, river or other submersed beds.
• all the details can be substituted by technically equivalent elements.
• the materials used, as also the dimensions, can vary according to technical requirements.
• the examples and lists of possible variants of the present patent application should be considered as being non-exhaustive lists.

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• Geology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Mining & Mineral Resources (AREA)
• Environmental & Geological Engineering (AREA)
• Fluid Mechanics (AREA)
• Physics & Mathematics (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Earth Drilling (AREA)
• Physical Or Chemical Processes And Apparatus (AREA)
• Other Liquid Machine Or Engine Such As Wave Power Use (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=44555112

Family Applications (1)

Country Status (6)

Citations (2)

• 2011
  • 2011-06-20 IT IT001112A patent/ITMI20111112A1/it unknown
• 2012
  • 2012-06-20 RU RU2013155769/03A patent/RU2013155769A/ru not_active Application Discontinuation
  • 2012-06-20 DE DE112012002553.9T patent/DE112012002553T5/de not_active Withdrawn
  • 2012-06-20 WO PCT/EP2012/061796 patent/WO2012175540A1/en active Application Filing
  • 2012-06-20 AP AP2013007337A patent/AP2013007337A0/xx unknown
  • 2012-06-20 RO ROA201300989A patent/RO129657A8/ro unknown

Patent Citations (2)

Non-Patent Citations (5)

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