RELATION TO PRIOR APPLICATIONS

[0001] This application claims priority through United States Provisional Application

62/534,333, filed July 19, 2017.

BACKGROUND

[0002] This invention relates to coiled tubing being utilized to intervene in a pipeline or well subsea while maintaining pressure integrity from the hydrostatic and dynamic conditions.

[0003] In a subsea environment, performing an intervention with coiled tubing to a pipeline, or oil/gas well historically used a semi-submersible rig or DP Monohull vessel with a riser conduit from surface to the subsea tree or pipeline.

[0004] When utilizing a riser or flexible conduit the pressure control equipment (BOP's and stripper assembly) are mounted at surface to control any release of fluids or gases from the well/pipeline during the intervention program.

[0005] However, when operating riserless utilizing Open Water Coiled Tubing (OWCT), the well control package including the strippers for dynamic control have to be modified to operate subsea and control both hydrostatic and wellbore conditions simultaneously.

[0006] Normally this equipment is hydraulically controlled to function subsea. Method of dynamic/static sealing of coiled tubing subsea for pipeline and well access with hydrostatic conditions up to 10,000 ft water depth while maintaining wellbore or pipeline pressures up to 10,000 psi. Current systems exist for surface application only and seal coiled tubing from wellbore or pipeline pressure with only ambient pressure at surface.

DRAWINGS [0007] Various figures are included herein which illustrate aspects of embodiments of the disclosed inventions.

[0008] Fig. 1 is a view in partial perspective of a first exemplary system;

[0009] Fig. 2 is a second in partial perspective of a second exemplary system; and

[0010] Fig. 3 is a view in partial perspective of an exemplary system showing a fluid source.

BRIEF DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0011] Referring now to Fig. 1, open water coiled tubing sealer 1, useful to control hydrostatic pressure and wellbore/pipeline pressures, comprises upper well control assembly 10, comprising a first geometric orientation; lower well control assembly 20 in fluid communication with upper well control assembly 10, where lower well control assembly 20 comprises a second geometric orientation substantially inverted to the first orientation; and quick disconnect connector 30 in fluid communication with upper well control assembly 10.

[0012] In typical embodiments, open water coiled tubing sealer 1 further comprises one or more electrically powered subsea assist jacks 40 which are operatively connected to quick disconnect connector 30 and a controller operatively in communication with the electrically powered subsea assist jack. Previously this equipment was to be hydraulically controlled (which is the industry norm). Typically, electrically powered subsea assist jacks 40 are controlled using three phase electric power and electric motors with a feedback loop of electronic communication over a power connector which may comprise or otherwise interface with umbilical 110 or the like. Thus, instead of hydraulic motors driving the jack cylinders, these would be replaced with electric motors utilizing a power converter operatively in communication with the power connector to handle the speed and direction through a main umbilical, such as umbilical 110, to subsea fluid source 100 which may be part of a subsea control skid.

[0013] The same thing could be done with one or more slip bowls, i.e. electric motors could replace hydraulic motors to activate and de-activate the slips. One or more electronic sensors, which can comprise proximity switches or similar equipment, can be utilized to provide feedback for control such as for closing and opening the slip bowls along with one or more position sensors to provide feedback on the position of the cylinders/roller bearing screw jacks, e.g. electrically powered subsea assist jacks 40, which are operatively connected to the electric motors.

[0014] Power and communication may be achieved through umbilical 120 to intervention system 200.

[0015] In certain embodiments open water coiled tubing sealer 1 further comprises one or more coiled tubing packers 50 disposed intermediate electrically powered subsea assist jacks 40 and quick disconnect connector 30.

[0016] Typically, upper well control assembly 10 comprises a plurality of control assemblies 12. Similarly, lower well control assembly 20 may also comprise a plurality of control assemblies 22 which may be the same as or similar to control assemblies 12. Where upper well control assembly 10 comprises the plurality of control assist assemblies 12, these may be arranged into pairs, which may be arranged redundantly and/or cooperatively or the like. Similarly, where lower well control assembly 20 comprises the plurality of control assist assemblies 22, these may also be arranged into pairs, which may be arranged redundantly and/or cooperatively or the like.

[0017] Upper well control assembly 10 may further comprise one or more inverted strippers 14. Upper well control assembly 10 may also further comprise one or more packer elements 16. Such packer elements 16 may be other otherwise comprise a subsea replaceable packer.

[0018] As illustrated in Figs. 1 and 2, quick disconnect connector 30 may be located intermediate strippers 14 and upper well control assembly 10 and a second quick disconnect connector, quick disconnect connector 31 (Fig. 2) may be optionally present and located intermediate electrically powered subsea assist jacks 40 and strippers 14.

[0019] Similarly, lower well control assembly 20 may comprise one or more strippers 24.

As with upper well control assembly 10, lower well control assembly 20 may also further comprise one or more packer elements 26 which may be other otherwise comprise a subsea replaceable packer.

[0020] In the operation of exemplary embodiments, hydrostatic pressure and wellbore/pipeline pressures may be controlled in a system that comprises subsea fluid source 100 which utilizes riserless open water coiled tubing system 1. In general, the method comprises operatively connecting open water coiled tubing sealer 1, as described above, to subsea fluid source 100 and an electrical power source and using upper well control assembly 10 and lower well control assembly 20 to pressurize a predetermined set of annular cavities existing between upper well control assembly 10 and lower well control assembly packer assembly 20. Hydrostatic pressure is then enabled to assist sealing upper well control assembly 10. Fluid pressure from subsea fluid source 100 may be used to assist sealing lower well control assembly 10. A predetermined amount of hydrostatic pressure may then be maintained with very low well/pipeline pressure and handling the subsequent differential pressure.

[0021] Hydrostatic pressure of up to a first pressure of around 4500 psi may be used.

Further, source fluid pressures from zero to around 10000 psi may be used. [0022] One or more pairs of bi-directional sealing elements may be set up in pairs as described above.

[0023] Where upper well control assembly 10 comprises a plurality of packer assemblies

16 with hydrostatic control assist and lower well assembly 20 comprises a plurality of packer units 25 which are adapted for assisting well control, the method further comprising using hydro- cushions to pressurize the annular cavities between the dual sets of packers.

[0024] Where the system further comprises subsea fluid source 100 such as a monoethylene glycol (MEG) fluid source or the like, the method may further comprise controlling the pressure using pairs of sealing elements with full backup for each system to enable the hydrostatic pressure to assist sealing the upper pair of packers and the wellbore pressure to assist sealing the lower pair of packers. In embodiments, full backup comprises using a duplicate set of sealing elements, each set of sealing elements further comprising one or more packers 16,26.

[0025] In embodiments, packers 16,26 may be replaced subsea, thereby allowing continuous operations without pulling open water coiled tubing sealer 1 back to surface to replace the packers.

[0026] It is noted that although various arrangements can be used, the basic arrangement is a first stripper/packer arranged in a first position relative to fluid flow and a second stripper/packer, essentially the same or similar to the first stripper/packer, fluidly coupled to the first stripper/packer but inverted with respect the first stripper/packer alignment. This can entail a plurality of each such stripper/packer units, e.g. two first stripper/packer assemblies with hydrostatic control assist and one or more second stripper/packer units for well control assist with hydro-cushions to pressurize the annular cavities between the dual sets of packers. By doing this, hydrostatic pressure is enabled to assist sealing the upper stripper/packers and the wellbore pressure to assist sealing the lower stripper/packers. It has been found that adding additional stages as described herein, splitting them into pairs, and then inverting one pair from the other so using ambient and well pressure to energize and seal.

[0027] As opposed to current systems for only surface application and seal coiled tubing from wellbore or pipeline pressure with only ambient pressure at surface, using the methods described above, dynamic/static sealing of coiled tubing subsea, such as for pipeline and well access, may be accomplished with hydrostatic conditions of up to around 10,000 ft water depth while maintaining wellbore or pipeline pressures up to around 10,000 psi.

[0028] The foregoing disclosure and description of the inventions are illustrative and explanatory. Various changes in the size, shape, and materials, as well as in the details of the illustrative construction and/or an illustrative method may be made without departing from the spirit of the invention.