SUBSEA TRANSITION SYSTEM

1 . Method of remotely facilitating the transition between hydrotesting and dewatering of a subsea pipeline initiated from the launch end of the pipeline without the involvement of an external source at the surface, or a UV, at the pig receiving end of the pipeline, the method comprising:

fluidly coupling a fluid flow conduit of an automated, self-powered, self-controlled subsea valve actuation system to the subsea pipeline at the pig receiving end thereof;

a control unit of the subsea valve actuation system disallowing fluid flow through the fluid flow conduit out of the pipeline at the pig receiving end thereof during hydrotesting of the pipeline;

at least one pressure transducer fluidly coupled to the fluid flow conduit detecting one or more pressure changes in the fluid flow conduit;

at least one of the pressure transducers emitting at least one signal relating to at least one pressure change in the fluid flow conduit;

based at least partially upon one or more signals emitted by at least one of the pressure transducers and without the involvement of an external source at the surface, or a UV, at the pig receiving end of the pipeline, the control unit determining whether hydrotesting of the pipeline has been completed; and

if the control unit determines hydrotesting of the pipeline has been completed, the control unit autonomously causing at least one flow isolation valve fluidly coupled to the fluid flow conduit to open without the involvement of an external source at the surface, or a UV, at the pig receiving end of the pipeline, allowing fluid to exit the pipeline to the sea through the fluid flow conduit to allow dewatering the pipeline from the launch end of the pipeline.

2 . The method of claim 1 further including

a pipeline servicing system connected to the launch end of the pipeline initiating a particular pressure change or sequence in the pipeline at the end of hydrotesting of the pipeline or to signal the pipeline is ready for dewatering without the involvement of an external source at the surface, or a UV, at the pig receiving end of the pipeline,

the at least one pressure transducer detecting the particular pressure change or sequence initiated by the pipeline servicing system and emitting at least one signal relating to the particular pressure change or sequence,

based at least partially upon the signal(s) emitted by the pressure transducer(s) relating to the particular pressure change or sequence and without the involvement of an external source at the surface, or a UV, at the pig receiving end of the pipeline, the control unit autonomously causing at least one flow isolation valve fluidly coupled to the fluid flow conduit to open without the involvement of an external source at the surface, or a UV, at the pig receiving end of the pipeline, allowing fluid to exit the pipeline to the sea through the fluid flow conduit to allow dewatering the pipeline from the launch end of the pipeline.

3 . The method of claim 1 further including pre-programming the control unit to recognize one or more particular pressure readings or changes based upon one or more signals emitted by the at least one pressure transducer to signify hydrotesting of the pipeline has been completed and autonomously causing at least one flow isolation valve fluidly coupled to the fluid flow conduit to open without the involvement of an external source at the surface, or a UV, at the pig receiving end of the pipeline, allowing fluid to exit the pipeline to the sea through the fluid flow conduit to allow dewatering the pipeline from the launch end of the pipeline.

4 . The method of claim 1 further including

after the completion of hydrotesting, a pipeline servicing system connected to the launch end of the pipeline pumping fluid into the pipeline to detect whether the control unit has opened at least one flow isolation valve, and

if the pipeline servicing system detects one or more of the flow isolation valves is open, the pipeline servicing system initiating dewatering of the pipeline from the launch end thereof without the involvement of an external source at the surface, or a UV, at the receiving end of the pipeline.

5 . The method of claim 1 further including

dewatering the pipeline from the launch end thereof without the involvement of an external source at the surface, or a UV, at the pig receiving end of the pipeline,

during dewatering of the pipeline, the subsea valve actuation system remotely, selectively, autonomously analyzing one or more samples of fluid exiting the subsea pipeline at the pig receiving end of the pipeline during dewatering and/or collecting samples of fluid exiting the subsea pipeline at the pig receiving end for further analysis without the involvement of an external source at the surface, or a UV, at the pig receiving end of the pipeline.

6 . The method of claim 5 further including the control unit receiving data about one or more of the samples of fluid analyzed during dewatering and transmitting such data to at least one recipient on a real-time basis.

7 . Method of remotely facilitating the successive transitions between flooding, hydrotesting and dewatering of a subsea pipeline initiated from the launch end of the pipeline, the pipeline having a launch end and an opposing pig receiving end, the method comprising:

fluidly coupling a fluid flow conduit of an automated, self-powered, self-controlled subsea valve actuation system to the subsea pipeline at the pig receiving end thereof;

allowing fluid to exit the pipeline to the sea through the fluid flow conduit during flooding of the pipeline;

a control unit of the subsea valve actuation system determining whether flooding of the pipeline has been completed;

if the control unit determines flooding of the pipeline has been completed, the control unit autonomously causing at least one flow isolation valve fluidly coupled to the fluid flow conduit to close without the involvement of an external source at the surface, or a UV, at the pig receiving end of the pipeline, disallowing fluid from exiting the pipeline at the pig receiving end thereof to fluidly isolate the pipeline for hydrotesting;

hydrotesting the pipeline from the launch end thereof;

the control unit determining whether hydrotesting of the pipeline has been completed; and

if the control unit determines hydrotesting has been completed, the control unit autonomously causing at least one flow isolation valve fluidly coupled to the fluid flow conduit to open without the involvement of an external source at the surface, or a UV, at the pig receiving end of the pipeline, allowing fluid to exit the pipeline to the sea at the pig receiving end thereof for dewatering of the pipeline from the launch end of the pipeline.

8 . The method of claim 7 further including

allowing at least one pig to pass through the pipeline to the pig receiving end thereof during flooding of the pipeline, and

the control unit, without the involvement of an external source at the surface or a UV at the pig receiving end of the pipeline, determining that flooding of the pipeline has been completed and the pipeline is ready for hydrotesting based at least partially upon the arrival of at least one pig at the receiving end of the pipeline at the end of flooding the pipeline.

9 . The method of claim 7 further including the control unit determining when hydrotesting of the pipeline has been completed based upon at least one detected pressure change in the fluid in the pipeline and fluid flow conduit at the pig receiving end of the pipeline.

10 . The method of claim 7 further including

dewatering the pipeline from the launch end thereof without the involvement of an external source at the surface, or a UV, at the pig receiving end of the pipeline,

during dewatering of the pipeline, the subsea valve actuation system remotely, selectively, autonomously analyzing one or more samples of fluid exiting the subsea pipeline at the pig receiving end of the pipeline during dewatering and/or collecting samples of fluid exiting the subsea pipeline at the pig receiving end for further analysis without the involvement of an external source at the surface, or a UV, at the pig receiving end of the pipeline.

11 . The method of claim 10 further including the control unit receiving data about one or more of the samples of fluid analyzed during dewatering and transmitting such data to at least one recipient on a real-time basis.

12 . A self-powered, self-controlled, automated subsea valve actuation system for remotely facilitating the successive transitions between flooding, hydrotesting and dewatering of a subsea pipeline initiated from the launch end of the pipeline, the automated subsea valve actuation system comprising:

a retrievable skid frame;

a fluid flow conduit mounted at least partially on said skid frame and fluidly coupled to the subsea pipeline at the pig receiving end thereof;

at least one flow isolation valve fluidly coupled to said fluid flow conduit, said at least one flow isolation valve being moveable between at least one open position and a closed position, wherein said at least one flow isolation valve in said at least one open position allows fluid to exit the pipeline at the pig receiving end of the pipeline through said at least one fluid flow conduit, and at least one said flow isolation valve in said closed position disallows fluid flow out of the pipeline at the pig receiving end thereof, said at least one flow isolation valve being in at least one said open position during flooding of the pipeline;

at least one pig configured to move through the pipeline to the pig receiving end thereof during flooding of the pipeline and emit one or more signals;

a control unit mounted on said skid frame and configured to selectively, remotely, autonomously move at least one said flow isolation valve from at least one said open position to said closed position when flooding of the pipeline has been completed based at least partially upon one or more of said signals emitted by said at least one pig without the involvement of an external source at the surface, or a UV, at the pig receiving end of the pipeline to allow hydrotesting of the pipeline, said control unit also being configured to determine when hydrotesting of the pipeline has been completed and thereafter autonomously move at least one said flow isolation valve from said closed position to at least one said open position without the involvement of an external source at the surface, or an UV, at the pig receiving end of the pipeline, allowing fluid to exit the pipeline through said fluid flow conduit to the sea to allow dewatering of the pipeline from the launch end of the pipeline; and

at least one battery associated with said skid frame and configured to provide sufficient power to said control unit for facilitating the successive transitions between flooding, hydrotesting and dewatering of the pipeline without power being supplied to said skid frame from an external source at the surface, or a UV, at the pig receiving end of the pipeline.

13 . The subsea valve actuation system of claim 12 wherein at least one of said signals of said pig relates to the arrival of said pig at the pig receiving end of the pipeline.

14 . The subsea valve actuation system of claim 12 wherein said at least one pig is an intelligent pig configured to evaluate the condition of the interior of the pipeline as it passes therethrough and at least one of said signals of said intelligent pig relates to the condition of the interior of the pipeline.