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NSRI: Support for the Developer Community

Ambient Lifting and Ballast Technology Update

23rd September 2015, Michael Cowie

Presentation Overview

•  Ecosse Subsea Systems

•  ESS Ethos

•  Imagine if……

•  Ambient Lifting Technology – theory and examples

•  Status of technology

Ecosse Subsea Systems

ESS is a Technology Based Company:

•  Established in 1996

•  100% Scottish owned

•  Initially O & G focused, diversified into Offshore Renewables

•  Core business:

Ø  Subsea engineering consultancy

Ø  Offshore contracting

Ø  Technology development and implementation

ESS Ethos

Provision of Subsea Services that are focused on being:

•  Safe

•  Simple

•  Robust

•  Cost-effective

Ø  Off-the Shelf Components

Ø  Negate the requirement for specialist vessels

Ø  Installable by local people and vessels

Ø  Recoverable, recyclable

Imagine if……..

•  Image installing a 450Te Foundation utilising a Multicat Vessel in extreme environmental conditions……

•  Imagine recovering a 600Te+ structure using an Anchor Handler vessel in remote locations……

This can be achieved with Ambient Lifting and Ballast Technology where:

Ø  Spread cost is more than halved

Ø  Weather risk is significantly reduced

Ø  Vessel choice is increased

Ambient Lifting

Ambient Lifting – General Overview

•  Ambient lifting is a flexible mechanism that allows you to control the ascent, descent and underwater positioning of offshore structures.

•  Innovative subsea lifting without use of heavy-lift vessels.

•  Ambient lifting can be used in a variety of industries including Oil & Gas, Decommissioning, Offshore Wind, Wave & Tidal Energy.

Ambient Lifting:

Theory Examples

9

Te

300Te

Neutrally Buoyant

•  Structure is designed to be buoyant when flooded with fluid

•  Structure is positioned over structure to be recovered

Structure INSTALLATION / RECOVERY Example

10

Te

•  Structure is neutrally buoyant•  Structure encloses over top of structure and

is locked in

300Te

Structure INSTALLATION / RECOVERY Example

11

Te

•  Fluid in receptacle is replaced by gas•  Structure is recovered to surface in a very

controlled manner

Structure INSTALLATION / RECOVERY Example

300Te

12

Te

250Te

0kg

•  In air structural weight

Structure FOUNDATION Example

Te

13

250Te

Neutrally Buoyant

250Te

250Te

•  In-water structural weight•  Buoyancy in receptacle designed

to ensure structure is neutrally buoyant

Structure FOUNDATION Example

14

Te

250Te

250Te

0-200Te

250Te

•  In-water weight increased by adding ballast material

•  Structure sinks to floor in a very controlled manner

Structure FOUNDATION Example

15

Te

250Te

250Te

250Te

200Te

•  Gas is replaced or compressed by fluid•  Now in-water structural weight plus

weight generated by water in receptacle•  Design ensures sufficient for temporary

stability

Structure FOUNDATION Example

16

Te

250Te

250kg

250Te

3 x Wt=600Te

•  Fluid is be replaced by denser fluid•  Fluid has SG = 3 and is pump-able•  On-bottom weight is trebled•  Structure is fit for extreme environmental

loading

Structure FOUNDATION Example

17

Te

•  Reverse process for recovery•  Fluid replaces heavy fluid

Structure FOUNDATION Example

18

Te

•  Structure is neutrally buoyant•  Structure is returned to surface in a

very controlled manner

Structure FOUNDATION Example

Te

19

250Te

Neutrally Buoyant

•  Structure on surface•  Can be towed to quayside for recovery

Structure FOUNDATION Example

Foundation Installation/Recovery Example

   Steel  Frame  (Lower  Sec/on)    

Lower  pipework  sec/on  (approx.  5000m)  

First  pipe  sec/on  loaded  to  Steel  Frame  on  quayside  and  secured    

Lower  sec/on  steelwork  and  pipework  loaded  in  to  water    

Mass   Buoyancy     Net  Upli2  

Second  pipework  sec/on  loaded  into  Steel  Frame  in  Quayside  water    

Mass   Buoyancy      

Net  Upli2      

Third  pipework  sec/on  loaded  into  Steel  Frame  in  Quayside  water    

Mass   Buoyancy      

Net  Upli2      

Upper  steelwork  aBached  to  Steel  Frame  in  Quayside  water    

Mass   Buoyancy     Net  Upli2  

BoBom  third  of  ABL  pipework  filled  with  SG  2.5  fluid  prior  to  tow  out.    

Mass   Buoyancy    

Net  Upli2      

50Te  external  ballast  added  to  frame  prior  to  tow  out.    

Mass   Buoyancy      

Net  Upli2      

Second  vessel  arrives  in  the  field  to  assist  in  ballas/ng  opera/ons.      

ABL  unit  is  aBached  to  both  vessel  winches.  The  unit  is  ballasted  via  the  control  umbilical  un/l  it  has  a  nega/ve  buoyancy  and  both  winches  are  showing  a  weight  of  5-­‐10Te.  

Vessels  simultaneously  pay  out  on  winches  to  lower  the  founda/on  to  the  seabed.      

Upon  laydown  on  the  seabed,  the  ABL  unit  can  be  fully  water  ballasted  and  then  disconnected.      

On  boBom  weight  when  fully  water  ballasted  with  boBom  third  filled  with  SG  2.5  fluid  External  Ballast=131Te    

   For  recovery  of  unit  the  removal  of  heavy  fluid  from  top  two  HDPE  sec/ons  gives  a  net  upliX  of  17Te  for  tow  back  to  port.  Reverse  Process  to  installa/on.    

Subsea Structure Recovery Example

Two  AHTS  vessels  are  implemented  for  the  removal  of  the  subsea  Structure  

19m  

4m  

LiX  connec/on  points  to  be  located  in  Structure  600Te  

The  ABL  unit  is  constrained  by  tow  chains  from  the  vessels.      

The  ABL  unit  ballasted  down  to  connect  to  the  Structure.  

ABL  aBached  to  the  Jacket  Foo/ng  using  the  mechanical  connectors  shown  on  following  slide.  

Male  por/on  aBached  to  underside  of  ABL  frame    

Female  por/on  to  be  placed  on  the  founda/on.  

Upon  connec/on,  buoyancy  is  added  to  ABL  unit  to  liX  Structure  from  the  seabed.    

The  unit  can  be  towed  by  a  single  vessel  to  port  for  decommissioning.      

Ambient Lifting – Status

Work to date: •  Technology is patent pending, submitted July 2014 •  Prototype constructed, 1:10 model

•  Test tank procured for ESS Workshop •  Successful prototype trials undertaken •  Trials witnessed by potential Clients •  Secured 1st Project – installation of gravity based foundation

•  450Te foundation being installed with multicats in extreme currents, Q1/Q2 2016

•  In discussions with a number potential Clients for Ambient Lifting as lifting systems and as removable foundations.

•  In discussions with Diving TA’s for Ambient Lifting as alternative to air-bags

Going forward: •  Renewables and Decommissioning focus •  Looking for demonstration opportunities and funding support

Thank you.

Michael Cowie – Technical Director

mcowie@ecosse-subsea.com