Shell U.K. Limited May 2004 Brent Remote Flare Decommissioning Programme and Revision to the Brent Spar Decommissioning Programme (Anchor Blocks) SUBMISSION TO DTI & THE SECRETARY OF STATE, MINISTRY OF TRADE & INDUSTRY Keywords: Decommissioning, Remote Flare, Anchor Blocks, Brent This document is the property of Shell U.K. Limited, and the copyright therein is vested in Shell U.K. Limited. All rights reserved. Neither the whole nor any part of this document may be disclosed to others or reproduced, stored in a retrieval system, or transmitted in any form by any means (electronic, mechanical, reprographic recording or otherwise) without prior written consent of the copyright owner. Brent Remote Flare Decommissioning Programme & Revision to the Brent Spar Decommissioning Programme (Anchor Blocks) Page i 1 Contents 1 Contents ........................................................................................................................................................i 2 Introduction..................................................................................................................................................1 3 Executive Summary ....................................................................................................................................3 4 Items To Be Decommissioned ...................................................................................................................4 4.1Remote Flare............................................................................................................................................4 4.1.1 Description ................................................................................................................................4 4.1.2 Structure and layout..................................................................................................................4 4.1.3 History .......................................................................................................................................6 4.1.4 Present condition ......................................................................................................................7 4.2Anchor Blocks...........................................................................................................................................8 4.2.1 Description ................................................................................................................................8 4.2.2 Structure and arrangement.......................................................................................................8 4.2.3 History .....................................................................................................................................11 4.2.4 Present condition ....................................................................................................................11 4.3Associated pipelines and near-by facilities ............................................................................................12 4.3.1 Flare pipelines.........................................................................................................................12 4.3.1.1 Description ....................................................................................................................12 4.3.1.2 Present condition ..........................................................................................................12 4.3.1.3 Potential re-use opportunities for the pipelines ............................................................13 4.3.2 Brent Spar pipelines and subsea manifold .............................................................................13 4.3.2.1 Description ....................................................................................................................13 4.3.2.2 Present condition ..........................................................................................................13 4.3.3 Brent South pipelines and subsea facilities ............................................................................13 4.3.3.1 Description ....................................................................................................................13 4.3.3.2 Present condition ..........................................................................................................14 5 Environmental conditions ........................................................................................................................15 5.1Environmental assessment ....................................................................................................................15 5.2Fishing and other sea users ...................................................................................................................16 5.2.1 Commercial fisheries ..............................................................................................................16 5.2.2 Oil and Gas activity .................................................................................................................17 5.2.3 Shipping ..................................................................................................................................17 5.3Conservation status................................................................................................................................17 6 Inventory of materials ...............................................................................................................................19 7 Decommissioning Options .......................................................................................................................21 7.1Supporting studies and selection process..............................................................................................21 7.2Options for the Remote Flare .................................................................................................................22 7.3Options For The Anchor Blocks .............................................................................................................24 8 Selected Options .......................................................................................................................................27 8.1Introduction.............................................................................................................................................27 8.2Remote flare ...........................................................................................................................................27 8.2.1 Options subjected to detailed assessment .............................................................................28 8.2.2 Preferred options for removal of the remote flare ...................................................................37 8.3Anchor Blocks.........................................................................................................................................37 8.3.1 Options subjected to detailed assessment .............................................................................37 8.3.2 Preferred options for the removal of the Anchor blocks .........................................................42 February 2009 Brent Remote Flare Decommissioning Programme & Revision to the Brent Spar Decommissioning Programme (Anchor Blocks) Page ii 8.3.3 Potential re-use opportunities .................................................................................................42 8.4Safety .....................................................................................................................................................43 9 Environmental Impact Assessment.........................................................................................................45 9.1Introduction and method.........................................................................................................................45 9.2Results of the environmental assessment .............................................................................................45 9.2.1 Results ....................................................................................................................................46 9.2.2 Environmental risks specific to Flare Option F1.1 ..................................................................46 9.2.3 Environmental risks specific to Flare Option F5.1 ..................................................................46 9.2.4 Environmental risks specific to Flare Option F6 .....................................................................46 9.2.5 Conclusions for the flare tower ...............................................................................................47 9.2.6 Environmental risks specific to Anchor Block Option B1.1 .....................................................47 9.2.7 Environmental risks specific to Anchor Block Option B3.3 .....................................................47 9.2.8 Conclusions for the anchor blocks..........................................................................................47 9.3Energy ....................................................................................................................................................48 9.3.1 Results ....................................................................................................................................48 9.4Social impact assessment......................................................................................................................49