SNS PHASE 1 DECOMMISSIONING PROJECT ENVIRONMENTAL STATEMENT FOR THE SNS DECOMMISSIONING PROJECT: VIKING VDP1 AND LOGGS LDP1 SEPTEMBER 2015 REVISION C3 BMT-SNS-P-XX-X-HS-02-00006 Environmental Statement for the SNS Phase 1 Decommissioning Project: Viking VDP1 and LOGGS LDP1 This page is intentionally blank BMT-SNS-P-XX-X-HS-02-00006 Environmental Statement for the SNS Phase 1 Decommissioning Project: Viking VDP1 and LOGGS LDP1 Information Sheet Environmental Statement for the SNS Phase 1 Decommissioning Project Name: Project: Viking VDP1 and LOGGS LDP1 Type of Project: Decommissioning Undertaker Name: ConocoPhillips (U.K.) Limited Rubislaw House Anderson Drive Address: Aberdeen AB15 6FZ ConocoPhillips (U.K.) Limited plans to decommission a number of assets in the southern North Sea (SNS). This Environmental statement details the findings of the Environmental Impact Assessment (EIA) conducted by ConocoPhillips (U.K.) Limited in support of its two decommissioning Programmes, Viking Decommissioning Programme 1 (VDP1) and Lincolnshire Offshore Gas Gathering Systems (LOGGS) Decommissioning Short Description: Programme 1 (LDP1) which form part of its phased decommissioning of its SNS assets. This EIA will support two decommissioning programmes (DPs). The infrastructure to be decommissioned and included as part of VDP1 and LDP1 is located in the United Kingdom continental shelf (UKCS) Blocks 48/25, 49/16, 49/17 and 49/21 and comprises 16 pipelines, eight satellite platforms and associated subsea structures and protection. Anticipated commencement of Q4 2015 works: This ES supports two Decommissioning Programmes: Other documents relative to this VDP1: COP-SNS-V-XX-X-PM-12-00001 project LDP1: COP-SNS-L-XX-X-PM-12-00001 Significant Environmental Impacts None Identified: Statement Prepared By: ConocoPhillips (U.K.) Limited and BMT Cordah Limited BMT-SNS-P-XX-X-HS-02-00006 Environmental Statement for the SNS Phase 1 Decommissioning Project: Viking VDP1 and LOGGS LDP1 This page is intentionally blank BMT-SNS-P-XX-X-HS-02-00006 Environmental Statement for the SNS Phase 1 Decommissioning Project: Viking VDP1 and LOGGS LDP1 TABLE OF CONTENTS ABBREVIATIONS, ACRONYMS AND UNITS ............................................................................... vii GLOSSARY ..................................................................................................................................... xi NON-TECHNICAL SUMMARY ....................................................................................................... xv 1.0 INTRODUCTION .......................................................................................................... 1-1 1.1 Viking Area Overview .................................................................................................... 1-1 1.2 LOGGS Area Overview ................................................................................................. 1-3 1.3 Purpose of the Environmental Impact Assessment ...................................................... 1-4 1.4 Regulatory Context ....................................................................................................... 1-4 1.5 Report Structure ............................................................................................................ 1-6 2.0 METHODOLOGY ......................................................................................................... 2-1 2.1 Environmental Impact Assessment Process ................................................................ 2-1 2.1.1 Scoping ....................................................................................................................................... 2-3 2.1.2 Cumulative and transboundary impacts ...................................................................................... 2-3 2.2 Comparative Assessment ............................................................................................. 2-4 3.0 PROJECT DESCRIPTION ........................................................................................... 3-1 3.1 Overview ....................................................................................................................... 3-1 3.1.1 Viking area .................................................................................................................................. 3-1 3.1.2 LOGGS area ............................................................................................................................... 3-3 3.2 Consideration of Alternative Use for the VDP1 and LDP1 Facilities ............................ 3-5 3.3 Scope of the Proposed Decommissioning Operations ................................................. 3-5 3.4 Description of the VDP1 and LDP1 Facilities ............................................................... 3-6 3.4.1 Platforms ..................................................................................................................................... 3-6 3.4.2 Topsides ..................................................................................................................................... 3-8 3.4.3 Jackets ........................................................................................................................................ 3-8 3.4.4 Pipelines and subsea structures ................................................................................................. 3-9 3.4.5 Wells ......................................................................................................................................... 3-12 3.5 Inventory of Materials .................................................................................................. 3-15 3.5.1 VDP1 facilities ........................................................................................................................... 3-15 3.5.2 LDP1 facilities ........................................................................................................................... 3-15 3.6 Overview of the Options Available for VDP1 and LDP1 Activities .............................. 3-20 3.6.1 Topside removal options ........................................................................................................... 3-20 3.6.2 Jacket removal options ............................................................................................................. 3-21 3.6.3 Pipeline decommissioning options ............................................................................................ 3-22 3.6.4 T-piece removal options ............................................................................................................ 3-24 3.6.5 Mattress removal options .......................................................................................................... 3-24 3.6.6 Well P&A ................................................................................................................................... 3-25 3.7 Overview of the VDP1 and LDP1 CA Process ........................................................... 3-26 3.8 Preparatory Work for Decommissioning the VDP1 and LDP1 Facilities .................... 3-27 3.8.1 Topsides ................................................................................................................................... 3-30 3.8.2 Jackets ...................................................................................................................................... 3-30 3.8.3 Pipelines ................................................................................................................................... 3-31 3.8.4 Mattresses ................................................................................................................................ 3-32 3.8.5 T-piece ...................................................................................................................................... 3-32 3.9 Selected Decommissioning Options for the VDP1 and LDP1 Facilities ..................... 3-32 BMT-SNS-P-XX-X-HS-02-00006 i Environmental Statement for the SNS Phase 1 Decommissioning Project: Viking VDP1 and LOGGS LDP1 3.10 Debris Clearance at the VDP1 and LDP1 Decommissioned Areas ........................... 3-33 3.10.1 Seabed clearance survey .......................................................................................................... 3-33 3.10.2 Verification of seabed clearance ............................................................................................... 3-33 3.10.3 Final condition of the offshore site ............................................................................................ 3-33 4.0 ENVIRONMENTAL BASELINE ................................................................................... 4-1 4.1 Pre-Decommissioning Environmental Baseline Surveys (EBS) ................................... 4-1 4.1.1 Bathymetry .................................................................................................................................. 4-3 4.1.2 Seabed sediments and chemistry ............................................................................................... 4-4 4.2 Physical Environment ................................................................................................... 4-9 4.2.1 Waves ......................................................................................................................................... 4-9 4.2.2 Water circulation and tides .........................................................................................................