Pipeline Replacement Project

 

17 March 2011 London Evening Meeting

Chairman Dr Bob Allwood, Chief Executive, SUT

Sponsored by Flexlife

 

Report

 

Flyer

 

Overview

In early January 2011, the 14" flowline between Forties Bravo (FB) and Forties Charlie (FC) platforms developed a leak in the vicinity of the FC platform. Several repairs were undertaken, however, new leaks occurred in the line at each pressure test after repairs. It was decided to cut out and remove a 10m section of the line for further examination and analysis to determine the cause of its failure. On removing this section, a Smart flanged section was put in its place. Unfortunately during the pressure test new failures were identified and it was therefore decided to retire the line altogether.

In order to mitigate both valuable production and associated financial losses, a decision was taken to provide a temporary connection between FB and FC, by re-routing the currently existing 8” produced water flexible injection line (PWRI) also running between FB and FC, which allowed for re-instatement of hydrocarbon transport. This work was extremely fast track and production was restored by using this measure on 6th March 2011.

A number of options were considered for the permanent line replacement. It was concluded that the temporary connection will be replaced by a permanent, trenched and buried 14” flexible pipeline, the design of which has already been approved; its fabrication and installation to be executed over the next 4 to 6 months.

 

Presentations

Apache Forties – Bravo to Charlie Pipeline Replacement Project and Interim Production through PWRI

The evening’s presentation was split into two portions. The first section presents the interim findings of the materials and corrosion examination and analysis including photographic evidence showing the failure modes in the line. This was presented by David Newman, Flexlife Asset Integrity Manager.

Following on from this, a presentation detailing the subsea campaigns since early January 2011 culminating in the novel rerouting of the produced water line (PWRI) and its connection into the Bravo – Charlie system was given by Paul Williams who is a Project Manager with Flexlife and was directly responsible for these works.

 

Subsea Solutions for Arctic in Extreme Weather Environments

 

9 March 2011 Aberdeen Branch Evening Meeting

Chairman Adrian Phillips

 

Report

 

Flyer

 

Overview

Excitement continues to grow around the prospects of major exploration and development in and around the arctic continental shelf. Russian gas giant Gazprom is voicing optimism about the prospects for a final investment decision this year in favour of the landmark Shtokman gas and liquefied natural gas development in the Barents Sea. The Shtokman offshore field is a joint project controlled by Gazprom with France’s Total and Norway’s Statoil as minority shareholders. The other major Russian player Rosneft is already talking to "global players" about exploration ventures in Russia’s Barents Sea and the Asian part of Russia’s Arctic waters. This follows major joint ventures signed last month to explore in the Arctic’s South Kara Sea with BP and in the Black Sea with ExxonMobil.

 

Presentations

Subsea Arctic Pipelines: Key to Successful Field Developments

Glenn Lanan, Intecsea

Hydrocarbon transportation is one of the controlling requirements for offshore Arctic field development and pipelines are often required for intrafield flowlines, export to shore-based facilities or for tanker loading systems. The offshore Arctic environmental and loading conditions provide unique challenges for conventional subsea pipeline technology. INTECSEA summarised the increasing industry experience with pipeline design, construction and operation in ice covered waters and highlighted some of the remaining challenges such as optimised design for ice loadings and subsea leak detection.

 

ENI Goliat Subsea Development

Richard Carter, Aker Solutions

Following Statoil’s pioneering and record breaking subsea project, Snohvit, the next major subsea development in the same area is ENI’s Goliat. Statoil opted for a 140km "long offset", whilst ENI have chosen for an FPSO. Aker Solutions provided some insights on the reason for the decision whilst offering a perspective on the engineering challenges of the subsea solution.

 

Recent Advances in Satellite Remote Sensing for Ice Monitoring

Nicholas Walker, eOsphere

Satellite remote sensing can provide useful information for operators working in ice infested waters, including information about ice extent, ice type, ice motion and icebergs. Recent advances in satellite SAR technology allow additional information to be extracted for successful ice monitoring. These new capabilities include improved resolutions, improved polarimetric and radar frequency options.

 

Geophysics and Geohazards – Defining Subsea Engineering Risk

 

24 February 2011 Joint SUT and ASEG International Seminar, Subsea Australasia Conference 2011,

Perth, Australia

 

Report

‘Geophysics and Geohazards – Defining Subsea Engineering Risk’, a joint SUT and ASEG one-day seminar, was held in Perth on the 24th February 2011 as part of the Australasian Oil and Gas (AOG) Exhibition and Conference. An almost full house ensured this second conference, which first took place in March 2010, was truly successful.

After the usual formalities including the thanks to Fugro as the principal sponsor, Dan McConnell, VP Marine Consulting, AOA Geophysics, gave the keynote presentation, ‘On Marine Seep Hunting for Oil and Gas Exploration’. The use of a combination of multibeam echo sounder bathymetry and backscatter data with accurately placed piston cores at the seep sites to directly sample a petroleum system was described. An astounding 46% of the targets showed unambiguous thermogenic gas and 13% showed evidence of migrated liquid petroleum.

Stephen Wardlaw, Business Development Consultant, Fugro Geoconsulting Pte Ltd, then described how autonomous underwater vehicles (AUVs) are now routinely utilised in deepwater site investigations for oilfield developments. Drawing on examples, Stephen’s paper reviewed the contribution from the various AUV instruments, and discussed techniques currently used in AUV data integration in the assessment of engineering geohazards.

The use of marine resistivity surveys on dredging projects, and cable and pipe route surveys to assist in port design and alluvial mining projects was described by Dr Ir Peteralv Brabers, General Manager, Demco NV (Belgium). Dr Ir Brabers provided an insight into the theory of resistivity principles and a brief comparison between acoustic methods and marine geo-electric methods.

After the morning tea and coffee break, Dr Ouzani Bachir, Geoscientist, Offshore Geo-Survey Sdn Bhd, discussed deepwater geohazards characterisation. Unlike the continental shelf where geohazards are well documented and site investigation methods are established, deepwater environments are unfamiliar and lack well logs and borehole data. The use of seismic inversion and amplitude versus offset (AVO) analysis for shallow water flows and gas hydrates assessments was discussed.

Dan McConnell returned to the podium to describe his involvement in the DOE-Chevron Joint Industry Gas Hydrate Project in the Gulf of Mexico, 2009 (Leg II). The three-week, $11.5m expedition drilled seven logging-while-drilling (LWD) holes at three sites that tested a variety of geologic/geophysical models for the occurrence of gas hydrate in sand reservoirs in the deepwater Gulf of Mexico.

The lunch break and an opportunity to visit the exhibition was followed by a description by Bachir Ouzani on how the iCUBE 3D volumes converted from 2D seismic lines shot at 50–500m spacing provide increased data density and allowed improved lateral geological continuity and definition of geological structures.

Dr Steve Tyler, Principal Geophysicist, Fugro Survey Pty Ltd, then described how data from a geohazard and environmental baseline survey within the Bonaparte Basin confirmed a barrier reef complex extended from the Sahul Platform through to the Ashmore reef area approximately 18 000 years ago. The geophysical data highlighted the structural complexity of this area with a significant number of pockmarks identified around the flanks of these outcropping palaeo-reefs.

A system of faults extending along the west coast and up to the North West Shelf was described by James Hengesh, Research Fellow, University of Western Australia (UWA). A magnitude 7.3 earthquake, the largest in Australia’s history, occurred along one of these faults, and other faults have the potential to produce similar large magnitude events. Work is underway at UWA to better understand the hazard posed by these faults and to incorporate them in future seismic hazard assessments for major infrastructure projects in Western Australia.

Dr Douglas Bergersen, CEO/Geophysicist, Acoustic Imaging, described the oil and gas industry desire to standardise the presentation of baseline marine survey data for better long- term management of information across offshore development areas. One such template for the storage of information is the Seabed Survey Data Model (SSDM) based around the ArcGIS geodatabase structure. Dr Bergersen’s paper presented an overview of the integration to date and discussed how software tools may be used to assist and optimise the identification, characterisation and quantification of marine geohazards. The seamless transfer of information to the SSDM was illustrated with a case example from the North West Shelf of Australia.

 

Subsea Hot Taps

 

8 June 2011 Aberdeen Branch Evening Meeting

Chairman James Woods, Subsea Execution Team Lead, Shell UK

Sponsored by Subsea 7

 

Flyer

 

Overview

Since the start of the modern subsea offshore oil industry the requirement to join, modify and extend pipelines underwater has been an operational requirement. As a consequence ‘Hyperbaric’ habitat welding evolved and once the technique reached an acceptable level of reliability it was extended to enable ‘Hot Taps’ to be performed. Hot tapping is a method of making a connection to a pipeline whilst the pipe remains pressurised and without interruption to the normal flow or operating regime of the pipeline, and has been carried out extensively subsea since the mid to late 70’s.

Hot tapping has traditionally been carried out manually by divers, although some automatic systems have been used in the past. However, now we have entered an era of ever deeper water depths outside the range of divers, and necessity, being the mother of invention, has promoted new remote and innovative systems.

The evening’s speakers covered traditional hot tapping, remote hot tapping and a non- welded system of hot tapping, and aimed to bring the audience up to date with current hot tap developments. In addition, a Tech Byte covered some of the available inspection techniques for the processes.

 

Presentations

Subsea Hot Tap Experiences by Technip Norge AS 2007–2010

Geir Leden, Principal Engineer – Technip Norge AS

Technip Norge AS has in the period 2007–2010 completed three projects with subsea hot tap operations. Hot tapping has been carried out by use of both diver operated and remotely operated drilling machines in water depths ranging from 95 to 845 meters. A total of six hot taps have been performed, three hot taps through welded tees and three hot taps through pre-installed flanges. This presentation showed the basic concept of Hot Tapping as well as a description of some of the specific challenges that have occurred during the three projects.

 

World’s First Deep Water Remote Hot Tap

Keith Evans, MD  – Clear Well Subsea Limited

Aberdeen based Clear Well Subsea have provided a unique hot tapping solution to Norwegian state oil company Statoil. As part of the Ormen Lange South Development, located in almost 1000m of water, Statoil required two new connections to the existing 30” gas export pipelines. The two hot taps constitute the first successful use of the remote hot tapping system in deep water and were performed at pressures and temperatures well beyond the capability of existing designs enabling the team to claim a number of world firsts. This presentation explained the evolution and implementation of the unique technology developed by Clear Well Subsea.

 

Tech Byte – Subsea Automated Ultrasonic NDT Inspection of Hot Tap Welds

Craig Emslie, Integrity Services Manager – Sonomatic Aberdeen

Sonomatic is a specialised inspection company who has been involved in a number of subsea hot tap campaigns. Their involvement has been focused on conducting specialised inspection, from measuring the profile of the pipeline prior to securing the hot tap, to inspection of field welds prior to connecting to the pipeline. This short presentation presented an overview of the inspections that Sonomatic has conducted and recent developments in ROV deployed inspection tools.

 

Subsea 7 Grouted Tee Hot Tap Technology

Dan Vu, Engineering Manager – Life of Field Services

Grouted Tee technology was developed for hot tapping onto cross country transmission pipelines in the late 1990s. It is now a proven and accepted method for carrying out live intervention on gas and oil pipelines. In 2009, Subsea Grouted Tee™ (SSGT) was successfully developed for subsea pipelines at diver depths. This presentation described the mechanics of Grouted Tee hot tap technology on subsea pipelines and provided high level technical, safety and time comparisons over the traditional welded and mechanical options. It also outlined a further design consideration enabling diverless hot tap operations in deep and ultra deep water environments.