Wednesday, 14 May, 0830–0900
Salima Baraka-Lokmane holds a PhD in hydrogeology from the University of Tübingen in Germany. On completion of her PhD she was appointed for eight years as a research fellow at Edinburgh University and Heriot-Watt University in Scotland. She then worked for four years as senior lecturer in hydrogeology at the University of Brighton in England. Baraka-Lokmane joined Total in 2011. She is a scale specialist for Total Headquarters in Pau, France. She has more than 30 published papers on fluid flow and transport in fractured porous rocks, reservoir characterisation, microscale characterisation of sandstone and carbonate cores and oilfield scale.
Experience on the Development and Implementation of a Scale Management Strategy in Central Graben Fields
In the Central Graben area of the North Sea, most of the produced water is condensed but wells have still been treated against scale buildup at the perforations using acid washes. Some wells showed productivity improvement, while others showed limited success. This paper demonstrates that these behaviours are linked with the lithology of the different reservoirs. The study indicated that calcium carbonate and sodium chloride are the only scale deposits susceptible to precipitate at bottomhole conditions. High temperatures at the bottom holes induced the formation of calcium carbonate precipitation, and Joule-Thomson cooling led to halite precipitation. From the subsurface safety valve (SCSSV) to the surface facilities, the reduction of temperature caused a reduction of solubility of zinc sulphide and lead sulphide. In terms of chronology, halite scale occurred first, followed by carbonate scale and finally formation of sulphide scale at a lower temperature. This keynote address will explore these findings in greater detail.
Session 1: Case Histories
Room: Gordon A
Session Chairs: Stephen Heath, NALCO Champion, an Ecolab Company and Helen Williams, Scaled Solutions
Guest Chair: Penille Raahauge, Maersk Oil
Publication of case histories are a crucial way in which the industry can learn, not only from success but also from failures. This session highlights powerful case histories that focus on scale deposition in condensate wells as well as pre-emptive squeeze treatments in deepwater environments. A third, and more theoretical case history reviews scaling in carbonate reservoirs based upon interpretation of a large water-injection dataset. This well-rounded set of case histories will prove valuable to many disciplines concerned with scale formation and provide a solid opening introduction to the conference.
Session 2: Innovative Solutions to Scale Control I
Room: Gordon A
Session Chairs: Myles Jordan, NALCO Champion, an Ecolab; Company and Nicole Williamson, BP
Guest Chair: Lana Armstrong, Solvay
This session discusses improvements to predictive tools using new laboratory data for application to more extreme physical and geochemical conditions and the benefits of multidisciplinary teamwork. Papers include improvements to the thermodynamic modelling of calcium carbonate and calcium sulphate at HP/HT; an investigation into the formation and inhibition of silica scale in steam floods; and the combined contribution of six companies to developing a squeeze strategy for a high-angle, multizone well with complex constraints. Innovation plays a part in each of these presentations and highlights how it is still very much alive in the oilfield scale discipline.
Session 3: New Perspectives for Scale Control and Management
Room: Gordon A
Session Chairs: Ross McCartney, Oilfield Water Services; Limited and Ying Xu, ConocoPhillips
Guest Chair: Eyvind Sørhaug, Talisman
This session will introduce new perspectives on scale control and management including development of geochemical models based on extensive brine chemistry data from an offshore field and its use to predict produced brine compositions in order to evaluate production well scale risk. Presentations will also be made on the use of nanotechnology to enhance squeeze lifetime, and experimental as well as modeling study on enhancement of squeeze treatment in sandstone by addition of zinc ion.
Session 4: Emerging Chemistries and Technologies
Room: Gordon A
Session Chairs: Hua Guan, OneSubsea and Gill Ross, Shell;
Guest Chair: Craig Cummine, Talisman Sinopec
This session covers a range of papers on upcoming technologies and emerging chemistries, including new test methodologies which allow the impact of shear and turbulence on scale precipitation to be observed under representative production conditions. It includes new insights for HP/HT fields on the impact on scale dissolver treatments, including reasons why high-temperature re-precipitation of scale leads to inevitable failures.
Scale inhibitors are intensively tested under turbulent conditions using new test methods with Reynolds numbers up to 34,000. Subsequently, new insights into inhibition mechanisms under such conditions are provided in the third paper.