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NIMES |
New Improved Muds from Environmental Sources |
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A team of world leading industry and academic partners has joined forces in a £1.7m research and development project that will tackle a pressing environmental problem for offshore oil and gas exploration. The collaboration has been enabled through investment by the UK Technology Strategy Board who have invested over £800,000 in the project.
The multi-disciplinary team, led by Durham University, intends to develop new clay swelling inhibitors for use as drilling fluid additives. It is hoped that these improved additives will boost cost effective accessing of reserves, sustain and improve existing production and enhance the environmental requirements for production in the UK continental shelf. This project brings together M-I SWACO, the leading supplier of drilling fluids, with the combined expertise in molecular modelling at Durham University and University College London, visualization science at Technium CAST in North Wales, and the functionalisation of biodegradable polymers at Glyndŵr University. This innovative project combines computational science with natural polymer chemistry that will fast-track development of new drilling fluid additives. 
The project, which began in February 2008, will run for 3 years culminating in a field trial of the new additives in early 2011. |
(Oil Rig Photo Courtesy of M-I SWACO) 
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The Technology Strategy Board's role is to promote and support research into, and development and exploitation of, technology and innovation for the benefit of UK business, in order to increase economic growth and improve the quality of life. www.innovateuk.org NIMES Project Code Q2506L |
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CLAY SWELLING – A CHALLENGE IN THE OIL FIELD INDUSTRY
During the drilling of oil wells, technical drilling fluids comprising a range of chemicals and polymers are used. These technical fluids fulfil a variety of roles; they lubricate the drill bit, maintain hydrostatic pressure and suspend cuttings. In addition to this the fluid contains additives to prevent swelling of any clayey formations encountered. Clay swelling which occurs when reactive formations are exposed during well construction can have a significant adverse impact on drilling operations. The large increase in bulk volume occurring from clay swelling hinders the removal of cuttings away from the drill bit, increases friction between the bit and the borehole, and time based changes in the drilled formations can lead to unstable boreholes and lost time. Clay swelling and partial hydration may also result in “bit balling” or accretion of cuttings around the bottom-hole assembly; this can dramatically slow drilling and significantly increase well costs. Estimates for downtime financial loss owing to borehole instability problems vary, however a figure in excess of $500M per annum is often quoted. The development of even more effective clay swelling inhibitors is therefore an important goal to keep well costs down and enhance the attractiveness of UK oil field development to international operators. PROTECTING THE MARINE ENVIRONMENT Oil based drilling fluids offer excellent technical performance but these fluids and cuttings contaminated with them must be fully contained. There is an associated cost for cuttings remediation, waste stream processing and compliance testing, all of which must be considered in the economics of the wellbore construction process. The risk of spills and therefore potential environmental damage remains a concern. For these reasons, water based systems are likely to remain the preferred choice on environmental grounds. Clay swelling and wellbore instability problems have been significantly reduced with the introduction of new chemistry by M-I SWACO, the NIMES lead industry partner, in the latest generation high performance water based fluids. However, even better technical performance and improved biodegradation to comply with further tightening of environmental legislation are key targets of this project. DEVELOPING IMPROVED SWELLING INHIBITORS: COMPUTER AIDED DESIGN Owing to the disordered nature of clay minerals, and the variability of natural clay composition, laboratory based analysis of swelling inhibitors in these minerals is highly challenging. With recent advances in computational hardware, and the development of increasingly efficient algorithms, computer simulation has become an extremely useful tool for understanding the underlying principles behind how swelling inhibitors interact with clay minerals. The NIMES team will use the latest developments in scientific computing to inform the synthesis of new and improved swelling inhibitors with increased biodegradability. This combined computer/experimental approach is an efficient and far “greener” process, cutting down on the synthesis of the large number of molecules necessary in a typical trial and error search. |
(Oil Rig Photo Courtesy of M-I SWACO) 
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