For every barrel of extracted oil, there are on average up to three barrels of water being produced. This unwanted but unavoidable water production gives rise to a number of problems; not only it adds costs to oil production, it also increases a potential environmental impact arising from the disposal of this produced water. Globally, the costs of water production are estimated to reach 40B€/year. As a result of this, over 90% of active oil wells are now under some degree of water control. As oilfields mature, such as in many parts of the North Sea, water production increases, and with it production costs. There is thus an interest in tackling some of the problems associated with water production and in particular scale formation. We propose to develop a prototype device for measuring calcium, strontium and barium ions at high temperature and high pressure allowing it to be deployed initially on a tool string, and operated in-site within the well. The development of this sensor will build upon our expertise in reservoir characterisation and monitoring, but will raise a number of scientific challenges, which will require basic research. We intend to build a prototype electrochemical sensor based upon amperometry. The purpose of the fellowships is to conduct research related to the effective management of oilfield mineral scales. The formation of mineral scales in production and surface facilities in oilfields leads to lowered oil production from many reservoirs. The fellows will work within a multidisciplinary and multinational team developing an electrochemical detector for those ions mainly responsible for scale formation. Schlumberger Cambridge Research is part of the Schlumberger group, an international company offering oil field services throughout all phases of oil and gas exploration and production. The Centre at Cambridge carries out fundamental and applied research directed towards new products and services for improving the efficiency of hydrocarbon recovery operation cost effectively, safely and without harming the environment. The candidates should have an excellent PhD in experimental physical or analytical chemistry, ideally, though not necessarily with some experience in electrochemical methods. The candidates must be dynamic, have excellent communication skills, and be good team players. Schlumberger is committed to employee diversity.