Large volumes of produced water are being discharged globally as byproducts of oil production. Commercial production chemicals are conventionally needed to avoid problems such as bacterial growth, pipe corrosion, and oil/water separation issues. These chemicals will partition between oil and water phases and may affect both treatment processes and the environmental impact when water is discharged to the ocean after treatment. Capillary zone electrophoresis is used to measure partitioning coefficients of oilfield chemicals when these are dissolved in the water phase and in contact with either octanol or crude oil. The technique is fast and, due to simplicity, could have merits as on-site assessment of the partition coefficient for direct assessment of the fate of chemicals. The method was first qualified by estimating partitioning coefficients of aliphatic carboxylic acids and chemicals with a molecular structure similar to those of some production chemicals. Subsequently, the coefficients were determined for two different commercial corrosion inhibitors and a biocide that are used in the oilfield as production chemicals. The results showed that the chemicals predominantly preferred to remain in the water phase after contact with either octanol or crude oil. The partitioning coefficients log(p) spanned between −0.36 and −1.68 in the case of water/octanol contact and between 2.68 and −1.41 in the case of water/crude oil contact. One of the corrosion inhibitors exhibited a significant difference in the partitioning depending on whether the organic phase was octanol or crude oil. The chemical had a preference for the water phase in the case of the former but a preference for the crude oil phase in the case of the latter. The result demonstrates that it makes it challenging to evaluate the use of partitioning coefficients for oilfield applications.
Marine space is overall under increasing pressures from human activities. Traditionally, the activities taken place in oceans and seas were related to fisheries and transport of goods and people. Today, offshore energy production – oil, gas, and wind, aquaculture, and sea-based tourism are important contributors to the global economy. This creates competition and conflicts between various uses and requires an overall regulation and planning. Maritime activities generate pressures on the marine ecosystems, and in many areas severe impacts can be observed. Maritime spatial planning is seen as an instrument to manage the seas and oceans in a more sustainable way, but information and tools are needed. The current paper describes a tool to assess the cumulative impacts of maritime activities on the marine ecosystems combined with a tool to assess the conflicts and synergies between these activities.