Understanding the nature of the solids present is key to optimising any separation process plant. For produced water, the solids present can range from sand, silt, algae, bacteria, scale, napthenates and many others. To attain good separation and achieve good quality water for injection or disposal, each species of solids present may need to be treated differently. For example, sand can be efficiently removed by using desanders; whereas algae and bacteria will require chemical treatment.
The Jorin ViPA, an online video microscope system, is equipped with intelligent software that conducts in depth morphological analysis on every particle it analyses and can differentiate between several types of common particles.
During recent fieldwork for a client initial data showed that the solids concentrations downstream of the final existing treatment process was 36ppm. However, these solids were believed to comprise of several particle populations, each of which would require different treatment and have a different impact on the process and formation.
It was imperative to obtain data on the different solids present so that the most cost-effective treatment package could be installed to ensure injection pump and formation security. A detailed analysis of the solids data produced was performed and sub-populations of solids were identified. Using two of the particle parameters that the ViPA measures, optical density and shape factor, it was possible to profile the solid particles collected present in the re-injection water and identify three separate particle types.
Large numbers of the solid particles were small and had both a low optical density and a high shape factor, characteristics of sand; of the two further particle populations determined, one was of large particles with low optical densities and medium to high shape factors (bio-growth and algae) and the other, medium sized particles with high optical densities with medium to low shape factors (oily agglomerates).
The proper identification of these three types of solid material allowed an effective treatment strategy to be proposed, using appropriate biocide dosing to remove organic growth, utilisation of correctly sized desanders to remove the small sand particles and dis-aggregation of the oily agglomerates provided a cost-effective solution for providing protection to both the pumps’ rotating machinery and the disposal well.
For further information contact Mr Nick Roth, Jorin Limited, tel +44 116 275 3300 fax: +44 116 275 3322.