Online Quality Measurements of Total Suspended Solids for Offshore Reinjection: A Review Study

Abstract

The importance and awareness of accurate online water quality measurements increase every year in the oil and gas sector, whether it is for reducing oil discharge, preparing produced water for reinjection, or improving operational performance. For online measurement techniques to yield valuable analytical information, an understanding of their outputs must be established. Produced water reinjection has gained increasing attention in the last decade, as it can minimize negative environmental impacts by reducing oil discharge and has the potential to extend the economic life of reservoirs. To increase the amount of produced water that can be reinjected, the water must be maintained at a sufficient quality to prevent unintended formation damage. This review paper thoroughly describes different water quality issues related to suspended solids that can occur in an injection water treatment system and how the issues are often interlinked. A case study of measuring the total suspended solids concentration of seawater sampled from the Danish sector of the North Sea has been carried out to effectively quantify water quality in an injection water treatment facility. Furthermore, numerous on- and in-line techniques have been evaluated as candidates for measuring suspended solids. The last part of the paper discusses considerations regarding future microscopy analyzers based on five promising online microscopy technologies.

Offshore Online Measurements of Total Suspended Solids Using Microscopy Analyzers

“…Monitoring the PW also support protecting the receiving environment when discharging. Accurate information on the amount of oil and particles, sizes, and classification of particles in the injection water (IW) can essentially be used for decision support, reporting, or even advanced control to achieve better operation in the treatment process [ 6 , 12 ]. Therefore, the importance and awareness of accurate online measurements of oil and suspended particles have gained increasing attention within the oil and gas industry [ 5 , 6 ].…”

“…The water quality in offshore injection water treatment (IWT) processes is usually assessed in terms of particles’ plugging tendency, also addressed as suspended solids or total suspended solids (TSS) [ 8 , 13 ]. However, the IW quality should be economically viable to achieve and counterbalanced against other solutions, e.g., well-stimulation [ 12 , 13 ]. Currently, offshore IWT processes rely on off-line measurements of TSS concentration following the ISO 11923; thus, in case of a decrease in IW quality, the reaction time is long due to the use of onshore laboratory measurements [ 14 ].…”

“…Several different methods for measuring particle sizes exist, each based on several design options from different manufacturers. Besides microscopy, which is based on direct observation, all other techniques are challenged by their property assumptions that only the equivalent diameter of a sphere is measured [ 12 ]. The existing morphologies are not taken into account, which complicates the ability to classify particles [ 12 ].…”

“…Besides microscopy, which is based on direct observation, all other techniques are challenged by their property assumptions that only the equivalent diameter of a sphere is measured [ 12 ]. The existing morphologies are not taken into account, which complicates the ability to classify particles [ 12 ]. Another advantage of microscopy is the manual discrimination of particles captured to evaluate the results.…”

The Impact of Riser-Induced Slugs on the Downstream Deoiling Efficiency

“…A testing facility is used to test both the transportation and the separator-hydrocyclone separation systems [28][29][30]. The work examined in [31] concluded that the separation performance decreased when severe riser-induced slugs are presents, however, the oil-in-water (OiW) concentration was not measured or estimated due to the challenges and limitations associated with online OiW monitoring [32]. Hence, in this paper, the recently developed hydrocyclone model from [33,34] will be utilized to quantify the riser-induced slug's impact on the OiW concentrations after the downstream separation processes.…”