Early detection of polymer breakthrough in cEOR
Archived, originally published in December 2017
Chemical enhanced oil recovery (cEOR) operations are used in mature oil fields to improve the recovery factor and extend field life. Polymer flooding is a widely used cEOR method that injects water containing high molecular weight polyacrylamide polymers such as Kemira’s KemSweep™ to improve sweep efficiency.
The polymer increases the viscosity of the injection water, improving the mobility ratio between the water and the hydrocarbon trapped in the reservoir. If polymer migrates to a producing well in the water phase, the polymer entering the facilities can impact separation efficiency and overall field production. The fluid viscosity changes can affect process level controllers and interaction with production chemicals can affect phase separation. Plans for polymer breakthrough should be included in cEOR chemical management programs including the early detection of the polymer , allowing the operator to monitor, control and mitigate the effects before they become problematic.
A patented time-resolved fluorescence (TRF) technique is being used successfully by Kemira to detect residual cEOR polyacrylamide polymers in produced water on-site.The KemConnect™ EOR technology uses TRF in conjunction with a europium complex and chemical modulators to detect the polymer at ppm levels in the water.
Laboratory and field trials are demonstrating a good correlation between KemConnect EOR and conventional methods. The real time measurement enables operators to make informed decisions based on the early warning of polymer breakthrough. Sample analysis is rapid and simple allowing for minimal operator competence and the onsite measurement eliminates the costs and time associated with returning samples onshore for analysis. The early detection of KemSweep polymers in produced water using Kemira KemConnect EOR is improving the overall efficiency of the cEOR chemical program and ultimately the field recovery factor.