New Environmentally Acceptable Chemistry and Evaluation Methods for Scale Inhibitor Testing Under Turbulent Flow and Harsh Scaling Conditions

Abstract

Abstract Dynamic scale loop tests are one of the major test methods used in the oilfield scale industry to evaluate the minimum inhibitor concentration (MIC) performance of scale inhibitors under laminar flow conditions. However, this laminar flow condition may not often be representative of field flow conditions especially around chokes, downhole safety valves and in wells with ESP and ICD completions where the flow is turbulent. Under these turbulent flow conditions the MIC derived by standard dynamic loop test may be too low to inhibit scale formation and very seldom has focus been placed on the effect of turbulence on MIC of scale inhibitors. It is possible to modify existing dynamic scale loop equipment to achieve turbulent flow conditions. However, the turbulent flow conditions imparted by the higher flow rate and narrow test coils still cannot match the really high Reynolds numbers experienced in real field conditions so a different approach was adopted to more closely replicate field conditions. This consisted of installing an adjustable small bore valve in the dynamic loop rig which closely simulates the turbulent environment around chokes and downhole safety valves. This new methodology and testing under turbulent and laminar conditions (at lower Reynolds numbers) was used to gain an understanding of the impact of flow on scale deposition and MIC and this information was used to design and identify new environmentally friendly P containing scale squeeze inhibitors that demonstrated excellent performance under turbulent flow conditions. This paper will give a comprehensive study of the effect of flow condition on the scale formation and inhibition and, in addition, will detail how this methodology and new chemistry can be coupled to a chemical technology toolbox, that also implements techniques for advanced scale inhibitor analysis and improved scale inhibitor retention, to design optimum scale squeeze packages for harsh scaling conditions.