Causes and preventive management of scale formation in oilfield systems: A review

Abstract

Scale formation in oilfield operations causes lot problems. In the reservoir, it reduces near wellbore permeability, resulting in high skin and lower inflow. In wells it causes flow restriction resulting in higher pressure losses or lower throughput. Moreover, in flow lines and surface facilities, it causes
loss of equipment functionality and corrosion. One of HSE concerns of scaling tendencies is the danger associated with Naturally Occurring Radioactive Materials (NORM) arising from sulphate scales deposit. There is therefore utmost need to identify the causes of scale formation in oilfield systems and proffer prudent preventative management. Findings from this study indicated that among others, some factors that lead to scale formation are mixture of incompatible fluids, temperature and pressure changes, pH changes, ionic and strength of the solution among others. Recommended practices to prevent or at least minimize scaling problems include minimizing of pressure and temperature drops, avoidance of mixture of incompatible brine streams, removal of at least one scaling component from the system, pH reduction, choosing a surface that resists scale adhesion, application of physical fields example magnetic or electrostatic, the use of scale inhibitors and proactive application of scale prediction models or soft wares.

Keywords: Scale formation, oilfield systems, fluid flow, pH changes, Wellbore permeability