Mineral scale deposition is a well-known problem for the petroleum industry. The application of scale inhlbitors can often prevent such deposits forming, but assessment of the concentrations of these needed for control has relied on indirect methods for assessing brine stability. Such methods use laboratory tests and measurement of scale inhibitor residuals. Recently a new technique for direct measurement of the stability of oilfield brines has been developed. This technique uses TSMR (Thickness Shear Mode Resonator) technology. Deposition on the probe alters resonant frequency, measured in real-time. This paper describes field applications of the equipment to a range of scaling environments.
The Middle East appfication allowed successful categorization of wells with into those with likely scale problems and those unlikely to see such deposits. The onshore USA trial showed that the equipment could give an indication of potential calcium carbonate scale, besides barium sulfate. For the North Sea application, where a severe barium sulfate potential existed, on-site optimization of required scale inhibitor dosage was achieved for particular wells and combined welistrearns. In this case evidence was also provided for situations where the current scale inhibitor was incapable of completely inhibiting barium sulfate deposition.