High Pressure, High Temperature
Phosphonate Scale Inhibitors under HP/HT Conditions
Over the last few years a considerable amount of work has been undertaken to examine the thermal stability of different generic scale inhibitors. The performances of five phosphonate scale inhibitors (HMDP, HMTPMP, DETPMP, PEHOMP and NTP) after thermal ageing at 160°C (and in some cases at 190°C) have been compared to those of polymeric scale inhibitors. The use of phosphonate scale inhibitor species in high temperature wells could have significant cost implications. The thermally aged inhibitors were tested against both carbonate and sulphate scale in dynamic tests and against sulphate scale in static tests. Under certain conditions some of the phosphonate species were found to perform well after thermal ageing.