Abstract
The impact of the presence of untreated sea water on the scaling risk has been considered using reservoir and scale prediction modelling. To ensure effective mitigation (if chemical inhibitors proved less than satisfactory) a range of alternative technologies were assessed in detailed laboratory studies. In particular, surface coatings were assessed to reduce scaling in wellbores and lower completion tubulars. Tests were conducted under conventional “coupon” type surface scaling approaches as well as large- scale “pilot rig” flow apparatus. The conclusion from this work was that a moderate to significant scaling challenge was expected despite the use of LSSW for future pressure support and even given moderate to extensive levels of in situ stripping as a result of the extended shut-in period. The laboratory results demonstrate that scaling could be mitigated by the use of conventional scale inhibitor chemistries. In addition, that coatings gave a marked reduction in scale deposition and ease of scale removal. However more significantly, in the presence of coatings, residual oil, and in the presence of certain types of scale inhibitor chemistries, a more considerable reduction in the amount of scale deposited on the coated pipe compared with the uncoated pipe, and considerably less adhesion strength, was observed.
