英語翻譯
The criteria for a failure of this testing protocol was the presence of phase separation or precipitation of solids in the inhibitor solution.The initial screening performed at 150°C for 48 hours saw failure by DETP,MA and EPA.A further 2 chemistries(PPCA and PVS/EPA copolymer) failed the 200oC tests.On cooling the inhibitors precipitated
crystalline solids,presumed to have formed from thermally decayed inhibitor molecule particulates.Nearly all inhibitors that did not show any precipitation or hazing darkened in colour but this is commonplace and was no cause for concern.FTIR analysis was performed on the thermally aged inhibitors to check for any change in molecular symmetry that would indicate thermal degradation.Where crystallisation had occurred,there were obvious differences in spectra with key active inhibitor component peaks.These peaks could either be distorted or absent,and in some cases where phase changes had occurred new peaks were present in aged samples.Three
examples of FTIR spectra have been depicted in Figures 3 and 4 inhibitors PPCA and SVS respectively.It can be seen that the ageing of Inhibitor C at 150°C has no real effect on the form of the spectrum but at 200°C the 1000-1500 cm-1 peaks radically change form in terms of shape,intensity and position representing a complete degradation of the active inhibitor product.Similarly the spectrum of SVS changes at 200°C with the absence a peak centered on 2375 cm-1 representing a breakdown of the inhibitor compound.The spectrum of Inhibitor B however has no discernable changes in form during any thermal conditions and this is reflected in visual
observations of the inhibitor.These breakdowns can also be discerned visually in the form of hazing or recrystallisation,but the FTIR analysis gives a definitive representation of changes to the form of the inhibitor molecules contained within the various packages.Indeed the FTIR serves to further prove the visual observations of the inhibitor intolerance to high temperatures.Compatibility Testing A successful squeeze candidate should be compatible with the formation waters of such a high salinity well.The criteria for a successful pass at this stage of testing would be the absence of precipitated species either present as particulates or as hazing of the solution.It is important for scale inhibitors to have a good calcium ion tolerance when being considered for application in high salinity wells.All chemicals that underwent this test passed the compatibility at both 150 and 200°C,and only one chemical,SVS/AA/MA failed,probably due to the formation of incompatible calcium-inhibitor complexes.