As the oil and gas industry strives to replace ageing, environmentally undesirable scale inhibitors there is an ever increasing use of polymeric inhibitors. Incorporation of phosphorus functionality into a polymer backbone has been shown to improve inhibition efficiency, enhance adsorption characteristics and allow the polymer concentration to be analysed by elemental phosphorus. It is known that some phosphorus tagged polymers can be problematic to analyse in oil field brines as they typically have a low phosphorus content which is difficult to determine from the background.The development of novel phosphorus functionalised polymeric scale inhibitors was previously described (SPE 130733). This paper follows the development of the inhibitor class. Utilising extensive laboratory testing the interactive nature of the scale inhibitors and reservoir lithology was studied. These novel phosphorus functionalised inhibitors were compared to a number of other available P-containing polymers.Following successful development, one of the phosphorus functionalised polymeric inhibitors was subject to sequential fieldtrial in a harsh BaSO 4 scaling, highly naturally fractured North Sea carbonate reservoir. The phosphorus functionalised inhibitor provided improved performance compared to the incumbent product. Following the successful deployment in a carbonate reservoir the novel inhibitor class was also deployed in a number of North Sea sandstone reservoirs and one field wide case study is reported with details on the innovative management and implementation strategy presented. Focus has been given to the application of these products and a detailed analysis of field proven benefits given. This paper concludes with a detailed comparison of these Phosphorus functionalized scale inhibitors with the incumbent products they have replaced in the case histories described. The benefits that these novel, innovative products have given to the operator are described along with a technical synopsis of incremental performance benefits.

This paper reports a new method for the synthesis of phosphorus tagged polymeric scale inhibitors, laboratory based testing to validate these new molecules and their application in oil field reservoirs with comparison to existing commercially available technologies. Existing phosphorus tagged polymeric scale inhibitors are expensive to synthesise and result in low levels of phosphorus making detection difficult. With growing environmental concerns regarding incumbent phosphonate based scale inhibitor chemistries a shift to more environmentally benign polymeric scale inhibitors is required. A new method for the synthesis of phosphorus tagged polymeric scale inhibitors has been developed. These novel molecules contain a greater level of phosphorus compared to existing techniques. This is achieved by polymerising new novel phosphonate monomers. These monomers may be polymerised or copolymerised with other species to yield phosphonate-functional polymers or oligomers. This results in highly detectable, environmentally friendly molecules with enhanced oilfield reservoir adsorption characteristics. These phosphorus tagged polymers are readily detected by ICP and HPLC techniques offering advantages over conventional phosphonate and polymeric scale inhibitors. These new phosphorus tagged polymers have been developed as a range of new scale inhibitors to be deployed as down hole squeeze products. Due to their high detection by both polymer and elemental methods this makes them excellent candidates to replace both existing phosphonate and polymer inhibitors. The large range of monomers available allows the chemistries to be tailor made to specific wells and to a range of scaling conditions. This paper will include laboratory evaluation of these new chemistries with coreflood data in comparison to existing chemistries. This new chemistry shows a significant step forward in the synthetic development of truly detectable phosphorus tagged polymers for an ever evolving industry.

1. Improvements are described in the methods for the extraction and colorimetric estimation of metals in dairy produce, using the carbamate reagent for copper and thiocyanate for iron.2. A combined filtration procedure has been developed to enable both metals to be determined on the same sample, and with slight modifications this procedure has been applied to the analysis of samples of butter, cream, buttermilk and whey.3. The wet-ashing technique has also been improved to enable it to be used for the estimation of both metals on the same digest.4. Comparisons show that the combined filtration method is capable of giving results which agree very well with those yielded by wet-ashing.5. The results of many analyses show that the majority of creamery butter samples have a satisfactorily low content of both copper and iron.6. Many whey butter samples have a rather high metallic content.7. Notes are given on the results obtained when the methods described are applied to other dairy produce.

Simple and rapid methods have been devised which utilize the minimum of apparatus and material for the routine bacteriological testing of butter. These involve the preparation of microplate cultures to obtain counts of total bacteria, “heat-resistant” bacteria, lipolytic organisms, yeasts, moulds; Grimes's method as a measure of the coliform content is also used.The method for counting colonies of lipolytic bacteria is based upon their ability to produce round each colony a halo of white solid fatty acids in place of the clear glistening fat globules.The new methods have been exhaustively compared with those hitherto accepted, and have been found to give satisfactory and reliable results.A variety of comparisons has been carried out to improve still further the methods in use and to provide additional information about the nature of the bacteria contamination present in the butter. The roll-tube method seems preferable to the microplate for mould counts, and is quite suitable for yeast counts.The results obtained confirm the view expressed by Wood & Thornton(6) that yeast and mould counts provide an inadequate criterion of factory sanitation, and should be supported at least by the total count of bacteria.The employment of these methods has enabled large numbers of samples to be dealt with. Thus samples from most of the principal New Zealand butter factories have been regularly tested. The information so obtained has been of material value to the Dairy Division's Instructors in drawing attention to factories where sanitary conditions left room for improvement.

The roll-tube method for estimating bacterial counts was devised by Esmarch(1), but was soon afterwards superseded by the introduction of Petri plates which have several advantages for cultural and counting purposes. The roll-tube method, however, has been revived by several workers (2,3,4), and where a simple, rapid and economical method is required it is very useful, especially if low counts are being dealt with. For this reason it is particularly suitable for yeast and mould counts in butter and has been so used in this laboratory for many years. In addition to its regular use for this purpose, several series of comparisons have shown that the roll-tube method is capable of giving results which compare very well with Petri plate counts upon milk, using the usual dilution technique in both cases.