The controlled release of scale inhibitors (SI) and other treatment chemicals in the near-wellbore region is a key strategy to improving water management and extended well production. In addition, during some completion and stimulation operations, it is desired that robust particles providing controlled release be placed in gravel and sand packs. A novel controlled release scale inhibitor particle is presented which provides beneficial properties due to its unique chemistry and polymer processing methods. This technology provides extended feedback of scale inhibitor with tunable release rates.

A typical oil dispersion (OD) contains an oil, a powder (agrochemical) suspended in the oil as a carrier, an emulsifier capable of emulsifying the oil when diluted in water before spraying, a rheology modifier that can thicken and suspend the powder in the oil during storage, and optionally a suspension aid that can suspend the powder during spraying after the OD is diluted in water. Current commercially available rheology modifiers (thickeners) used or suggested for OD formulations have drawbacks. They are either difficult to handle (very dusty powder) or require heating or the use of a protonic solvent to activate thickening. In addition, their thickening property is sensitive to ionic surfactants such as Ca-DDBS and temperature change. In this paper, a new type of oil thickener, a polymer, without the drawbacks of current oil thickeners, is introduced. It is believed that the new type of oil thickener uses a chain entanglement or excluded volume-thickening mechanism rather than the associative- or solidification-thickening mechanism employed by the current thickeners. A few stable OD prototypes containing powder pesticides (5 %–48 %), emulsifiers (6 % or less), and this unique polymeric rheology modifier (3 % or less) in oils (soy methyl ester or Aromatic 200) are presented. A correlation between OD stability and the loss-factor frequency dependence (G″/G′, the ratio of loss modulus to storage modulus) is established. In particular, when G″/G′ is less than 1, the OD is stable. When G″/G′ is greater than 1, the OD is unstable and the solid particles tend to settle to the bottom.

Trimethylamine, (CH 3 ) 3 N, (TMA), odors are often associated with limed and polymer conditioned sludges. This odor has a fishy smell and can be a nuisance to the community surrounding a wastewater treatment plant or land application site. Several factors are thought to determine the amount of TMA generated from limed biosolids. These are, the presence of cationic polymer, the polymer dose, the time between addition of polymer and lime stabilization, shear imparted on the sludge in the dewatering process and dewatered cake solids concentration. All of these were investigated in this study. The results showed that TMA could be generated from sludge that did not contain polymer but the concentrations were low compared to sludge conditioned with cationic polymer.As the polymer dose increased, the TMA increased. Shear also showed to play an important role for TMA production. In addition to higher shear increasing the polymer demand, shear in itself can increase TMA generation. However, the most important factor in generating TMA was the time between conditioning and liming. If this time was minimized, little TMA was produced, even at high polymer doses. Data also suggests that methanogens play an important role in the breakdown of TMA.iii Acknowledgements