Inhibition of Scales Deposited in oil Well Ii-Some Factors Effecting the Selection of Scale Inhibitor For Field Application

*Th, Abdel-Moghny, M. Ramzi, S. M. Desouky, and M. EL-Batanoney

Egyptian Petroleum Research Institute, Nasr City- 117 27, Cairo (Egypt)

In this paper the antiscalants synthesized in part I20 are used for study the effect of functional group, molecular weight, salinity and thermal stability on the inhibitor performance efficiency. The results reveal that the presence of more hydroxyethyl groups may retard the attraction between the negatively charged anions of the inhibitor and the positively charged cations at the scale surface and may lead to steric effect. The results also reveal that there is an optimum molecular weight for a given inhibitor at which a maximum effect would be obtained. This optimum would occur as a result of the degree of adsorption increasing with increasing molecular weight whereas the rate of adsorption would be expected to decrease. The calcium ion concentration remaining in the solution increased with increasing salinity up to a certain value (20%). Further increase in the salt content is accompanied by a slight decrease in calcium ion concentration. The prepared scale inhibitors show high thermal stability this allows their use without any precautions.

Scale inhibitors; Electrostatic interaction; Thermal stability; Coordinative bonds; Ionization of functional acidic groups