A Study On The Scale And Scale Dissolver Of The Water Injection Wells

The scale distribution, preventive measures and cleaning methods of the water injection well were analysed. Through the X diffraction analysis, most main form of the scale is SiO2,A12O3,CaO,Fe2O3,BaO which account for 87%. Most of the scale is calcium carbonate and silica. Carrying on quantitative analysis to the oxide ingredient of the scale, the MgO and CaO account for 56.7%, the second is iron oxide which accounting for 9.97%. The least silica and the iron sulphide included. Through the Langlier saturated exponential method, the injected water can produce the CaCO3.In view of characteristic and the type of the oil field scale, through the orthogonal method, the best formula of scale dissolver is determined. The total concentration of acidizing fluid is 13% (hydrochloric acid is 5%, organic scale dissolver is 8%). The concentration of the highly effective corrosion inhibitor is 1.8%. The cleansing agent is 1.8%and the penetrant is 0.8%. Under this formula, the efficiency is bigger than 85%. At the same time, using the self-made catalyst synthesis antisludging agent. The best allocated proportion for maleic anhydride, acrylic acid and the initiator is 1:1:0.47. The amount of the catalyst is 0.9%. Under this allocated proportion, the production of the scale inhibitor is the best. The LM-3 bactericide can eliminates sulphate reducing bacteria, iron bacteria and saprophytic bacteria effectivly. When the concentration is 25mg/L, its bactericidal coefficient is bigger than 99%.Through the optimization of the scale dissolver, the field craft and the field medicament were determined on the field experiment. The scale was solved in 12 water-injection wells which might result in peeling off, disturing tests and plugging the tap. Before clearing the scale, instrument cannot be gotten down to test. After clearing the scale, the instrument can be gotten down normally. The test assignment has been completed.