Experimental Study Of Ultrasonic Antiscaling

The oil-field scaling problem is one of the most important factors in obstructing EOR. There are plenty of ions in the oil-field water, so massive scale would be produced when external environment changes. Pumping rod's load would be rasing when rod is covered by scale. Well pumpage would be decreasing, valve sealing would not be well, and pump efficiency would be fall when pump inwall is covered by scale. Normally, chemical agents are added into the equipments for antiscaling; however, it could lead to environment pollution as well as high costs. The advantages of ultrasonic antiscaling technique which is a physical method are: low costs and zero pollution. Above all, it is necessary to study more about ultrasonic antiscaling technique, and I believe it possesses huge development potential.In this thesis, the main research approach is laboratory experiment. Including: the impact of ultrasonic on solution's physical properties, scale dissolving, static antiscaling experiment and dynamic antiscaling experiment. Water is treated by ultrasonic in a given period time, and its physical properties could change, like: surface tension falling down, electrical conductivity and temperature raising. In the part of scale dissolving experiment, calcium ion concentration can be caculated by conductance method. Then the rate of meltage increment which is used to evaluate the effect of ultrasonic on calcium carbonate's solution can be caculated. So the optimum frequency, treating time and acoustic intensity can be figured out. In the part of antiscaling experiment, the coupon is immersed in the calcium carbonate solution in a period time, and the coupon's surface would be covered by calcium carbonate scale. The mass difference can be used to caculate the rate of antiscaling so as to evaluating the antiscaling effect. During the static antiscaling experiment, the effect of frequency, treating time , acoustic intensity and water level on the rate of antiscaling is studied, and the best rate of antiscaling can be about 80%. During the dynamic experiment, orthogonal tests on 6 different point coupons are carried out. There are 3 factors of every orthogonal test: interval time, treating time, flow velocity. The size of impact and the optimum parameter combination are studied in the thesis, and the results show the highest rate of antiscaling can be 81.12%.