A concentration measurement model of suspended solids in oilfield reinjection water based on underwater scattering

There are many particles such as suspended solids (SS) and oil particles in oilfield reinjection water, of which the concentrations have important effect on the property of reinjection water. To measure the concentration of SS accurately, an underwater scattering model is proposed in the paper. The light extinction effect resulting from oil particles, SS and water was discussed based on Lambert-Beer Law. According to the Mie scattering theory, the integral calculation for a single particle within the scattering angle was accomplished, and the relationship between the SS concentration and the intensity of 90° scattered light was worked out. The influences of the diaphragm spot, the light beam position and the concentration of oil particles to the measurement model were analyzed. An underwater scattering measuring system corresponding to this model was established to measure the concentration of SS in solution samples that simulated the oilfield reinjection water. The regression analysis results show that the correlation coefficient of the model and the actual experimental results is 0.998, and the root-mean-square error is 0.0775 V, which proved the feasibility of the SS underwater scattering model.