A rapid oil concentration analytical method based on the optical properties of the oilfield re-injection water

The oil concentration is a key parameter of great significance to evaluate the oilfield re-injection water (it generally shortened to re-injection water). However, the detection of the oil concentration for the re-injection water is limited due to the lack of the rapid and efficient detection technology for the evaluation of the organics concentration. The present study proposed a rapid analytical method for oil concentration of the re-injection water based on its optical properties, which has been similarly used in rapid detection of materials content, such as gas mixture and water steam quality. The transmittance spectra of the re-injection water were measured by the ultraviolet and visible (UV–Vis) spectrometer, and the effect on the spectra by the oil concentration was also investigated. A fitting relationship between the optical properties and the oil concentration was established. The results showed that the oil concentration has a great impact on the transmittance spectra of the re-injection water. The accuracy of fitting relationship between the optical properties and the oil concentration developed by the double-thickness inversion model and spectroscopy method is good, in which the minimum fitting error is 1.57% and the best fitting accuracy is 99.96%. The oil concentration also plays an important role in the optical properties of re-injection water, which greatly influence on the fitting accuracy.