An Improved Method for Measuring the Distribution of Water Droplets in Crude Oil Based on the Optical Microscopy Technique

The distribution of water droplets in crude oil is one of the key issues involved in the processes of oil extraction and transportation, and these water droplets might also be habitats for microorganisms in oil reservoirs. However, it is still a challenge to observe and measure the distribution of water droplets in crude oil quickly and directly. In this work, an improved method based on the optical microscopy technique is introduced, which is named the Plate Pressing (PP) method and can observe and determine the distribution of water droplets in crude oil directly. The reliability of this method was verified by comparing the results with those of a computed tomography (CT) scan, indicating that the PP method can measure the distribution of water droplets accurately. Meanwhile, the total number and size distribution of water droplets in three crude oil samples from different oilfields were obtained by the PP method, which consolidated the idea that the PP method is capable of determining the distribution of the water droplets in crude oil directly and is suitable for the statistical analysis of water droplets in multiple samples of crude oil.