A Comprehensive Approach for Evaluating and Treating Tight Emulsion

Abstract

Summery Although there are numerous research activities done on challenging oil samples to be separated from tight water emulsions, there are still critical elements missing about onsite characterization of the real oil samples with emulsion. This disparity could be the major reason that is leading to limitation towards the design and implementations of better demulsification strategies. Emulsions’ characterization shall inform about its type (water in-crude oil, crude oil-in-water, or multiple), describe surfactants, water cut, droplets size and distribution, and depict the viscosity of the dispersed and continuous phases. Knowledge about the rheological properties of the fluid is vital in engineering design of gathering systems and choose pumps and tubing sizes for wells and pipelines. In this work, we showed an integrated framework for emulsion characterization and apply that framework in the characterization of real oil samples with tight emulsion. We follow a holistic approach that look at the challenge from downhole in the well to the processing plant. Characterization of the emulsion samples depicts high asphaltenes content (10 wt%), composed of ionizable groups such as carboxylic acid, high water cut, high formation water salinity (> 150, 000 ppm Ca2+ with pH ˜6). Since change in the water cut changes the crude oil, high salinity in the formation water generally leads to very high salt amount per total volume of emulsion (about 2000 ppm Ca2+). Identification of the major factors leading to tight emulsions through characterization of real oil/water emulsion led us to design better roadmap for demulsification strategies in matured wells. This information is also vital for designing of new wells to accommodate better choices of equipment and process for future highly likely appearance of emulsion.