Technology Focus: Oilfield Chemistry

Abstract

Technology Focus A true structure performance understanding of asphaltenes and the chemical methods used to control them has eluded the industry for many years. Despite many hundreds of published works (and no doubt many more unpublished studies), there is still no singular technique that can definitively characterize a crude oil for asphaltene risk and control that is scalable to the field. The answer to why this is lies in the sheer complexity of the asphaltene molecule itself and, just as important, the variances in asphaltene type and content from crude to crude. As production chemists, we have relied upon generalizations born from seminal academic and industry studies over the last 3 decades. For instance, asphaltenes are polar, asphaltene precipitation very much depends upon pressure and the change of that throughout a system, and asphaltene-control chemicals are dispersant in action. But how does the exact mechanism of adsorption onto a surface take place, and how can we prevent it? These idiosyncrasies still cause much debate among academics and industrialists alike. Much work remains to be done to get the final answers. The sheer complexity of the asphaltene molecule is now within our grasp as the digital age creeps up on our industry. Having the analytics to decipher and measure asphaltene structures and then use high-throughput techniques to determine structure performance relationships gives us a chance to accelerate our understanding. The featured papers summarize some of the state-of-the-art techniques in use—techniques to determine the onset of asphaltene precipitation, adsorption, and inhibition. Readers are encouraged to research the recommended additional reading and take some time to delve into the references contained in these papers. These papers contain an extensive review of the history of, and current state of the art in, asphaltene science for the oilfield chemist and engineer. Recommended additional reading at OnePetro: www.onepetro.org. SPE 178956 Asphaltene-Prevention Work Flow Enhances Oil Production in High-Temperature Fractured Carbonate Reservoirs by R. Ortiz, Pemex, et al. SPE 183940 Experimental Investigation of Effects of Asphaltene Stability on Interfacial Behavior of Live-Reservoir-Fluid Systems by Ram R. Ratnakar, Shell, et al. SPE 186008 Re-Evaluation of Asphaltene-Precipitation Risk Depending on Field-Operational-Condition Change/Variation: Case Study Comparing Risks in Past (2008) and Present (2016) for Future Prediction by Katsumo Takabayashi, Inpex, et al.