Case Study: Investigation of the Performance of an Asphaltene Inhibitor in the Laboratory and the Field

Asphaltene deposition is an increasing problem in many oil fields around the world. One of the most common strategies to mitigate asphaltene deposition is based on the continuous injection of asphaltene inhibitors. These chemicals are usually screened in the laboratory following one or more of the many techniques available to evaluate their performance, such as precipitation tests or deposition tendencies, using various setups, such as a Taylor-Couette cell, flow loop, capillary tube, or packed-bed column. The performance ranking of chemicals for a given crude oil sample depends upon the type of test used. There are cases where chemicals that perform well in the laboratory are not as effective in the field, as a lab to field correlation for asphaltene inhibitor screening is still being developed. In this work, we investigate the case of a commercial asphaltene inhibitor that shows adequate performance in a deepwater-oil well. We analyze its behavior in the laboratory using a series of tests on treated and untreated oil samples collected from the field. Depostion behavior of model oils prepared from the deposits retrieved from this field has also been studied. Moreover, we have put special attention on the effect of asphaltene polydispersity on the performance of the chemical and track the performance of the product over a period of several years. The results and analyses presented in this work aim to expand our knowledge on this topic and provide some best practices for testing the performance of asphaltene inhibitors in the laboratory, with the ultimate objective of establishing a series of laboratory tests and a workflow to correlate laboratory and field performance of these chemicals.