Design of an automated packed-bed microfluidic system with in situ Raman spectroscopy to better understand the self-assembly of asphaltenes in porous media.

Asphaltenes, which are the most aromatic component of heavy oil, are responsible for the fouling and impairment in flow lines, wellbores, and other production facilities in the petroleum industry. Aromatic solvents such as xylenes are commonly used for the asphaltenes’ cleaning process. Understanding the mechanism of asphaltenes’ dissolution in aromatic solvents is significant for the development of a remediation strategy. The reduction of a reactor’s characteristic length scale leads to the decrease in experimental period while providing high-throughput information. Microfluidic systems with in situ spectroscopy is an excellent platform for time-effective studies of the molecular behavior of asphaltenes in simulated sandstone reservoirs. Here, we injected the HZSM-5 zeolite nanoparticles (707 nm aggregate–1 in isopropanol solution) with varying Al2O3/SiO2 ratios (from 0 to 1/26) into the quartz porous media to represent reservoirs with different characteristic acidity. In-line ultraviolet–visible light (UV-vis) spectroscopy enabled the direct measurement of the dissolution percentage, while in situ Raman spectroscopy revealed where the dissolution occurred within the porous media. In addition to bed occupancy, sheet sizes of asphaltenes molecules can also be determined by in situ Raman spectroscopy. Our results show that the average sheet size of deposited asphaltenes molecules decreased from 2.97 ± 0.25 nm to 2.74 ± 0.26 nm after cleaning the porous media with xylenes. This trend is confirmed with the fluorescence emission spectra of dissolved asphaltenes molecules, where a 10–30 nm red-shift is present, when referenced to asphaltenes source samples. These results provide an explanation to why the dissolution percentage of asphaltenes in aromatic solvents increases from 20.15 wt % to 51.00 wt % as the Al2O3 content increases. We can speculate that this increase in weight percentage is attributed to the differences in deposited asphaltenes molecules’ sheet size. These results reveal the importance of π–π interactions during asphaltenes dissolution process in the aromatic solvent. Our results provide the fundamental understanding of asphaltenes dissolution, which otherwise would be challenging to observe using any other analytical methods.

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Successful identification, evaluation, and management of bottlenecks in a complex, offshore production processing system—though challenging—can significantly increase daily production for the system owner. Historically, such optimization plans were developed in relative isolation of the entire production system from wellhead to export pipeline. That approach benefits simplistic systems with sufficient ullage and in which discrete changes do not affect other flow system components. However, the Constitution platform in the Green Canyon area of the Gulf of Mexico, which was commissioned in 2006 with a nameplate capacity of 70,000 BOPD, is a complex system with four fields in varying stages of development. These fields have both dry and wet tree wells with varying fluid compositions and pressures flowing through the facility, which necessitates varying process requirements, making it challenging to manage. Such a system requires a holistic and focused approach by all technical and commercial disciplines. This paper focuses on a multidisciplinary process developed to identify, evaluate, and eliminate interdependent bottlenecks on the Constitution platform and its flowline network during a 16-month period. A multidisciplinary study was kicked off in 2017 to address these complex bottlenecking issues, and the resulting project achieved a 30% improvement in deliverability of the process system.