Mechanistic study to investigate the effects of different gas injection scenarios on the rate of asphaltene deposition: An experimental approach

Abstract

Asphaltene deposition during enhanced oil recovery (EOR) processes is one of the most problematic challenges in the petroleum industry, potentially resulting in flow blockage. Our understanding of the deposition mechanism with emphasis on the rate of the asphaltene deposition is still in its infancy and must be developed through a range of experiments and modelling studies. This study aims to investigate the rate of asphaltene deposition through a visual study under different gas injection scenarios. To visualise the asphaltene deposition, a high-pressure setup was designed and constructed, which enables us to record high-quality images of the deposition process over time. Present research compares the effects of nitrogen (N2), carbon dioxide (CO2) and methane (CH4) on the rate of asphaltene deposition at different pressures. The experimental results in the absence of gas injection revealed that the rate of asphaltene deposition increases at higher pressures. The results showed that the rate of asphaltene deposition in the case of CO2 injection is 1.2 times faster than CH4 injection at 100 bar pressure. However, N2 injection has less effect on the deposition rate. Finally, it has been concluded that the injection of CO2 leads to more asphaltene deposition in comparison with CH4 and N2. Moreover, the experimental results confirmed that gas injection affects the mechanism of asphaltene flocculation and leads to the formation of bigger 2 flocculated asphaltene particles. The findings of this study can help for a better understanding of the mechanism of the asphaltene deposition during different gas-EOR processes.

Modeling of Asphaltene Deposition Kinetics

“…Asphaltene precipitation and deposition with a thermodynamic change of the system condition has been the subject of rigorous debate in literature for almost a century . Asphaltenes, still resorting to solubility class definition, are known as a fraction of crude oil that on the contrary to other parts, i.e., saturates, aromatics, and resins, are not soluble in n -alkane solvents and only remain soluble in aromatic solvents. , The high research interest associated with asphaltene can be attributed to their precipitation and afterward deposition inside the porous reservoir medium and more commonly in transportation pipelines, which eventually leads to flow passage restriction or, in severe cases, passage blockage. , The production loss and asphaltene treatment expenses hugely impact the production revenue. − Numerous research studies that have been performed on asphaltenes can be categorized into three classes: asphaltene chemistry, asphaltene thermodynamics, and asphaltene kinetics. Asphaltene chemistry attempts to determine the asphaltene molecular structure and molecular weight.…”

“…2,3 The high research interest associated with asphaltene can be attributed to their precipitation and afterward deposition inside the porous reservoir medium and more commonly in transportation pipelines, which eventually leads to flow passage restriction or, in severe cases, passage blockage. 4,5 The production loss and asphaltene treatment expenses hugely impact the production revenue. 6−8 Numerous research studies that have been performed on asphaltenes can be categorized into three classes: asphaltene chemistry, asphaltene thermodynamics, and asphaltene kinetics.…”

Evaluation of the Influence of a Chemical Inhibitor on Asphaltene Destabilization and Deposition Mechanisms under Atmospheric and Oil Production Conditions Using QCM and AFM Techniques

“…This sharp change in the resonance frequency reflects the fast destabilization of the asphaltenes in the system. In order to confirm the sensor response observed with this system, the experiment was repeated with higher CH 4 contents (43,46, and 51 mol %). The results obtained for the four systems that exhibit destabilization are plotted on the same graph for Δf 3,load in Figure 16.…”

“…These include the Taylor–Couette device, capillary tube, , and quartz crystal microbalance (QCM). ,,, Additionally, recent progress in scanning tunneling microscopy and atomic force microscopy (AFM) have allowed the visualizing of asphaltene aggregates or asphaltene films on different media − and imaging of the atomic structure of complex, polydisperse molecules, including individual asphaltene molecules. − AFM has also been used for particle size analysis to characterize how an additive can inhibit the flocculation and/or deposition of asphaltenes on mineral surfaces . While the majority of studies have focused on the effects of carbon dioxide injection on the asphaltene deposition rate during enhanced oil recovery processes, few experimental studies have been conducted to examine the effects of miscible hydrocarbon injection on the asphaltene precipitation. , In particular, when natural gas is preferred to CO 2 in deep high-pressure reservoirs with high permeability, it is important to test the performance of chemical inhibitors to prevent the destabilization and deposition of asphaltenes over a wide range of temperature and pressure conditions during oil production. The novelty of the present work resides in the evaluation of the effect of the inhibitor addition on asphaltene stability in a dead oil sample recombined with methane using a fully immersed quartz crystal resonator (QCR).…”

“…3 While the majority of studies have focused on the effects of carbon dioxide injection on the asphaltene deposition rate during enhanced oil recovery processes, few experimental studies have been conducted to examine the effects of miscible hydrocarbon injection on the asphaltene precipitation. 46,47 In particular, when natural gas is preferred to CO 2 in deep high-pressure reservoirs with high permeability, it is important to test the performance of chemical inhibitors to prevent the destabilization and deposition of asphaltenes over a wide range of temperature and pressure conditions during oil production. The novelty of the present work resides in the evaluation of the effect of the inhibitor addition on asphaltene stability in a dead oil sample recombined with methane using a fully immersed quartz crystal resonator (QCR).…”