Characterizing Asphaltene Deposition in the Presence of Chemical Dispersants in Porous Media Micromodels

Abstract

Asphaltenes are components in crude oil known to deposit and interrupt flows in critical regions during oil production, such as the wellbore and transportation pipelines. Chemical dispersants are commonly used to disperse asphaltenes into smaller agglomerates or increase asphaltene stability in solution with the goal of preventing deposition. However, in many cases, these chemical dispersants fail in the field or even worsen the deposition problems in the wellbores. Further understanding of the mechanisms by which dispersants alter asphaltene deposition under dynamic flowing conditions are needed to better understand flow assurance problems. Here, we describe the use of porous media microfluidic devices to evaluate how chemical dispersants change asphaltene deposition. Four commercially used alkyl-phenol model chemical dispersants are tested with model oils flowing through porous media, and the resulting deposition kinetics are visualized at both the matrix-scale and the pore-scale. Interestingly, initial asphaltene deposition worsens in the presence of the tested dispersants, but the mechanism by which plugging and permeability reduction in the porous media varies. The velocity profiles near the deposit are analyzed to further investigate how shear forces affect asphaltene deposition. The deposition tendency is also related to the intermolecular interactions governing the asphaltene-dispersant systems. Furthermore, the model system is extended to a real case. The use of porous media microfluidic devices offers a unique

Multiscale dynamics of colloidal deposition and erosion in porous media

“…As particle injection continues, these deposits continue to grow, as shown in movie S2, suggesting that the hydrodynamic stresses due to fluid flow are sufficient to overcome any possible electrostatic repulsion between like-charged particles, detailed further in the Supplementary Materials, although nanoscale heterogeneity in the colloidal interactions may also play a role (49). This observation is consistent with previous findings in 2D media (24)(25)(26)(27)(28)32). The deposits do not all grow monotonically, however.…”

Asfalteny naftowe – przegląd wybranych zagadnień

“…Lin i in. w swojej pracy [17] sprawdzili wpływ dodatków z rodzaju alkilofenoli na ilość osadów asfaltenowych powstających podczas tłoczenia substancji zawierających asfalteny przez porowaty mikrokanał. Okazało się, że w przypadku roztworu asfaltenów w toluenie zmniejszenie osadotwórczości wystąpiło tylko przy zastosowaniu p-dodecylofenolu oraz p-izododecylofenolu.…”

“…W przypadku obu zastosowanych dodatków, tj. p-oktylofenolu oraz p-dodecylofenolu, zaobserwowano szybszy przyrost ilości osadów w czasie [17]. Prawdopodobnie dodatki zakłóciły równowagę układu żywic i asfaltenów w badanej ropie, same nie wytwarzając wystarczającej bariery sterycznej.…”

Effects of reservoir rock pore geometries and ultrasonic parameters on the removal of asphaltene deposition under ultrasonic waves

“…While asphaltene does not pose an issue while coexisting with in situ crude oil, various circumstances (such as a change in pressure, temperature, or the crude's composition) can disrupt the equilibrium of asphaltenes in the crude and cause them to precipitate [3] . The asphaltenes that have precipitated might cluster together (aggregation) and form bigger particles known as flocs [4] , [5] . Following that, the flocs may adhere to and build on reservoir rock surfaces, a process known as asphaltene deposition [6] .…”