Page 283 - Formation Damage during Improved Oil Recovery Fundamentals and Applications

254 Rouzbeh G. Moghanloo et al.

6.4.1.1 Asphaltene depostion in capillary flow
Seifried discusses Wang et al.’s (2004) asphaltene deposition study in a
stainless steel capillary for two different crude oils. They reported a higher
deposition rate with higher molecular weight precipitants (n-pentadecane)
than with lower molecular weight components (n-heptane). Also, they
didn’t find any influence of the flow rate on the deposition rate. Wang
et al. (2004) used a stainless steel capillary, which is a closer representation
of process tubing, while Boek et al. (2008) investigated asphaltene deposi-
tion in a glass capillary, since a glass is a good representation of a sand-
stone reservoir rock. Boek et al. (2010) later studied the deposition in
capillary flow of asphaltenes precipitated from the whole crude oil. They
observed a deposition-erosion/entrainment cycle for higher flow rates, as
well as higher pressure fluctuations when compared to experiments at
lower flow rates. Broseta et al. (2000) investigated the onset point and
deposition rate with respect to pressure, temperature, and varying fluid
compositions. Broseta et al. (2000), Wang et al. (2004) and Lawal et al.
(2012) put forward a Homogenous Deposition Model to determine the
effective hydrodynamic thickness of a layer of deposited asphaltenes,
assuming a homogeneous layer of deposits. The experimental pressure
drop data were used to estimate the deposit layer of the asphaltenes by the
change of the inner diameter of the capillary. The model is based on
the assumption of a homogeneous deposition with a uniform thickness of
the asphaltene deposit layer (Seifried, 2016).

6.4.2 Taylor Couette device studies
By varying the flow rate, the shear rate can be changed and the deposit
mass growth can be measured over time (Buckley, 2012). Rahmani et al.
(2003) studied asphaltene floc size distributions in a Couette device for an
Athabasca bitumen (Alberta, Canada). This distribution was studied with
respect to the contribution of varying shear rate to aggregation in
Couette Flow. According to Rahmani et al. (2003), the frequency of
collision and sticking probability control particle aggregation rate. They
state that, on the other hand, fragmentation is not yet well understood
and for that purpose they established a population balance.

6.4.3 (Imaging) Core flood experiments
X-ray computed tomography (CT) is a technique used to observe single
and multiphase fluid flow in porous medium and to characterize the