Modelling Asphaltene-Induced Formation Damage in Closed Systems

Abstract

This paper implements a simple one-parameter semi-analytic model for asphaltene-induced reduction of porosity, pore-radius and permeability in closed systems. By treating sedimentation as the dominant deposition mechanism, dynamics of asphaltene deposition under "stagnant" conditions is provided, elucidating the dependence of damage rate on the size of asphaltene aggregates as well as rock and fluid properties. Parametric studies indicate that while the rate of formation degradation depends on rock and fluid properties, ultimate severity of impairment is primarily controlled by in-situ asphaltene content. The proposed model has been used to explain the general observation that light oil systems are more vulnerable to asphaltene damage, than the heavy oil systems. Validity of proposed model is demonstrated by comparing with available experimental datasets that include both sandstone and carbonates. In all cases, experimental results have been matched within 7% accuracy using the proposed model with a single adjustable parameter. Furthermore, thermal simulation studies conducted on a hypothetical but representative heavy oil reservoir highlight the detrimental effects of impairment on field-scale oil recovery and thermal efficiency. Both the models and results presented should be useful for studying impairments induced by asphaltene and other deposits.

Modeling Permeability Impairment in Porous Media due to Asphaltene Deposition under Dynamic Conditions

“…Although not indicated in Table , the oils used in runs 2, 6, and 3 have viscosities of 1.1, 0.71, and 0.59 cP, respectively, suggesting that damage rate is less pronounced in viscous crudes. This may partly explain the typical observation of lower rate and magnitude of impairment in viscous crudes, despite their much higher asphaltene content. , A similar finding on the influence of viscosity in the damage process was reported by Lawal and Vesovic …”

“…61,68 A similar finding on the influence of viscosity in the damage process was reported by Lawal and Vesovic. 71 It is noteworthy that the data sets of Fadili et al, 59 notwithstanding the similarity of the porous medium, result in fitting parameters that differ significantly (see Table 2). This is a direct consequence of the fact that when our model is used for history-matching, the empirical parameters reflect the historical behavior of the system and not its initial state.…”

An Improved Estimation of the Storage Capacity of Potential Geologic Carbon-Sequestration Sites

“…Similarly, we have tacitly ignored possible CO2-induced asphaltene problems in oil reservoirs as well as salt precipitation in saline aquifers and their negative impacts on injectivity and reservoir dynamics [49][50][51][52][69][70] . its physical properties such as viscosity would not be markedly altered by intervention processes such as heating and dilution.…”

Productivity Prediction of Horizontal Well by Integration of Formation Damage Model during Gravel-pack Completions

“…The sand plugging mechanism of gravel packed well is proposed using flooding tests with multi-point tube, which evaluates the influence of sand migration to gravel layer permeability (Hu et al 2004;Zeng et al 2005;Wang et al 2008). Many theoretical models to evaluate the permeability impairment for particulates deposition are proposed (Gravelle et al 2011;Lawal et al 2005Lawal et al , 2010Lawal et al , 2011Civan et al 2002Civan et al , 2003Civan et al , 2005. The filtration and formation-damage coefficients are important empirical parameters for theoretically evaluate the permeability damage.…”