An improved modeling approach for asphaltene deposition in oil wells including particles size distribution

Abstract

There are several approaches to model asphaltene deposition process in the wellbore. There are different assumptions to simplify the problem in the previous investigations for specific conditions, limiting the prediction range of the models. In this work, the effect of precipitated asphaltene particles size is included, to extend the available modeling approaches for deposition profile. To do so, two-dimensional partial differential equations based on asphaltene micro aggregates material balance including asphaltene aggregation, diffusion and deposition are numerically discretized and solved to find asphaltene deposition profile, in radial and vertical directions of vertical oil wells. The modeling results are verified with the results of the well-known ADEPT (asphaltene deposition tool in flow lines) model of Kurup et al. (2011). The size dependent diffusion coefficients of Escobedo & Mansoori (2010) are used to extend the base model. In addition, the Population Balance Method (PBM) was included to improve the aggregation process description with size distribution of asphaltene particles. Based on the developed model a parametric study is performed to study the effect of asphaltene particles average size, flow rate, wellbore radius and fluid viscosity. The model evaluation shows the importance of asphaltene particle size in the deposition profile. In addition, the evaluation results show that as the average asphaltene particle size increases for a given distribution, the amount of deposition in the wellbore decreases.

Study the rheological properties of waxy oil with modified pour point depressants for the South Turgai oil field in Kazakhstan

“…It can be seen from Figure 10 that, the crystal structure of Akshabulak oil at 5°C without EVA is much larger than crystal structures of oil when we applied EVA and EVA-M. Moreover, Akshabulak oil at 5°C easily solidified without adding any additives due to formation of various shapes of wax depositions [25,26]. According to studies the morphology of the crystal structures of paraffins after the addition of modified EVA it should be concluded that the formation of plate-like structures is due to repellent of wax crystals by the polar acetate group in EVA copolymer that prevent the formation of large agglomerates of Table 7.…”

Analysis of the Modern State of Researches on Deposition of Asphalt-Resin Substances, Paraffin and Modeling Methods Review Part I: Precipitation of Asphaltenes

“…Changes in pressure, temperature, composition and sliding velocity can lead to the deposition of asphaltenes and the accumulation of deposits [2,3]. These changes can occur due to various processes, such as primary depletion, injection of natural or carbon dioxide (Gas injection is one of the main types of enhanced oil recovery (EOR) methods), acid treatment or coproduction of incompatible fluids.…”

The Simultaneous Effect of Brine Salinity and Dispersed Carbonate Particles on Asphaltene and Emulsion Stability

“…Therefore, during the waterflooding process, they are mostly attracted to the oil/water interface and form a rigid film that prevents the water droplet coalescence. This process can lead to stable emulsion formation, asphaltene instability, and deposition. ,− Moreover, asphaltene particles could adsorb and deposit on the reservoir rock surface and alter the rock wetting state to oil-wet conditions, causing pore plugging and injectivity/productivity decline. ,− …”