Characterization and Modelling of Asphaltene Precipitation and Deposition in a Compositional Reservoir

Abstract

This paper presents results of phase behavior calculations and simulation of asphaltene precipitation and deposition in The Carito-Mulata Field, based on a reliable experimental support. The Carito-Mulata Field is a complex compositional system which changes from gas condensate at the top to an under saturated black oil in the flank. In this area Asphaltene precipitation becomes a serious problem where plugging of the formation, wellbore and production facilities dramatically affect the productivity and final recovery of the area. To help to prevent the asphaltene precipitation a high pressure maintenance project has been applied by gas and water injection. Therefore it has been considered mandatory to define a representative numerical model to predict the phase behavior of asphaltene precipitation and deposition. As first part of this study a complete experimental plan was carried out involving several PVT analyses, measurements of precipitation onset pressures and plugging core analyses. PVT analysis was used to match a Peng-Robinson EOS in order to reproduce the phase behavior of the system. Asphaltene precipitation as function of pressure was modeled by a pure solid model which was matched by measurements of precipitation onset pressures. A Solid deposition model was matched based on core analysis to reproduce the reduction of porosity and permeability by asphaltene deposition. At the end, a simulation study based on a radial single-well and a 3D model was carried out to validate the predicting model and analyze the Impact of the asphaltene deposition in the well productivity and how it affects the efficiency of different production strategies. It was compared to the impact in the design of production plans taking into consideration the asphaltene modelling and not taking this into consideration. Also it showed how the reported observations in the field, in Lab and in the literature were adequately reproduced.

Asphaltene Precipitation/Deposition Estimation and Inhibition through Nanotechnology: A Comprehensive Review

“…The asphaltene agglomeration process can be distinguished into four stages: precipitation, flocculation, aggregation, and deposition [10]. Among these steps, precipitation is the most difficult process to predict and can be identified when an insoluble phase composed of solids appears in the hydrocarbon [11][12][13]. It is described that, when in equilibrium, asphaltenes are found in petroleum as a colloidal dispersion.…”

Asphaltene Deposition Preference and Permeability Reduction Mechanisms in Oil Reservoirs: Evidence from Combining X-ray Microtomography with Fluorescence Microscopy

“…Recent studies , integrated the models proposed by Wojtanowicz et al and Minssieux to simultaneously consider three mechanisms: surface deposition, pore bridging, and filtration cake formation. Although these models cover almost all the permeability reduction mechanisms and were effectively applied to some field cases, − they are still unable to sufficiently explain the sequence and contribution of the varied permeability reduction mechanisms, , the primary control mechanisms in various kinds of porous media, ,,− or the various asphaltene deposition locations or stages within a single reservoir. , Disregarding the pore connectivities and morphologies has led to model shortcomings …”