is a comprehensive package of computer programs and database developed at the Thermodynamics Research Laboratory of the University of Illinois at Chicago which calculates various properties of petroleum fluids containing heavy organ ics. This package which has taken over 20 years to be developed and tested is based on the following principles: Quantum mechanics, statistical mechanics, neural network statistics, rdf-based mixing rules and conformal solution equations of state, polydisperse monomer-polymer solution theories with renormalization group theory corrections for appreciable large size differences, polydisperse statistical mechanics and thermodynamics, various continuous mixture phase equilibrium algorithms, solid-fluid phase transition theories (variational, lattice models,dislocation theory, polymer collapse), electrokinetic phenomena, transport phenomena, micellar and steric colloidal solution theories, and FRACTAL kinetics of aggregation and percolation theories. This package is general enough to predict the heavy organics-oil- wall interaction problems wherever they may occur during oil production, transportation or processing. The emphasis of the package is on the prediction of the behavior of asphaltenes, resins, diamondoids, sulphur, organometallics and paraffin-waxes and their roles and interactions in the production and processing of natural and synthetic hydrocarbons.
ASPHRAC can be utilized by:
(i). Reservoir and production engineers for oil recovery simulation studies and design of well completions and surface facilities.
(ii). Research and process engineers for the design and performance evaluation of crude, bitumen, and heavy oil related facilities and processes.
(iii) Petroleum engineers, refiners and NGL processing engineers for the design of cost-effective anti-foulants for heavy organic fouling mitigation in various processes.
As examples of its utility the package is tested for the following cases with success:
1. Prediction of the onset, amount, size distributions, and redisolving conditions of asphaltenes, resins, and other heavy organics present in various petroleum crude oils and gas condensates due to: (a) introduction of high pressure miscible gaseous or liquid solvents; (b) Changes of composition, pressure, temperature, and well bore effects.
2. Prediction of the onset and amount of heavy organic precipitation in pipeline transport when blended with NGL at different blending ratios, temperatures, and flow conditions.
3. Design and selection of anti-foulants to improve heavy organic dispersivancy and, as a result, to prevent heavy organic fouling in processing equipment.
The kind of input data which may be used in the package are: Static and dynamic pour points, cloud point, onsets of precipitation, flocculation, and deposition data due to addition of known miscible solvents, bottom-hole (and/or stock-tank oil) sample(s) composition and physical property data, oil aromaticity, oil paraffin, resin, asphaltene, organometallics, sulphur and diamondoid content, Zetha potential and refraction data, characterization data for C7+ fraction of oil, and NMR and chromatography (GC, LC, HPLC and GPC) data of oil fractions.