Evaluation of the Different Compatibility Indices to Model and Predict Oil Colloidal Stability and Its Relation to Crude Oil Desalting

Abstract

Thirty crude oils, belonging to light, medium, heavy, and extra heavy, light sulfur, and high sulfur have been characterized and compatibility indices defined. Nine crude oil compatibility indices have been employed to evaluate the compatibility of crude blends from the thirty individual crude oils. Intercriteria analysis revealed the relations between the different compatibility indices, and the different petroleum properties. Tetra-plot was employed to model crude blend compatibility. The ratio of solubility blending number to insolubility number was found to best describe the desalting efficiency, and therefore could be considered as the compatible index that best models the crude oil blend compatibility. Density of crude oil and the n-heptane dilution test seem to be sufficient to model, and predict the compatibility of crude blends.

Application of Intercriteria and Regression Analyses and Artificial Neural Network to Investigate the Relation of Crude Oil Assay Data to Oil Compatibility

“…Also, high-temperature gas chromatography was applied to determine the boiling point distribution of the studied oil samples according to ASTM D7169 [77]. The predictive crude oil compatibility model of Nemana et al [65] was used to assess the colloidal stability of the investigated 48 petroleum samples. Nemana et al's predictive model comprises the assignation of solvent power (Sp) and critical solvent power (Sp critical).…”

“…The analytical procedure includes the determination of heptane insolubles by centrifugation, boiling point, and density assays. The crude oil Sp was estimated as described in [65], and it is shown in Equation (1).…”

“…Wiehe and Kennedy [1] introduced the oil compatibility model that includes two reduced-solubility parameters: solubility blending number (S BN ) and insolubility number (I N ). The S BN of each crude oil was estimated using Equation ( 8) and the solubility parameter values of crude oil (δ CO ), toluene (δT = 18.3 MPa 0.5 ), and n-heptane (δH = 15.2 MPa 0.5 ) [65]. A correlation reported by Correra et al [84] (Equation ( 9)) and crude oil density at 20…”

“…Likewise, Guzmán et al [26] point out that the correlations reported in the literature are not adequate when they are used individually to establish limits on asphaltene stability in crude oils and that they have low effectiveness for stability prediction. Therefore, researchers continue their search in an attempt to find a suitable approach for predicting crude oil stability [50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66][67]. The viscosity of crude oil to be examined by the oil compatibility tests also needs to be taken into account [10,[68][69][70].…”

“…However, the full analysis of the examined petroleum fluids has not been juxtaposed with the compatibility characteristics in these research articles that could provide an explanation for the different values of colloidal stability indices. That was the reason for us choosing to investigate 48 crude oil samples pertaining to extra light (SG < 0.8017), light (0.8017 < SG < 0.855), medium (0.855 < SG < 0.922), heavy (0922 < SG < 1.00), and extra heavy petroleum crudes (SG > 1.00), which were examined for their colloidal stability by the procedure described in [65,66]. In this procedure, the solvent power and critical solvent power [34] of the studied petroleum fluids are determined.…”