225.00 275.00 250.00 200.00
ASI estimated, Lifespan model predictions Experimental values Oil compat i bility model
175.00
150.00 125.00
100.00
75.00
50.00
25.00
0.00
0
10.00
20.00
30.00
40.00
50.00
60.00
70.00
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% crude C
Figure 2 Comparison of the Lifespan blending model predictions vs the standard Oil Compatibility Model
and data on crude composition available from any crude assay, Baker Hughes developed a proprietary method for the determination of blending compatibility of crude oils based on asphaltenes thermodynamics. While there are known compatibility models, these mod- els, when tested vs experimental data on test blends, fail with the important class of ‘asymmetric’ crude mixtures, mixtures of crudes with very different content, and In value of their asphaltenes (see Figure 2 ). The typical case is blending of light vs heavy crudes. The Lifespan blending model is also available online as a service on a web plat- form for access 24/7 with a very wide database of compo- nent crudes, allowing complex blends of many crudes to be tested. RAM uses the collaboration with Baker Hughes to determine the stability and fouling potential of binary blends and more complex blends and optimise the eco- nomics with the best trade-off between fouling and prod- uct yields/quality. Figure 3 shows the determination of the compatibility by the Lifespan blending model for Azeri crude with one WTI cargo and Southern Green Canyon. It is clear from Figure 3 that WTI significantly decreases the stability of the Azeri crude. In the case of Southern Green Canyon, there is
evidence of incompatibility with a minimum of stability at about 5% Southern Green Canyon. LSCI: From stability to fouling potential Stability is a balance of the impact of the difference of sol- ubility parameter of oily matrix (solvating power) and the asphaltenes solubility parameter. This is measured by the field ASIT at laboratory conditions up to a maximum tem - perature of 100°C. The thermodynamic theory on which the field ASIT is based, combined with laboratory tests, shows an exponential increase of asphaltenes phase separation, resulting in an exponential increase of the fouling potential (amount of destabilised asphaltenes). The stability measurements, like the ASIT, are based on the destabilisation of the asphaltenes by adding a par- affinic precipitant. This effect of destabilisation happens during crude unit processing due to temperature increases. Literature on thermodynamic modelling of asphaltene sta- bility is confirmed by calculations by our technology team. Therefore, there is a need to relate the ASIT measurement to the fouling potential (fouling rates) at the typical crude unit process conditions. Based on thermodynamics, test data from laboratory heat
Stability (ASI), AZERI + WTI
Stability (ASI), WTI + Southern Green Canyon
350.0 400.0
130.0 150.0
300.0
110.0
250.0
90.0
200.0
70.0
150.0
50.0
100.0
30.0
0 50.0
-10.0 10.0
10
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0
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% WTI
% SGC
Figure 3 The determination of the compatibility by the Lifespan model for Azeri crude with one WTI cargo and Southern Green Canyon
37
PTQ Q4 2024
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