Model Molecules for Evaluating Asphaltene Precipitation Onset of Crude Oils

Abstract

Predicting the compatibility of crude oils from different streams can be done by applying models that use the solubility parameter of the oils. The approximate solubility parameter value of a given crude oil can be calculated by observing the asphaltene precipitation onset caused by titration with n-heptane. For oils whose precipitation onset is not well defined, a small quantity of another petroleum with easily detected onset can be added. It would be ideal to always use the same petroleum for this addition, but this is obviously not possible. The purpose of this study was to replace this petroleum by a synthetic molecule. Therefore, molecules were selected and synthesized to obtain structures containing aromatic ring, aliphatic chain and heteroatom. The molecules were characterized by infrared spectrometry, gas chromatography-mass spectrometry, elemental analysis and gel permeation chromatography. Nitrated cardanol, polycardanol obtained by addition polymerization (PCA) and nitrated PCA presented the desired behavior. However, the concentration of the molecule in toluene needs to be adjusted in function of the characteristics of the petroleum. For a particular crude oil, when model molecule present solubility in a wider solubility parameter range, lower concentration will require to identify the precipitation onset of that oil.

Cardanol/SiO2 Nanocomposites for Inhibition of Formation Damage by Asphaltene Precipitation/Deposition in Light Crude Oil Reservoirs. Part I: Novel Nanocomposite Design Based on SiO2–Cardanol Interactions

“…Moreover, the Si–O in-plane stretching of the silanol Si–OH was detected at around 960 cm –1 , and siloxane functional groups could be detected by the symmetric stretching vibrations of Si–O–Si at 800 cm –1 . , The spectrum of the CDN reveals the O–H axial deformation of the phenol rings due to the intensity of the peaks at 3600–3200 cm –1 and the stretching and axial deformation of C–H groups at 3009 and 2920–2848 cm –1 , respectively . Besides, the axial deformation of the aromatic ring observed at 1600–1450 cm –1 and the CC out-of-plane angular deformation of alkene groups was detected by the intensity bands observed at 900 and 1000 cm –1 . , …”

“…12 Besides, the axial deformation of the aromatic ring observed at 1600−1450 cm −1 and the CC out-of-plane angular deformation of alkene groups was detected by the intensity bands observed at 900 and 1000 cm −1 . 68,78 The surface modification of the SiO 2 nanoparticles with CDN leads to a reduction in the Si−OH intensity band, which could be associated with the interaction of the polar side of the CDN monomer with the silanols groups, that promote its attachment in the SN surface. The presence of alkene compounds was detected due to the stretching and deformation of CC groups at 2920−2850 and 880 cm −1 , respectively.…”

Synthesis of Polycardanol Using BF3.O(C2H5)2 as Initiator: Influence of Polymerization Conditions on Reaction Products

“…Due to these characteristics, the structures of asphaltenes are highly complex and variable, making them difficult to identify. [28][29][30][31][32] The high molar mass, structural heterogeneity and the presence of functional groups enable their destabilization in response to variations of pressure, temperature and composition of the petroleum in production conditions. 33,34 One of the theories accepted regarding the mechanism of stabilizing asphaltenes involves the presence of surfactant molecules, whose polar groups interact with the asphaltenes and whose nonpolar groups interact with the other components of the oil.…”

Time domain NMR: An alternative for study of the asphaltenes precipitated in petroleum

“…Many techniques can detect asphaltene precipitation and the SARA (saturates, aromatics, resins, and asphaltenes) content. To name a few, viscosimetry, [11] High-Performed Liquid Chromatographic (HPLC), optical microscopy, [10] near-infrared spectroscopy (NIR), [12,13] acoustic resonance, and gravimetric methods as well thermodynamic models are some examples. [14,15] In other hand, the asphaltene quantification is commonly performed applying the ASTM D6560 standard method.…”

“…Currently, high-field NMR spectrometer is extensively used to study asphaltenes nanoaggregation and structural investigations using different pulse sequences both in solid and liquid states. Relaxation analysis with 1 H and 13 C nucleus proved to be able to monitoring asphaltene aggregation even at very low concentration ($0.2 g/L). [20][21][22][23] However, recently, the literature shows increase in the use of time domain nuclear magnetic resonance (TD-NMR) in low-field equipment for asphaltene investigations.…”