AFM Characterization of Organic Deposits on Metal Substrates from Mexican Crude Oils

Abstract

Atomic force microscopy (AFM) has been used to investigate eight different Mexican crude oils in the form of deposited films on metal substrate. Most oils had reported asphaltene deposition problems during production. Two other techniques related to hydrodynamic size determination were applied: light scattering and HPLC-SEC. According to the observed AFM surface morphology characteristics oil films were classified and grouped into distinct groups. Some had dense population of 40-200 nm particles, while others had larger discoid features and smaller particles. Light scattering analysis indicates observed particles to be organic as they disappear upon dilution with toluene. Correlation between the oil film AFM morphology and physicochemical properties of the oil did not reveal a simple relationship. Indeed, oils with similar bulk fluid properties show different morphology as films. With respect to the crude oil instability and the well-deposition problem, it was found that five of the investigated oils (unstable) with known problems of asphaltene deposition during production, contain spherical or discoid nanoparticles in the range of 35 to 500 nm. Films prepared from the stable oils possess apparent two-dimensional (2D) characteristics (spread over the substrate) without particular features. Detail of AFM analysis show that oil instability can be related to films and oils with higher density of particles, and films with larger particles. It emphasizes AFM, as a technique potentially useful for the welldeposition problem detection. HPLC-SEC data show that oils from similar geographic zones have similar fluid properties in terms of composition and hydrodynamic size distribution but on the other hand could display different AFM morphology features. The results show that AFM is a promising tool for the oil film characterization and determination of surface properties, which may leads to development of a better understanding of well-deposition and adherence.

Study of the Corrosive Behavior of the AISI 1020 Steel in Acid Crude Oil by Microscopic Techniques (LM, AFM and SEM/EDX) and Raman Spectroscopy

“…SEM/EDX analyses ( Figure 3 and Table 4) were also employed in these studies because they presented a spatial resolution higher than of LM. 23,32 SEM/EDX analyses reveal that the light layer (external) is characterized by sulfur crystals and the dark layer (internal) by a homogeneous layer of iron oxides and oxyhydroxides ( Figures 3B-3F and Table 4). This morphology is altered after 48 h of thermal degradation (Figure 3F), where the formation of a single layer occurs and is composed of crystals of FeS ( Figure 3G).…”

“…22,23 Negative asymmetry indicates a predominance of valleys, whereas a positive asymmetry indicates the formation of peaks. 23 The peak-peak height is determined by subtracting the value of the highest peak from the lowest peak value in the specific topographic area.…”

“…22,23 Negative asymmetry indicates a predominance of valleys, whereas a positive asymmetry indicates the formation of peaks. 23 The peak-peak height is determined by subtracting the value of the highest peak from the lowest peak value in the specific topographic area. 22 The Ssk is determined by equation 5, that measures the difference of symmetry of the profile with regard to the median plane, where R Q is the root mean square of the height deviation; n is the number of points within the image grid and Z is the height of the surface with regard to the median plane.…”

Adsorption and Aggregation of Asphaltenes in Petroleum Dispersed Systems

“…Asphaltene and resin adsorption was studied by a great number of research groups (Ekholm et al, 2002;TatNIPI, 1988;Balabin&Syunyaev, 2008;Syunyaev et al, 2009;Acevedo et al, 2000;Lopez-Linares et al, 2006;Gonzalez&Middea, 1987;Drummond&Israelachvili, 2004;Toulhoat et al, 1994;Akhlaq et al, 1997;Dudasova et al, 2007;Alboudwarej et al, 2005;Batina et al, 2003;Batina et al, 2005;Castillo et al, 1998;Acevedo et al, 1998;Acevedo et al, 2000;Acevedo et al, 2003;Ekholm et al, 2002;Xie&Karan, 2005;Dudasova et al, 2008;Rudrake et al, 2009;Abdallah&Taylor, 2007;Labrador et al, 2007;Turgman-Cohen et al;. Adsorption of asphaltenes on solid surfaces has been characterized by several experimental techniques, including measurement of contact angles (Drummond & Israelachvili, 2004;Toulhoat et al, 1994;Akhlaq et al, 1997), UV and NIR spectroscopy (Dudasova et al, 2007;Alboudwarej et al, 2005), atomic force microscopy (Toulhoat et al, 1994;Batina et al, 2003;Batina et al, 2005), Fourier transform infrared microscopy (Batina et al, 2005), photothermal surface deformation Acevedo et al, 1998;Acevedo et al, 2000;Acevedo et al, 2003), quartz microbalance (Ekholm e...…”

“…Adsorption of asphaltenes on solid surfaces has been characterized by several experimental techniques, including measurement of contact angles (Drummond & Israelachvili, 2004;Toulhoat et al, 1994;Akhlaq et al, 1997), UV and NIR spectroscopy (Dudasova et al, 2007;Alboudwarej et al, 2005), atomic force microscopy (Toulhoat et al, 1994;Batina et al, 2003;Batina et al, 2005), Fourier transform infrared microscopy (Batina et al, 2005), photothermal surface deformation Acevedo et al, 1998;Acevedo et al, 2000;Acevedo et al, 2003), quartz microbalance (Ekholm et al, 2002;Xie&Karan, 2005;Dudasova et al, 2008;Rudrake et al, 2009), X-ray photoelectron spectroscopy (Dudasova et al, 2007;Abdallah&Taylor, 2007) and ellipsometry (Labrador et al, 2007;Turgman-Cohen et al, 2009). In this study we studied influence of porosity of the rock on adsorption parameters of the asphaltenes.…”