The Choice of the Optimal Strategy for the Use of Solvents of High-Molecular Organic Deposits, Considering their Complex Composition and the Effect on the Oil Dispersion System

The long-term practice of operating wells producing oil rich in paraffins and asphaltenes has shown that the optimization of technologies for the removal of solid high-molecular organic deposits (asphaltene-resin-paraffin deposits) in oilfield equipment, lifting pipes and flow lines makes it possible to effectively solve the issues of improving the environmental friendliness and energy efficiency of oil production. The use of composite hydrocarbon solvents is one of the most well-known methods used to remove asphaltene-resin-paraffin deposits. Thus, to date, there is no systemic solution to this issue. This paper is aimed at discussing the provisions that determine the possible prospects for the development of an optimal strategy for the use of solvents for the removal of asphaltene-resin-paraffin deposits.

Effect of Wettability on Vaporization of Hydrocarbon Solvents in Capillary Media

Summary Tight rock reservoirs have gained popularity and become a subject of great interest because of their huge recovery potential. A substantial portion of the potential hydrocarbon could be removed from the reservoir by injecting solvent gases [hydrocarbon or carbon dioxide (CO2)] as an enhanced-oil-recovery (EOR) application. Achieving precise modeling of these processes and an accurate description of hydrocarbon dynamics requires a clear understanding of phase-change behavior in a confined (capillary) medium. It was previously shown that early vaporization of liquids could occur in channels that were larger than 1000 nm. The surface wettability plays a critical role in influencing the vaporization and condensation nature in confined systems. This paper studies the influence of the medium wettability on phase-transition temperatures of liquid hydrocarbons in macrochannels (greater than 1000 nm) and nanochannels (less than 500 nm) by using different types of rock samples. The boiling temperature of hydrocarbon solvents was measured in two extreme wetting conditions: (1) strongly water-wet and (2) strongly oil-wet. Boiling temperatures of heptane and octane in sandstone, limestone, and tight sandstone were observed to be lower than their bulk boiling points by 13% (4% in Kelvin units), on average. Altering rock wettability characteristically changes the average hydrocarbon nucleation temperatures, being as critical as the pore size. Changing sandstone’s wettability to strongly oil-wet shifted the average nucleation temperature of heptane and octane by 6% (1.3% in Kelvin units) and 15% (0.8% in Kelvin units), compared with cases before wettability alteration. The experimental outcomes also showed that reducing the solvent adsorption on clays in Berea sandstone lowers the nucleation temperature of heptane and octane from their normal phase-change temperatures by 20% (4.3% in Kelvin units) and 30% (6.5% in Kelvin units). In comparison with the medium wettability alteration, reducing the solvent adsorption had a greater influence on nucleation temperatures. Such a phenomenon shows that molecule-solid interactions have more control of altering the phase behavior of solvents than of medium wettability.

Preparation of High-Purity Ammonium Tetrakis(pentafluorophenyl)borate for the Activation of Olefin Polymerization Catalysts

Homogeneous olefin polymerization catalysts are activated in situ with a co-catalyst ([PhN(Me)2-H]+[B(C6F5)4]− or [Ph3C]+[B(C6F5)4]−) in bulk polymerization media. These co-catalysts are insoluble in hydrocarbon solvents, requiring excess co-catalyst (>3 eq). Feeding the activated species as a solution in an aliphatic hydrocarbon solvent may be advantageous over the in situ activation method. In this study, highly pure and soluble ammonium tetrakis(pentafluorophenyl)borates ([Me(C18H37)2N-H]+[B(C6F5)4]− and [(C18H37)2NH2]+[B(C6F5)4]−) containing neither water nor Cl− salt impurities were prepared easily via the acid–base reaction of [PhN(Me)2-H]+[B(C6F5)4]− and the corresponding amine. Using the prepared ammonium salts, the activation reactions of commercial-process-relevant metallocene (rac-[ethylenebis(tetrahydroindenyl)]Zr(Me)2 (1-ZrMe2), [Ph2C(Cp)(3,6-tBu2Flu)]Hf(Me)2 (3-HfMe2), [Ph2C(Cp)(2,7-tBu2Flu)]Hf(Me)2 (4-HfMe2)) and half-metallocene complexes ([(h5-Me4C5)Si(Me)2(k-NtBu)]Ti(Me)2 (5-TiMe2), [(h5-Me4C5)(C9H9(k-N))]Ti(Me)2 (6-TiMe2), and [(h5-Me3C7H1S)(C10H11(k-N))]Ti(Me)2 (7-TiMe2)) were monitored in C6D12 with 1H NMR spectroscopy. Stable [L-M(Me)(NMe(C18H37)2)]+[B(C6F5)4]− species were cleanly generated from 1-ZrMe2, 3-HfMe2, and 4-HfMe2, while the species types generated from 5-TiMe2, 6-TiMe2, and 7-TiMe2 were unstable for subsequent transformation to other species (presumably, [L-Ti(CH2N(C18H37)2)]+[B(C6F5)4]−-type species). [L-TiCl(N(H)(C18H37)2)]+[B(C6F5)4]−-type species were also prepared from 5-TiCl(Me) and 6-TiCl(Me), which were newly prepared in this study. The prepared [L-M(Me)(NMe(C18H37)2)]+[B(C6F5)4]−-, [L-Ti(CH2N(C18H37)2)]+[B(C6F5)4]−-, and [L-TiCl(N(H)(C18H37)2)]+[B(C6F5)4]−-type species, which are soluble and stable in aliphatic hydrocarbon solvents, were highly active in ethylene/1-octene copolymerization performed in aliphatic hydrocarbon solvents.

Impact of acid activated Bentonites on foster swelling capacity and sorption dynamics of hydrocarbons, phenol and water

The successful protonation of the dissociable 𝐻 + from different organic acids (with varying alkyl chains) to supplant sodium ions in the inter layers of bentonites resulting in increased surface area has been carried out. The resultant materials were characterized using foster swelling and adsorption capacity techniques. Results show that the foster capacities of acid activated bentonites were greater than the un-activated bentonite (UAB) upon interaction with petroleum hydrocarbons. The bentonite activated with the organic acid having the most alkyl chain, hexanoic acid activated bentonite (HAAB) showed high affinity for all petroleum hydrocarbons. This demonstrates the hydrophilicity of UAB and upon activation, the hydrophobic properties of HAAB. The adsorption capacity result records that bentonites and HAAB adsorbed more petroleum hydrocarbon solvents than other lower alkyl chain acid activated bentonites and UAB. This study shows that HAAB is an excellent adsorbent for the removal of hydrocarbons from industrial wastes. Keywords: Acid Activated Bentonite, Foster Swelling, Adsorption Capacity, Organic Acids, Phenol

Removal of Vanadium and Nickel Ions from Iraqi Atmospheric Residue by Using Solvent Extraction Method

Iraqi crude Atmospheric residual fraction supplied from al-Dura refinery was treated to remove metals contaminants by solvent extraction method, with various hydrocarbon solvents and concentrations. The extraction method using three different type solvent (n-hexane, n-heptane, and light naphtha) were found to be effective for removal of oil-soluble metals from heavy atmospheric residual fraction. Different solvents with using three different hydrocarbon solvents (n-hexane, n-heptane, and light naphtha) .different variables were studied solvent/oil ratios (4/1, 8/1, 10/1, 12/1, and 15/1), different intervals of perceptual (15, 30-60, 90 and 120 min) and different temperature (30, 45, 60 and 90 °C) were used. The metals removal percent were found depending on the yield of asphaltene. The solvent-oil ratio had important effects on the amount of metal removal. The metals removal was increased at increasing temperatures from 30 to 90 0C increases the metal ion precipitated. The highest Ni precipitated was 79.23 ppm using heptane at 90 0C while for V the highest value was 64.51 ppm using also heptane at 90 0C, while the mixing time decreased metals removal. With increasing asphalt yield, the removal of metal was more selective. Among the solvents used in the extraction treatment method, the highest Ni precipitated was 76 ppm using hexane at 150 ml solvent and showed the most promising results. Increasing mixing time increases metals removal for V, the highest value was 65.51 ppm using either heptane or light naphtha. The highest Ni precipitated was 78 ppm using heptane at 120 min while for V the highest value was 67 ppm using either heptane or light naphtha after 120 min.

Effect of Clay Type on Emulsion Formation in Steam and Solvent Steamflooding

Summary The objectives of this study are to perform a fundamental analysis of the mutual interactions between crude oil components, water, hydrocarbon solvents, and clays, and to determine the optimum hydrocarbon solvent in solvent steamflooding for a particular reservoir type. The water/oil emulsion formation mechanism in the obtained oil for steam and solvent steamflooding processes has been studied via intermolecular associations between asphaltenes, water, and migrated clay particles. A series of 21 steam and solvent-steamflooding experiments has been conducted, first without any clays in the oil/sand packing, and then using two different clay types in the reservoir rock: Clay 1, which is kaolinite, and Clay 2, which is a mixture of kaolinite and illite. Paraffinic (propane, n-butane,n-pentane,n-hexane,n-heptane) and aromatic (toluene) solvents are coinjected with steam. Cumulative oil recovery is found to decrease in the following order: no clay, Clay 1, Clay 2. Based on the obtained produced oil analyses, Clay 1 and Clay 2 are found to have an affinity with the water and oil phases, respectively. Moreover, the biwettable nature of Clay 2 makes it dispersed in the oil phase toward the oil/water interface, stabilizing the water/oil emulsions. Paraffinic solvent n-hexane is found to be an optimum coinjector for solvent steamflooding in bitumen recovery.