Flowability Of Crude Oil Research Articles

Molecular dynamics simulation of CO2 dissolution-diffusion in multi-component crude oil

In order to study the dissolution-diffusion process and mechanism of CO2 in multi-component crude oil, a model of multi-component crude oil system with octane as the main component and 16 other alkanes as a compound was constructed by using molecular dynamics simulation method. We estimated the CO2 density distribution in crude oil model and the shift in crude oil model volume change. We then investigated the microscopic influence mechanism of CO2 dissolution-diffusion on the volume expansion of crude oil by simulating the action of CO2 dissolution-diffusion in the multi-component crude oil model. Based on the variation law of mean square displacement between crude oil molecules, the dissolution and diffusion coefficients of CO2 were predicted, and the influence of CO2 dissolution-diffusion on crude oil mobility was analyzed. It is found that temperature intensifies the molecular thermal motion and increases the voids between alkane molecules, which promotes the dissolution of CO2 and encourages CO2 molecules to transmit, making the crude oil expand and viscosity decrease, and improving the flow ability of crude oil; with the enhancement of given pressure, the potential energy difference between the inside and outside of the crude oil model becomes larger, and the voids between alkane molecules become larger, which is favorable to the dissolution of CO2. Nevertheless, the action of CO2 molecules’ diffusing in the crude oil sample is significantly limited or even tends to zero, besides, the mobility of crude oil is affected due to the advance of external pressure. The mechanism of CO2 dissolution and diffusion in multi-component crude oil is revealed at the microscopic level, and provides theoretical guidance for the development of CO2 flooding.

The effects of SKO on Assam crude oil

The energy demand for crude oil (CO) has increased globally which encourages the growth in the petroleum industry worldwide. When CO is transported through a pipeline over long distances, due to the change in environmental circumstances, the flow behavior of CO also changes. To improve the flowability of CO through the pipeline, a better understanding of the rheological behavior of CO is very important. In this paper, several experiments were conducted to improve the flowability of CO through pipeline transportation. Dilution of CO with its products like Superior Kerosene Oil (SKO) was selected as it improves the CO flowability through the pipeline and is economically affordable. In this study, the effect of SKO on oAPI gravity, Pour Point, Gel Point, Viscosity Gravity Constant, and rheological parameters were studied for the CO of Upper Assam Basin, Assam. SKO was mixed with CO in different ratios to examine the effect of SKO on it. The results obtained showed that with the addition of SKO, oAPI increases, the minimum limit of attaining paraffinic nature of CO samples can be determined, heavier CO may not always have high Pour Point and Gel Point. The variation in yield stress of CO with SKO was also observed. Hershel-Buckley Model (HBM) was used and from the three parameters of HBM, the shear-thinning or shear thickening behavior of CO was determined. Therefore, this paper attempts to study the flow behavior of CO and also to identify the % of SKO required for improving their flowability through the pipeline.

Effect of modified ethylene vinyl acetate copolymers pour point depressants on flow properties of crude oil and corresponding mechanism analysis

In order to explore the influences of the alkyl chain length and type of polar groups of the PPDs (pour point depressants) on the crystallization characteristics and flow ability of crude oil, a series of new maleic anhydride derivative graft modified EVA (ethylene vinyl acetate) copolymers PPDs were synthesized. All the new copolymers were characterized by fourier transforms infrared (FT-IR) spectrum analysis, proton nuclear magnetic resonance ( 1 H NMR) and gel permeation chromatography (GPC). The results showed that all the new PPDs exhibited better performance in improving the fluidity and delaying the gelling of crude oil than EVA PPD. Moreover, copolymer containing alkyl chain with 18 carbon atoms exhibited better performance than those bearing alkyl chains of other carbon number in depressing the pour point, a pour point drop up to 19 ℃ was obtained by using 0.1 wt% of that PPD, which was conductive to co-crystallization of PPD molecules and wax molecules. However, copolymer containing benzene ring exhibited the best performance in depressing the pour point by 22 ℃ at the concentration of 0.1 wt%, which can change the growth characteristics of wax crystals and delay the aggregation of asphaltene and resin, thus effectively improve the flow ability of crude oil. • A series of new graft modified ethylene vinyl acetate (EVA) copolymers PPDs were synthesized. • The effects of graft modified EVA copolymers PPDs were obviously superior to that of EVA PPD. • 0.1wt% EM-B PPD exhibited best depression effect on the crude oil with 25wt% wax content. • The mechanisms of the interaction between crude oil and PPD were analyzed and described in detail.

Change in the cold flowability and wax deposition of crude oil by weak magnetic treatment

The research aims to study how the magnetic fields affect the cold flowability and wax deposition of the crude oil, which has been stirred by the low-intensity magnetic field for a long time. The corresponding cold flowability of crude oil can be improved under a certain level of exposure of magnetic field (60 mT with 600r/min stirring, in a 30 min exposure), which the crude oil tends to behave like Newtonian liquids. The magnetized oil could still maintain the viscosity-reduction effect when the temperature drops to a lower level, the viscosity-reduction rate was more than 10% near the pour point. What lead to the viscosity-reduction effect of magnetized oil is the promotion of the nucleation process of crystal, and subsequently, the obstruction of crystallization. It could be concluded that the weak magnetic treatment could also inhibit wax deposition based on the investigations of the deposition mass under two setups by treating the oil with or without magnetic field. Based on what has been observed in the present study, the wax who adhere to the cold finger tend to be more compact than it used to be after the magnetic treatment.

Effect of Heteroaromatic Pendants in Comb Copolymers on Paraffin Crystallization and Cold Flow Ability of Crude Oil

Adding comb copolymers as chemical additives is considered an effective and convenient method to improve the cold flow ability of crude oils. To improve the effectiveness of comb copolymers on the flow ability modification for crude oils with asphaltenes, poly(maleic acid amide-α-octadecene) with benzimidazolyl pendants (MACB) were designed and synthesized. In comparison to reported comb maleic anhydride copolymers (MAC) with octadecyl (MACO) or phenyl (MACP) pendants, MACB with heteroaromatic pendants are more efficient in reducing the yield stress of both model oil and Liaohe crude oil, as revealed by rheological measurements, in modifying the morphology of wax crystals, as observed by polarizing light microscopy (PLM), in lowering the wax appearance temperature (WAT) and quantity of wax precipitation, as determined by differential scanning calorimetry (DSC), and in decreasing the crystallinity of paraffins, as measured by X-ray diffraction (XRD). The benzimidazolyl pendants in MACB can provide both hyd...

Effect of Comb-type Copolymers with Various Pendants on Flow Ability of Heavy Crude Oil

Modification of the paraffin crystallization and flow ability of waxy crude oil is of vital importance during transportation and restart processes at low temperature. To investigate the influence of pendants in comb-type copolymers on the cold flow ability of crude oil, maleic anhydride-α-octadecene copolymer and its derivatives with octadecyl (MAC), phenyl (AMAC), or naphthalene (NMAC) pendants were synthesized. These derivatives, when added to waxy crude oil, change the size and quantity of the paraffin crystals observed by polarizing light microscopy (PLM), improve the flow ability of waxy oils by reducing the viscosity and yield stress revealed by rheometer, and decrease the paraffin crystallization temperature and quantity of wax precipitation determined by differential scanning calorimetry (DSC). AMAC had the greatest effect followed by MAC and NMAC, respectively. It seems that small aromatic pendants improve the flow ability of waxy oils by adsorbing on the surface of asphaltenes, while large aroma...

ISC Application in Heavy Oil Reservoir after CSS

In order to improve the flowability of crude oil, heavy oil reservoir usually developed by steam injection. While this process produces a lot of greenhouse gases. To deep reservoir, heat loss in the wellbore tends to more severe and thermal efficiency is lower. In-situ Combustion (ISC) is featured by heavy components’ combustion, high thermal efficiency and high oil recovery. Those advantages are outstanding especially in the aspects of improving thermal efficiency and reducing greenhouse gas emissions. This paper researched on ISC EOR process in a complex fault block, including reservoir design and performance evaluation. Remarkable development results have been achieved, which shows the potential for ISC technology and this paper provides a reference for the development of similar reservoirs.

Synthesis of poly(maleic acid alkylamide-co-α-olefin-co-styrene) and their effect on flow ability of oils

To improve the flow ability of crude oil with high content of aromatic asphaltenes, new comb-type copolymers of poly(maleic anhydride-co-α-olefin-co-styrene) (MASCs) with different ratios of maleic anhydride (MA) to styrene were designed and synthesized. 1H NMR and FTIR spectra were used to characterize the chemical structure of the copolymers. The effect of copolymers on the flow ability of model waxy oil and crude oil were studied by rheological method and polarizing light microscopy. Upon the addition of MASCs, the yield stresses of oils were decreased by 1 to 3 orders of magnitude, and the morphology of paraffin crystals were reduced and changed from plates to needles.