How polymer additives reduce the pour point of hydrocarbon solvents containing wax crystals

Mitigation and Remediation Technologies of Waxy Crude Oils’ Deposition within Transportation Pipelines: A Review

Deposition of wax is considered one of the most significant culprits in transporting petroleum crude oils, particularly at low temperatures. When lowering pressure and temperature during the flow of crude oil, the micelle structure of the crude oil is destabilized, allowing oil viscosity to increase and precipitating paraffin (wax) in the well tubulars and pipeline, which increase the complexity of this culprit. These deposited substances can lead to the plugging of production and flow lines, causing a decline in oil production and, subsequently, bulk economic risks for the oil companies. Hence, various approaches have been commercially employed to prevent or remediate wax deposition. However, further research is still going on to develop more efficient techniques. These techniques can be categorized into chemical, physical, and biological ones and hybridized or combined techniques that apply one or more of these techniques. This review focused on all these technologies and the advantages and disadvantages of these technologies.

Role of a Nanocomposite Pour Point Depressant on Wax Deposition in Different Flow Patterns from the Perspective of Crystallization Kinetics

Wax deposition is one of the core issues affecting flow assurance studies of crude oil pipelines, particularly with deep and ultradeep water conditions. Nanocomposite pour point depressants (NPPDs) provide a novel and effective strategy for inhibiting wax deposition and have recently attracted increasing research attention. Although recent advances have been made in understanding the performance and mechanism of NPPDs, the effect of flow pattern remains an open question. In this paper, deposition thicknesses of waxy oils with different flow patterns and NPPD dosages were obtained using a flow loop experimental device. It was found that the NPPD used in the current work can effectively inhibit the formation of wax deposition layers in different flow patterns. The Avrami model-focused beam reflectance measurement and polarizing microscope experiment method were used to characterize crystallization kinetics parameters and mesoscopic structure parameters of wax crystals. The consistency of results from Avrami equation fitting parameters, wax crystal morphology, and particle number supported the validity of crystallization kinetics analysis. The mechanisms of NPPD in different flow regimes were discussed. The inhibition of laminar and turbulent deposition layers by NPPD was attributed to the improvement of wax crystal morphology and the reduction of wax crystal number, respectively. This has important consequences for our understanding of the utilization and mechanism of nanocomposite pour point depressants.

Synthesis of crystallizable poly(behenyl methacrylate)-based block and statistical copolymers and their performance as wax crystal modifiers

Behenyl methacrylate-based diblock and statistical copolymers are evaluated as additives for the crystal habit modification of a model wax (n-octacosane) in n-dodecane. The statistical copolymers more strongly influence the wax crystal morphology.

Magnetic Organic-Inorganic Nanohybrid for Efficient Modification of Paraffin Hydrocarbon Crystallization in Model Oil

Crystallization modification has been applied in many fields, such as materials science, petroleum engineering, and chemical engineering. The modification of organic-inorganic hybrids via paraffin hydrocarbon crystallization has been significantly important for the exploration of undersea oil and gas resources. In this work, a metal oxide organic-inorganic hybrid pour point depressant (MOIH-PPD) is provided along with an analysis of the microscopic structure of the paraffin hydrocarbon crystal employing small-angle X-ray scattering and X-ray diffraction. The MOIH-PPD modified crystal grain exhibited a decrease in the long period and in the radius of gyration of the crystal grain and an increase in the thickness of the interface layer compared with those of the unmodified paraffin crystal. In addition, the synergistic effect of heterogeneous nucleation and the magnetic response of MOIH-PPD on the paraffin hydrocarbon system was also investigated, revealing that the synergism modification yields stress superior to that of MOIH-PPD or magnetic field alone, which provides insight into the possibility of the modification of paraffin hydrocarbon crystallization.