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Chen F.,Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province | Chen F.,Southwest Petroleum University | Yang M.,Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province | Yang M.,Southwest Petroleum University | And 8 more authors.
Drilling Fluid and Completion Fluid | Year: 2016

Many technologies handling CO2 contamination to drilling fluids have shortages in practical use. This paper summarizes the deficiencies of the methods commonly used, and presents advices for the treatment of CO2 contamination based on the mechanisms of contamination: drilling fluid should have moderate bentonite content, and Ca(OH)2 and CaCl2 should be used. High temperature saltresistant and highly adsorptive drilling fluid additives should be used, and old mud replaced with new one if necessary. Contamination of drilling fluids by CO2 has been encounteredin drilling the wells XX46-X1 and XX008-6-X2. To cope with the CO2 contamination in drilling the well XX46-X1, centrifuges were used to control solids content and vacuum degassers used for continuous degassing of the drilling fluid at the surface. Mud density was increased to 2.0 g/cm3 to prevent CO2 gas cut. A proper amount of 0.2% Ca(OH)2, SMP-II, SMP-III, RSTF (high temperature salt-resistant filter loss reducer), HTX (high temperature thinner) and NaOH solution were usedto minimize the negative effects of CO2 on the properties of the drilling fluid. 0.5% CaCl2 solution was used when the CO2 gas cut became severe in late period. With these treatment, the viscosity and gel strengths of the drilling fluid were reduced, and the rheology and filter loss controlled, satisfying the needs of engineering and achieving the desired results. © 2016, The Editorial Board of Drilling Fluid & Completion Fluid. All right reserved.

Dai S.,Southwest Petroleum University | Dai S.,Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province | Liu Y.,Southwest Petroleum University | Zhang J.,Southwest Petroleum University | And 3 more authors.
Composite Interfaces | Year: 2017

The interaction between acrylamide acrylicacid copolymer (PAMAA) and the modified surface of nano-SiO2 is investigated using the molecular dynamic (MD) simulation. The binding energies (Ebinding) of interface, the concentration profiles of PAMAA and functional groups (carboxyl and acylamino) of corresponding model, the mean square displacements (MSD) and diffusion coefficients (D) of PAMAA in four systems with different modifiers are all calculated at 325 K in vacuum. Vinyl trimethoxy silane (VTEOS) shows best modification effect in the systems mentioned above. Furthermore, the effects of temperature on the interaction between VTEOS modified surface of nano-SiO2 and PAMAA are studied at 300, 325, 350, 375 and 400 K in aqueous solution. Interesting results show that, water molecular layer reduces with the increase of temperature, and then improves the interaction between PAMAA and VTEOS modified surface of nano-SiO2. The corresponding Ebinding of interface, the radial distribution functions (RDF) of carbon atoms on the surface and oxygen atoms of water molecules, the concentration profiles of PAMAA on the surface of nano-SiO2, the MSD and D of PAMAA are all studied seriously to find the reason of this counterintuitive phenomenon. © 2017 Informa UK Limited, trading as Taylor & Francis Group

Zhang C.,Southwest Petroleum University | He Y.,Southwest Petroleum University | He Y.,Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province | Li F.,Southwest Petroleum University | And 3 more authors.
Journal of Alloys and Compounds | Year: 2016

A novel hybrid materials Fe3O4 nanoparticles supported by hexagonal boron nitride (h-BN) is successfully prepared via mussel-inspired chemistry of dopamine by hydrothermal synthesis method. The surface modification and microstructure of h-BN-Fe3O4 are characterized by FT-IR, XRD, XPS, SEM and TEM. The nano-Fe3O4 obtain well dispersion supported by h-BN layer platform, and the h-BN-Fe3O4 hybrid materials exhibit a remarkable superiority in enhancing the anticorrosion performance of epoxy coatings. The lamellar structural h-BN and nano-Fe3O4 provide a significant synergistic effect in anticorrosion performance for epoxy composite coatings. In addition, the anticorrosion mechanisms of h-BN-Fe3O4 are tentatively discussed. © 2016 Elsevier B.V.

Zhang Y.,Southwest Petroleum University | Fang S.,Southwest Petroleum University | Fang S.,Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province | Tao T.,Southwest Petroleum University | And 4 more authors.
Journal of Dispersion Science and Technology | Year: 2016

Oil-in-water emulsion is an innovate manner by which heavy crude oil can be transported from producing sites to transforming sites through pipelines. The effect of emulsifier on the interfacial properties and demulsification performance of demulsifier for heavy crude oil–in-water emulsion has been studied by many researchers. However, the influence of asphaltene in heavy crude oil on the interfacial properties of demulsifier has not been investigated yet. In this article, the influence of asphaltene concentration of two typical demulsifiers (straight-chained SP-1 and branch-chained AE-1) was systematically studied in terms of absorption thermodynamics, absorption kinetics, and coalescence kinetics. The results revealed that the demulsifier adsorption was a ΔS controlled spontaneous process. The absolute value of ΔG of SP-1 adsorption was found to decrease with asphaltene concentration, whilst the asphaltene concentration had no significant influence on that of AE-1. With the increase of asphaltene concentration, the demulsifiers’ adsorption rates increased, but the reorganization rates on the interface decreased. Coalescence speed of asphaltene droplet decreased with asphaltene concentration in spite of demulsifier type. Additionally, AE-1 had higher absolute value of ΔG, adsorption speed, and coalescence speed than that of SP-1 at the same condition. © 2016, Copyright © Taylor & Francis Group, LLC.

Li K.,Southwest Petroleum University | Duan M.,Southwest Petroleum University | Duan M.,Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province | Wang H.,Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province | And 3 more authors.
Colloid and Polymer Science | Year: 2015

Demulsifier is widely used in the petroleum industry to remove water from crude oil all over the word. It is believed that demulsifier reduces the stability of the oil-water interface by adsorbing on asphaltene. However, the adsorption kinetic is still unrevealed. Herein, the investigation was carried out to measure the adsorption behavior of triblock copolymer demulsifier poly (propylene oxide)-poly (ethylene oxide)-poly (propylene oxide) (PPO-PEO-PPO, which also named as SP-169 in petroleum industry) on asphaltene. In this paper, the adsorption behaviors of SP-169 on the asphaltene were investigated by dual polarization interferometry (DPI). DPI is a real-time and label-free analytical technique used to measure the structure changes of molecular layers in the solid/liquid interface. First, asphaltene was immobilized onto the silicon oxynitride chip surface by spin coating. Then, different concentrations of SP-169 solution were, respectively, injected onto the immobilized chips. Finally, the real-time mass, thickness, density changes during the adsorption process were accordingly recorded and calculated. The overall results show that the adsorption behavior of SP-169 on asphaltene obeys a two-step process. Concentration and the rearrangement of adsorbed molecule are both contribution to the adsorption of SP-169. Furthermore, the release of monomer from micelle above 300 mg/L results in special adsorption behavior. © 2015 Springer-Verlag Berlin Heidelberg

Yu Z.,Southwest Petroleum University | Yu Z.,Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province | Li F.,Southwest Petroleum University | Li F.,Oil & Gas Field Applied Chemistry Key Laboratory of Sichuan Province | And 10 more authors.
Journal of Materials Science: Materials in Electronics | Year: 2016

CuSO4·5H2O and Na2S2O3 were used as the copper and sulfur sources which were mixed with the graphene oxide (GO) solution to synthesize rGO–CuS/Cu2S heteronanostructures by a facile one-pot method. Scanning electron microscopy, transmission electron microscope, and X-ray photoelectron spectroscopy observations show the morphology and elemental distribution of the composites, confirming that CuS/Cu2S heteronanostructures are decorated on the GO sheets. The experimental results of photocatalytic degradation also show that the novel composites exhibit remarkable visible-light photocatalytic activities for methylthionine blue dye degradation whose degradation rate is 96 %. The high visible photocatalytic performances are attributed to photoinduced interfacial charge transfer in the heteronanostructures and their further transfer by rGO sheets. This new composition is expected to show considerable potential applications in water purification. © 2016 Springer Science+Business Media New York

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