Surface modification of polymers by ion-assisted reaction

This paper deals with a new surface modification technique of polymers, the so-called ion-assisted reaction (IAR) to improve the surface properties of polymers and provides outstanding experimental results regarding wettability and adhesion of various polymers. In the IAR, polymer surfaces were subjected to low energy ion irradiation at different dosage in reactive gas environment. Dramatic improvements in wettability and surface energy are observed for the IAR-treated polymer surfaces and can be explained by the addition of functional groups, responsible for the increase of polar component in surface energy. The formation of functional groups results from the interaction among ion, reactive gas and polymer chain involved in IAR treatment, depending on the reactive ion species, the flow rate of the reactive gas and the irradiating ion fluence. The improvement in adhesion between the IAR-treated polymers and coating materials was explained in terms of the increased surface energy as well as surface roughness in the polymers modified by the IAR and possible adhesion enhancement mechanism is to be discussed.     

Effect of scale and corrosion inhibitors on well productivity in reservoirs containing asphaltenes

During oil production from several wells in Arabian Gulf area, significant productivity decline was noticed. One of the reasons behind the productivity decline might be asphaltene precipitation. Production data of the particular wells were collected and analyzed. It was found that many of these wells were injected with scale and corrosion inhibitors in downhole and surface equipment. Thus, it was desired to investigate the potential of formation damage due to asphaltene in the presence of scale and corrosion inhibitors as field chemicals. The effect of asphaltenes on the wettability, surface, and interfacial tensions were measured in the presence of scale and corrosion inhibitors. It was observed that the scale inhibitor did not indicate any alteration of the wettability, while the presence of corrosion inhibitor indicates high potential for wettability change into oil-wet conditions especially in the presence of asphaltenic oil. Similar results were obtained from the measurements of surface and interfacial tensions, in which corrosion inhibitors showed a significant decrease in surface and interfacial tensions. To assess the potential of asphaltene precipitation in the presence of both inhibitors and to study the effect of asphaltenes on the oil productivity, flooding experiments were carried out and oil/water relative permeability was determined.The results of flooding displacements showed that the presence of scale inhibitors indicates no effect on the oil/water relative permeability even in the presence of asphaltenes, while a significant decrease in oil relative permeability associated with an increase of residual oil saturation was observed in the presence of corrosion inhibitors.Mixture of scale and corrosion inhibitors showed no effect on relative permeability curves.     

(AgCu28)80InxSn(20-x)钎料的熔化特性及其铺展性研究

采用差示扫描量热仪研究了合金的熔化特性。结果表明：该合金在489～496℃处具有554～604℃两个明显的吸热带，添加11wt％的In时，其只存在496℃与603．6℃两个吸热峰。润湿与铺展性能测试表明该合金能很好地润湿紫铜，在In添加量大于12wt％时，随着In含量的增加铺展率变大。     

Theoretical and experimental evidence of different wettability classes

In this paper we analyze data from thirteen North Sea sandstone reservoirs that fall into the large group of intermediate wettability. By dividing this group into three sub-classes, fractionally-wet (FW), mixed-wet large (MWL) and mixed-wet small (MWS), we find an improved understanding of the intermediate-wet state. In the fractionally-wet state oil- and water-wet sites are random with respect to size, while in the mixed-wet state water- and oil-wet pores are sorted by size. We assume two classes of mixed wettability; MWL where the large pores are oil-wet and MWS where the small pores are oil-wet. The paper includes both theoretical considerations, pore–scale observations by ESEM, SEM and thin sections, as well as core scale wettability indices that indicate that these wettability states may exist in reservoirs.     

响应面法优化纳米材料稳定的泡沫钻井液

为提高泡沫钻井液的稳定性,向体系中引入纳米材料,并研究了纳米材料润湿性对于泡沫质量的影响。根据Box-Behnken Design设计原理,采用三因素三水平响应曲面法,优化了起泡剂BS-12、亲水性纳米SiO2和增黏剂XC的加量,探究了它们之间交互作用对于泡沫综合指数的影响,并以此为基础研制了泡沫钻井液体系。结果表明,纳米材料润湿性会显著影响不同类型起泡剂的泡沫质量,疏水性纳米材料能够提高阴离子起泡剂SDS的泡沫稳定性,但对两性离子起泡剂BS-12的泡沫起泡量和半衰期呈现负相关关系,亲水性纳米材料才能提高两性离子起泡剂BS-12的泡沫稳定性;通过响应曲面优化设计得到的最优浓度配比为：0.6% BS-12+4%纳米SiO2+0.3% XC。响应曲面分析表明,对于泡沫综合指数的显著性影响程度,纳米材料浓度 > 起泡剂浓度 > XC浓度;纳米稳定的泡沫钻井液体系性能评价表明,该体系表观黏度为42mPa·s,密度为0.81 g/cm3,半衰期达60 h,能长时间保持性能稳定,抑制性强,线性膨胀率较清水下降65%,储层保护效果好,煤岩岩心气测渗透率恢复率在90%以上,携岩效果好,岩屑和煤屑的沉降速度较清水降低92%以上,能够满足现场煤层气钻井的需要。     

The effect of nanoparticles on wettability alteration for enhanced oil recovery: micromodel experimental studies and CFD simulation

The applications of nanotechnology in oilfields have attracted the attention of researchers to nanofluid injection as a novel approach for enhanced oil recovery. To better understand the prevailing mechanisms in such new displacement scenarios, micromodel experiments provide powerful tools to visually observe the way that nanoparticles may mobilize the trapped oil. In this work, the effect of silicon oxide nanoparticles on the alteration of wettability of glass micromodels was investigated in both experimental and numerical simulation approaches. The displacement experiments were performed on the original water-wet and imposed oil-wet (after aging in stearic acid/n-heptane solution) glass micromodels. The results of injection of nanofluids into the oil-saturated micromodels were then compared with those of the water injection scenarios. The flooding scenarios in the micromodels were also simulated numerically with the computational fluid dynamics (CFD) method. A good agreement between the experimental and simulation results was observed. An increase of 9% and 13% in the oil recovery was obtained by nanofluid flooding in experimental tests and CFD calculations, respectively.     

Experimental investigation into Fe3O4/SiO2 nanoparticle performance and comparison with other nanofluids in enhanced oil recovery

Nanofluids because of their surface characteristics improve the oil production from reservoirs by enabling different enhanced recovery mechanisms such as wettability alteration, interfacial tension (IFT) reduction, oil viscosity reduction, formation and stabilization of colloidal systems and the decrease in the asphaltene precipitation. To the best of the authors’ knowledge, the synthesis of a new nanocomposite has been studied in this paper for the first time. It consists of nanoparticles of both SiO₂ and Fe₃O₄. Each nanoparticle has its individual surface property and has its distinct effect on the oil production of reservoirs. According to the previous studies, Fe₃O₄ has been used in the prevention or reduction of asphaltene precipitation and SiO₂ has been considered for wettability alteration and/or reducing IFTs in enhanced oil recovery. According to the experimental results, the novel synthesized nanoparticles have increased the oil recovery by the synergistic effects of the formed particles markedly by activating the various mechanisms relative to the use of each of the nanoparticles in the micromodel individually. According to the results obtained for the use of this nanocomposite, understanding reservoir conditions plays an important role in the ultimate goal of enhancing oil recovery and the formation of stable emulsions plays an important role in oil recovery using this method.     

Characteristics of Polypeptide/Phospholipid Monolayers on Water and the Plasma-Activated Polyetheretherketone Support

Polyetheretherketone (PEEK) is a highly biocompatible polymer widely used in medicine as an implant production material. In this article, the PEEK surface was characterized in terms of its wettabillity properties after the physicochemical modifications by treatment with the low-temperature air plasma and covering with the Langmuir–Blodgett (LB) monolayers of polypeptide (cyclosporine A, CsA) and/or phospholipid (1,2-dipalmitoyl-sn-glycero-3-phosphocholine, DPPC). The LB deposition was preceded by the analysis of miscibility and morphology of monolayers at the air/water interface by means of the Langmuir technique and Brewster angle microscopy (BAM). Then, wettability of the polymer-supported films was evaluated by the contact angle measurements of three probe liquids of different characters (two polar—water and formamide, one apolar—diiodomethane). The measured contact angles allowed for determination of the surface free energy and its components based on the Lifshitz-van der Waals/acid–base (LWAB) approach. Some relations between the kind and magnitude of interactions within the model membranes on the water subphase and those of the PEEK-supported membranes with the liquids were found out. The results allowed obtaining the interesting models of biological coatings with potential applications.     

Capillary effects on flax fibers – Modification and characterization of the wetting dynamics

Introducing bio-based composites has now become an opportunity of development for industry. Accordingly, Liquid Composite Moulding (LCM) processes are increasingly used for manufacturing those composites, mainly in the transportation industry, since they are considered as effective and low cost routes to manufacture bio-based composites fitting high quality requirements, even for parts with complex shape. However observations of a large amount of voids in bio-based composites call for an improved understanding of the local wetting phenomena that occur during impregnation of the natural reinforcements. The purpose of the present work is to study the influence of flax fiber surface chemistry on the local wetting dynamics. Flax reinforcements were submitted to a thermal treatment to modify the chemical composition of fiber surface. In order to analyze the fiber’s wetting behavior, some methods for measuring apparent static contact angles and surface energy were firstly validated on solids of defined geometry, and subsequently applied to untreated and treated flax fibers. The Owens–Wendt’s approach was used to determine both components of apparent surface energy, indicating polar and dispersive interactions in materials. Subsequently dynamic tests were carried out on both types of chopped flax fibers in order to evaluate apparent advancing dynamic contact angles. Considerations about morphological effects have also been included. Finally bio-based composite plates reinforced with untreated and treated flax quasi-UD were simultaneously fabricated by LCM process, and observation of the porosities highlighted some benefits of using treated flax fibers.     

析晶污垢生长影响因素概述

结垢问题存在于各个行业,尤其在油田表现更甚。但材料表面特性对油田采出水中析晶污垢的影响并没有得到太多关注。主要对影响析晶污垢生长的三种主要表面特性因素进行简要综述。