Structure–property relationship of polyetheramines as clay‐swelling inhibitors in water‐based drilling fluids

The influences of structure parameters of polyetheramines as clay‐swelling inhibitors in water‐based drilling fluids on the application performances were studied. Interactions of polyetheramines with clays were investigated through elemental analysis (EA), X‐ray diffraction (XRD), and thermogravimetric analysis (TGA). The results showed that lower molecular weight, hydrophobic oxypropylene segment, and plentiful amino group of polyetheramines favored improvement of inhibitive properties, enhancement of adsorption abilities, and expelling interlayer bound waters of clays (as confirmed by cutting rolling test, bentonite inhibition test, EA, XRD, and TGA studies). Simultaneously, the polyetheramines did not produce adverse effect to filtration control of the drilling fluids. In addition, XRD patterns revealed that these polyetheramines could intercalate into interlayer spaces of clays and display a monolayer arrangement. The corresponding basal spacing of clays was correlated only with molecular weight of polyetheramines. The dense loading of polyetheramines in the interlayer of clays was beneficial in improving inhibitive properties. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Preparation,swelling properties,and displacement performance of functional amphiphilic microspheres

Because polymers containing benzyl chloromethyl groups are easily modified for functional production, the dispersion polymerization of acrylamide, 4‐vinylbenzyl chloride, and N,N‐methylene bisacrylamide in dimethylformamide initiated with α,α‐azobisisobutyronitrile was carried out to produce amphiphilic microspheres containing benzyl chloromethyl groups. The structure of the amphiphilic microspheres was determined by IR and ¹H‐NMR spectroscopy. The polymerization conditions, the temperature, amount of crosslinking agent, and initiator included, were optimized. The size distribution of the microspheres after swelling equilibrium ranged from 4 to 62 μm. The swelling behavior of the microspheres was also investigated. The increase in temperature and the decrease in salinity caused a gradual increase in the swelling ratio. The prepared microspheres were transported uniformly in porous media when the permeability was 0.436 μm². The oil displacement experiments indicated that amphiphilic microspheres had the ability to enhance oil recovery under homogeneous and heterogeneous conditions but was more suitable for heterogeneous formation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41578.     

Cationic and hydrophobically modified chitosans as additives for water‐based drilling fluids

Water‐soluble chitosan derivatives are synthesized via a two‐step procedure that includes the hydrophobization of chitosan using different acyl chlorides, and then the alkylation of some of the amine groups. Rheology, conventional rolling, and filtration tests are performed to evaluate the effect of the modified polysaccharides on the rheological behavior of the fluid, as well as on the clays cuttings integrity and on the control of fluid loss for the geological formations. The results indicate that the product with C16 segments, 2% (wt/vol) concentration and high molar weight led to aqueous solutions with a pseudoplastic behavior equivalent to the one presented by the commercial rheology modifier used in water‐based drilling fluids. In addition, the hydrophobically modified cationic chitosan shows an excellent capacity for inhibiting the clays reactivity and for keeping the cuttings integrity. The results also show that this product can significantly decrease the volume of filtrate, leading to values comparable to the ones obtained with commercial additives, and therefore suggesting that it could be considered to replace some of the drilling fluid additives commonly used. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40300.     

Effect of electric field on polymer/clay nanocomposites depending on the affinities between the polymer and clay

Applying an electric field is an efficient way to fabricate polymer/clay nanocomposites. It helps to achieve a good dispersion of nanoclays which improves the performance of the polymeric system. In this study, the effect of an alternating current (A.C.) electric field was investigated on clay exfoliation with various combinations of polymer/clay nanocomposites. Three different types of organoclays (Cloisite 10A, 20A, 30B) were introduced in polypropylene (PP) and poly(lactic acid) (PLA) matrices. Their rheological properties showed that the A.C. electric field was effective in enhancing the dispersion of organoclays in both the PP/clay and PLA/clay composites. The efficiency of the A.C. field varied depending on the combination of polymer and clay nanoparticles. In the case of PP, the best combination was PP/C20A followed by PP/C10A and PP/C30B. In contrast, PLA/clay showed an opposite trend. This difference arises from the different affinities between the polymers and the functional groups of the clays. The Hansen solubility parameter was introduced to quantify the affinities between the polymer and clay. The electric field was more effective for polymer/clay combinations that had less difference in the Hansen solubility parameter. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43582.     

Equilibrium swelling behavior and elastic properties of polymer–clay nanocomposite hydrogels

Nanocomposite hydrogels were prepared by free‐radical polymerization of the monomers acrylamide (AAm), N,N‐dimethylacrylamide (DMA), and N‐isopropylacrylamide (NIPA) in aqueous clay dispersions at 21°C. Laponite XLS was used as clay nanoparticles in the hydrogel preparation. The hydrogels based on DMA or NIPA monomers exhibit much larger moduli of elasticity compared with the hydrogels based on AAm monomer. Calculations using the theory of rubber elasticity reveal that, in DMA‐clay or NIPA‐clay nanocomposites, both the effective crosslink density of the hydrogels and the functionality of the clay particles rapidly increase with increasing amount of Laponite up to 10% (w/v). The results suggest that DMA‐clay and NIPA‐clay attractive interactions are stronger than AAm‐clay interactions due to the formation of multiple layers on the nanoparticles through hydrophobic associations. It was also shown that, although the nanocomposite hydrogels do not dissolve in good solvents such as water, they dissolve in dilute aqueous solutions of acetone or poly(ethylene oxide) of molecular weight 10,000 g/mol, demonstrating the physical nature of the crosslink points. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Polyacrylamide copolymer/aminated carbon nanotube‐based aqueous nanofluids for application in high temperature and salinity

Polymer aqueous nanofluids have numerous industrial applications due to their synergic properties as a polymer and nanoparticle in the same fluid. The main goal of this work was to prepare stable aqueous nanofluids with improved viscosity in high temperature and salinity conditions. Aminated carbon nanotube (OCNT‐TEPA) presented a C? N photoemission peak at 285.5 eV in X‐ray photoelectron spectroscopy spectra, which is evidence of a grafting reaction. Fourier transform infrared spectra presented absorption bands attributed to amide and amine bonds. Elemental analyses showed 1.9 and 3.2 mass % N content increases for OCNT‐TEPA and OCNT‐TEPA‐AM, respectively. Samples aged at 70 °C in brine confirmed that the addition of OCNT‐TEPA increased the viscosity of nanofluids to 30% at day 90 compared to acrylamide–acrylic acid copolymer fluids. N anotubes presented only 35% of the aminated functions compared to carbon black (Lima et al., Carbon 2016, 109, 209) , and their effects in the enhancement of viscosity and thermal and colloidal stability were 2× greater. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46382.     

The effect of swelling agents and characterization of polyurethane/polymer electrolytes/clay composites

This study discusses the interaction model and characterization of a clay organic processed with different swelling agents blended with PU/polymer electrolytes. The change in d‐spacing of the clay and modified clay in the PU/polymer electrolytes blends was analyzed using X‐rays. A rigid‐body pendulum rheometer was used to determine the curing behavior of PU/polymer electrolytes matrix in the clay and modified clay with different proportions. Dynamic mechanical analysis has been applied to discuss the intermolecular interaction between clay and organoclay with different proportions and PU/polymer electrolytes blends. We have also analyzed the mechanical properties, stress, and strain. As a result, the compatibility of polymer electrolytes, clay, and organoclay is better. The swelling agent that intercalated among the layers of clay will be crowded out and adsorbed onto the surface of clay. The curing time, intermolecular interaction, thermal properties, and mechanical properties of composites were clearly influenced by the clay and swelling agent. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1206–1214, 2005     

Effects of swelling agents on the crystallization behavior and mechanical properties of polyamide 6/clay nanocomposites

Montomorillonite was organically modified with three different swelling agents: n‐dodecylamine, 12‐aminolauric acid, and 1,12‐diaminodecane. These organoclays and polyamide 6 (PA6) were blended in a formic acid solution. X‐ray diffraction analysis showed that the clay still retained its layer structure in the PA6/clay nanocomposite. Consequently, these materials were intercalated nanocomposites. The effects of the swelling agent and organoclay content on the crystallization behavior of the PA6/clay nanocomposites were studied with differential scanning calorimetry. The results showed that the position and width of the exothermic peak of the PA6/clay nanocomposites were changed during the nonisothermal crystallization process. The clay behaved as a nucleating agent and enhanced the crystallization rate of PA6.The crystallinity of PA6 decreased with an increasing clay content. Different swelling agents also affected the crystallization behavior of PA6. The effects of the type and content of the swelling agent on the tensile and flexural properties of PA6/clay nanocomposites were also investigated. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 1686–1693, 2003     

Swelling behavior of poly(acrylamide)/clay nanocomposite hydrogels in acrylamide aqueous solution

The swelling behaviors of poly(acrylamide) (PAAm)/clay nanocomposite hydrogels (hereinafter abbreviated as NC gels) in acrylamide (AAm) aqueous solution have been investigated. As‐prepared PAAm/clay hydrogels (S‐M gels) were posttreated by immersing them in AAm aqueous solution. It was found that the swelling ratio of the NC gels increased greatly when the concentration of the solution is below a critical concentration (c*), whereas the gels were disintegrated in the solution when the concentration of the solution is above the c*. Some disc‐like particles were found in the AAm solution accompanying with the unusual swelling behaviors. This unusual swelling behavior is resulted from the change of network structure of the NC gels in AAm aqueous solution, which was further convinced by transmission electron microscopy and element analyses. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

钻屑和粘土对重泥浆流变性能的影响及筛网目数在固相控制中的作用

高密度钻井液体系的使用中,流变性的调控是性能维护的关键,实验测试了钻屑、粘土对塔里木油田大北301井、104井、克深5井泥浆性能的影响;利用分样筛测试了筛网目数对钻井液流变性的关系;并利用Winner2116型激光粒度仪测试了钻井液的粒径分布。实验结果表明:对于重泥浆需采用更为严格的固控措施,降低体系中的粘土和钻屑含量、振动筛的筛网应控制在200目以内。     

New insights into the viscosity features of cationic polyacrylamide microgels in aqueous solutions

Increasing attention has recently been paid to the rheological behavior of microgel colloids and to the physical forces that control their behavior. Here, based on a series of cationic microgels that were synthesized by inverse microemulsion polymerization, the physical forces were explored by viscosity analysis of swollen microgels with different crosslinking densities and cationic contents. The results indicate that within a wide concentration range, the viscosity curves for these cationic microgels perfectly correspond to the Krieger–Dougherty model as modified by Tan et al. In particular, the specific volume in this model decreases at the critical overlapping concentration and reveals the interaction intensity between neighboring microgels. Furthermore, the viscosity index in the Herschel–Bulkley equation indicates that the interaction domain among microgels undergoes a transfer from an electroviscous effect to osmotic deswelling with increasing concentrations. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46297.     

Cationic starch derivatives as reactive shale inhibitors for water‐based drilling fluids

One of the major problems associated with the use of water‐based drilling fluids is the interaction of water with specific rock formations, such as shales, and the consequent swelling of reactive clays that may be present in that type of rock. Several types of clays reactivity inhibitors have been used by the oil industry, and the most effective ones are the cationic polyelectrolytes, such as the poly(diallyldimethylammonium chloride) (PDADMAC). However, this polyelectrolyte is very toxic. In this work, a series of cationic starch derivatives with different cationic degrees were synthesized with the objective of evaluating their potential as environmentally correct shale reactivity inhibitors. The results showed that the synthesized derivatives presented a good capacity of adsorption on bentonite and an efficient inhibition of the shale reactivity. The derivative with an intermediate cationic degree presented the best performance. In the tests with the formulated fluids this derivative provided an intact cuttings recovery of 84.8% and a total recovery of 92.3%. These values are very close to those found for the PDADMAC additive, therefore indicating that this cationic starch derivative presents a good potential as inhibitor of the shale reactivity. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46621.     

Synthesis of comb‐type copolymers with various pendants and their effect on the complex rheological behaviors of waxy oils

To improve the flowability of waxy crude oil containing a high concentration of asphaltenes (AS), novel comb‐type copolymers of poly(maleic acid polyethylene glycol ester‐co‐α‐octadecene) (PMAC) and poly(maleic acid aniline amide‐co‐α‐octadecene) (AMAC) with various grafting ratios (R_g) of PEG/aniline to maleic anhydride are synthesized. Model oils containing wax mixtures and AS are prepared to explore the effect of asphaltene concentration and the copolymers on the yield stress. The influence of the copolymers on the wax appearance temperature (WAT) of Liaohe high waxy oil is examined by rheological and microscopic methods. Experimental flow curves of shear stress as a function of shear rate are fitted following the Casson model to interpret the rheological properties of gelled waxy crude oil in the presence of AMACs, PMACs, and MAC. Compared with MAC, PMACs, and AMACs are more efficient in reducing the yield stress of both model oil and crude oil, which indicates a better flowability. It is found that PMAC1.0 and AMAC1.0 with a medium R_g can balance the interaction of copolymers with waxes and AS and reduce the yield stress much more than others. Between them, AMAC1.0 that possesses aromatic pendants is better than PMAC1.0, which only has polar pendants. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41660.     

依兰煤在液化溶剂中的溶胀动力学研究

笔者以依兰煤为原料,研究了依兰煤在室温至2000℃范围内在液化起始溶剂和循环溶剂中的溶胀行为,并确定了依兰煤在试验条件下的溶胀动力学参数。试验结果表明：依兰煤在液化起始溶剂和循环溶剂中的溶胀度随溶胀温度的增加和溶胀时间的延长而增大;依兰煤在这2种溶剂中的溶胀都是受Case-Ⅰ扩散控制为主的过程,其溶胀活化能分别为4．18和4．22kJ·mol^-1。     

水基钻井液用防塌封堵剂封堵效果实验研究

采用高温高压静失水评价方法,开展了沥青类封堵剂、刚性颗粒封堵剂以及其它封堵剂等单剂的评价与优选,并开展了复配封堵剂优化的实验。结果表明,乳化沥青在沥青类封堵剂中封堵效果最优,超细碳酸钙(1 000目)在刚性颗粒封堵剂中封堵效果最优,乳化石蜡在其它封堵剂中封堵效果最优。在常用封堵剂的组合中,3%超细碳酸钙(1 000目)+2%乳化沥青为水基钻井液用最佳封堵配方。     

Gelation mechanism and rheological properties of polyacrylamide crosslinking with polyethyleneimine and its plugging performance in air‐foam displacement

Gels based on polyacrylamide crosslinking with polyethyleneimine have attracted attention because of their resulting high strength and good thermal stability. This study investigated the gelation mechanism of the polymeric gel and its plugging performance in air‐foam flooding. An optic microrheology analyzer was used to monitor the gelation process. The crosslinking reaction occurred in two steps, as determined from the elasticity factor curves, and the polymeric gels adopted a semisolid state from solution, as determined from the solid liquid balance curves. The elastic modulus values were higher than the viscous modulus values, indicating that mature gels were elastic‐based materials. The yield stress increased gradually with increasing polymer dosage, which was consistent with the breakthrough pressure and the trend of displacement pressure. The mature gels showed significant thixotropy. In the core displacement test, the preferred injection volume of the gel was 0.1 pore volume, and the stable pressure of the foam flooding was increased by about three times after the core was plugged. The blocking effect for cores with small original permeability was better than that with large permeability. The best blocking resulted from simultaneous treatment of both ends of the cores, followed by front‐end treatment and rear‐end treatment. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45778.     

Synthesis and clay stabilization of a water‐soluble copolymer based on acrylamide,modular β‐cyclodextrin,and AMPS

A modular β‐cyclodextrin copolymer for clay stabilization was prepared from 2‐O‐(allyloxy‐2‐hydroxyl‐propyl)‐β‐cyclodextrin (XBH), acrylamide (AM), 2‐acrylamido‐2‐methyl propane sulfonic acid (AMPS), and sodium acrylate (NaAA) via redox free‐radical copolymerization. The effects of reactive conditions (such as initiator concentration, monomer ratio, reaction temperature, and pH) on the apparent viscosity of the copolymer were investigated and the optimal conditions for the copolymerization were established. The copolymer obtained was characterized by infrared spectroscopy, scanning electron microscope, viscosity measurements, rheological measurement, core stress test, and X‐ray diffractometry. The crystalline interspace of MMT could be reduced from 18.95323 Å to 15.21484 Å by copolymer AM/NaAA/AMPS/XBH. And this water‐soluble copolymer also showed remarkable anti‐shear ability, temperature resistance, and salt tolerance (1000 s^?1, viscosity retention rate: 35%; 120°C, viscosity retention rate: 75%; 10,000 mg/L NaCl, viscosity retention rate: 50.2%; 2000 mg/L CaCl₂, viscosity retention rate: 48.5%; 2000 mg/L MgCl₂, viscosity retention rate: 42.9%). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Polymer microspheres: Influence of composition and porosity on filtrate reduction from aqueous fluids

During the drilling and completion of oil wells, the drilling fluid flowing down the annulus can invade the rock formation, possibly causing irreversible damage to the reservoir. One of the main functions of these fluids is to form a film with low permeability on the borehole wall to prevent invasion of filtrate in the rock formation. Polymeric additives are increasingly used to control these infiltrations. Recent studies have shown the potential of using microspheres made of poly(methyl methacrylate‐co‐vinyl acetate) (PMMA‐co‐PVAc) with dimensions compatible with the size of the formation pores. In this study, PMMA and PMMA‐co‐PVAc polymers were synthesized by suspension polymerization, producing in the presence or absence of porogenic agents. The particles porosities influence the glass transition temperature, surface roughness and apparent density. The results also demonstrate that less rigid spheres with pores in their structure form a more efficient barrier against filtration to the rock formation. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44484.     

Adsorption performance of Al-pillared bentonite clay for the removal of cobalt(II) from aqueous phase

In this research, the natural bentonite clay collected from Ashapura Clay Mines, Gujarat State, India, was utilized as a precursor to produce aluminium-pillared bentonite clay (Al-PILC) for the removal of cobalt(II) [Co(II)] ions from aqueous solutions. The original bentonite clay and Al-PILC were characterized with the help of chemical analyses, methylene blue (MB) adsorption isotherm, powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and infrared spectroscopy (IR), while the thermal stability of the samples were studied using thermogravimetry (TG). Surface charge density of the samples as a function of pH was investigated using potentiometric titrations. Adsorption experiments were conducted under various conditions, i.e., pH, contact time, initial concentration, ionic strength, adsorbent dose and temperature. The most effective pH range for the removal of Co(II) ions was found to be 6.0–8.0. The maximum adsorption of 99.8% and 87.0% took place at pH 6.0 from an initial concentration of 10.0 and 25.0 mg l⁻¹, respectively. Kinetic studies showed that an equilibrium time of 24 h was needed for the adsorption of Co(II) ions on Al-PILC and the experimental data were correlated by either the external mass transfer diffusion model for the first stage of adsorption and the intraparticle mass transfer diffusion model for the second stage of adsorption. The intraparticle mass transfer diffusion model gave a better fit to the experimental data. The Arrhenius and Eyring equations were applied to the data to determine the kinetic and thermodynamic parameters for explaining the theoretical behaviour of the adsorption process. The equilibrium isotherm data were analyzed using the Langmuir, Freundlich and Scatchard isotherm equations and the adsorption process was reflected by Freundlich isotherm. The efficiency of the Al-PILC was assessed by comparing the results with those on a commercial ion exchanger, Ceralite IRC-50. The suitability of the Al-PILC for treating Co(II) solutions was tested using simulated nuclear power plant coolant samples. Acid regeneration was tried for several cycles with a view to recover the adsorbed Co(II) and also to restore the adsorbent to its original state.     

Influence of glycerides–xanthan gum synergy on their performance as lubricants for water‐based drilling fluids

Water‐based fluids for drilling wells are an environmentally friendly alternative to oil‐based formulations typically used in the oil industry. Aqueous mixtures of nonionic monoglyceride surfactants (C6, C8, C10, C12, and C18 carbon chains) and xanthan gum (XG) were investigated with that purpose, correlating their lubricity and solubility in water, as well as using surface tension and contact angle measurements. The results showed that monoglycerides behave as excellent lubricants in water, with a steady decrease of the friction coefficient as the hydrocarbon chain length increased. Monoglycerides were able to reduce the friction coefficient even further when used in XG suspensions, suggesting that they are probably forming a complex with the polysaccharide that shows a synergy toward their performance as lubricants. Experiments of adsorption onto iron oxide nanoparticles also produced evidence of the interaction between these molecules, which favors their adsorption on the metal surface. These results indicate that interactions occurring in solution between the surfactants and the polysaccharide are crucial in the mechanism of action of these mixtures as lubricants in water‐based drilling fluids. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41085.