Supramolecular polymer-based gel fracturing fluid with a double network applied in ultra-deep hydraulic fracturing

A gel based on polyacrylamide,exhibiting delayed crosslinking characteristics,emerges as the preferred solution for mitigating degradation under conditions of high temperature and extended shear in ultralong wellbores.High viscosity/viscoelasticity of the fracturing fluid was required to maintain excellent proppant suspension properties before gelling.Taking into account both the cost and the potential damage to reservoirs,polymers with lower concentrations and molecular weights are generally preferred.In this work,the supramolecular action was integrated into the polymer,resulting in significant increases in the viscosity and viscoelasticity of the synthesized supramolecular polymer system.The double network gel,which is formed by the combination of the supramolecular polymer system and a small quantity of Zr-crosslinker,effectively resists temperature while minimizing permeability damage to the reservoir.The results indicate that the supramolecular polymer system with a molecular weight of(268—380)×10^(4)g/mol can achieve the same viscosity and viscoelasticity at 0.4 wt%due to the supramolecular interaction between polymers,compared to the 0.6 wt%traditional polymer(hydrolyzed polyacrylamide,molecular weight of 1078×10^(4)g/mol).The supramolecular polymer system possessed excellent proppant suspension properties with a 0.55 cm/min sedimentation rate at 0.4 wt%,whereas the0.6 wt%traditional polymer had a rate of 0.57 cm/min.In comparison to the traditional gel with a Zrcrosslinker concentration of 0.6 wt%and an elastic modulus of 7.77 Pa,the double network gel with a higher elastic modulus(9.00 Pa)could be formed only at 0.1 wt%Zr-crosslinker,which greatly reduced the amount of residue of the fluid after gel-breaking.The viscosity of the double network gel was66 m Pa s after 2 h shearing,whereas the traditional gel only reached 27 m Pa s.

PREPARATION AND PROPERTIES OF GEL POLYMER ELECTROLYTE BASED ON PVDF/ACRYLATE INTERPENETRATING POLYMER NETWORK FOR DYE-SENSITIZED SOLAR CELL

The gel polymer electrolytes（GPEs）based on poly（vinylidence fluoride）（PVDF）/acrylate interpenetrating polymer network（IPN）are prepared.The micro-phase separation type GPEs are characterized by Fourier transform infrared（FTIR）spectroscopy,scanning electron microscope（SEM）,respectively.Moreover,the conductivity and the voltage-current curves of the electrolytes are measured by electrochemical workstation.The higher porosity and electrolyte uptake are observed in the membranes prepared at lower crosslinker concentration.The suitable cross-linking acrylate monomer improves the porosity and the electrochemical behavior of GPE.A dye-sensitized solar cell（DSSC）employing PGE based on PVDF/poly（ethylene glycol dimethacrylate）（PEGDMA）IPN yields an open-circuit voltage of 0.674 V,short-circuit current of 8.476 mA·cm-2and the conversion efficiency of 2.710% under 100 mW·cm-2illumination.

One-pot synthesis of network supported catalyst using supramolecular gel as template

A simple and general strategy is described for preparing network supported catalyst through a one-pot synthetic procedure using supramolecular gel as template.This procedure directly attaches ligand to support during fabricating the support.Using this strategy,supported CuBr/di-（2-picolyl） amine catalyst with U-shaped fibrillar network was prepared and used in atom transfer radical polymerization of methyl methacrylate.XPS and SEM characterization of the catalyst revealed homogeneous distribution of ligand,sufficient reactive sites,adequate mechanical strength and macroporosity.The polymerization results demonstrated high activity and reusability of such catalyst.This strategy might be extended to other supported catalysts used in column reactors.

PREPARATION OF STAR NETWORK PEG-BASED GEL POLYMER ELECTROLYTES FOR ELECTROCHROMIC DEVICES

An amorphous,colorless,and highly transparent star network polymer with a pentaerythritol core linking four PEG-block polymeric arms was synthesized from the poly(ethylene glycol)(PEG),pentaerythritol,and dichloromethane by Williamson reaction.FTIR and ~1H-NMR measurement demonstrated that the polymer repeating units were C[CH_2-OCH_2O-(CH_2CH_2O)_m-CH_2O-(CH_2CH_2O)_n-CH_2O]_4.The polymer host held well mechanical properties for pentaerythritol cross-linking.The gel polymer electrolytes based on Lithium pe...

Comprehensive evaluation of chemical breakers for multistage network ultra-high strength gel

Polymer gels have been accepted as a useful tool to address many sealing operations such as drilling and completion,well stimulation,wellbore integrity,water and gas shutoff,etc.Previously,we developed an ultra-high strength gel(USGel)for medium to ultra-low temperature reservoirs.However,the removal of USGel is a difficult problem for most temporary plugging operations.This paper first provides new insights into the mechanism of USGel,where multistage network structure and physical entanglement are the main reasons for USGel possessing ultra-high strength.Then the effects of acid breakers,encapsulated breakers,and oxidation breakers(including H_(2)O_(2),Na_(2)S_(2)O_(8),Ca(ClO)_(2),H_(2)O_(2)+NaOH,Na_(2)S_(2)O_(8)+NaOH,and Ca(ClO)_(2)+NaOH)were evaluated.The effects of component concentration and temperature on the breaking solution were studied,and the corrosion performance,physical simulation and formation damage tests of the breaking solution were carried out.The final formulation of 2%-4%NaOH+4.5%-6%H_(2)O_(2) breaking solution was determined,which can make USGel completely turn into water at 35e105C.The combinations of“acid t breaking solution”,“acid+encapsulated breaker”and“encapsulated breaker+breaking solution”were evaluated for breaking effect.The acid gradually reduced the volume of USGel,which increased the contact area between breaking solution and USGel,and the effect of“4%acid+breaking solution”was 23 times higher than that of breaking solution alone at 35C.However,the acid significantly reduced the strength of USGel.This paper provides new insights into the breaking of high-strength gels with complex network structures.

Unlocking the potentials of gel conformance for water shutoff in fractured reservoirs: Favorable attributes of the double network gel for enhancing oil recovery

The double-network prepared with an in-situ monomer gel and a fast-crosslinked Cr(III) gel is introduced to develop a thixotropic and high-strength gel (THSG), which is found to have many advantages over the traditional gels. The THSG gel demonstrates remarkable thermal stability, and no syneresis is observed after 12 months with high salinity brine (95,500 mg/L). Moreover, the SEM and XRD results indicate that the gel is intercalated into the lamellar structures of Na-MMT, where the gel can form a uniform and compact structure. In addition, the THSG gel has an excellent swelling behavior, even in the high salinity brine. In the slim tube experiments, the THSG gel exhibits high rupture pressure and improves blocking capacity after being ruptured. The core flooding results show that a layer of gel filter cake is formed on the face of the fracture, which may be promoted by a high matrix permeability, a small aperture fracture, and a high injection rate. After the gel treatment, the fracture can be completely blocked by the THSG gel. It is found that a high incremental oil recovery (65.3%) can be achieved when the fracture was completely blocked, compared to 40.2% if the gel is ruptured. Although the swelling of ruptured gel can improve oil recovery, part of the injected brine may be channeled through the gel-filled fractures, resulting in a decrease in the sweep efficiency. Therefore, the improved blocking ability by gel swelling (e.g., in fresh water) may be less efficient to contribute to an enhancement of oil recovery. It is also found that the pressure gradient and residual resistance factor to water (Frrw) are higher if the matrix is less permeable, indicating that the fractured reservoir with lower matrix permeability may require a higher gel strength for treatment. The findings of this study may provide novel insights on designing robust double network gels for water shutoff in fractured reservoirs.

PREPARATION AND SECOND-ORDER OPTICAL NONLINEARITY OF NOVEL PHENOXYSILICON NETWORKS BY SOL-GEL PROCESS

Four phenoxysilicon networks for nonlinear optical (NLO) applications were designed and prepared by an extended sol-gel process without additional H2O and catalyst. All poled polymer network films possess high second-order nonlinear optical coefficients (d(33)) Of 10(-7)similar to 10(-8) esu. The investigation of NLO temporal stability at room temperature and elevated temperature (120 degreesC) indicated that these films exhibit high d(33) stability because the orientation of the chromophores are locked in the phenoxysilicon organic/inorganic networks.

Criteria for Distinguishing Floc Sedimentation and Gel-Like Network Sedimentation of Cohesive Fine-Grained Sediment in a Turbulent Flow

The study on the criteria used to distinguish floc sedimentation and gel-like network sedimentation of cohesive fine-grained sediment in a turbulent flow has rarely been carried out. In this preliminary study, we derive three criteria to distinguish these two different sedimentation phases by considering the comparison of the time that a characteristic floc takes to settle through mean distance between characteristic flocs and the time that it takes to move through the same distance under the influence of a turbulent flow. These criteria incorporate physical and chemical factors that have been verified to have some influences on the sediment flocculation in some published literatures, and a simple analysis result is found to be consistent with our qualitative understandings of flocculation phenomenon of cohesive fine-grained sediment.

Sol-Gel法制备有机/无机纳米复合材料的进展

概述了溶胶－凝胶法（Ｓｏｌ－Ｇｅｌ）制备有机－无机纳米复合材料（ＯＩＮＣ）的原理和ＯＩＮＣ的主要类型、结构特点及主要应用领域，并提出了几点今后的发展展望。

Novel Semi-IPN Gel Electrolyte for Polymer Lithium-ion Battery

A new type of semi-IPN gel electrolyte was prepared by thermal polymerization in this article.The cross-linked PEG200 (MXPEG) was prepared by condensation reaction in the presence of methacryloxypropyltrimethoxysilane (MAPTMS),the condensation product was then blent with PMMA and polymerized to form polymer blends with semi-IPN fabric.Differential scanning calorimetry and X-ray diffraction spectroscopy were used to investigate the thermal transition behavior of the polymer blends prepared.Ion-conducting behaviors and the electrochemical stability window for semi-IPN gel electrolyte were investigated by means ofimpedance spectroscopy and linear sweep voltammetry.The Arrhenius-type relationship was observed in the temperature dependence ofionic conductivity.All the properties shows that the prepared semi-IPN gel electrolyte possesses certain levels of electrolye salt and plasticizer were expected to have applications of gel polymer electrolyte for lithium polymer secondary batteries.

Sol-gel Preparation Copper-cadmium Halide DopedPhotochromic Glass Coating on Plate Glass

Copper-cadmium halide doped photochromic glass coating on plate glass has been prepared by a sol-gel process. The sample shows reversible photochromic effect. The results of X-ray diffraction (XRD) and infrared (IR) spectrum investigations indicate that the photochromic phase of tile coating is CuBr_xCl_(1-x), solid solution, and that the structure network of the coating is connected with the bonds of Si-O-Si, Si-O-B and Si-O-Al.

离子液体凝胶催化剂在合成乙酸正龙脑酯中的应用

乙酸正龙脑酯作为医药中间体,具有广泛用途。无论是传统工艺的酸性催化剂,还是离子液体催化剂都存在催化剂与反应物有效分离困难、不易循环使用的缺点。将具备温敏性的离子液体凝胶作为乙酸正龙脑酯的新型催化剂,可突破离子液体催化酯化反应工业化的技术瓶颈。本工作以离子液体1-丁基-3-甲基咪唑硫酸氢盐、聚乙烯醇、单宁酸为原料,基于超分子组装原理,制备了温敏性离子液体凝胶催化剂。采用流变仪、热重分析仪、傅里叶变换红外光谱仪、核磁共振波谱仪对离子液体凝胶进行表征。结果显示,PVA-Ta-[BMIM]HSO4离子液体凝胶中存在羧酸酯键和氢键,是由咪唑环和苯环的π-π堆积作用构成的混合双网络聚合物,具有较高的机械强度和韧性。以乙酸正龙脑酯为反应模型,考察了离子液体凝胶催化剂的活性,通过单因素实验法优化了离子液体凝胶催化剂合成乙酸正龙脑脂的反应条件,得到反应温度为90℃,反应时间为6 h,α-蒎烯与冰醋酸的物质的量比为1∶1。实验结果表明,该催化剂对温度产生可逆相变响应,高温时反应体系为均相,保证了催化效率,反应结束后降温凝固成为凝胶并析出。离子液体凝胶的催化活性与酸性离子液体的活性差别不大,重复使用五次后,α-蒎烯转化率保持在75%以上,乙酸正龙脑酯的选择性在8.5%以上。

3种凝胶结构对天然橡胶塑炼特性的影响

天然橡胶(NR)加工过程中的熟化作用及后续的贮存硬化会导致橡胶烃分子链端基或异常基团与非胶组分形成交联结构产生凝胶。按照凝胶产生的3个主要阶段,可以将凝胶分为胶乳熟化凝胶、凝块熟化凝胶和贮存硬化凝胶,分别制备了含胶乳熟化凝胶的生胶(NR-L)、含凝块熟化凝胶的生胶(NR-C)和含贮存硬化凝胶的生胶(NR-S),研究了凝胶结构的形成方式与NR性能之间的联系。塑炼特性结果表明,门尼黏度和凝胶含量在塑炼时间2 min内快速下降,但NR-L的下降速率要明显慢于NR-C和NR-S,塑炼结束后也保持了更高的门尼黏度值和凝胶含量,说明凝胶网络结构的强度不同,NR-L的网络结构强度更高;氮含量方面,NR-L最高,NR-C最低,酯基含量方面,NR-L最高,NR-S最低。温度扫描应力松弛试验结果表明,NR-L的网络结构主要是由磷脂为枝化点的天然网络组成,NR-S的网络结构主要由以蛋白质为枝化点的天然网络组成。同时,以磷脂作为枝化点的天然网络强度高于以蛋白质作为枝化点的天然网络。

植物乳植杆菌通过抑制蛋白水解改善罗非鱼发酵鱼糜凝胶强度

利用微生物发酵能有效改善淡水鱼鱼糜的凝胶强度。罗非鱼鱼糜的凝胶强度低且在加工过程中易出现凝胶劣化。为开发高品质的罗非鱼发酵鱼糜制品,以植物乳植杆菌(Lactiplantibacillus plantarum)为发酵菌株,探究了加菌发酵对罗非鱼发酵鱼糜凝胶强度的影响。结果表明,加菌发酵能够显著改善罗非鱼发酵鱼糜的凝胶强度,降低大部分游离氨基酸以及总氨基酸的含量。采用16S rRNA高通量测序技术研究加菌发酵对罗非鱼发酵鱼糜中微生物菌群的影响,结果显示,加菌发酵鱼糜中乳植杆菌属一直为优势菌属,到发酵末期增至63.71%,而其他腐败微生物菌属的丰度显著下降,同时菌落总数明显低于自然发酵鱼糜。构建了不同发酵时期的相关性网络图,结果表明在整个发酵期凝胶强度与菌落总数和总氨基酸含量呈显著负相关,仅乳植杆菌属与菌落总数和总氨基酸含量呈显著负相关,而与凝胶强度呈显著正相关。研究表明,植物乳植杆菌可以通过抑制腐败微生物的生长以及对蛋白质的水解作用来改善罗非鱼发酵鱼糜的凝胶强度。植物乳植杆菌可以作为专用发酵剂开发高品质罗非鱼鱼糜发酵制品。

低密度有机-无机互穿网络堵漏体系研究

采用常规可固化堵漏剂解决低压地层裂缝性漏失时会产生密度过大或承压不足的技术难题,因此研究低密度高抗压的堵漏体系具有重要意义。通过合成聚丙烯酰胺(polyacrylamide,HPAM)交联形成有机网络,并优选水泥材料形成无机网络,构建低密度有机-无机互穿网络堵漏体系;采用模拟水驱实验、X射线衍射、扫描电子显微镜(scanning electron microscope,SEM)、高温高压(high temprature and high pressure,HTHP)堵漏模拟实验、抗压实验等分析了堵漏体系的性能和堵漏机理。结果表明,聚丙烯酰胺交联反应形成的有机网络与水泥水化形成的无机网络通过静电力和范德华力等作用可形成互穿网络体系,体系抗压达6.3 MPa,密度为1.28 g/cm^(3),固化时间实现2~5 h可控,固化前后的酸溶率分别为87.8%和63.4%,堵漏及解堵性良好。

A tree-growing graphic model for asymmetrical phantom networks in polymeric gels undergoing dynamic mechanochemical coupling

Network structures of various polymers have significant effects on their mechanical properties;therefore,numerous studies have investigated the constitutive relationship between symmetrical network structures and their rubber elasticity in polymers.However,few studies have focused on asymmetrical network structures in polymers that undergo bond exchange reactions,selfassembly,or mechanochemical coupling—all of which are induced by transition probabilities of chemical bonding processes.In this study,an extended constraint junction and phantom network model is formulated using the tree-growing theory to establish a constitutive relationship between asymmetrical network structures and their rubber elasticity in polymers.A free-energy equation is further developed to explore working principles of configurational transitions on the dynamic rubber elasticity of symmetrical and asymmetrical network structures.The constitutive relationship between dynamic rubber elasticity and symmetrical and asymmetrical network structures has also been proposed for the gels undergoing mechanochemical and hydromechanical coupling.Finally,the effectiveness of this newly proposed tree-growing model has been verified by comparing with the classical affine network model,finite element analysis,and the experimental results of gels reported in literature.

La^(3+)掺杂TiO_(2)粉体的高分子网络凝胶法制备工艺优化及其光催化降解甲基橙性能(英文)

采用高分子网络凝胶法制备La^(3+)掺杂TiO_(2)粉体,通过正交实验优化制备工艺,采用比表面积测试(BET)、X射线衍射仪(XRD)、紫外-可见光谱仪(UV-Vis)和扫描透射电子显微镜(STEM)对TiO_(2)粉体的晶体结构和光吸收性能进行了表征,并以甲基橙为目标进行了光催化降解实验。结果表明:高分子网络凝胶法制备La^(3+)掺杂TiO_(2)粉体时对TiO_(2)光吸收波长影响最大的是煅烧温度,其次是掺杂量,最后是保温时间;正交实验得到的最优制备条件为:La^(3+)掺杂量为0.5%mol、煅烧温度为800℃,保温时间为30 min;煅烧温度过高与过低都不利于提高La^(3+)掺杂TiO_(2)的光催化活性,其存在一个最佳的温度范围:650~700℃;La^(3+)掺杂抑制了锐钛矿相向金红石相的转变,也抑制了晶粒的长大,但当La^(3+)掺杂量为1.0%mol时,其光催化效果最好;二氧化钛光催化降解甲基橙是零级反应,掺杂并没有改变光催化反应类型。

NaHCO_(3)和KHCO_(3)复合保水剂对凡纳滨对虾虾肉保水效果的影响

【目的】探究复合添加NaHCO_(3)、KHCO_(3)两种无磷保水剂的添加量和浸泡时间对凡纳滨对虾(Litopenaeus vannamei)虾肉保水能力的影响。【方法】通过不同添加质量分数(0.5%、1.0%、1.5%、2.0%、2.5%、3.0%)的NaHCO_(3)和KHCO_(3)两种保水剂及浸泡时间单因素实验,分析NaHCO_(3)和KHCO_(3)对凡纳滨对虾虾肉pH、浸泡增重率、蒸煮损失率等指标的变化;并对NaHCO_(3)和KHCO_(3)联合使用时的添加质量分数和作用时间进行响应面优化,确定最佳添加量及浸泡时间;以电位、水分分布、微观结构等指标分析不同保水剂对虾肉蛋白的内在影响。【结果】单因素实验结果表明,添加NaHCO_(3)和KHCO_(3)能有效提升虾肉保水效果,且均在添加质量分数为2.0%时保水效果最佳。浸泡6~15 h间,虾肉pH和浸泡增重率变化较小。响应面优化结果表明,NaHCO_(3)和KHCO_(3)添加量存在交互影响,复合添加1.5%NaHCO_(3)和1.5%KHCO_(3),浸泡9 h后虾肉有较高的浸泡增重率(22.65%)和适宜的pH(8.06)。保水剂对蛋白的影响表明,复合保水剂添加主要通过促进虾肉蛋白的电位增加、自由水增加、分子解离及凝胶结构的形成来提高虾肉的保水能力,其保水能力强于添加质量分数0.5%复合磷酸盐组。【结论】联合添加使用质量分数1.5%NaHCO_(3)与质量分数1.5%KHCO_(3)并浸泡9 h处理,可增加虾肉肌原纤维蛋白分子电位、增强虾肉蛋白凝胶网络结构、改变虾肉内部水分分布,对提升虾肉保水能力有明显作用。

健脾温阳凝胶剂脐疗治疗脾胃虚弱型慢性腹泻的疗效及机制:一项临床随机对照试验

目的探讨健脾温阳凝胶剂(SSWYG)治疗慢性腹泻的临床疗效及作用机制。方法80例脾胃虚弱型慢性腹泻患者随机分为对照组和试验组,每组40例。两组均调整规范的生活方式,对照组给予双歧三联活菌胶囊、试验组给予SSWYG脐疗,1周后评估慢性腹泻的情况。依托中药系统药理学分析平台(TCMSP)、GeneCards、NCBI、OMIM数据库及GEO数据库(GSE14841)获得SSWYG的活性成分和靶点蛋白以及慢性腹泻相关疾病靶点,构建蛋白互作网络(PPI)后,应用拓扑分析获得关键靶点,并对关键靶标进行基因本体(GO)功能富集分析、京都基因与基因组百科全书(KEGG)通路富集分析,运用AutoDock软件进行分子对接以验证SSWYG对特定靶标的亲和力及结合特性。结果对照组和试验组患者胃肠道症状评定量表(GSRS),Bristol评分及中医证候评分均有改善(P<0.05),试验组均优于对照组(P<0.05);经筛选,SSWYG治疗慢性腹泻的靶点共68个,拓扑分析筛得最可能的关键靶点33个,GO及KEGG富集分析预测出与慢性腹泻相关的TNF、IL-17等多条通路;分子对接研究提示SSWYG的核心成分均与CASP3、JUN、IL6、AKT1、VEGFA关键靶点有较好的亲和力,尤其JUN和CASP3与复方中多种主要活性成分结合能最低、结合最稳定。结论SSWYG不仅明显改善腹痛、便溏等慢性腹泻的临床症状,还能缓解脘腹痞满、倦怠乏力、神疲懒言等症状,从多个维度提高患者生存质量,其作用机制可能主要通过CASP3、JUN调控TNF、IL-17等信号通路发挥治疗慢性腹泻的药理效应,具有多成分、多靶点、多通路协同调节的特点。

菁类染料敏化的固态纳米TiO_2光电化学电池

A novel unsymmetrical cyanine dye(noted as CD) was applied to dye sensitized nanoporous TiO 2 photoelectrochemical cells. The incident photon to electron conversion efficiency up to 84 34% was achieved, which is notably high for cells employing pure organic dyes. To circumvent the sealing difficulties present in wet type cells, the solid state cell was fabricated using poly(ethyleneoxide)(PEO) based gel network polymer electrolyte as charge transfer material between two electrodes. The resulting solid state cell had an energy conversion efficiency of 0 86%, with open circuit voltage of 0 53 V and short circuit current density of 0 96 mA/cm 2 under 38 1 mW/cm 2 white light illumination. The results show that the gel network polymer electrolyte is appropriate for assembling solid state photoelectrochemical cells.