Oil well sand consolidation. I. Resins for a three-step process

Oil-bearing formations often consist of loose sandy material. In the production of oil from these formations sand tends to be carried to the well bore along with the oil. The flow of sand can be prevented by consolidating or cementing together the sand particles of the formation around the well bore. The cementing has to be accomplished in such a manner that fluid flow channels between particles remain open. This paper describes a new three-step process that was developed to consolidate oil well sand. The steps in the process involve injection of: (1) resin, (2) inert fluid, and (3) inert fluid containing a catalyst. In the first step of the process, resin in injected into the formation where it fully saturates the interstices between sand grains. Permeability is established in the second step by displacement of the excess resin from the interstices, thereby leaving a thin film of resin on the sand grains. In the third step, polymerization is activated by migration of catalyst from the inert fluid into the thin resin film on the sand. The process has the advantage that resin is placed and permeability is established before the resin is catalyzed. This avoids premature polymerization of the resin which might cause plugging of the formation or the tubing string used to inject resin. Desirable characteristics of a resin for the three-step process are: (1) viscosity of 25–200 cp. at well bore temperature; (2) stability for several days at well bore temperature; (3) high adhesion to sand in the presence of an inert flushing fluid; (4) polymerization by less than 10% catalyst; (5) the polymerized resin binds sand together with a strong bond that is not affected by well fluids. Five different resin types have been tested for use in the three-step sand consolidation process. These are: (1) epoxy–anhydride cured with a tertiary amine; (2) epoxy–epoxy diluent cured with a primary–tertiary amine mixture; (3) furan; (4) unsaturated polyester–vinylpyrrolidone; (5) unsaturated polyester–styrene. The two epoxy resins give strong, permeable consolidated sand which is resistant to well fluids such as brine and crude oil. The furan resin gives a weak consolidation. The unsaturated polyester–vinylpyrrolidone gives good strength and oil resistance but is sensitive to brine. The unsaturated polyester–styrene is difficult to apply. Many oil wells have been successfully treated in the Gulf Coast area and in California with the two epoxy resins. Almost all of these wells are producing free of sand, and, to date, more than five million barrels of oil have been produced from these wells.     

Copolymerization of unsaturated polyester with styrene in inverted emulsion

Copolymerization of unsaturated polyester with styrene in water-in-oil (W/O) type emulsion was carried out with the use of various basic compounds as emulsifiers. It was found that a stable, gellike W/O type emulsion of unsaturated polyester resin is formed only when pK_a's of the bases are above 6 and their concentrations are higher than some critical value. In these conditions, water can be dispersed in emulsion up to 900% to the resin. By polymerization, the stable W/O type emulsion is transformed to a white solid copolymer which is dry to the touch and which contains 90–95% of initially added water. It was confirmed that the basic compounds react with the carboxylic group of the polyester to form at the water-resin interface polyester salts, which act as true emulsifying agents. The stabilization mechanism of the emulsion at various concentrations of the polyester salt was investigated, mainly by microscopic observations, and an interpretation of the critical value of emulsifier concentration is proposed.     

The effect of the chemical structure of low-profile additives on the curing behavior and chemorheology of unsaturated polyester resin

An experimental study was conducted to investigate the effect of the chemical structure of low-profile additives on the curing behavior and chemorheology of unsaturated polyester resin during isothermal cure. For the study a general-purpose unsaturated polyester resin was cured in the presence of t-butyl perbenzoate as Initiator. The curing behavior of the resin was investigated using differential scanning calorimetry (DSC). Three different thermoplastic low-profile additives were used, namely poly(vinyl acetate) (PVAc), poly(styrene-co-butadiene), which is also known as KRATON DX-1300, and dehydrochlorinated Isobutylene/isoprene copolymer, often referred to as conjugated diene butyl (CDB) rubber. Each of the these additives, about 30 weight percent, was first dissolved in styrene. The solution was then mixed with unsaturated polyester resin and CaCO₃. The CaCO₃ particles helped stabilize the emulsions consisting of resin and KRATCN, and of resin and CDB. For each resin formulation, a series of isothermal DSC runs were made at various levels of cure pressure. It was found that for all three low-profile resins investigated, the final degree of cure went through a maximum as cure pressure was increased from atmospheric to 6.21 MPa (900 psi). We have observed evidence that in the presence of an initiator generating free radicals, the unsaturated double bonds in the KRATON and CDB undergo grafting reactions with the styrene monomers and unsaturated polyester resin, increasing the glass transition temperature of KRATON and CDB, to an extent which varies with the cure conditions employed. Both steady and oscillatory shearing flow properties were determined using a cone-and-plate rheometer. The rheological measurements indicate that the resin/CaCO₃/KRATON and resin/CaCO₃/CDB systems give rise to gel times shorter than the resin/CaCO₃/PVAc system. It is concluded that both KRATON and CDB are more effective, both for enhancing the rate of cure of unsaturated polyester resin and imparting impact properties to the cured composites, than those thermoplastic low-profile additives that contain neither unsaturated double bonds nor a chemical structure that has rubber-like properties in the solid state.     

MPD在高固体聚酯氨基烘干磁漆中的应用研究

介绍了用MPD(2-甲基-1,3-丙二醇)合成高固体分聚酯的合成工艺、影响条件和高固体分聚酯氨基烘干磁漆的产品性能。     

高固体分卷材涂料用聚酯的研制

通过引入叔碳酸缩水甘油酯单体,并采取分步聚合法工艺合成高固体分聚酯树脂,制得了施工 VOC满足环保要求的卷材涂料。探讨了不同二元酸类型、叔碳酸缩水甘油酯用量、相对分子质量及合成工艺对聚酯树脂及漆膜性能的影响。实验结果表明：采用分步法聚酯合成工艺,第一步选用甲基丙二醇及己二酸、六氢苯酐及苯酐合成的端羧基聚酯,酸超量 40%;第二步中引入叔碳酸缩水甘油酯及三羟甲基丙烷及甲基丙二醇,醇超量 50%,可得到数均相对分子质量为 1 862、固含量为 81%、黏度（ 23 ℃）为 1 860 mPa·s的高固体分聚酯树脂,以此树脂配制的白色卷材面漆性能良好,施工 VOC为 305 g/L,满足低于 420 g/L的要求。     

高固体分卷材面漆用聚酯树脂的研制与性能研究

使用多元醇和多元酸单体开发了一种卷材面漆用低黏度聚酯树脂,探讨了多元酸单体、树脂相对分子质量及其结构等因素对树脂黏度的影响。通过比较涂料黏度以及VOC含量确定适宜的树脂为相对分子质量为1 300的以甲基四氢邻苯二甲酸酐为多元酸主体的线性聚酯树脂,其蓝色面漆VOC含量为417 g/L。通过各项性能测试发现,制备的高固体分卷材面漆的机械性能以及耐性都达到或超过主流产品,并具有高固低黏、环保的特点。     

Preparation and characterization of bismaleimide (N,N′‐bismaleimido‐4,4′‐diphenyl methane)–unsaturated polyester modified epoxy intercrosslinked matrices

An intercrosslinked network of unsaturated polyester–bismaleimide modified epoxy matrix systems was developed. Epoxy systems modified with 10, 20, and 30% (by weight) of unsaturated polyester were made by using epoxy resin and unsaturated polyester with benzoyl peroxide and diaminodiphenylmethane as curing agents. The reaction between unsaturated polyester and epoxy resin was confirmed by IR spectral studies. The unsaturated polyester toughened epoxy systems were further modified with 5, 10, and 15% (by weightt) of bismaleimide (BMI). The matrices, in the form of castings, were characterized for their mechanical properties. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) of the matrix samples were performed to determine the glass transition temperature (T_g) and thermal degradation temperature of the systems, respectively. Mechanical properties, viz: tensile strength, flexural strength, and plain strain fracture toughness of intercrosslinked epoxy systems, were studied by ASTM methods. Data obtained from mechanical and thermal studies indicated that the introduction of unsaturated polyester into epoxy resin improves toughness but with a reduction in glass transition, whereas the incorporation of bismaleimide into epoxy resin improved both mechanical strength and thermal behavior of epoxy resin. The introduction of bismaleimide into unsaturated polyester‐modified epoxy resin altered thermomechanical properties according to their percentage concentration. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2853–2861, 2002     

Manufacturing and impact characterization of soy‐based polyurethane pultruded composites

Composites have several advantages such as high corrosion resistance, high strength to weight ratio, and lower maintenance costs over conventional materials. The major cost drivers for composites are raw materials and manufacturing process. Automated manufacturing processes like pultrusion and low cost raw materials can significantly lower the cost of composites. Polyurethane (PU) resin systems are commonly used in the pultrusion industry as they have higher performance characteristics and manufacturing feasibility when compared to conventional resin systems such as polyester and vinyl ester. Manufacturing cost can be further decreased by the use of bio‐based materials such as soy‐based resin systems. In the present work, solid pultruded panels have been manufactured using the base PU and two soy‐based PU resin systems. Pultruded panels were subjected to low velocity impact testing. Soy‐based PU resin systems showed comparable properties to that of the base PU resin system and is a viable alternative to the conventional petroleum‐based PU. POLYM. COMPOS., 35:1070–1077, 2014. © 2013 Society of Plastics Engineers     

用环氧氯丙烷合成阻燃性不饱和聚酯树脂顺反异构化研究

本文研究了用环氧氯丙烷合成不饱和聚酯树脂的方法.使用催化剂可以使低活性的顺丁烯二酸酯聚酯异构化为高活性的反丁烯二酸酯聚酯,并测定了液体树脂和固化树脂的性能.     

Bending and breaking fibers in sheared suspensions

An experimental study was made of single fibers rotating and bending in Couette flow of a Newtonian liquid. A previous result for critical fiber buckling was re-tested and found satisfactory, and the transition between ‘springy’ and ‘snake’ rotation was delineated. The minimum radius, of curvature achieved during rotation in the “snake orbit” regime was measured as a function of fiber aspect ratio, Young's modulus, and fluid shear stress. Two correlations are presented which are constrained to satisfy limiting conditions for very stiff and very flexible fibers. Together with a result from thin rod theory, these correlations may be used to predict breaking conditions for fibers of known Young's modulus and ultimate tensile strength. Predictions are tested in experiments where two types of glass fiber are broken in suspension and found satisfactory. Results show that several reinforcing materials will probably break within the range of conditions covered by our experiments, or in a region which can be treated by extrapolation from our results.     

Vacuum‐assisted resin transfer molding model

A model of the vacuum‐assisted resin transfer molding (VARTM) process is developed that includes the most important aspects of the processing physics. The model consists of several submodels, such as preform mechanics, Darcy flow, wicking flow, and void formation. The preform mechanics model treats the preform as a linearly elastic, one‐dimensional (1D) solid. However, the key physical process is the lubrication of the preform due to fluid wetting, and this is modeled as a reduction in preform modulus, an easily measurable parameter. Residual stress, three‐dimensional (3D) structural behavior, and nonlinearity are neglected, but can all be included. The fluid flow model of capillary wicking is not tacked onto the Darcy equation as a modified boundary condition, as was previously done. The wicking is treated simply, but more realistically, by performing a force balance on the fluid in a pore. Balancing the capillary pressure and the viscous drag allows the development of a wicking front that precedes the main Darcy flow front to an extent that depends on several easily measurable factors. It is this wicking front that is responsible for the small void formation that reduces the quality of VARTM parts, relative to resin transfer molding (RTM) parts. POLYM. COMPOS. 26:477–485, 2005. © 2005 Society of Plastics Engineers     

Water-containing resin based on unsaturated polyester

Unsaturated polyester resins containing water were prepared through two steps: formation of a stable W/O emulsion of polyester prepolymer and subsequent polymerization of the emulsion. In this paper, conditions for formation of the resins from the W/O type emulsion and the heat-protection properties of the resulting water-containing resins are reported. The stability of the emulsions was measured, and the results are discussed in relation to the gelation time, since the polymerization of the emulsions is required to proceed faster than their disintegration. It was found that with increasing viscosity of the emulsions their stability increases and the gelation time shortens. The above requirement is fulfilled at almost all regions of emulsifier concentration where stable W/O emulsions are formed. Water-containing unsaturated polyester resins exhibit a remarkable heat-protection effect at elevated temperatures (500 and 2500°C.) in comparison with polyester resins not containing water.     

Probabilistic micromechanical model for two-dimensional slow particulate flow: Dry friction

This paper presents a probabilistic micromechanical model for the slow shearing motion of particulate systems dominated by inter-particle frictional forces. A particle can either slide, roll or jump relative to neighboring particles, or can be involved in a solid body rotation. The flow phenomenon is viewed as a Markov process in discrete time and continuous space. The relative position vector between a pair of neighboring particles is taken as the primary variable in the probabilistic approach. The physical constrains are implemented by considering the dynamic equilibrium of a particle interacting with its surrounding particles. The two-dimensional idealized motion of circular cylinders with negligible effects of the interstitial fluid is analyzed in detail in this paper. The macroscopic properties and rheological behavior are predicted starting from the material microstructure, which include the inter-particle friction laws, the number of contact points between particles and the local orientations of the relative position vector.     

Numerical simulation of non‐Newtonian polymer film flow on a rotating spoked annulus

The current study presents results from a series of numerical analyses of non‐Newtonian liquid film formation on a rotating spoked annulus. The film flow of a common type of polyester, poly(ethylene terephthalate) (PET), on a vertically rotating disk was modeled numerically. Two different molecular weights, corresponding to different viscosities for PET, and under flow at different rotating speeds, were considered. The film thickness profile was obtained at different radial and angular positions of the rotating disk in the simulations, which is beneficial in calculating the volume of polymer taken up by the rotating disk and also in calculating the volumetric flow rates on the disk. Two types of disks, including a standard solid disk and a number of hollow disk designs with spoked annuli, were considered, and the film flow was modeled using a volume of fluid computational fluid dynamics analysis. The analyses of flow over spoked annulus designs highlighted the advantage of such designs over the use of a conventional solid disk. It was found that the variation in the film thickness for the spoked annulus was lower than that for the conventional solid disk. The parametric study also provided a favorable spoked annulus design for which the film thickness was essentially constant. A constant film thickness would provide a constant film flow, which can be a benefit to many industrial applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44943.     

叔碳酸酯改性聚酯色浆在涂料中的应用

采用叔碳酸酯改性聚酯制得白色浆，研究了此色浆在涂料中的通用性及对涂膜硬度、柔韧性、耐水性、耐碱性和耐候性等的影响。     

Thermal properties of chlorendic acid based polyester resins

Polyester resins were prepared from chlorendic acid, maleic anhydride, and ethylene- and/or propylene-glycol. The resins were cured at room temperature with two different crosslinking agents including styrene and methyl methacrylate. The thermal behaviour of these polyester resins and their cured products was studied. From the thermogravimetric data it was observed that the polyester resins cured with styrene are thermally more stable than the methyl methacrylate cured products. It was also observed that the polyester resin prepared from propylene glycol is thermally more stable relatively than the ethylene glycol based polyester resin. The activation energies of thermal degradation of the resins and their cured products were calculated. The implications of these results are discussed.     

The Interfacial Bond Strength in Glass Fibre-Polyester Resin Composite Systems

The interfacial bond strength in glass fibre-polyester resin composites has been investigated using various experimental techniques. These included blocks of resin containing fibre (in which, depending on the geometry of the specimen, failure occurs in either a shear or tensile mode) the pullout of a fibre from a disc of resin and a short beam shear test for interlaminar shear strength determination.

Low power optical microscopy and optical retardation measurements of stress induced birefringence were used to detect the difference between intact and debonded fibre resin interfaces. The shear modulus and shear strength of the resin were obtained from torsion tests on cylindrical rods of the resin.

The single fibre shear debonding specimen and the short beam shear test are shown to be the most viable test methods but interpretation of the results is complicated by the various modes of failure possible and by the different stress states which exist in the area of the specimen where debonding starts. Stress concentration factors obtained by finite element analysis and photoelastic analysis have been applied to the results from these tests and the corrected interfacial bond strengths are in close agreement.

The real interfacial bond strengths of well bonded glass-fibre polyester resin systems is shown to be of the order of 70 MN m^?2.     

Thermo mechanical behaviour of unsaturated polyester toughened epoxy–clay hybrid nanocomposites

The intercrosslinked networks of unsaturated polyester (UP) toughened epoxy–clay hybrid nanocomposites have been developed. Epoxy resin (DGEBA) was toughened with 5, 10 and 15% (by wt) of unsaturated polyester using benzoyl peroxide as radical initiator and 4,4′-diaminodiphenylmethane as a curing agent at appropriate conditions. The chemical reaction of unsaturated polyester with the epoxy resin was carried out thermally in presence of benzoyl peroxide-radical initiator and the resulting product was analyzed by FT-IR spectra. Epoxy and unsaturated polyester toughened epoxy systems were further modified with 1, 3 and 5% (by wt) of organophilic montmorillonite (MMT) clay. Clay filled hybrid UP-epoxy matrices, developed in the form of castings were characterized for their thermal and mechanical properties. Thermal behaviour of the matrices was characterized by differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA) and dynamic mechanical analysis (DMA). Mechanical properties were studied as per ASTM standards. Data resulted from mechanical and thermal studies indicated that the introduction of unsaturated polyester into epoxy resin improved the thermal stability and impact strength to an appreciable extent. The impact strength of 3% clay filled epoxy system was increased by 19.2% compared to that of unmodified epoxy resin system. However, the introduction of both UP and organophilic MMT clay into epoxy resin enhanced the values of mechanical properties and thermal stability according to their percentage content. The impact strength of 3% clay filled 10% UP toughened epoxy system was increased by 26.3% compared to that of unmodified epoxy system. The intercalated nanocomposites exhibited higher dynamic modulus (from 3,072 to 3,820 MPa) than unmodified epoxy resin. From the X-ray diffraction (XRD) analysis, it was observed that the presence of d ₀₀₁ reflections of the organophilic MMT clay in the cured product indicated the development of intercalated clay structure which in turn confirmed the formation of intercalated nanocomposites. The homogeneous morphologies of the UP toughened epoxy and UP toughened epoxy–clay hybrid systems were ascertained from scanning electron microscope (SEM).     

用聚酯材料制备高固体分聚酯/氨基烘漆

以废聚酯材料为原料,经过醇解、酯化,制成高固体分高羟基聚酯树脂,再与高固体分氨基树脂配合,制成高固体分聚酯/氨基清漆或磁漆,其具有较高的施工固体分和出色的涂膜性能。简述了涂料配方、生产工艺和产品性能,分析了该涂料的经济效益和社会效益。     

Effect of acid groups in hydroxyl functional resins on the properties of polyester-urethane powder coatings

The concept of using hyperbranched polymers as scaffolds for solid thermoset resin applications is de-scribed. A series of semi-crystalline methacrylae-functional aliphaic poly-esters has been synthesized and characterized for applications as solid thermoset resins, e.g., powder coating resins. The polyester resin have been croslinked by UV irradiation producing either amorphous or semi-crystalline crosslinked films depending on the initial structure. The esins are based on hyperbranced aliphatic polyesters onto which crystaline linear aliphatic polyester chains have been grafted and end-capped with methacrylate moieties. The resins exhibit a rheological behavior suitable for low temperature curing powder coaings, i.e., films that can be readily formed and UV cured a temperatures below 80 °C. 2000 Lake Park Drive Smyrna GA 30080 E-Mails: bin.wu@ucb-group.com and sanilay.padaki@ucb-group.com