地层变形的流固耦合数值模拟

石油开采当中,地层变形往往是造成套管损坏的首要因素,而开发过程中例如高压注水采油在很大程度上造成了地层的变形。本文针对石油工程中高压注水采油引起的地层变形,运用有限元软件ADINA建立了七井点流固耦合数值模拟模型,具体描述了高压注采过程中地层的变形情况,并对其计算结果进行了研究分析,结果表明,高压注水采油易使井壁处地层应力集中、岩层滑移与膨胀变形、储油地层凹陷等,且与较大孔隙度油层相比,低孔隙度油层高压注采时的孔隙压力与流体流速增加幅度要更大,以上结论为预防和减少流固耦合作用下地层变形造成的影响等提供了理论依据。     

不同场热-水-应力耦合过程二维有限元分析

从建立应力平衡方程、水连续性方程、能量守恒方程和弹塑性矩阵入手,提出了一个饱和-非饱和孔隙介质中的热-水-应力耦合模型和开发了相应的有限元程序.为验证本耦合模型及程序的可靠性和重点探讨不同场的热-水-应力耦合过程,以高放射性核废料地质处置的Prototype Repository Project(PRP)原位试验为模拟对象,对一个处置试验坑道近场进行了水单场、热-水耦合、水-应力耦合、热-应力耦合和热-水-应力耦合条件下的数值分析,考察了工程屏障及围岩中的温度、饱和度及应力的变化、分布情况,并得出了一定的认识.     

变形多孔介质温度–渗流–应力完全耦合模型及有限元分析

根据多孔介质中温度、渗流及应力之间复杂的耦合关系,基于连续介质力学和混合物理论,导出变形多孔介质热–流–固三场耦合模型及其控制方程,探讨有限元法的求解过程,以ABAQUS软件为求解器,在MATLAB语言环境下编制相应的计算程序,并通过典型算例考证程序的正确性。然后研究石油钻井过程中的热–流–固耦合作用过程,详细分析场耦合作用对井壁孔隙压力、温度和应力的影响,计算结果表明,热–流–固耦合作用对井壁稳定有重要的影响,应全面考虑各物理场之间的耦合作用。研究成果为分析岩土介质多场耦合过程提供一条有效的途径,从而为进一步研究温度–渗流–应力–化学(THMC)耦合问题奠定基础。     

轴对称荷载下饱和地基热-水-力耦合动力响应

基于Biot波动理论,通过建立饱和地基的热-水-力耦合动力响应的控制方程,对轴对称荷载作用下半无限地基的热-水-力耦合动力响应问题进行探讨。利用Hankel变换技术,得到外荷载作用下地基中温度增量、应力、位移和孔隙水压力积分形式的解答。利用Hankel数值逆变换得到计算结果,对热-水-力耦合条件下地基土体中温度增量、应力、位移和孔隙水压力响应的分布进行分析,并与水-力耦合动力响应情况下的结果进行比较。     

采用孔隙热弹性模型分析页岩井眼失稳规律

基于多孔介质连续力学,考虑各向异性页岩的热流固耦合作用,建立了各向异性多孔介质孔隙热弹性力学基本方程和页岩地层井眼稳定分析数学模型,采用MATLAB软件编制了数值求解程序,分析了流固耦合、热固耦合、热流固耦合三种不同耦合模式下井周孔隙压力、地层温度、应力分布和井眼稳定性随时间变化的特征。结果表明:数值解与解析解计算结果吻合较好(误差仅0.028%),实例井井眼扩径率计算结果与实际情况基本吻合,验证了本文模型和方法的正确性;温度和孔隙压力的改变对井周应力分布影响较大,地层温度降低、井内压力增加有利于井眼稳定,孔隙压力升高不利于井眼稳定;页岩地层井眼稳定性具有显著的时变效应,随着钻开地层时间的增加,井眼不稳定区域和井眼扩径率逐级变大。孔隙热弹性力学分析方法可用于分析不同时间的井眼失稳规律,可为解决页岩井眼失稳问题提供更加科学的计算手段和方法。     

多孔介质流-固-热三场全耦合数学模型及数值模拟

给出多孔岩体介质的流–固–热三场全耦合数学模型。假定流体为单相流,固体介质为非沸腾的饱和、热弹性多孔介质,该模型由流体物质守恒方程、力学平衡方程和能量守恒方程这3个相互耦合的方程组成,其中包含了众多耦合项,并定义一系列的本构关系及耦合变量。以FEMLAB工具为基础,将该数学模型转化成为一个统一的偏微分方程组,在人机交互的环境下,实现流–固–热三场全耦合数值求解,一次解出渗流场、位移场和温度场,给出更接近真实物理过程的数值解答,避免松散耦合法求解多场耦合问题带来的误差。利用一个已知解析解和数值解的算例来证明了耦合模型及求解方法的正确性。最后模拟通过井孔向岩体中注入冷水时流–固–热全耦合过程,详细地分析全耦合作用对井壁围岩应力的影响,计算结果表明:流–固–热三场耦合作用对井壁的稳定分析有非常重要的影响。     

热-流-固耦合的群井抽灌环境效应分析

分析了地下水源热泵系统3个物理场之间的耦合作用,利用有限元软件建立了热-流-固三场不完全耦合的数值计算模型;通过对渗流场、温度场、应力场、位移场的分析得出:抽灌水引起的水头差导致的强迫渗流对渗流场的分布起主导作用;土体传热和热对流对温度场的影响远小于渗流的影响;应力场主要有两部分:一是温度变化引起的热膨胀应力;二是地下水的强迫渗流对土骨架的作用力;位移场是应力场的外在表现,规律与应力场基本相似。     

稠油油藏热流耦合“两箱”分析模型及应用研究

在热采过程中存在热、流、固等多场耦合作用,目前的研究方法和分析模型存在一定不足。针对油藏特点,提出油藏热质传递过程的“两箱”分析法,即用于一般分析的“黑箱分析法”和用于精细分析的“白箱分析法”,“黑箱分析法”不涉及油藏多孔介质内部热质传递过程,研究油藏与外界的能量传递过程,以及体系内能量的变化,而“白箱分析法”包括“黑箱分析法”的内容,同时要研究体系内部各部分间的能量转换过程。在此基础上,应用CMG软件进行数值模拟计算和分析,对于热采注汽过程中的蒸汽凝结区域和蒸汽凝结前缘位置,给出分析和判定方法。该研究结果可为深入开展稠油热采注汽过程流体运移特性和提高油气采收率研究提供依据。     

注采压差对储层井壁围岩应力场动态演化研究

应力敏感性使得低渗透油藏在开发过程中地应力变化比较明显。考虑储层渗流场与应力场的耦合作用,揭示了注水井及采油井附近围岩体孔隙压力随注采压差的动态演化规律。     

稠油热采注汽锅炉清灰技术研究与应用

辽河油田是以稠油热采为主的油田,稠油热采所需的高温高压蒸气来源于热采注汽锅炉,对流段是稠油热采注汽锅炉重要组成部分,在对流段中,水将吸收大量的热量,但对流段积灰状况、清灰方式等严重影响锅炉热效率。通过分析稠油热采注汽锅炉清灰技术现状,研究安全高效的清灰方式,可以延长清灰周期、降低排烟温度、提高热采注汽锅炉的热效率、减少燃料用量、降低锅炉单耗,从而达到节能增效的目的。     

数字0

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Annual index of HV&AC 2 0 0 1

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江油市房屋震害损毁原因分析

通过地震后对江油市区房屋的大面积实地评估鉴定及阅读鉴定报告,分析了在地震中部分房屋受到较重损毁的具体原因,并结合实际情况给出了加强中西部地区中小城镇砌体房屋抗震能力的措施,以确保砌体结构安全使用.     

浅论机械设备的前期管理

机械设备的前期管理是设备经济管理的重要内容,它是从计划投资,调研论证、决策,选择方案,到选型订货的整个阶段。直接关系到投资效益、可能性;关系到能否延长设备寿命,降低施工成本,使设备各得其所,提高设备利用率,减少闲置等问题;也关系到设备先进适用性及年度使用费用;对于节省资金,提高资金使用效果,避免资源浪费,充分发挥设备使用性能及生产能力促进经济发展具有重要意义。     

材料工艺

自由穿梭光与影———威盛亚透光板在追求通达透亮的设计风潮中,有一种理想的材料:既轻盈、安全、方便施工,还具有多样化颜色和纹理以供选择,它便是威盛亚透光板。优良特性威盛亚透光板融合了艺术与光的质感,具有高达40%的透光率。并有多达24种颜色可供选择,而且无论正反效果,均情趣独具。透光板的比重约为无机玻璃的1/3,不仅方便运输,而且轻盈安全。尽管如此,它的耐冲击性能却能达到玻璃的10倍,亚克力的7倍。透光板加工性能理想,只要利用普通电动工具,便可轻松完成透光板的切割或打孔。根据国家防火建筑材料质量监督检验中心出具的检验报告…     

Ceramsite obtained from water and wastewater sludge and its characteristics affected by (Fe2O3 + CaO + MgO)/(SiO2 + Al2O3)

To control and optimize the process for making ceramsite from wastewater treatment sludge (WWTS) and drinking-water treatment one (DWTS), the effect of mass ratios of (Fe₂O₃ + CaO + MgO)/(SiO₂ + Al₂O₃) (defined as F/SA ratios); SiO₂:Al₂O₃ and Fe₂O₃:CaO:MgO (under the condition of fixed F/SA ratio) on the characteristics of ceramsite were investigated. It was found that the optimal F/SA ratios for making ceramsite range 0.175-0.45. Na-Ca feldspars and amorphous phases increase in ceramsite as F/SA ratios increase. Ceramsite with porous surfaces, expanded structures, and complex crystalline phases can be obtained at 0.275 ≤ F/SA ≤ 0.45, which accordingly cause the decrease in compressive strength. Higher strength of ceramsite with lower porosity can be obtained at 0.175 ≤ F/SA < 0.275, and under the condition of F/SA ratio = 0.275, the raw materials can produce ceramsite with desired physical properties at 18.2:35 ≤ SiO₂:Al₂O₃ ≤ 45:10.2 and 10:2.7:1.4 ≤ Fe₂O₃:CaO:MgO ≤ 5.3:6:1.6. Ceramsite with higher compressive strength and lower porosity can be obtained at SiO₂:Al₂O₃ > 27.2:15.8 and Fe₂O₃:CaO:MgO > 6:3.5:1.8. Results indicate that F/SA ratios could be used as an important parameter to control the production process of ceramsite with desired physicochemical properties and resolve the disposal problems of residual sludges.     

Optimization of the configuration of 290 × 140 × 90 hollow clay bricks with 3-D numerical simulation by finite volume method

This paper is aimed at finding the optimum configuration of the number of holes and their arrangement for the 290 × 140 × 90 hollow clay bricks with 3-D numerical simulation by a home-made code with finite volume method. Seventy-two kinds of configurations with different hole number and arrays are chosen elaborately and their equivalent thermal conductivities are numerically predicted. In addition, the effects of the hole surface radiation and the indoor–outdoor temperature difference on the equivalent thermal conductivity are also investigated. The major findings are as follows. The radiation of the hole surfaces makes heat transfer enhanced and the equivalent thermal conductivity enlarged in some extent, ranging from 25.8% to 4.6%. The optimum configuration has eight holes in length, four holes in width and one holes in height, whose equivalent thermal conductivity is the lowest and of 0.400 W/(m K),which is only 59% of the highest thermal conductivity of the all cases studied. When the indoor–outdoor temperature difference varies from 50 °C to 20 °C, the equivalent thermal conductivity of the 72 kinds of hollow bricks does not vary too much, usually within ±5%. Especially, the equivalent thermal conductivity of the optimum configuration holds no change within this variation range of indoor–outdoor temperature difference.     

Combined (alkaline + ultrasonic) pretreatment effect on sewage sludge disintegration

The individual effects of alkaline (pH 8-13) and ultrasonic (3750-45,000 kJ/kg TS) pretreatments on the disintegration of sewage sludge were separately tested, and then the effect of combining these two methods at different intensity levels was investigated using response surface methodology (RSM). In the combined pretreatment, ultrasonic treatment was applied to the alkali-pretreated sludge. While the solubilization (SCOD/TCOD) increase was limited to 50% in individual pretreatments, it reached 70% in combined pretreatment, and the results clearly showed that preconditioning of sludge at high pH levels played a crucial role in enhancing the disintegration efficiency of the subsequent ultrasonic pretreatment. By applying regression analysis, the disintegration degree (DD) was fitted based on the actual value to a second order polynomial equation: Y = −172.44 + 29.82X₁ + 5.30 × 10⁻³X₂ − 7.53 × 10⁻⁵X₁X₂ − 1.10X₁² − 1.043 × 10⁻⁷X₂², where X₁, X₂, and Y are pH, specific energy input (kJ/kg TS), and DD, respectively. In a 2D contour plot describing the tendency of DD with respect to pH and specific energy input, it was clear that DD increased as pH increased, but it seemed that DD decreased when the specific energy input exceeded about 20,000 kJ/kg TS. This phenomenon tells us that there exists a certain point where additional energy input is ineffective in achieving further disintegration. A synergetic disintegration effect was also found in the combined pretreatment, with lower specific energy input in ultrasonic pretreatment yielding higher synergetic effect. Finally, in order to see the combined pretreatment effect in continuous operation, the sludge pretreated with low intensity alkaline (pH 9)/ultrasonic (7500 kJ/kg TS) treatment was fed to a 3 L of anaerobic sequencing batch reactor after 70 days of control operation. CH₄ production yield significantly increased from 81.9 ± 4.5 mL CH₄/g COD_added to 127.3 ± 5.0 mL CH₄/g COD_added by pretreatment, and this enhanced performance was closely related to the solubilization increase of the sludge by pretreatment. However, enhanced anaerobic digestion resulted in 20% higher soluble N concentration in the reactor, which would be an additional burden in the subsequent nitrogen removal system.     

CF80混凝土的配制应用

结合具体工程实例，介绍了CFSO混凝土的配制及应用，着重阐述了CFS0混凝土的选材，配比设计，运输泵送浇筑等内容，并通过实施效果及实验检测证明CFSO钢纤维混凝土符合设计要求。     

Biogenic silver nanoparticles (bio-Ag 0) decrease biofouling of bio-Ag 0/PES nanocomposite membranes

Biofouling is a major problem for the application of membrane technology in water and wastewater treatment. One of the practical strategies to decrease biofouling is the use of advanced anti-biofouling membrane material. In this study, different amounts of biogenic silver nanoparticles (bio-Ag⁰) were embedded in polyethersulfone (PES) membranes, using the phase-inversion method. The effects of the bio-Ag⁰ content on the structure of the membrane and its filtration performance were systematically investigated. The results demonstrated that silver-containing nanostructures were uniformly distributed on membrane surface. Bio-Ag⁰ incorporation slightly increased the hydrophilicity of the PES membrane and increased the permeate flux. The anti-bacterial and anti-biofouling properties of the bio-Ag⁰/PES nanocomposites membrane were tested with pure cultures (Escherichia coli and Pseudomonas aeruginosa) and a mixed culture (an activated sludge bioreactor), respectively. The bio-Ag⁰/PES composite membranes, even with the lowest content of biogenic silver (140 mg bio-Ag⁰ m⁻²), not only exhibited excellent anti-bacterial activity, but also prevented bacterial attachment to the membrane surface and decreased the biofilm formation during a 9 weeks test.