固井环空气窜机理和防窜水泥浆体系及其措施

如何防止环空气窜一直是固井技术研究的重点之一,为此国内外各个固井公司进行了大量的系统研究工作。在详细介绍环空气窜形成的机理、预测方法以及防气窜水泥浆体系和工艺技术措施基础上对防气窜固井工艺技术提出了一些建议。     

防气窜固井技术在阿拉新气田应用

阿拉新区块地处松辽平原北部,黑龙江省西部,具有较丰富的浅层天然气资源,1991年进行初步开发。阿拉新区块浅层气井固井气窜严重,固井质量较差。通过认真分析我们找出了该区块固井质差的主要原因,并提出了解决方案,借鉴2009年在葡浅区块浅层气井固井的成功经验,采用适合大庆地区浅层气井固井的双密度双凝防气窜水泥浆体系成功解决阿拉新气田固井质量问题。     

胶乳水泥浆对水泥石防窜能力的改善作用

实验对胶乳水泥浆的防窜性能进行研究,结果表明应用SDJR胶乳与水泥和外加剂配伍而成的胶乳水泥浆体系能有效地改善水泥浆性能,达到防止气/液窜、支撑套管和地层、保护油气层、延长油井寿命等目的。     

高温水平井环空化学封隔多重网络凝胶的研究

针对高温水平井存在的定点堵水难题,以淀粉为骨架材料、丙烯酰胺为接枝单体、固体H₂O₂为高温引发剂、钛-三乙醇胺螯合物为触变剂、N,N-亚甲基双丙烯酰胺为交联剂合成了高温水平井环空化学封隔多重网络凝胶,并通过正交实验确定了最优配比。同时对合成产物进行红外光谱表征、触变性能评价和封堵能力测试。结果表明,制得的耐高温水平井环空化学封隔器(ACP)材料性能良好,成胶时间在2～8 h可控;运用储能模量与恢复时间的关系方程和幂律流体方程对材料的触变性能进行评价,由此证明耐高温ACP体系的触变性能良好。采用环形填砂管物理模拟方法测量产物的持压能力,当温度在120～130℃时材料的封堵率达到98%以上,矿化度在20 000 mg/L附近时材料的封堵率达到97%以上。     

黏弹性流体环空内的起动流分析

利用分离变量法得到了Maxwell型黏弹性流体在环空内起动流时的解析解,并对其流动特性进行了计算和分析。结果表明,黏弹性流体在环空内的起动流呈现出周期性的、衰减的振荡流特点,环空内的速度剖面在不同时刻呈现出不同的规律,并且在流体弹性效应较强时,环空内有可能出现暂时的逆流现象。环空内不同位置处的振荡规律是不同的,环空中央附近的振荡强度要强于壁面附近的。流体的弹性效应越强,振荡幅度越大,趋于稳定的时间就越长。随着时间的延续,流体的弹性对速度剖面的影响逐渐减弱。环空间距对振荡流有抑制作用。间距变小,将使振荡流的振幅减小、频率增加,平均速度的稳定值减小。     

高温防窜水泥浆体系研究及应用

高温防窜水泥浆体系成功解决了水泥浆在高温条件下防窜性能差、稳定性差,以及高温水泥浆在低温条件下强度不能正常发展的缺陷。该水泥浆体系能够解决深井、超深井油气窜槽等固井质量问题。     

水平井偏心环空两相流模型

多相流技术为大部分工程设计难题提供了可行的解决方案。在钻井工程中,多相流理论主要用于解决井控、充气钻井和其平衡钻井过程中的井底压力计算。多年来,识别流型和准确计算摩擦损耗一个难题,甚至对环空几何形状考虑也很少。为了解决这一问题,本文建立了一个新的力学模型。模型能准确的判断偏心环空流型和计算摩擦损失。分析得出,流型边界对流型识别和摩擦力损耗计算有很大的影响。     

利用窜流层提高蒸汽驱油效果数值模拟研究

本文应用油藏数值模拟软件,对储层窜流层进行详细刻划和描述,并在此基础上利用窜流层对油藏的生产动态特征作出不同方案的精确数值模拟研究。结果表明,窜流层存在时,蒸汽到达窜流层后,在窜流层快速水平突进,并以较大接触面积向上继续加热油层,最终可以实现油层纵向上的均匀波及。研究指出水平井注蒸汽水平段适合打在窜流层下方,距窜流层的距离不宜太近,窜流层越厚,蒸汽驱油效果变差。该研究对存在窜流层的油藏所进行的开发提供了新思路,对类似油藏开发方案具有重要意义。     

一种低黏韧性双防低密度水泥浆的室内性能研究

陆丰油田大位移井储层渗透率低、欠压稳,容易发生气窜,造成固井质量不佳,存在底部高温区域沉降稳定性差、易漏等固井技术难题。针对这些难点,室内筛选3M高强抗压中空玻璃微球来降低水泥浆密度为1.4 g·m^-3的同时可以提高水泥石的抗压强度,选用纤维与胶乳混合作为增韧材料,降低了水泥石的渗透率,有效达到目的层增韧防漏的效果。该增韧材料协同防窜剂CT-1和膨胀剂EXP-1,提高水泥石的胶结强度,具有防漏防窜的作用。由上述主要材料协同其他相关水泥浆添加剂构建了一套具有低黏韧性兼具防漏和防窜性能的低密度水泥浆体系,该低密度水泥浆体系具有良好的流变性,自由液为零,且水泥石上部密度和下部密度差值均小于0.03 g·m^-3,可以看出该韧性水泥浆体系具有优异的沉降稳定性能。低黏韧性双防低密度水泥浆具有良好的力学性能,抗压强度达28 MPa,弹性模量小于7 GPa,抗窜强度大于10 MPa·m^-2,且抗窜效果较普通低密度水泥浆抗窜能力提高了81.2%,说明该水泥浆具有较强封隔能力,可以有效提高固井质量。     

磁极结构对磁流体密封性能的影响

研究了磁流体密封装置中磁极的组合方式、磁极的级数、磁源的磁场方向和密封间隙对密封性能的影响。实验结果表明,磁流体密封性能随级数的增加和间隙的减小而有所提高,且与磁极组合方式和磁场方向有关     

超临界流体技术制备超细炸药与超细混合炸药研究进展

本文阐述了超临界流体技术在制备超细粉体方面的发展概况以及相应的原理、特点,并重点对超临界流体技术目前在制备超细炸药与超细混合炸药方面的应用进行了综述,同时对超临界流体在含能材料中的应用前景进行了展望。     

三元复合驱采出液分离装置的优化研究

针对油田三元复合驱采出液乳化严重等特点,通过现场试验对油水分离器进行结构及操作条件的优化。现场试验结果表明,优化后的分离器对三元复合驱采出液的分离,油相和水相均达到采出液分离标准,且油水分离效率可达到98%以上。     

Surrogate-model-based,particle swarm optimization,and genetic algorithm techniques applied to the multiobjective operational problem of the fluid catalytic cracking process

Abstract

This article provides a concise multiobjective optimization methodology for an industrial fluid catalytic cracking unit (FCCU) considering stochastic optimization techniques, genetic algorithms (GA) and particle swarm optimization (PSO), based on surrogates or meta-models in order to approximate the objective function. A FCCU was considered and simulated in an AspenONE process simulator. In addition the article examines the claim that PSO has the same effectiveness (finding the optimal global solution) as GA, but with significantly better computational efficiency (fewer function evaluations). The optimization results obtained with the PSO technique, based on the evaluation of less functions and adjustment of less parameters, showed a 3% increase in yield of naphtha as compared to results obtained with the GA technique. Finally, the results of the optimization obtained with the stochastic optimization techniques were compared and analyzed with a deterministic one. The performance targets of the multiobjective operational optimization supported the FCCU design and production planning to ensure refinery profitability and a regulatory environment.     

高贝利特水泥熟料与硅酸盐水泥熟料复合体系的性能研究

实验研究了不同高贝利特水泥(HBC)和硅酸盐水泥(PC)配合比,不同缓凝剂掺量以及不同粉磨细度对HBC-PC复合体系水泥的物理性能的影响。结果表明,HBC与PC混合时,HBC的适宜比例为50%～80%,以50%为最佳。在最佳HBC掺量下,采用二水石膏作缓凝剂,水泥中w(SO3)控制在2.0%～3.0%时水泥具有较好的早期和后期强度;采用硬石膏作缓凝剂,水泥w(SO3)控制在2.0%～3.5%时综合效果较好。当HBC掺量为50%,w(SO3)为2.6%±0.2%时,其复合体系水泥的适宜粉磨细度为320～400m2蛐kg。     

从硼泥制取氢氧化镁阻燃剂

本文讨论了从硼泥制备氢氧化镁阻燃剂工艺的适宜条件和影响因素，制得的氢氧化镁纯度〉９４％。比表面积〈２０ｍ＾２／ｇ，平均粒径１μｍ～２μｍ应用试验表明其具有优良的阻燃和消烟性能。     

Effect of nozzle external geometry on the pressure and shear stress exerted on the surface being gauged in fluid dynamic gauging

Fluid dynamic gauging (FDG) is an experimental technique that exploits the behaviour of a suction flow through a nozzle located near a fouling deposit to determine the thickness of the layer. The nozzle does not contact the layer but the shear stress imposed by the flow could cause it to deform. The effect of the external shape of the nozzle on the stresses on the surface being gauged was investigated using computational fluid dynamics (CFD) simulations. Different nozzle shapes were studied using a 2D axi-symmetric computational domain. CFD results were validated by comparison with (i) a set of experimental values for the normal stresses acting on the gauged surface, and (ii) an analytical solution for the limiting case approached under certain conditions. The results obtained for different simple geometries show that certain desirable pressure and surface shear stress distributions can be obtained by selection of the appropriate external nozzle shape.     

Unified equation of state based on the lattice fluid theory for phase equilibria of complex mixtures part I. Molecular thermodynamic framework

Consistent calculation of fugacities of fluid mixtures remains as one of the most important subjects in contemporary molecular thermodynamics. In practice, equations of state (EOSs) and g^E-models have been used. However, most EOSs are erroneous for condensed phases at high densities and g^E-models are inapplicable for pressuresensitive systems. Recently to remedy the shortcomings in both approaches, there has been a surge of new g^E-EOS mixing rules. By equating any set of EOS and g^E-models, the limitations in both approaches could be resolved significantly. However, the self-consistency in the underlying concept of those mixing rules remains controversial. During the last several years, the present authors proposed a new lattice-fluid EOS and its simplification relevant to phase equilibrium calculations. Without employing any g^E-EOS mixing rule and with only two parameters for a pure component and one adjustable interaction energy parameter for a binary mixture, results obtained to date demonstrated that the EOSs are quantitatively applicable to a great variety of phase equilibrium properties of mixtures, especially, for complex and/or macromolecular systems. In the present article we summarize the EOSs and extended the applications to liquid-liquid Equilibria. In part I, we discussed briefly the molecular thermodynamic aspects of general derivation of the EOS and a brief discussion of applying the EOSs to pure fluids while the illustrative application to various real mixture systems is discussed in part II.