Study on high-strength composite portland cement with a larger amount of industrial wastes

It is one of important measures for the sustainable development of cement industry to utilize industrial wastes. High-strength composite portland cement with a large amount of granulated blast furnace slag (GBFS), fly ash and limestone was prepared by separate grinding method, optimizing gypsum and using activators. The total amounts of blending materials are between 45% and 65% and the strength grades of cements reach 525 or even 625 according to Chinese national standard for composite portland cement. Besides setting time and strength, the hydration heat, drying shrinkage and sulfate resistance were also determined.     

喷锚结合水泥搅拌桩在基坑支护中的应用

结合紫金苑工程实例,分析喷锚结合水泥搅拌桩在基坑支护中的应用并总结施工、监测经验。     

固井水泥环缺陷对套管强度影响仿真分析

固井水泥环质量对套管的强度影响很大。建立了水泥环缺少1／12的井筒平面应变有限元模型，通过对固井水泥环缺陷引起的套管应力变化进行仿真模拟分析，得出无内压下套管的最大径向位移是水泥环完整时的3．9倍，水泥环的缺少导致Mises应力集中系数为2．0，套管外壁的最大塑性应变达到0．0152，定量分析固井质量对套管强度的影响，为热采井套管损坏提供一些定量数据。     

DG抗高温隔离液在古深1井的应用

古深1井是大庆油田在古龙地区的一口风险探井,设计井深5 500 m,实际完钻井深为4 739 m。钻进过程中,多次出现塌、漏、卡等事故,造成井径不规则。为平衡压力,压稳地层,更好地隔离钻井液和水泥浆,提高顶替效率,设计采用DG抗高温隔离液。DG抗高温隔离液抗高温可达150℃,密度调节范围宽,抗高温悬浮稳定性好,失水量少,与水泥浆和钻井液相容性好。古深1井采用双级注水泥工艺,固井施工过程十分顺利,隔离液密度均匀,泵送容易,无发泡现象。从声幅测井情况来看,水泥面上部与隔离液交界处界面清楚,水泥环胶结良好,水泥返高达到了设计要求,混浆过渡段短,固井质量合格。     

超低密度早强水泥浆在天然气井固井中的应用

在天然气井固井中,上部固井质量一直存在问题。为了提高固井质量,达到保护套管的目的,研制了新型水泥浆体系。经室内研究,选择了减轻剂的种类与粒级配比;根据低密度水泥浆的性能要求,确定了配方,并对该配方进行了触变防漏特性及稳定性分析,形成了具有体系稳定、水泥浆密度波动对水泥浆体系产生影响较小、抗漏失能力强、早期强度发展快等特点的超低密度水泥浆体系。经现场试验,获得了较好的效果。     

利用自生气的油气田开发开采工艺技术概况

油气田开发工艺技术中使用的自生气有N2、O2、CO2、ClO2和混合气五大类型，来源于化学反应和微生物的代谢产物。自生N2主要来自亚硝酸盐和铵盐的氧化还原反应。自生O2则来自过硫酸盐和过氧化物的高温分解。白生CO2来自碳酸盐与酸的反应及含氮类有机物的高温分解。自生混合气包括高能气体和生物气，高能气体是火药或炸药爆燃产生的混合气，生物气是微生物代谢产生的混合气。自生气工作液在油气田现场已应用于固井、射孔、解堵、压裂、调剖和三次采油等广阔的领域。本文概述油气田开发开采中利用五大类自生气的19项工艺技术。参43.     

混合材对超细灌浆水泥流变性能的影响

 为研究粉煤灰和矿渣混合材对超细水泥流变性能的影响，采用SEM，XRD，Malvern激光粒度仪、表面电位分布仪、旋转粘度计等现代测试技术对材料的粉体特性、表面性能、矿物组成和流变性能进行了系统研究,并应用材料科学理论研究材料的组成、粉体特性、表面性能等与流变性能的关系及其作用机理。研究表明：超细粉煤灰具有较高的表面电位,能提高超细水泥浆液的流变性能，减少浆液的经时流变性损失，改善与高效减水剂的相容性；矿渣降低了超细水泥的流动性，增加了浆液的稳定性。因此，采用粉煤灰与矿渣复掺，能配制出水泥浆的流动性和稳定性均较好的复合灌浆水泥。     

偏高岭土及其对油井水泥性能的影响

综述了偏高岭土特性及其在水泥混凝土领域中的应用情况,初步研究了偏高岭土对油井水泥性能的影响。结果表明,偏高岭土能显著提高油井水泥的抗压强度,表现出很强的火山灰活性,完全可以作为新一代的油井水泥掺合料。     

纤粒复合型油井水泥石增韧剂的性能及机理研究

针对国内油田油气井因后续施工(射孔、压裂、酸化等)造成水泥环脆裂的问题,根据断裂力学原理和复合材料理论设计配方,选用GX(1.0%的特种无机富硅纤维 2.5%的有机弹性颗粒)作为油井水泥石增韧材料;并对掺有GX的油井水泥浆的工程性能、物理性能、与其他外加剂的配伍性以及水泥石的微观结构进行考察,结合性能评价试验,分析了GX在水泥石中的增韧作用机理。结果表明,GX可以显著提高油井水泥石的韧性和弹性,并且与其他外加剂配伍性良好。     

The hydration phase and pore structure formation in the blends of sulfoaluminate-belite cement with Portland cement

Sulfoaluminate-belite (SAB) cements are an attractive class of low-energy cements from the viewpoint of saving energy and releasing less CO₂ into the atmosphere during their production. Their hydraulic activity, however, does not match that of the ordinary Portland cement (PC) and needs improvement before they can be used on their own. However, SAB cements when blended with PC have the potential to be used effectively in traditional applications as shown by this study. Mortars made with blends of SAB cements and PC, and a cement-to-sand ratio of 1:3 by weight and a water-to-cement ratio of 0.5, indicate a superior protection against corrosion of steel to those made with blends of PC and blast-furnace slag (BFSPC). The prepared mortars were stored at 20 °C for 90 days under either a 60% relative humidity (RH)-dry air, or 100% RH-wet air conditions. With further improvement in the SAB cement quality through better understanding of their characteristics, a genuine competition between SAB/PC and BFSPC can be expected in practice.