Horizontal wells and steam-assisted gravity drainage

Petroleum can be produced more efficiently using horizontal wells instead of conventional wells. For a typical 16 hectare well spacing, the pressure drawdown is as small as one-fiftieth of that for conventional wells. In some cases, where coning is a problem in conventional production, horizontal wells allow operation with much less coproduction of the displacing fluid. In the thermal recovery of bitumen and heavy oils, the Steam-Assisted Gravity Drainage process with horizontal production wells allows the systematic sweeping of the reservoir with economic production rates and without steam bypass. This paper described and reviews the application of horizontal wells to the production of heavy crude oils and bitumen by both non-thermal and thermal methods.     

制氢装置转化催化剂失活原因分析及对策

中石化西安分公司制氢装置转化催化剂在短期生产运行过程中,因催化剂积碳导致转化炉管表面出现大面积花斑,近半数炉管出现红管,炉管差压增大,转化出口甲烷含量超标,芳烃穿透.对催化剂失活原因进行细致分析后表明:装置开停车频繁;转化催化剂多次积碳-烧碳使催化剂表面剥蚀破碎、跑损严重为主要原因.针对失活原因制定了相应对策.     

Activation of a Au/TiO2 Catalyst by Loading a Large Amount of Fe–Oxide: Oxidation of CO Enhanced by H2 and H2O

Catalytic activity of a 1 wt% Au/TiO₂ catalyst is markedly improved by loading a large amount of FeO_x, on which the oxidation of CO in excess H₂ is selectively promoted at temperature lower than 60 °C. Oxidation of CO with O₂ on the FeO_x/Au/TiO₂ catalyst is markedly enhanced by H₂, and H₂O moisture also enhances the oxidation of CO but its effect is not so large as the promotion by H₂. We deduced that activation of Au/TiO₂ catalyst by loading FeO_x is not caused by the size effect of Au particles but a new reaction path via hydroxyl carbonyl intermediate is responsible for the superior activity of the FeO_x/Au/TiO₂ catalyst.     

MOBILIZATION OF SLUDGE IN HORIZONTAL CYLINDRICAL TANKS WITH SUBMERGED NOZZLES

Over 378,000 m³ (100 million gal) of radioactive waste is being stored in hundreds of tanks at several U.S. Department of Energy (DOE) sites. The environment within the tanks is highly radioactive and chemically harsh. The waste typically consists of a heterogeneous sludge layer covered by a layer of supernatant. A few of the tanks have leaked to the environment, while others are corroding. Removing the waste from the tanks and processing it to a stable final form are desired to prevent any additional contamination of the environment. The tanks vary in size and geometric shape and do not have systems for removing the sludge waste.

Mobilization and mixing studies were conducted with a surrogate sludge (e.g., kaolin clay) using submerged jets in two sizes of horizontal tanks with nominal capacities of 0.87 m³ (230 gal) and 95 m³ (25,000 gal). Mobilization efficiencies and mixing times were determined for single and bidirectional jets in both tanks with the discharge nozzles positioned at various locations in the tanks. Approximately 80% of the surrogate sludge was mobilized in the 95-m³ tank using a fixed bidirectional jet (inside diameter = 0.035 m) and a jet velocity of 6.4m/s (21 ft/s). The effective cleaning length, which is defined as the distance between the jet and the edge of the remaining sludge bank, was approximately 3.2 m (10 ft) on each side of the bidirectional jet.     

A203型低温氨合成催化剂使用小结

对Ａ２０３型低温氨合成催化剂的使用进行总结，介绍了该催化剂的装填，升温还原情况及使用效果。     

花岗岩残积土-土工格栅界面的后循环剪切行为研究

花岗岩残积土在华南、东南沿海、南岳、新疆等地区广泛分布,前人的研究多集中在结构性及微观特性上,后循环加载、位移演化、土壤密度等因素对筋-土界面的剪切特性及加筋作用效果的影响评估研究较少。从循环试验剪切刚度这一重要参数入手,以加载次数、加载频率值、位移振幅值、土壤重度值为自变量,应用控制变量法,通过设计循环直剪试验,得到加筋花岗岩残积土的剪切应力与剪切位移、垂直位移与剪切位移关系曲线进行观察对比,结果表明:花岗岩残积土土工格栅界面剪切刚度受位移半振幅、土壤干重度影响很大,受加载频率影响很小,循环加载并没有弱化后循环界面剪切强度,剪切位移与位移半振幅呈负相关关系。     

设抗震增强体的桩基础力学特性的原位试验研究

在过去的大地震中,许多桩基础因强烈振动和地基变形而遭受结构性破坏,因而提出一种既可以应用于新建桩基础,也可以应用于现有桩基础的抗震加固方法,即采用地基加固技术在桩基础中设置抗震增强体,以与桩基础的钢筋混凝土承台形成双层抗弯结构。采用等比例模型原位水平载荷试验和振动试验以及开挖检查等方法,对抗震加固的力学特性和构建质量进行加固前后的对比研究,进而证实了该加固方法的有效性和可行性,为同类工程起到了一定的参考意义。     

An economic–ecological model to evaluate impacts of nutrient abatement in the Baltic Sea

This paper presents a coupled economic–ecological model that integrates a catchment model with a marine model and incorporates economic data to analyse the long-term economic and ecological consequences of nutrient abatement in the Baltic Sea. The spatially explicit model describes dynamics of soil phosphorus in arable land, developments of nutrient concentrations and phytoplankton biomass in the sea basins, and inter-annual variation in nutrient loads and biophysical processes. The performance of the model is demonstrated by computing the least-cost solution to reach the good environmental state of the sea – as implied by the Baltic Sea Action Plan – within a time span of 40 years. The total cost of achieving this target is 1487 M€ annually. Spatially optimal allocation of load reductions differs from the load reduction targets of the Baltic Sea Action Plan, and focuses more on the control of phosphorus loads.     

Effect of the metal oxide loading on the activity of silica supported MoO3 and V2O5 catalysts in the selective partial oxidation of methane

Precipitated silica catalysts loaded with either MoO₃ (0.2–4.0 wt%) or V₂O₅ (0.2–5.3 wt%) have been studied in the selective partial oxidation of methane to formaldehyde with molecular oxygen at 520 °C. The functionality of the SiO₂ surface towards the formation of HCHO is significantly promoted by V₂O₅, while it is depressed by the MoO₃.     

Free convection heat transfer over a horizontal plate at low prandtl number

Boundary layer equations for free convection heat transfer along a semi-infinite horizontal plate are derived by giving more importance to the energy equation. The equations are obtained for low Prandtl number and two separate polynomials are used to approximate the temperature and velocity profiles in these regions. The rate of heat transfer is compared with the available analytical and numerical results based on conventional boundary layer equations.