Mechanism study of the ethanol oxidation reaction on palladium in alkaline media

In this work, the mechanism of the ethanol oxidation reaction (EOR) on a palladium electrode was studied using the cyclic voltammetry method. The dissociative adsorption of ethanol was found to proceed rather quickly and the rate-determining step was the removal of the adsorbed ethoxi by the adsorbed hydroxyl on the Pd electrode. The Tafel slope was found to be 130 mV dec⁻¹ at lower potentials, which suggests that the adsorption of OH⁻ ions follows the Temkin-type isotherm on the Pd electrode. In comparison, the Tafel slope increased gradually to 250 mV dec⁻¹ at higher potentials. The change in the Tafel slope indicated that, at higher potentials, the kinetics is not only affected by the adsorption of the OH⁻ ions, but also by the formation of the inactive oxide layer on the Pd electrode.     

Case study: Comparison of enhanced heavy-oil recovery by CGI,WAG, and GAGD

Continuous gas injection (CGI) in the conventional horizontal flooding patterns leads to severe gravity segregation and poor reservoir contact (sweep) volumes. To improve the sweep efficiency, the Water-Alternating-Gas (WAG) process has been widely practiced in the industry. However, the WAG process has not measured up to expectations, as evidenced by the low recoveries observed in several field cases.

The Gas-Assisted Gravity Drainage (GAGD) process is designed and practiced based on gravity drainage idea and uses the advantage of density difference between injected gas and reservoir oil to overcome the drawbacks of the WAG process.

In this study, a comparison of enhanced heavy-oil recovery by three methods (CGI, WAG, and GAGD) is conducted by a commercial numerical simulator in a sector model of an Iranian offshore field. For this purpose, different production scenarios are designed. Moreover, the effect of several parameters such as injection fluid (CO₂, hydrocarbon gas), in situ oil viscosity (heavy or extremely heavy oil), rate and volume of injection, and also three different WAG ratios are studied.

The results show that the GAGD method is not suitable for this field as the thickness of pay zone is low for vertical sweep efficiency and causes early breakthrough of injected gas. Also, CGI leads to lower recoveries compared to the WAG process, due to its unfavorable mobility ratio. Injection of CO₂ instead of hydrocarbon gas results in higher sweep efficiency because of its viscosity reduction and swelling effects. In case of extremely heavy-oil recovery, with decreasing well spacing, the oil recovery factor increases as the drainage radius of wells reduces substantially due to high-viscosity oil.     

碳酸盐岩油藏提高采收率技术研究应用进展

介绍了国内外碳酸盐岩油藏实施的注CO2驱、注N2驱、注空气驱、注烃气驱、热采技术和化学驱的历史与现状,同时探讨了未来碳酸盐岩油藏提高采收率技术发展趋势:注气提高采收率技术仍会是主要方法,化学驱可能成为气驱的替代或辅助方式。对于化学驱而言,开发新型化学剂是提高采收率的重要途径,未来的研究应主要集中在以下两个重要领域:①选择显碱性的有机化合物;②研究基于新工程材料("纳米流体")的新流体配方。     

ASP三元复合体系在孔隙介质中的流变性

利用室内物理模拟的方法,对三元复合体系在多孔介质中的流变行为进行了研究,分析了聚合物、碱、表面活性剂浓度和岩芯渗透率对三元复合体系在多孔介质中的流变特征的影响规律,研究结果认为复合体系在多孔介质中呈现出剪切变稀和增稠双重流变特性,复合体系在多孔介质中出现粘弹流变特征的临界剪切速率随着聚合物浓度的升高而减小,随着表面活性剂和碱浓度的增加而增大。     

低相对分子质量聚丙烯酸钠的制备和应用

摸索了一种作为三次采油中聚丙烯酰胺分散剂的低相对分子质量聚丙烯酸钠的合成工艺，并对产品聚丙烯酸钠（相对分子质量为2000－3000）的分散效果进行了测试，结果令人满意。     

高含水井调剖堵水技术及现场应用分析

百色油田仓16块已进入高含水采油期，为改善区块开发效果，提高采收率，调剖堵水是一项有效的工艺技术措施。通过大量的室内实验研究，从堵剂的类型及封堵机理，优选出符合仓16块储层特点、价格合理的粘土堵剂及其使用浓度，并优选出适合油田开发特征的工艺方案，确定了大剂量封堵储层大孔道，达到深部调剖的区块整体调剖堵水技术，通过对仓16块不同注水井组进行现场施工，工艺取得了突破，有明显的增油降水效果，取得了较好的经济效益，并为百色油田今后解决调剖堵水难题提供了宝贵的经验。     

胜利油田边际稠油油藏提高采收率方法研究

胜利油田陈家庄油藏是一个典型的稠油高渗透油藏 ,常用的热力采油无法大幅增加产量。通过开展深入细致的油藏地质研究和开发规律分析 ,根据剩余油分布规律研究 ,应用水动力学原理 ,加强注水工作 ,应用配套技术和精心的油藏管理 ,实现了油田年产油量稳中有升 ,综合含水稳定 ,油田开发效果明显改善 ,采收率提高 5 .6 % ,可采储量增加了 10 0× 10 4t     

泡沫增效三元复合驱油体系渗流行为研究

将交替注入碱-表面活性剂-聚合物（简称ASP）和氮气时，针对泡沫的生成及稳定性影响因素开展了大量的实验研究，着重探讨了不同流速、不同压力条件下的渗流行为。实验结果表明，泡沫的形成与运移严重受流速和压力的影响，流速太大，存在严重气窜现象，流速太小，不利于泡沫在孔隙介质中的传播。压力越小，越利于形成稳定的泡沫。一旦形成泡沫，流动阻力明显增加，大大降低驱替流体的流度。氮气/ASP交替注入地时，在入口端生成的泡沫可以被高粘流体驱替向远处传播。     

温度观察井系统在超稠油SAGD开发中的应用

完善的油藏监测系统是SAGD先导试验成功的保证,油藏温度的有效监测对于油藏动态变化、生产参数调整及后期评价具有指导意义.介绍了基于分布式测温光纤建立的温度观察井系统,该系统克服了热电偶测试不连续的缺点,能够获得连续、实时的温度监测数据.通过温度观察井所测得的温度曲线,可判断蒸汽腔的形成及扩展方向与速度,指导优化注采参数,改善SAGD开发效果.此系统还可推广应用于蒸汽吞吐、蒸汽驱等热采开发中,具有广泛的应用空间.     

提高凝析气藏采收率的新思路

我国目前的凝析气藏多属凝析油含量中偏低的饱和凝析气藏，且多采用衰竭方式开发，采收率低，有的已处于开发中、后期，如何提高凝析气井产量和气藏凝析油采收率已成为关键问题。在借鉴俄罗斯开发凝析气藏经验的基础上，着重介绍了４种提高凝析气藏采收率的开发方式：开发中后期低于最大反凝析压力下循环注干气；注N₂开发水淹气藏；防水、治水与利用地层能量相结合的水驱气藏开发方式；注水提高凝析气藏采收率。上述方法对于提高我国凝析气藏采收率具有指导与借鉴作用。