Study of steam heat transfer enhanced by CO_(2) and chemical agents: In heavy oil production

Steam flooding with the assistance of carbon dioxide (CO_(2)) and chemicals is an effective approach for enhancing super heavy oil recovery. However, the promotion and application of CO_(2) and chemical agent-assisted steam flooding technology have been restricted by the current lack of research on the synergistic effect of CO_(2) and chemical agents on enhanced steam flooding heat transfer. The novel experiments on CO_(2)–chemicals cooperate affected steam condensation and seepage were conducted by adding CO_(2) and two chemicals (sodium dodecyl sulfate (SDS) and the betaine temperature-salt resistant foaming agent ZK-05200).According to the experimental findings, a “film” formed on the heat-transfer medium surface following the co-injection of CO_(2) and the chemical to impede the steam heat transfer, reducing the heat transfer efficiency of steam, heat flux and condensation heat transfer coefficient. The steam seepage experiment revealed that the temperature at the back end of the sandpack model was dramatically raised by 3.5–12.8 °C by adding CO_(2) and chemical agents, achieving the goal of driving deep-formation heavy oil. The combined effect of CO_(2) and SDS was the most effective for improving steam heat transfer, the steam heat loss was reduced by 6.2%, the steam condensation cycle was prolonged by 1.3 times, the condensation heat transfer coefficient was decreased by 15.5%, and the heavy oil recovery was enhanced by 9.82%. Theoretical recommendations are offered in this study for improving the CO_(2)–chemical-assisted steam flooding technique.

A New Experimental Rig of Testing Flow Boiling Heat Transfer of Refrigerantand Lubricant Mixture

This paper proposed a new experimental rig of testing flow boiling heat transfer of refrigerant and lubricant oil mixture. The quantity of oil in the test section can be controlled and regulated conveniently and accurately by connecting separate lubricant oil circuit with test section in parallel. It was built up by retrofitting a multiple air-conditioner and installing three oil-separators in serials at the compressor outlet. And so the lubricant oil in the discharged refrigerant gas of compressor can be removed completely.The refrigerant flow rate through test section can be bypassed by the by-path circuit of indoor unit.This experimental rig has advantages such as on-line and continuous oil injection, short time of obtaining stability, flexible operation, simple control, which lead to high efficiency in the research of flow boiling heat transfer of refrigerant and lubricant oil mixture.

Geologic-Geophysical Indicators of the Deep Structure of Zones of Geothermal Anomalies for Allocation of Channels of the Deep Heat and Mass Transfer

On the basis of the analysis of field thermogeochemical data along abnormal zones of a thermal stream in the Bukhara-Khiva, oil-and-gas region of the Turan (Tegermen, Chagakul, Shimoly Alat, Beshtepa) was succeeded to obtain important data on a deep structure of sites. Data of gas-chemical and geothermal observations show about confinedness of abnormal concentration of methane to zones of the increased values of the temperature field the measured values of temperatures (Tegermen Square and others). On geoelectric section mines 2-D of inversion of the MT-field depth of 4000 m are lower, among very high-resistance the chemogenic and carbonate deposits of the Paleozoic is traced the subvertical carrying-out abnormal zone. This zone is identified as the channel of a deep heat and mass transfer with which hydrocarbon (HC) deposits are connected. It is shown that electro-investigation when using a geophysical complex can and has to become “advancing” at exploration by oil and gas.

Identification of Heat Transfer Coefficients by Use Conditions of Quenching Oil

Heat transfer coefficients of the quench medium are necessary for heat-treatment simulation. Cooling characteristics of quenching oil vary with kinds and usage greatly. Users are selecting oil solutions that come up to their desired hardness and quenching distortion requirements. In particular cooling performance rises by agitation and decompression. Therefore we identified a heat transfer coefficient by usage and kinds of quenching oil. Cooling characteristics are different greatly by a kind of quenching oil. A difference of a cooling characteristic by a kind of oil depends on a temperature range of a boiling stage and the maximum heat transfer coefficient mainly. On the other hand, in a convection stage, there are few changes in a boiling stage. Even if quenching oil temperature is changed, heat transfer coefficients do not change greatly. When quenching oil stirred, heat transfer coefficients of vapor blanket stage and a convection stage rise, but there are a few changes in a boiling stage. When quenching oil is decompressed a temperature range of a high heat transfer coefficient moves to the low temperature side. In addition, a heat transfer coefficient in a vapor blanket stage comes down. For precision improvement of heat-treatment simulation, it is important that the heat transfer coefficient is calculated in conformity to the on-site use reality.

Thermal influence of ponding and buried warm-oil pipelines on permafrost: a case study of the China-Russia Crude Oil Pipeline

Buried pipelines are widely used for transporting oil in remote cold regions. However, the warm oil can induce considerable thermal influence on the surrounding frozen soils and result in severe maintenance problems. This paper presents a case study of the thermal influence of ponding and buried warm-oil pipelines on permafrost along the China-Russia Crude Oil Pipeline(CRCOP) in Northeast China. Since its operation in 2011, the operation of the warm-oil pipelines has led to rapid warming and thawing of the surrounding permafrost and development of sizable ponding along the pipeline route,which, in return, exacerbates the permafrost degradation. A field study was conducted along a 400-km long segment of the CRCOP in permafrost regions of Northeast China to collect the location and size information of ponding. A two-dimensional heat transfer model coupled with phase change was established to analyze the thermal influence of ponding and the operation of warm-oil pipelines on the surrounding permafrost. In-situ measured ground temperatures from a monitoring site were obtained to validate the numerical model. The simulation results show that ponding accelerates the development of the thaw bulb around the pipeline. The maximum thaw depth below the pipeline increases from 4 m for the case without ponding to 9 m for the case with ponding after 50 years of operation, and ponding directly above the pipe induces the maximum thaw depth. Engineering measures should be adopted to control the size or even eliminate surface water-rich ponding for the long-term performance of buried warm-oil pipelines.

Magnetic Oil Thermal Behavior under Electromagnetic Induction for Energy Efficient Heating System Design

This study describes thermal behavior of magnetic lubricant oil under electromagnetic induction. Experimental set up include oil pump, oil tank, induction heating unit, and heat exchanger. It is a closed loop system where the oil pump circulates oil through oil tank to the system, at the same time induction heating unit heats up to the heat exchanger where the lubricant oil thermal behavior is examined. The unit has been largely studied and tested both magnetic and regular motor oil in a laboratory environment and promising results have been obtained for an actual indoor floor to space heating system design.

相溶性对R32-润滑油混合物管内流动沸腾换热及压降特性的影响

R32已成为家用空调器的主流制冷剂,其换热性能受到溶入其中的润滑油相溶性影响,为此需要确定有利于提升换热性能的最佳相溶性。本文通过实验测试R32与完全互溶、部分互溶和完全不互溶的润滑油形成的混合物在换热管内的流动沸腾传热系数与压降,研究了相溶性导致的R32-润滑油分层现象及其对于换热与压降的影响机制。为覆盖空调器实际运行工况并体现R32与润滑油的不同相溶性,实验工况选取蒸发温度为-5~15℃,平均干度为0.2~0.7,平均油浓度(质量分数)为1%与5%。实验结果表明:三种油品中部分互溶润滑油的传热系数最高,压降最低;当蒸发温度为5℃、干度为0.7、平均油浓度为5%时,部分互溶润滑油相比于完全互溶与完全不互溶润滑油的优势达到最大,传热系数最大提升幅度分别达36.8%和357.8%,压降最大降幅分别达9.0%和58.2%。在三种油品中,部分互溶润滑油表现出最好的换热及压降特性,具有更好的应用前景。

部分互溶的R32-润滑油混合物核态沸腾中分层与换热特性

在空调器中采用与制冷剂部分互溶的润滑油代替现有完全互溶的润滑油,能避免制冷剂循环量不足的问题,前提是掌握部分互溶的润滑油对沸腾换热的影响。本文针对空调器中广泛使用的制冷剂R32,搭建可视化的沸腾换热特性测试实验台,观测混合物分层现象并测定换热系数。实验结果表明:部分互溶混合物随润滑油质量分数增大先后经历均一混合、分层、均一混合状态;换热系数随时间先不变后减小,减小时刻随热流密度和初始润滑油质量分数增大、初始液相高度减小而提前;平均换热系数随热流密度增大而增大,受初始润滑油质量分数和液相高度的影响可忽略不计;热流密度从5 kW/m^(2)增大至15 kW/m^(2),平均换热系数增大118.3%。

Ammonia corrosion analysis of copper tubes and experimental research on non-copper improvement for heat exchanger in power plant

Ammonia corrosion in copper tube will affect the safety of boiler running in power plant. Therefore, no copper in heating system has become a technical orientation in heat exchanger reconstruction, This paper analyzes the condition and mechanism of ammonia corrosion occurring in copper tube used in coal-fired power plants. Using a general steam condensation testing equipment only for horizontal single tube, with water vapor and water as working fluid, on two types of steel tube with 2-side enhancement heat transfer, namely, a spirally fluted tube and a ratchet tube with internal spiral groove （RISG tube） which was developed recently, a set of experimental tests are conducted to investigate the characteristics of heat transfer and hydromeehanics. In order to compare easily, both one copper smooth tube and one steel smooth tube are also used in the experiment. The experimental results, which get from single horizontal tube, show that the overall heat transfer coefficient of steel spirally fluted tube are improved by 10%o to 17%, and that of the steel RISG tube（22%-28%） is better than steel spirally fluted tube, its flow resistance coefficient is only increased by 22% to 66% when compared with smooth tube. Based on a lot of experimental data, the steel spirally fluted tube and the steel RISG tube were applied in a low pressure preheater and an oil-cooler of some or other power plant respectively. The field testing results showed that their heat transfer coefficient with each types of enhancement heat transfer tubes were improved by 2.5% and 21%-45% comparing with copper smooth tube heat exchangers. Both basic and field experiment indicates that the steel tube with 2-side enhancement heat transfer is an ideal choice for heat exchanger reconstruction in no copper issue in power plants.

动态热条件下原油罐储维温过程主要影响因素分析

掌握原油罐储维温过程主要影响因素,对原油库实现节能降耗目的起重要作用。在建立动态热条件下含蜡原油罐储维温过程三维理论模型的基础上,提出了加热盘管空间结构、周向效应对罐内对流传热的影响,划分了内、外因素影响区以及过渡区域;采用多元非线性回归的方法,建立不同季节边界位置主控影响因素模型,定量表征了罐边界油温与内、外因素之间的作用机制。结果表明:罐内大涡结构受无加热盘管区域局部湍涡影响,导致大涡结构向无盘管区域发生偏移。罐底低温区域受盘管周向效应影响较大,罐顶边界油品受内外因素影响大,形成最大厚度1.79 m的外界环境影响区;罐壁受保温层影响,只形成了内部维温热流影响区;冬季罐底形成了0.13 m的外界土壤影响区。

富油煤原位热解技术战略价值与科学探索

【背景】我国油气需求缺口大、供给制约多、煤炭绿色低碳转型任务艰巨,富油煤作为集煤、油、气属性于一体的煤炭资源,具有立足国内增加油气供给的巨大潜力。【进展】富油煤原位热解技术已在陕西榆林成功实施工程试验,目前仍处于探索阶段。其具备两大战略价值:一是弥补我国油气需求缺口,提高油气自主保障能力;二是变革煤炭开采技术,推动煤炭产业绿色、低碳转型发展。富油煤原位热解包括钻孔式和矿井式两种实践途径,目标是持续高效提取煤中油气资源,主要面临热解选区、加热技术与高效传热传质等难题。【展望】“四性”是原位热解技术研发的关键,包括地质条件适宜性、加热技术匹配性、传热传质有效性和热解安全稳定性。主要内容为:(1)从富油煤资源条件、地层封闭条件、水文地质条件和构造条件等方面阐明适宜富油煤原位热解的地质基础,揭示热辐射范围内围岩封闭动态稳定性的约束条件,为原位热解选址和工程设计提供地质依据。(2)深刻认识富油煤在温度、应力约束下的热物理性质演化行为,基于地质−工程条件论证原位加热技术适宜性,并针对煤层低导热特性开展高效加热工艺设计,通过风、光、电多种供能方式互补实现供热能源经济性。(3)地应力、大尺度煤体、焦油高黏度是制约原位热解油气运移、产出的主要因素,煤层致裂、载热介质优化与温压调控、焦油降黏轻质化是改善煤层传热传质性能和提高热解油气可产出性的潜在方法。(4)原位热解持续稳定运行依赖于全过程监测与动态预警,需要监测手段立体化、地质信息反演精准化、多相多场环境模型化、突变阈值预测预警等技术予以支撑。进一步探索与地质条件相匹配的富油煤原位持续高效热解关键技术,破解煤炭资源开发与地质环境之间的制约矛盾,是推动富油煤原位热解技术深入发展的关键。

深层环境下固井水泥水化放热特性及井周温度场演化规律研究

塔里木盆地已建成我国最大的超深层油气生产基地,深层环境会对水泥水化放热特性产生一定的影响,研究深层环境下水泥水化放热及传热特性对明确井周温度场演化规律至关重要。文章首先根据现场实测资料建立了塔里木油田近井和远井地层温度方程,根据不同地层深度的温度分布情况,开展了不同温度下G级水泥水化放热实验,基于Krstulovic-Dabic(K-D)经典水化动力学模型,结合水泥成核结晶与晶体生长、相边界反应以及扩散三过程反应特征推导了不同温度下水泥水化放热预测曲线,进一步推导了套管-水泥环-地层热传导模型,并将放热曲线作为热源代入到有限元模型中,得到了不同井深的套管与水泥在水化放热与高温地层的共同作用下温度场的变化情况。研究结果可为下一步分析有限局部空间的温度场变化对地层压力和套管变形影响提供技术支持。

温等静压工艺过程中导热油压力与温度关系研究

为进一步精确等静压生产工艺过程中高压密闭容器内温度变化的控制,提升温等静压工艺精度,结合导热油在温等静压工艺生产使用中升压时温度上升、泄压时温度下降以及工艺过程中的不均匀温度场等现象开展实验研究,从导热油的可压缩性角度出发对导热油进行研究。分析了导热油因压力变化造成密度变化而导致温度变化的形成机理与规律,结合理论和数据分析对导热油温度随压力变化的关系式进行推导,通过开展不同升压速率以及不同初始温度的实验验证了关系式的有效性。该关系式可用于温等静压高压密闭容器的温度计算。

双循环蓄热式导热油加热系统在工业领域的应用探究

当今工业领域中有很多间歇式生产流程,在工作时需要过热蒸汽进行生产运转。而随着国内企业节能环保意识的逐步加强,将厂区内低品质蒸汽更清洁、高效地利用起来成为各企业研究的方向。本文通过建立一种双循环蓄热式导热油加热系统,将清洁的电能转换为热能,间接加热蒸汽,将一个工作周期内的间断供汽所需最大热负荷需求转变为该周期内连续平均的电加热负荷,避免电加热器频繁启停,延长电加热器寿命,同时降低对电网的影响。由此对于下一步大规模工业实践提供了参考和借鉴。

Numerical simulation of downhole temperature distribution in producing oil wells

An improved numerical simulation method is presented to calculate the downhole temperature distribution for multiple pay zones in producing oil wells. Based on hydrodynamics and heat transfer theory, a 2-D temperature field model in cylindrical coordinates is developed. In the model, we considered general heat conduction as well as the heat convection due to fluid flow from porous formation to the borehole. We also take into account the fluid velocity variation in the wellbore due to multiple pay zones. We present coupled boundary conditions at the interfaces between the wellbore and adjacent formation, the wellbore and pay zone, and the pay zone and adjacent formation. Finally, an alternating direction implicit difference method （ADI） is used to solve the temperature model for the downhole temperature distribution. The comparison of modeled temperature curve with actual temperature log indicates that simulation result is in general quite similar to the actual temperature log. We found that the total production rate, production time, porosity, thickness of pay zones, and geothermal gradient, all have effects on the downhole temperature distribution.

L-QC310导热油的研制

热稳定性是导热油关键性能之一,文章考察了胺型抗氧剂A、B,酚型抗氧剂和硫醚酚型抗氧剂及其加入量对Ⅲ类加氢基础油150N热稳定性的影响。结果表明:硫醚酚型抗氧剂具有最佳的改进效果,仅0.4%的加量即能满足GB 23971-2009中L-QC310导热油标准要求。

压裂-注氮原位裂解油页岩加热工艺及传热模拟

提出了一种油页岩地下原位转化的新方法,即压裂-注氮原位裂解油页岩技术.油页岩储层压裂后,在加热井内下入电加热器,然后向井内注入氮气,利用加热后的高温氮气原位裂解油页岩.介绍了该方法与传统的电加热法和对流加热法相比的优势,以及特别适用的地层,并且对加热氮气过程进行了传热模拟,优化了气体加热器的参数,确定加热器的最佳长度为30 m,其热流密度为11 k W/m2.针对本工艺方法特别适用的薄层油页岩地下原位开采,进行了地层加热时间的传热模拟,确定了80 d即可将井距15 m,矿层1.5 m厚的油页岩加热到裂解温度,较电加热法和对流加热法的加热时间明显缩短.

R410A-油混合物在7mm水平直光管内流动沸腾的换热特性 Ⅱ.关联式

基于R410A-油混合物管内流动沸腾换热的实验数据,对现有的制冷剂-油混合物的换热关联式进行了评价,对比发现已有关联式的预测值与实验值的误差最大达到80%.基于混合物物性,开发了R410A-油混合物在7 mm直光管内流动沸腾的流型图,并基于流型图和混合物物性开发了R410A-油在7 mm直光管内流动沸腾的换热关联式.所得关联式与90%的实验数据的误差在±20%以内,平均误差为11.8%,最大误差为26.7%.

R410A-油混合物在7mm强化管内流动沸腾的换热特性

实验研究了环保替代制冷工质R410A-润滑油混合物在强化管内的流动沸腾换热特性，探索了质流密度、干度和平均油浓度对换热特性的影响。实验测试管为内螺纹强化管，长度为2000mm、外径为7．0mm。实验结果表明，纯制冷剂R410A的传热系数随干度的增大先增大后减小，峰值出现在干度为0．7～0．8左右；对于R410A-油混合物，在干度小于0．5的工况下，油的存在增强换热，在干度大于0．6的高干度情况下，传热系数随平均油浓度和干度的增大迅速降低。基于混合物性开发了R410A-油混合物在7mm强化管内流动沸腾的换热关联式，新的关联式预测值与89％的实验数据的误差在±30％以内，平均误差为17．3％。

基于流固耦合传热模型的井下注天然气流量测量仿真研究

注气是一种常见的提高油田采收率、延长油田生产寿命的措施,将气体(天然气、二氧化碳、空气等)通过注入井注入到油层中,以保持或恢复油层压力,使油藏有很强的驱动力,进而提高油藏的开采速度和采收率。综合考虑气源稳定性、成本、运输、腐蚀性及混相压力等因素,天然气或伴生气被认为是最有前景的选择。井下气体流量测量是实现精确定量分层注气的重要技术手段,然而由于天然气组分不固定以及井下高温高压的复杂工况,其流量的精确测量及现场标定面临很大挑战。基于流固耦合传热模型对热式流量计在不同工况下的天然气流量测量进行仿真研究,模拟高温高压下的实验环境,建立气体质量流量与温差之间的输入输出关系,为后续现场实验和测量提供有效指导。