Numerical Simulation of a Batch-Type Reheating Furnace

A numerical analysis of a batch-type reheating furnace with and without thermal load was carried out using the Computational Fluid Dynamics technique. The furnace has two premixed burners and methane is used as fuel. Previous to the numerical experiments, a mesh convergence test was carried out and the average internal furnace temperature and the exhaust gases temperature were monitored as function of the number of cells in the discretized system. The influence of the Air/Fuel ratio, the position of the burners, and the thermal load on the average internal temperature, the exhaust gases temperature, and the molar fraction of methane and oxygen in the exhaust gases was numerically explored.

Numerical Study of Gas Production from a Methane Hydrate Reservoir Using Depressurization with Multi-wells

With the implementation of the production tests in permafrost and offshore regions in Canada,US,Japan,and China,the study of natural gas hydrate has progressed into the stage of technology development for industrial exploitation.The depressurization method is considered as a better strategy to produce gas from hydrate reservoirs based on production tests and laboratory experiments.Multi-well production is proposed to improve gas production efficiency,to meet the requirement for industrial production.For evaluating the applicability of multi-well production to hydrate exploitation,a 2D model is established,with numerical simulations of the performance of the multi-well pattern carried out.To understand the dissociation behavior of gas hydrate,the pressure and temperature distributions in the hydrate reservoir are specified,and the change in permeability of reservoir sediments is investigated.The results obtained indicate that multi-well production can improve the well connectivity,accelerate hydrate dissociation,enhance gas production rate and reduce water production as compared with single-well production.

Application of deviation rate in oil and gas reservoir exploration

Three dimensional geophysical models were abstracted and established according to characteristics of oil and gas reservoir.Then direct current fields for different models were simulated with finite element software(finite element program generator) by hole-to-surface resistivity method.Numerical solution was compared with analytical one for the homogeneity earth model.And a new parameter of deviation rate was proposed by analyzing different plot curves.The results show that the relative error of solution for homogeneity earth model may attain to 0.043%.And deviation rate decreases from 18% to 1% and its anomaly range becomes wide gradually when the depth of oil and gas reservoir increases from 200 to 1 500 m.If resistivity ratio of oil and gas reservoir to sur-rounding rock decreases from 100 to 10 for the resistive oil and gas reservoir,the amplitude attenuation of deviation rate nearly reaches 8%.When there exists stratum above oil and gas reservoir,and influence of resistive stratum may be eliminated or weakened and anomaly of oil and gas reservoir can be strengthened.

Oil/Gas Migration and Aggregation in Intra-Continental Orogen Based on Numerical Simulation: A Case Study from the Dabashan Orocline, Central China

Geofluid, driven by tectonic stress, can migrate and aggregate in geological body. Thus, numerical simulation has been widely used to rebuild paleo-tectonic stress field and probe oil/gas （one type of geofluid） migration and aggregation. Based on geological mapping, structural data, and mechanical parameters of rocks, we reconstruct the traces for gas/oil migration and aggregation in Dabashan intra-continental orogen using numerical simulation. The study shows that gas/oil, obviously dominated by late Middle Jurassic-Early Cretaceous paleo-tectonic stress field that is characterized by NE-SW shortening in the Dabashan thrust belt and SW-emanating shortening in its foreland belt, massively migrate from the Dabashan thrust belt to its foreland belt, that is, NE to SW, resulting in the formation of some probable favorable areas for oil/gas mainly along the Tiexi -Wuxi fault, in some superposed structure （e.g., Zhenba , Wanyuan , Huangjinkou , and Tongnanba areas）, and in the Zigui Basin. Thus, our study shows that numerical simulation can be effectively applied to study oil/gas migration and aggregation in intra-continental orogen and provided some significant evidences for oil/gas exploration.

OIL AND GAS TRANSPORTATION AND STORAGE

Relative literatures and accident statistics published at home and abroad in recent years show that in addition to the natural disasters such as earthquakes, landslides, etc., events closely relative to such human activities as wars, terrorist attacks and blasting construction have become important reasons of oil and gas pipeline damage and failure. Conducted are 3D dynamic numerical simulation on spread of blasting seismic waves and dynamic response of vibration process of buried oil and gas pipelines after accidental explosion of explosive storage and numerical analysis on simulation results and obtained are vibration speed response characteristics of the pipelines. Based on calculation results obtained in a number of different conditions, such as dynamite inventories of explosive storage, site media properties, materials and sizes of buried pipelines, etc., combined with quantitative analysis on vibration safety criterion, safety distances of buried pipelines are obtained in different conditions, which has important theoretical significance and application value for safe and proper operation of buried oil and gas pipelines.

Hydrocarbon gas huff-n-puff optimization of multiple horizontal wells with complex fracture networks in the M unconventional reservoir

The oil production of the multi-fractured horizontal wells(MFHWs) declines quickly in unconventional oil reservoirs due to the fast depletion of natural energy. Gas injection has been acknowledged as an effective method to improve oil recovery factor from unconventional oil reservoirs. Hydrocarbon gas huff-n-puff becomes preferable when the CO_(2) source is limited. However, the impact of complex fracture networks and well interference on the EOR performance of multiple MFHWs is still unclear. The optimal gas huff-n-puff parameters are significant for enhancing oil recovery. This work aims to optimize the hydrocarbon gas injection and production parameters for multiple MFHWs with complex fracture networks in unconventional oil reservoirs. Firstly, the numerical model based on unstructured grids is developed to characterize the complex fracture networks and capture the dynamic fracture features.Secondly, the PVT phase behavior simulation was carried out to provide the fluid model for numerical simulation. Thirdly, the optimal parameters for hydrocarbon gas huff-n-puff were obtained. Finally, the dominant factors of hydrocarbon gas huff-n-puff under complex fracture networks are obtained by fuzzy mathematical method. Results reveal that the current pressure of hydrocarbon gas injection can achieve miscible displacement. The optimal injection and production parameters are obtained by single-factor analysis to analyze the effect of individual parameter. Gas injection time is the dominant factor of hydrocarbon gas huff-n-puff in unconventional oil reservoirs with complex fracture networks. This work can offer engineers guidance for hydrocarbon gas huff-n-puff of multiple MFHWs considering the complex fracture networks.

Modeling underwater transport of oil spilled from deepwater area in the South China Sea

Based on a Lagrangian integral technique and Lagrangian particle-tracking technique,a numerical model was developed to simulate the underwater transport of oil from a deepwater spill. This model comprises two submodels: a plume dynamics model and an advection-diffusion model. The former is used to simulate the stages dominated by the initial jet momentum and plume buoyancy of the spilled oil,while the latter is used to simulate the stage dominated by the ambient current and turbulence. The model validity was verified through comparisons of the model predictions with experimental data from several laboratory flume experiments and a field experiment. To demonstrate the capability of the model further,it was applied to the simulation of a hypothetical oil spill occurring at the seabed of a deepwater oil/gas field in the South China Sea. The results of the simulation would be useful for contingency planning with regard to the emergency response to an underwater oil spill.

Evaluation of gas condensate reservoir behavior using velocity dependent relative permeability during the numerical well test analysis

Gas condensate is one of the most different fluids in reservoir simulation due to retrograde condensation in case of pressure reduction.In this kind of fluids,two phenomena named negative inertia and positive coupling,become significant in the high velocity zone around the wellbore.In this study,a modified black oil simulator is developed that take into account the velocity dependent relative permeability.Against the industrial simulator that assumes linear variation of transmissibilities by pressure,modified black oil nonlinear equations are solved directly without linearization.The developed code is validated by ECLIPSE simulator.The behavior of two real gas condensate fluids,a lean and a rich one,are compared with each other.For each fluid,simulations of PVT experiments are carried out to calculate black oil property applying Coats approach for gas condensate fluids.For both fluids,the proposed models for gas condensate velocity dependent relative permeability show different influence of velocity on relative permeability in the same conditions.Moreover,it is observed that higher flow rate of gas production leads to more condensate production during constant rate well testing.

火烧油层热力采油过程的数值模拟

根据火烧油层室内燃烧管模拟实验台的条件 ,建立了一个一维数学模型。用有限差分法对该数学模型在较宽的参数范围内进行了数值计算 ,分析了若干重要参数对采收率、空气消耗量和燃烧前缘推进速度的影响。计算结果表明 ,采收率和空气消耗量对原油的相对渗透率很敏感 ,而绝对渗透率对其影响不大 ;燃烧前缘的推进速度与空气注入速率成正比 ,而提高空气注入速率对采收率和空气消耗量没有太大的影响。数值计算结果与实验结果吻合较好 ,说明所建立的数学模型和采用的数值求解方法是正确和可靠的。

植物油料实际压缩比计算模型与数值模拟

基于双曲线型应力应变模型建立了植物油料实际压缩比理论计算模型,模拟计算出的菜籽、菜籽仁、花生、大豆、芝麻和亚麻籽的实际压缩比与实测值吻合,菜籽仁的实际压缩比比菜籽平均高20%。根据实际压缩比变化率及其斜率曲线,近似确定植物油料工程实际临界压榨压力为:菜籽、菜籽仁、花生、亚麻籽80MPa,芝麻100MPa,大豆60MPa。

低渗透裂缝油藏渗吸法采油数值模拟理论研究

根据低渗透裂缝油藏渗吸法采油渗流机理,建立了双孔双渗渗吸法采油数学模型,并给出了数值解法和流动系数的取值方法。通过实例验证,该方法计算的含水率指标与矿场实际值符合程度较高。在此基础上,定量分析了渗吸法采油的主要影响因素,结论是:裂缝与基质渗透率比大于100,裂缝密度大于0.030条/m,油水粘度比小于15,毛管力较大的水湿油藏适合渗吸法采油,能够提高水驱采收率1%以上。

注水开发小型断块凝析气藏的方法及适应性

对于规模小、储量低的小型凝析气藏,枯竭式开发产量递减快,凝析油气采收率低,然而限于气藏的规模,注气开发也不经济。针对该类凝析气藏的特点,从地质特点、气藏工程、采气工艺及地面工程等角度对其实施注水开发的可行性进行了综合分析论证,同时结合具有以上特点的BG5区块滨Ⅳ-2凝析气藏,对其注水开发的适应性进行了气藏数值模拟研究。结果表明,通过合理的注水开发能够显著提高该类气藏的凝析油气采收率,增加气田经济效益,为其他类似气藏的开发提供了借鉴。

胜利油区超稠油油藏热采开发设计优化研究

针对胜利油区三类超稠油油藏 ,设计了九种热采布井方式 ,通过数值模拟计算 ,研究各种井网对不同类型超稠油油藏的适应性 ,并结合经济分析 ,优化出各类超稠油油藏所适宜的布井方式、井距及热采操作参数。

渗透率变异系数对聚合物驱油影响的数值模拟研究

研究了渗透率变异系数(Vk)、聚合物注入量和油水黏度比对聚合物驱采收率的影响规律。结果表明,水驱与聚合物驱采收率随Vk的增加而降低。聚合物驱采收率增幅曲线分为3个阶段:稳定段(0≤Vk≤0.3)、上升段(0.3<Vk≤0.5)和下降段(0.5<Vk≤0.85)。Vk为0.5时的增幅最大,为17%OOIP。不论Vk大小,随着聚合物注入量的增加,采收率增幅增大并逐渐稳定。Vk增加,聚合物拐点注入量增大,采收率增幅增大。当Vk≥0.5时,增加聚合物注入量可以进一步提高采收率。采收率增幅随油水黏度比的增加而增加,最佳油水黏度比为3∶1。

海上稠油砂岩油藏采出程度敏感性分析与评价——以秦皇岛32-6油田为例

以秦皇岛32-6油田为研究对象,结合海上稠油砂岩油藏的实际情况,综合考虑了地质因素和开发因素对采出程度的影响。利用单因素分析方法,建立了秦皇岛32-6油田采出程度随井距、原油粘度、提液时机、油层厚度、采油速度和纵向渗透率非均质性变化的数值模型。通过对比不同模型的模拟结果可知,不同条件下采出程度的主控因素不同。其中,井距对采出程度的影响最显著,其次是地层原油粘度和纵向渗透率非均质性,而提液时机、油层厚度和采油速度的影响较小。此外,对各影响因素进行了无因次化,通过多元线性回归,得到了不同地质、流体物性、开发等因素表征采出程度的关系式,更直观地表现了不同因素变化对采出程度的影响程度。

相控条件下剩余油的数值模拟

针对非均质油田的地质特点 ,分析了剩余油的分布 ;按沉积微相选用相对渗透率曲线 ,研究了各类油层的水驱规律 ,建立了相控条件下的地质模型 ,并对单井及全区的含水率、产油量进行了历史拟合 .数值模拟结果表明 :用相控方法建立的地质模型 ,能反映各个单砂层的平面分布特点及对流体平面流动的控制 ,误差为 17.3 % ;相控条件下的数值模拟分相带区域进行精细历史拟合 ,其成果能量化不同开采时期和一定阶段下的不同沉积微相动用状况和剩余油分布 ,拟合含水率符合率为 92 .60 % ,较常规拟合提高 10 .0 0 % ,模拟数值与实际数值比较接近 .

泡沫复合驱三维多相多组分数学模型的应用

为评价泡沫复合驱的试验效果 ,预测泡沫复合驱的最终采收率 ,利用泡沫复合驱油三维多相多组分数学模型 ,对大庆油田北二区东部泡沫复合驱矿场试验进行了数值模拟研究 .跟踪拟合了试验区实施方案的开采动态指标 ,中心井区含水率跟踪拟合的相对误差为 4.48% ;利用拟合修正后的地质模型预测了试验区的泡沫复合驱油阶段采收率为2 2 .74% ,中心井区总采收率为 67.3 6% .应用结果表明 :泡沫复合驱三维多相多组分数学模型具有较强的实用性 .

水平压裂辅助蒸汽驱开采有夹层稠油薄互层油藏数值模拟研究

利用数值模拟技术 ,分别研究了具有物性和岩性夹层 (包括单个和多个夹层 )的稠油油藏对水平压裂辅助蒸汽驱开采效果的影响。模拟结果表明 :油藏中夹层的存在对开采不一定是不利因素 ;注汽井打开程度不同对开采有夹层的稠油油藏有一定的影响 ;开采过程中 。

K稠油油藏开采优化数值模拟研究

我国西部K油藏为浅层稠油油藏,油层平均埋深240 m,属于边缘氧化型稠油油藏。针对K油藏开发过程中注入蒸汽波及的效率低,热连通不充分,油汽比低,经济效益差的现状,选择该油藏有代表性的井组,利用数值模拟方法,对该油藏连续汽驱、间歇汽驱、低干度汽驱等技术方案进行了深入的研究,综合经济因素和最终采收率确定了合理的开发方案为高注汽强度的间歇汽驱,注汽强度80~100 m3/d,注汽周期为6个月。数值模拟结果对油田实际开发有指导作用。

大庆油田萨尔图中区西部合理地层压力研究

确定合理地层压力,对提高油田采收率、减少油田耗水量、降低套损速度等方面具有重要作用。地层压力是否合理关系到油田的稳定生产和经济效益。对于特高含水期的油藏,地层压力研究比较少,已有的方法都未综合考虑不同黏度、采出程度、气油比对合理地层压力的影响。为此,运用了物质平衡法、气油比动态资料分析法、数值模拟法,开展了不同黏度、采出程度、气油比和地层压力变化规律的研究,计算了各区块合理地层压力,考察了溶解气对原油黏度的影响,进而考察对采收率的影响,确定了中区西部合理地层压力。结果表明,中区西部合理地层压力接近饱和压力,萨、葡油层合理地层压力为9.11MPa;高台子合理地层压力为10.12MPa,对大庆油田后期注水开发具有重要的指导意义。