Single Phase Flow Pressure Drop in Glass Ballotini Particulate Beds

A study was made of pressure drop during single fluid phase flow to determine the pressure drop characteristic of the porous media (glass ballotini particulate beds) for coalescence. It is also served to check the reproducibility of the packing technique, and to detect any foreign particulate matter or re-arrangement of the individual particles in the coalesce bed. Furthermore these data provided a basis for comparison with that during two-phase flow with coalescence. For spherical particle the modified Carman-Kozeny equation was applied; the commonly accepted value for Kozeny constant is 5.0. However, K, depends on, among other factors, the structure of the bed, voidage fraction, particle shape, tortuosity, superficial velocity, bed depth, particle size, and wall effect.     

LPT-2型液体分布器的流体力学及传质性能研究

在Φ1 000 mm的有机玻璃塔中,采用空气-氧-水物系对LPT-2型单喷头式液体分布器的流体力学性能和传质性能进行研究。结果表明：在液体流量1.0~5.0 m3/h、气体流量2 000~10 000 m3/h的条件下,LPT-2型液体分布器的压降为40~120 Pa/m,仅为高效规整干填料压降的15%左右;雾沫夹带分率为0.2%~2.4%,仅为GXD型复式导流浮阀塔板的24%左右;等板高度为0.10~0.25,与泡沫碳化硅波纹、丝网波纹等高效填料相比,在低液体流量下,传质效果接近,在高液体流量下,LPT-2型液体分布器的传质效率提高50%左右。     

流化床气体分布板结构对流化特性的影响

In the present paper, the experimental method and computational fluid dynamics (CFD) method were used to investigate the effect of gas distributors with different orifice size and orifice pitch on fluidization characteristics in gas-solid fluidized bed. The distributor pressure drop, bubble evolution, bed pressure drop and the distribution profile of solid volume fraction were investigated with using the four types of gas distributor plates. Euler- Euler two fluid model(TFM) approach based on the kinetic theory of granular flow (KTGF) and Standard k-epsilon turbulence model were employed in the numerical simulation with using ANSYS Fluent 15.0. The results showed that the orifice size and orifice pitch of gas distributor plate have the significant influence on the flow characteristics in gas-solid fluidized bed. With decreasing orifice size and orifice pitch of gas distributor plates under the same opening area, the distributor pressure drop, the initial bubble size and height of dead zone just above distributor was decreased, and the bed pressure drop was more increased than that of the larger orifice size and orifice pitch of distributors, the distribution of solid volume fraction was also more homogeneous for the small orifice size.     

钻杆旋转影响大斜度井段岩屑分布的数值模拟

为了研究钻杆旋转对复杂结构井大斜度井段环空岩屑分布状态的影响规律和钻井液-岩屑两相流动压降的变化规律,应用三维建模软件建立了复杂结构井大斜度井段物理模型,应用CFD动网格运动模型模拟钻杆在环空的旋转效果,流动域内采用Realizable涡黏模型近似求解钻井液-岩屑两相纳维-斯托克斯方程。模拟结果显示,钻杆旋转作用使岩屑沿井眼周向呈非对称状分布,钻杆旋转能够提高钻井液对岩屑沿切向的拖曳程度,显著提高了井眼清洁效果。根据CFD数值模拟结果,应用最小二乘法,结合Buckingham-π定理,建立了岩屑床比面积模型和环空压降计算模型。     

产水气藏气液两相管流动态规律研究

由于气液两相流流型的多变性和流动机理的复杂性,需要建立适用于任何流动条件的压降模型。目前工程常用的两相流压降模型主要是基于圆管流动实验数据得到的,其适用条件均具有一定的局限性。对于含水气井,其气水比一般比油井高得多,而且水和油物性差异大,气水两相流液体滑脱严重。现有的两相流压降模型用于气井压降预测时误差较大。因此对其进行了修正,给出了修正曲线。依据气水两相流实验,深入研究了气水两相上升流流动机理及特性参数变化规律,在现有气液两相流压降模型基础上探讨了适用于产水气井的H-B修正模型,应用现场资料对该模型进行的评价和验证表明,提高了预测产水气井压降分布的准确性,更符合实际情况。     

塑料孔板旋转填料床吸收性能研究

目前旋转填料床已在天然气中选择性除硫和脱硫除尘等方面得到了较好的应用。塑料孔板填料与金属填料相比，具有气阻小、造价低、堆密度小和加工简便等优点。为此，以CO₂-NaOH为系统，研究了塑料孔板错流旋转填料床的吸收性能，重点考查了液量、超重力因子和气量等对流体力学和传质性能的影响。试验结果表明：塑料孔板错流旋转填料床的压降随气量和超重力因子的增加而增大，与液量几乎无关；传质性能随气量、液量和超重力因子的增加而增大，其综合传质性能比传统填料塔设备高1～2个数量级。应用MATLAB语言编制了应用程序，并通过对试验数据的回归分析得出了体积传质系数的关联式。     

Optimization of Required Volumetric Flow Rates for Aerated Mud Underbalanced Drilling

Abstract

In the aerated mud underbalanced drilling, the bottomhole pressure is intentionally reduced by reducing the hydrostatic mud column due to the two-phase flow occurrence in the annulus. However, in the field, it is incorrectly assumed that the aerated mud can be treated as a homogenous mixture of liquid and gas, neglecting the slippage between the two phases and, thus, the flow pattern and its effect on pressure drop calculation. Accurate prediction of bottomhole pressures and optimal flow rates requires the modeling of the complex flow mechanisms involved in aerated mud flow, which includes flow pattern prediction and slip liquid hold-up. The objective of this study is to develop a simulation tool to optimize the gas and liquid volumetric flow rates using bottomhole pressure and borehole stability as the selecting criterion. The investigation of the drill pipe size effect on the optimal gas and liquid flow rates was also part of this study. A vertical, two-phase, flow comprehensive mechanistic model is modified and incorporated in the simulator to predict the pressure drop in the annulus according to the existing flow pattern. The modified model predicts the annulus bottomhole pressure and the corresponding optimal gas and liquid flow rates for various drill pipe diameters. The simulator was validated using field data, and the results show a fairly accurate match. In conclusion, the optimization of required flow rates for aerated mud drilling was achieved by the developed simulator, which considers flow pattern occurrence in the pressure drop calculation. Furthermore, the drill pipe size was found to be an influential parameter for flow rate optimization.     

负压差对固体进料系统压力分布和气固两相流动规律的影响

A series of experiments on a solid feed system was performed to investigate the effects of negative pressure gradient on the gas-solid flow pattern and hydrodynamic characteristics. Based on the non-fluidized gas-solid two phase flow and particulate mechanics in the standpipe, a method for predicting the pressure of the air passing through the recycle chamber and the pressure drop through the loop seal slit in these systems is also presented. The predicted pressure profile along the negative pressure gradient from the proposed model exhibits a good agreement with the experimental data. The experimental data show that the gas flow in the standpipe is always upward in the negative pressure gradients, while the direction of gas cannot be changed by the drag force. The solid flow rate, the materiel bed height in the recycle chamber (Hf), the pressure drop across the slit (△Pg） decrease with an increasing negative pressure gradient. At a given negative pressure gradient, the superficial gas velocity through the recycle chamber of the loop seal does not affect the pressure drop in standpipe. It increases with an increasing negative pressure gradient.     

催化裂化装置提升管T型出口结构压力降的实验分析

在大型循环流化床装置上对提升管的T型出口结构压力降进行了实验研究。首先,在不同实验条件下对循环流化床提升管T型出口结构的压力降进行了实验测量。重点分析了提升管浓度和气体速度与提升管T型出口结构压力降的关系。实验结果表明,由于大型循环流化床提升管T型出口结构处特殊的气流输送机制,循环流化床提升管T型出口结构的压力降主要受提升管T型出口结构处变截面尺寸、提升管出口处流体转向和提升管内气固两相之间摩擦的影响,在循环流化床提升管T型出口结构处形成较大的压力降。循环流化床提升管T型出口结构的压力降与提升管内催化剂浓度的一次方成正比关系,与提升管内气体速度的二次方成正比关系。最后,在实验数据的基础上,给出循环流化床提升管T型出口结构的压力降计算公式。     

新型导向复合塔板的性能研究

结合导向筛板与规整填料的优点,开发出具有导向功能的新型导向复合塔板。在内径60cm的玻璃塔中,采用氧气-水物系进行了实验,考察了导向复合塔板的塔板压降、雾沫夹带、漏液、单板氧解析效率等流体力学性能和传质性能,并与F1型浮阀塔板及导向固定阀塔板的性能进行了比较。由实验数据关联得到了干板压降、湿板压降和雾沫夹带率的经验式。实验结果表明,导向复合塔板的干板压降为50～200Pa,湿板压降为700～1100Pa,液流强度低于5.263m3/(m.h)时雾沫夹带率小于10%,筛孔气速大于7.9m/s时漏液率几乎为零,单板氧解析效率保持在80%以上;导向复合塔板的总体性能优于F1型浮阀塔板和导向固定阀塔板。     

Influence of sand production on pressure drawdown in horizontal wells: Theoretical evidence

Poorly consolidated reservoirs are susceptible to sand production that tends to increase the pressure drawdown along the well length. This problem, which has not received adequate attention in the literature of petroleum engineering, is quantitatively assessed in this paper. Different flow regimes typically encountered in two-phase transport systems of liquid and solid are discussed. In an effort to evaluate the degree of influence the presence of sand exerts on pressure drop, a suitable relation applicable for heterogeneous flow is employed to compute the energy gradient of the mixture. The difference in the energy gradient of pure oil and mixture is examined for horizontal pipelines in terms of volumetric solid concentration and flow velocity. The study demonstrates that for a specific sediment size and pipe roughness, the effect of sand movement on pressure drop cannot be ignored in many cases of poorly consolidated reservoirs, being 5.1–168% times greater than the pressure drop resulting from pure oil under the same flow condition.     

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��Based on the theoretical analysis and the experiments on two-phase flow in laboratory, some rules of the distributions of the porosity in two-phase gas bubble flow and the velocity under laminar flow and turbulent flow conditions are obtained.The pressure drop calculation method obtained from above results can be used to accurately determine the pressure loss of two-phase gas bubble flow.     

沁水盆地煤层气水平井井筒煤粉迁移及控制

煤层气水平井煤粉的产出易造成储层伤害和卡泵问题,严重影响煤层气的产量。通过进行水平井井筒煤粉迁移规律物理模拟试验,研究了不同压差下,煤粉在水平井筒内的迁移特征。研究结果表明:煤粉和水两相流动为层流流动,煤粉迁移的速率与压差呈非线性增加关系,存在临界启动差压,压差增加到一定程度后,煤粉的迁移趋于稳定。根据煤粉产生机理分析、物模迁移实验和生产经验,提出了控制煤粉产出的生产措施。     

泡沫排水采气井井下节流压降规律实验及模型修正

气井井下节流是气田低成本开发的一项关键技术,“井下节流+泡沫排水采气”工艺在适宜条件下可提高气井带液能力。采用传统气液两相嘴流压降模型开展泡排井井下节流气嘴尺寸设计不能满足气井配产要求,通过节流压降规律测试并建立或者完善数学模型有助于提高泡排井井下节流设计水平。设计并搭建了泡沫排水采气井井下节流物理模拟实验装置,利用泡排剂UT-11开展了在不同泡排剂质量分数情况下的节流压降规律测试,利用实验数据对4个常用气液两相嘴流机理模型(Sachdeva模型、Perkins模型、Ashford模型、滑脱数值模型)进行了嘴流流态过渡预测能力评价、质量流速及嘴前压力的预测能力评价。基于实验数据构建了泡沫流滑脱因子计算关系式,提高滑脱数值模型的准确性,质量流速的绝对百分误差从13.7%降至7.69%,嘴前压力的绝对百分误差从16.5%降至8.01%。该研究为泡沫排水采气井井下节流嘴径设计和嘴前压力预测提供了重要理论依据。     

圆筒型填料的性能研究

针对一种开有两层相互交错窗孔并带有齿形结构弧片的新型圆筒型填料,在内径为600mm的有机玻璃塔内,采用空气-水物系,研究了它的流体力学性能;在内径为600mm的不锈钢塔内,采用环己烷-正庚烷物系,在常压、全回流的情况下,研究了它的传质性能;在内径为300mm的有机玻璃塔内,研究了分别以圆筒型填料、固定阀塔板和复合塔板为塔内件时脱除工业废水中丙烯腈的效果。实验结果表明,圆筒型填料的齿状结构改善了气液两相在填料层中的微流动和液体分布;与鲍尔环填料相比,当F因子为1.0～3.0kg0.5/(m0.5.s)时,圆筒型填料的干床压降降低了23%～40%;当喷淋密度为20m3/(m2.h)、F因子为1.0kg0.5/(m0.5.s)时,湿床压降降低了约40%;圆筒型填料的液泛点提高;当F因子为1.0～2.5kg0.5/(m0.5.s)时,等板高度比鲍尔环填料降低了11%～20%;当采用圆筒型填料作为塔内件时,丙烯腈脱除率比固定阀塔板高约8%,比复合塔板稳定。     

LSXPT-1型双向液体喷头的研究

在 ?1 000 mm有机玻璃冷模试验装置上利用空气-水系统考察LSXPT-1型双向液体喷头的分布性能、喷出的液滴粒径、喷头入口压力、雾沫夹带等随液体流量变化的规律。结果表明：LSXPT-1型双向液体喷头的分布不均匀度系数在0.031～0.040之间,低于传统槽式液体分布器和缓冲沉降式液体分布器的分布不均匀度系数,分布性能优异;随着液体流量的增大,喷头入口压力增大,在液体流量为2.15～9.62 m3/h的范围内,喷头入口压力为 0.04～0.66 MPa;喷出的液滴粒径在1 975～2 350 μm之间,远高于当气速在3.0～4.0 m/s时因气液流动呈湍流状态液滴沉降所要求的液滴粒径（400～700 μm）;该双向液体喷头即使在空塔气速高达4 m/s时,其雾沫夹带量仍不超过7%,可允许更高的操作气速上限,提高塔的处理能力。     

基于CFD的井下油水两相文丘里流量计优选

为解决因流量、油水比变化及两相流态的复杂性所带来的井下文丘里管油水两相测量精度和设计选型等问题,根据多相流理论及计算方法,在不同入口流量、不同油水比条件下,模拟计算3种不同文丘里流量计的油水两相流场并进行方案优选。计算结果表明,介质接近油相或水相时,两相流态分别接近层流或湍流。流体经文丘里喉部后,油水两相分层特征显著。根据多相流计量精度的需要,通过CFD计算对比,优选出小流量下压降随液体粘度有显著变化的文丘里管设计方案。     

水平井筒射孔完井变质量流动压降规律

影响水平井产能和向井入流剖面的因素很多,水平井筒沿程压降是其中一个重要因素。结合水平井筒生产实际,在大庆多相流试验环道基础上,设计了壁面注入系统和变质量流动试验段,针对射孔水平井筒变质量流动规律进行了单相和两相变质量流动试验研究。结果表明,单相水平井筒沿程压降随注入比变化,并且存在临界注入比,当注入比超过临界注入比时,压降随着注入比增加显著。进一步的数值模拟研究揭示了其中的原因:当超过临界注入比后,射孔孔眼下游出现流动分离,混合压降开始起作用,从而引起压降的显著增加。油水两相变质量流动除了受注入比影响外,还受到含水率变化的影响,在高流量条件下,40%含水率时压降最高,流型为分散流型;低流量下,压降随含水率变化不大,流型为分层流型。该研究结果对完井设计有一定指导意义。     

旋流扶正器作用下环空中气液两相螺旋流场压降研究

目前国内外对于旋流扶正器作用下环空中螺旋流场的研究主要针对单相流体。结合两相流的特点,借助于螺旋角的概念,修正了达西公式中的沿程阻力系数的计算公式,最终得到了环空中气液两相螺旋流场压降的计算方法,并进行了试验验证。运用VB语言编写了环空中气液两相螺旋流计算分析软件,分析了螺旋流场的非线性衰减特征。     

气井气水两相节流温降模型

准确预测气液两相节流温降是井下节流天然气水合物防治和携液分析的前题。基于能量守恒原理和Peng Robinson状态方程,结合Huron和Vida1提出的含强极性物质体系的G^E（超额吉布斯能量）混合规则和UNIFAC活度系数模型,建立了气-水两相节流温降数学模型。利用天然气-水节流压降温降实验数据验证了该模型的正确性,平均误差为-0.49 ℃（-2.55%）,平均绝对误差为0.76 ℃（3.80%）,标准差为1.13 ℃（5.40%）,明显优于Perkins的热力学模型。以广安002 38有水气井气体组分数据为例,进行了不同气水比下的节流温降计算,当GWR＜800 m³/m³时,地面节流不会生成天然气水合物,由此无需将嘴子安装在井下。