稠油热采闭式热流体循环井筒温度场分析

针对"两高"油田原油流动性差的特点以及闭式热流体循环降粘工艺的复杂性,建立了3种闭式热流体循环井筒传热模型及其边界条件,并采用Matlab编写了相应的模型求解程序。通过对现场具体井眼进行模拟计算,对比分析了3种闭式热流体循环效果,给出了最优热流体循环方案。计算了循环流量、循环介质和管柱材料物性参数等对井筒加热效果的影响。计算结果表明,两侧加热方案最好,随着循环流量的增加井筒温度不断升高,导热油作为循环热载体较好,导热性能差的管柱材料能够提高循环加热段产液流动的平均温度。     

极地钻井井筒温度压力预测模型及分布规律研究

极地永久冻土层的低温条件会影响钻井液的流变性,从而影响极地钻井中井筒温度和压力的分布.为了解极地永久冻土层低温条件对钻井中井筒温度和压力分布的影响规律,为极地钻井设计和钻井施工提供依据,分析了低温对水基和油基钻井液流变性的影响,考虑低温对钻井液流变性的影响、永久冻土层与井筒之间的耦合作用,建立了极地钻井井筒温度压力预测...     

井眼循环温度分布规律

结合实际运用分析各种井内温度确定方法,并根据能量守恒的原理,结合传热学和流体力学的基本原理,建立了相应的井眼内温度数学模型和确定任意时刻、井深处的钻具内和环空中的温度值的计算公式。     

井筒电加热技术温度分布模拟研究

基于热量传递原理和多相流动理论,建立了电加热降粘工艺下产液沿井筒流动与传热的热力学模型,计算了产出流体沿井筒的温度分布,并利用现场实测数据,验证了模型的准确性。利用该模型,模拟计算了不同加热深度、功率以及加热位置下产出液的温度分布,分析了各参数对电加热井流体温度分布的影响,提出了基于温度分布模拟下选择电加热参数的方法。     

稠油掺稀开采井筒内温度分布规律

稠油在井筒中的流动阻力很大,造成稠油生产困难,而采用套管掺稀油工艺,可以使井筒中的混合液保持较低黏度,减小井筒流动阻力。根据传热学和能量守恒原理,采用节点系统分析的思想,考虑油管、套管、水泥环及地层之间的传热,建立稠油掺稀井筒和套管内流体温度分布数学模型。运用高斯列主元对模型进行求解,并对油管中的温度分布规律进行了分析,总结出影响掺稀效果的主要影响因素,为掺稀开采稠油油藏的参数设计提供了依据。     

油井热洗过程中井筒温度场研究

油井热洗是保持油井正常生产最常用的维护措施之一,但影响油井热洗效果的最重要因素是热洗介质在整个井筒内的温度分布,若洗井温度、洗井排量等参数设置不合理,热洗介质在井筒结蜡段的温度就会低于熔蜡温度,进而使得洗井效果不明显,或者洗井后产油恢复周期长,甚至出现洗井后产量急剧下降等现象。针对以上问题,本文建立了油井热洗时井筒温度分布数学模型,通过模型可以直观的反映油井热洗时井筒内的温度变化,并在此基础上对洗井温度、洗井排量对热洗井筒温度分布规律进行了讨论,同时提出了油井热洗时工艺参数优化的基本原则与方法,并在W15-12井油井热洗进行了现场应用,W15-12油井通过热洗参数优化后,洗井过程中上下行电流和载荷均有一定程度的下降,实现了较好的清蜡效果。     

斜井井筒中流动温度分布的预测方法

根据油气水在斜井中流动的特点，从能量方程、气体定律及连续性方程出发，综合考虑传热、相变、焦尔－汤姆森效应等因素，结合前人的研究成果，得出了考虑井筒与水平夹角的斜井井筒中流动温度分布的计算方法。     

储油罐温度分布规律初探

为保持罐中油品储存温度，现场主要采取了倒罐方式，但缺少必要的测温装置，对罐内原油的温度状况不清楚。近年研制了一套温度实时监测和报警系统，对各监测点的温度进行实时监测、记录和超温预警及报警；同时监测并记录了储油罐的进出口温度、环境温度、地温以及储油罐液位等参数，并对储油罐有关温度分布规律进行了初探。     

预测井筒流动温度分布的新方法

传统的Ramey,Satter,Shiu和Hasan-Kabir等井筒流动温度计算模型大多忽略环空流体对流的影响,容易造成井底油、套管温度差异较大,计算误差过大.为此,在现有模型基础上,充分考虑环空流体强对流的影响,以油管底端温度、压力与环空平衡为必要条件,建立了考虑油、套连通的井筒温度分布计算模型;通过采用补偿系数计算方法,将井底总传热系数U按井深线性的离散化到各节点计算单元,保证井底油、套环空之间温度的连续性.利用现场实测数据进行验证,计算结果误差小,具有较高计算精度.     

Heat Distribution within the Wellbore While Drilling

Abstract

Analysis of the drilling fluid temperature in a circulating well is the main objective of this study. Initially, different analytical temperature distribution models were studied. Variables that have significant effect on temperature profile are observed. Since the verification of the analytical model is not probable for many cases, a computer program that uses a finite element method is employed to simulate different well conditions. Three different wells are modeled by using rectangular elements with four nodes. Maximum drilling fluid temperature data corresponding to significant variables are collected from these models. These data are then used to develop an empirical correlation in order to determine maximum drilling fluid temperature. The proposed empirical correlation can estimate the temperature distribution within the wellbore with an average error of less than 16%, and maximum drilling fluid temperature with an average error of less than 7%.     

Research on Two-Phase Closed Thermosyphon to Improve Fluid Temperature Distribution in Wellbores

Abstract

A two-phase closed thermosyphon (TPCT) is introduced to improve fluid temperature distribution in wellbores by utilizing its characteristics of efficient heat transfer. Laboratory experiments show that TPCT in wellbores can heat the upper fluid in wellbores by absorbing the surplus energy of the lower fluid in the wellbore, and no extra energy is consumed. The roles of TPCT are affected by several factors. The type of working media needs to match with the inlet temperature of simulation oil. A filling ratio of 15% is optimal for different TPCT wellbores in experiments. With higher vacuum degree in the TPCT cavity, TPCT has a better role. With higher simulation oil flow rate, the role of TPCT is worse.     

超临界二氧化碳钻井流体井筒温度传递特性

循环钻井流体温度计算一直是钻井工作者希望解决的难题。建立了井眼温度传递数学模型,并通过对模型求解,给出了钻具内和环空流体温度计算解析式;利用该解析式结合超临界二氧化碳钻井流体的物理特性,对使用φ89mm钻头、φ31.8mm钻杆钻进的井眼中二氧化碳流体温度进行了计算,绘制了钻具内和环空二氧化碳流体温度剖面图;对比了在不同井深时和不同井眼尺寸条件下井眼内二氧化碳流体温度剖面图,发现随着井深的增加,钻具内二氧化碳流体更易进入超临界状态,且超临界二氧化碳钻井液更适合小井眼钻井。     

考虑非牛顿流体螺旋流动的钻井井筒温度场研究

准确了解钻井过程中井筒温度及其变化规律对于安全、高效钻井具有重要的意义。根据热力学第一定律及传热理论,建立了完整的钻井循环过程中温度场数学模型,分析了井筒中非牛顿流体螺旋流动的传热机理以及水力学能量和机械能量对井筒温度场的影响规律,对高温高压循环当量密度计算和井筒温度控制方法进行了初步探讨。模型计算结果与现场试验数据吻合较好。由数值模拟结果得出:在井深2 000.00 m处,钻柱转速从0 r/min升至200 r/min时该处温度升高4.5 ℃;在井深5 000.00 m处,钻柱转速从0 r/min升至200 r/min时该处温度升高7.8 ℃。研究结果表明,井底温度随钻柱转速的增加呈指数增长,随着井深的增加,钻柱旋转对井底温度的影响更加明显。建立的温度场模型可为高温高压地层钻井水力学设计和现场作业过程中的温度控制提供理论参考。      

电磁加热凝析气井井筒温度分布

井下电磁加热使凝析油蒸发或流动。在反凝析区域,若升高温度可以得到蒸发凝析油的效果,甚至成为单相。所以通过加热方法升高近井区温度,使凝析油蒸发。凝析气井井筒温度分布是进行气井节点分析和动态分析必不可少的参数。根据传热学原理推出了凝析气井井筒温度分布计算公式,研究了温度计算基础数据求取方法。对某一井深为3390m的凝析气井进行了计算,该气井气油比为3000;地层温度为114℃。计算结果表明:气井温度随井深呈非线性分布;气井井口温度随储层温度的增加而增加。     

钻井液热物性参数测量及其对井筒温度场的影响

为准确计算钻井过程中井筒内的温度分布,基于瞬态热线法及热平衡原理设计了钻井液热物性参数测试仪.利用该仪器对聚合物钻井液和聚磺钻井液的导热系数和比热进行了实测研究,分析了钻井液导热系数和比热变化对井筒内温度计算值的影响,得到了2种钻井液的导热系数和比热随温度变化的规律,并依据实验数据拟合出了不同温度下2种钻井液的导热系数和比热求取公式.考虑温度对钻井液物性参数的影响,建立了井筒温度场模型.研究表明,钻井液热物性参数的变化对环空温度计算值的影响明显,并通过温度场间接影响到井筒内其它参数的计算.     

Numerical Simulation on Deepwater Drilling Wellbore Temperature and Pressure Distribution

Abstract

Considering the effect of temperature and pressure on the characteristics of drilling fluid, a coupled model of deepwater drilling wellbore temperature and pressure was established. By numerical simulation, the wellbore temperature and pressure distribution were obtained. Studies have shown that minimum temperature appears in the position slightly upward of the mud line, and maximum temperature appears in the position slightly upward of the bottom hole. Maximum equivalent circulation density (ECD) appears in the shallow layer. In order to accurately predict wellbore temperature and pressure, the effect of temperature and pressure on mud should be coupled; moreover, the variation of convection heat transfer coefficient should be considered.     

Prediction of Dynamic Wellbore Pressure in Gasified Fluid Drilling

The basis of designing gasified drilling is to understand the behavior of gas/liquid two-phase flow in the wellbore. The equations of mass and momentum conservation and equation of fluid flow in porous media were used to establish a dynamic model to predict weIlbore pressure according to the study results of Ansari and Beggs-Brill on gas-liquid two-phase flow. The dynamic model was solved by the finite difference approach combined with the mechanistic steady state model. The mechanistic dynamic model was numerically implemented into a FORTRAN 90 computer program and could simulate the coupled flow of fluid in wellbore and reservoir. The dynamic model revealed the effects of wellhead back pressure and injection rate of gas/liquid on bottomhole pressure. The model was validated against full-scale experimental data, and its 5.0% of average relative error could satisfy the accuracy requirements in engineering design.