高含硫气井井筒温度—压力预测

发布时间：2018-05-11 08:03

本文选题：高含硫 + 硫沉积　；参考：《西南石油大学》2017年硕士论文

【摘要】：高含硫气藏与常规气藏的主要区别在于硫化氢含量高以及在井筒内复杂的相态变化使其难以下入井下温度、压力计,为了充分利用高含硫气井井口测试资料作动态监测,有效回避井底测压安全风险大、工作开展受限程度高的问题,本文从流体物性参数、井筒中特殊相态变化出发,建立高含硫气井井筒硫沉积动态预测模型以确定井筒内硫析出的位置、析出量与硫扩散沉积情况,从井筒向地层的实际导热情况、流体流动规律出发来建立高含硫气井的井筒非稳态温度压力模型,并耦合井筒非稳态温度压力模型、硫沉积扩散模型编译程序进行计算,为实现高含硫气藏的动态监测提供依据。在对井筒温度、压力分布计算与硫沉积预测的分析中主要取得以下几方面的成果:(1)进行高含硫天然气的物性参数(偏差因子、黏度)计算,优选计算模型并编制程序,对井筒-地层的传热物性参数进行计算,得出:由于井筒内温度压力的变化,天然气的物性参数、导热过程相关的热物性参数均随时间与井深变化而变化。(2)硫沉积预测的理论方法:对井筒内出现的复杂相态变化进行分析,耦合井筒温度压力与溶解度模型,研究硫析出量与析出位置,并进行受力分析确定临界悬浮速度与临界流量,根据传质传热学理论建立的沉积扩散模型对硫沉积进行动态预测。(3)井筒非稳态温度压力模型:研究井筒流体-地层的导热情况,将井筒内与地层的导热均考虑成非稳态导热建立模型,利用laplace变换和stefest数值反演进行求解并与流体热力学模型结合求得井筒的非稳态温度模型,针对不同流态下(单一气相、气-液硫、气-固硫两相)的流动采用不同的压力模型,将温度压力模型进行耦合求解并编程。(4)在程序的基础上进行模型的对比验证与实例分析,结果表明本模型计算结果与商业软件、实测数据接近且精度较高;对影响温度压力的因素如产量、比热、总传热系数、流体组成与井筒结构等开展敏感性分析,结果表明生产时间、产量、比热、总传热系数对温度影响较大,流体组成及井径对压力影响较大,而生产时间、临界硫溶解度、流体组成、产量对井筒内硫的析出位置、析出量、硫垢厚度具有较大影响。
[Abstract]:The main difference between high sulfur gas reservoir and conventional gas reservoir lies in the high content of hydrogen sulfide and complex phase change in wellbore, which makes it difficult to enter downhole temperature and pressure gauge, in order to make full use of the well head test data of high sulfur gas well for dynamic monitoring. In order to avoid the problem of high safety risk and limited work, this paper starts from the parameters of fluid physical properties and the variation of special phase state in wellbore. A prediction model of sulfur deposition performance in high sulfur bearing gas wells is established to determine the location of sulfur deposition in the wellbore, the amount of sulfur release and sulfur diffusion deposition, and the actual heat conduction from the wellbore to the formation. The fluid flow law is used to establish the unsteady temperature and pressure model of the wellbore with high sulfur content gas well, and coupled with the wellbore unsteady temperature and pressure model, the sulfur deposition diffusion model compiler is used to calculate the model. It provides the basis for dynamic monitoring of high sulfur gas reservoir. In the analysis of wellbore temperature, pressure distribution and sulfur deposition prediction, the following achievements are obtained: 1) calculation of physical parameters (deviation factor, viscosity) of high sulfur bearing natural gas, optimization calculation model and programming. The physical parameters of heat transfer in wellbore and formation are calculated. It is concluded that due to the change of temperature and pressure in wellbore, the physical parameters of natural gas are obtained. The theoretical method of predicting sulfur deposition with the variation of time and well depth: analyzing the complex phase change in wellbore, coupling wellbore temperature, pressure and solubility model, The amount and position of sulfur release are studied, and the critical suspension velocity and critical flow rate are determined by force analysis. According to the theory of mass transfer and heat transfer, the sedimentary diffusion model is used to predict the sulfur deposition dynamically. (3) the unsteady temperature and pressure model of wellbore: the heat conduction of fluid-formation in wellbore is studied. The heat conduction in wellbore and formation is taken into account as an unsteady heat conduction model, which is solved by laplace transform and stefest numerical inversion and combined with fluid thermodynamics model to obtain the unsteady temperature model of wellbore, aiming at different flow states (single gas phase). Different pressure models are used for gas-liquid sulfur (gas-solid sulfur) flow. The temperature and pressure model is solved by coupling and programming. 4) on the basis of the program, the model is compared and verified and an example is analyzed. The results show that the calculated results of this model are close to commercial software, and the measured data are close and accurate, and sensitivity analysis is carried out for the factors affecting temperature and pressure, such as output, specific heat, total heat transfer coefficient, fluid composition and wellbore structure, etc. The results show that production time, production rate, specific heat, total heat transfer coefficient have great influence on temperature, fluid composition and well diameter have great influence on pressure, while production time, critical sulfur solubility, fluid composition and production rate have great influence on the release position of sulfur in wellbore. The amount of precipitation and the thickness of sulfur scale have great influence.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE37

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