大斜度井下套管波动压力计算分析

发布时间：2018-08-26 08:01

【摘要】：随着勘探开发的不断深入以及复杂油气层的大量开采,大斜度井的应用范围越来越广。大斜度井具有井眼轨迹复杂、井斜角大、裸眼井段长、净化难度大、套管串下入深度大等特点,给后续工作带来诸多挑战。如果大斜度井下套管产生的波动压力预测不准确会造成井壁不稳定以及井漏等复杂情况和工程事故的发生,致使固井作业时的井径不规则,从而导致固井质量差,影响后续的生产及油气井寿命。因此,对大斜度井下套管瞬态波动压力计算分析进行研究具有非常重要的现实意义。本文根据波的基本性质分析了下套管过程中波动压力产生的原因以及压力波在钻井液中的动态传播机理,建立压力波在钻井液等可压缩流体中的传播速度模型。针对环空直径复杂计算的问题,通过对比圆管流动和环空流动,提出了等效直径简化环空直径的计算直径思路,建立了下套管过程中流道的壁面剪切应力计算模型。根据弹性管-可压缩流体理论对大斜度井下套管钻井液的流动状态进行分析,建立了大斜度井下套管瞬态波动压力二维计算模型,在此基础上考虑井斜角方位角,建立了大斜度井下套管瞬态波动压力三维计算模型,推导出了二维、三维条件下对应的波动压力连续性方程和运动方程组,为便于编程,给出对应方程组的麦考马克数值解法。基于本文建立的求解大斜度井下套管瞬态波动压力计算模型,在VB开发环境下编制了一套大斜度井下套管波动压力计算软件,运用软件对实例开发井波动压力进行预测计算,通过软件计算结果分析影响大斜度井下套管波动压力的各种因素及其对波动压力影响作用的规律,为大斜度井套管安全下入奠定了理论基础。
[Abstract]:With the deepening of exploration and development and the development of complex oil and gas reservoirs, the application of large deviated wells is becoming more and more extensive. Due to its complex well trajectory, large angle, long open hole section, great difficulty in purification and large depth of casing string, it brings many challenges to the follow-up work. If the prediction of fluctuating pressure produced by high slope downhole casing is not accurate, it will lead to the instability of wellbore, the occurrence of complex conditions such as well leakage and engineering accidents, and the irregularity of well diameter in cementing operation, which will lead to poor cementing quality. Affects subsequent production and life of oil and gas wells. Therefore, it is of great practical significance to study the calculation and analysis of transient fluctuation pressure of downhole casing with large slope. In this paper, according to the basic properties of the wave, the causes of wave pressure and the dynamic propagation mechanism of pressure wave in drilling fluid are analyzed, and the velocity model of pressure wave propagation in compressible fluid such as drilling fluid is established. In view of the complicated calculation of annular diameter, by comparing the annular flow and annular flow, the paper puts forward the idea of equivalent diameter to simplify the calculation of annular diameter, and establishes the wall shear stress calculation model of the runner in the process of casing. Based on the theory of elastic tube-compressible fluid, the flow state of downhole casing drilling fluid with high inclination is analyzed, and a two-dimensional calculation model of transient fluctuating pressure of downhole casing with large inclination is established, on which the azimuth angle of well inclination angle is considered. A three-dimensional calculation model for transient wave pressure of downhole casing with large slope is established, and the corresponding wave pressure continuity equation and motion equations are derived under two-dimensional and three-dimensional conditions. In order to facilitate programming, a McCormack numerical solution to the corresponding equations is given. Based on the model established in this paper for calculating the transient fluctuation pressure of downhole casing with large slope, a set of software for calculating the fluctuating pressure of downhole casing with large slope is developed under the environment of VB. The software is used to predict and calculate the fluctuating pressure of an example development well. Through the analysis of the results of software calculation, various factors affecting the fluctuation pressure of downhole casing with high inclination and the law of its influence on the fluctuating pressure are analyzed, which lays a theoretical foundation for the safe entry of casing in the high slope well.
【学位授予单位】：中国石油大学(华东)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE931.2

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