高频钻井液压力波衰减模型及规律研究. (Chinese)

Attenuation model and law of high-frequency drilling fluid pressure wave. (English)

The technology of transmitting high-frequency drilling fluid pressure wave information with high transmission rate. It is also one of the key technologies to achieve the automated and intelligent drilling. However, the field application of this technology is hindered by the substantial attenuation experienced by high-frequency drilling fluid pressure waves during the transmission process. Thus, exploring the attenuation characteristics of these waves is crucial for the development of high-speed transmission technology. Herein, it is assumed that the drilling fluid pressure is equivalent on the same section of drill string, and the flow rate of drilling fluid is radially distributed. On this basis, an attenuation model for high-frequency drilling fluid pressure waves was established based on the two-dimensional axisymmetric transient flow theory with the small signal analysis method, for which the applicable conditions were given. In the model, the impact of pressure wave signal parameters, drilling string dimensions, and drilling fluid properties were taken into account, and the accuracy of the model was verified through ground experiments. In addition, the effects of the frequency and transmission distance of drilling fluid pressure wave, the density and viscosity of drilling fluid, and the inner diameter of drill string on the attenuation of high-frequency pressure waves were analyzed employing this model. The analysis results demonstrate that the amplitude attenuation of high-frequency drilling fluid pressure waves increases exponentially with higher pressure wave frequencies, longer transmission distances, and greater drilling fluid viscosity. Moreover, the amplitude attenuation is primarily influenced by the wave frequency, gradually decreasing as the density of drilling fluid and the inner diameter of drill string increase. Generally, this study could offer theoretical guidance for developing the transmission technology of high-frequency drilling fluid pressure wave information. [ABSTRACT FROM AUTHOR]

高频钻井液压力波信息传输技术传输速率高，是实现自动化、智能化钻井的关键技术之一， 由于高频钻井液压力波在传输过程中存在较大的衰减，阻碍了该技术的现场应用，探明其衰减规律 对于高速传输技术开发具有重要意义。在假设同一钻柱截面钻井液压力相等且钻井液流速存在径向 分布的基础上，基于二维轴对称瞬态流动理论，采用小信号分析方法，综合考虑了压力波信号参数、 钻柱尺寸及钻井液参数的影响，建立了高频钻井液压力波衰减模型并给出了适用条件。最后采用地 面实验验证了该模型的正确性。随后分析钻井液压力波频率、压力波传输距离、钻井液密度及黏度、 钻柱内径对高频压力波衰减的影响。结果表明：高频钻井液压力波幅值衰减量随钻井液压力波频率、 压力波传输距离及钻井液黏度的增加而增大，且变化规律为指数型；幅值衰减量受频率影响最大， 并随钻井液密度及钻柱内径增加逐渐减小。本研究可为高频钻井液压力波信息传输技术研发提供理 论指导。 [ABSTRACT FROM AUTHOR]

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