射流作用下岩石局部渗流压力分布的研究

Study on the Pressure of Percolation Flow in a Part of the Rock by Jetting

高压射流辅助破岩在油气井钻井工程中得到广泛应用，其破岩机理还很不明了。本文提出了射流作用下岩石局部范围具有较高渗流压力的思想，并认为该渗流压力大小对射流破岩有重要影响，建立了该渗流压力的计算模型。通过在地面条件下，射流作用于湿砂岩体的多因素数值计算与分析得出：射流的喷射速度大，岩石局部范围内的渗流压力也较大；计算平面的深度位置增加，岩石渗流压力明显减小；压力波（纵波）在岩体中的传播速度变化，对岩石局部范围内的渗流压力影响不大的规律，这对认识岩石在射流作用下的破碎机理有重要意义。

The high-pressure jet is applied widely to the fragmentation of the rock in drilling engineering, but the mechanism of rock fragmentation with jet is not very clear by now. In this paper, an idea is presented about a larger pressure of percolation flow existed in a part of rock by a high - pressure jet, and the pressure has great effect on the rock fragmentation with jet. A model of calculating the pressure is established. The model is used to calculate and analyze the influence several factors of on the wet sandstone in normal conditions. Some results are obtained： the faster the jet velocity, the larger the pressure; the deeper the calculated location, the smaller the pressure; and the velocity variation of the compression wave in the rock has a little influence on the pressure of percolation flow. It is important for understanding the rock fragmentation mechanism with jet.