深井钻井的压力平衡研究

深井钻井具有高温高压及地层压力和地层破裂压力间安全钻井液密度窗口极为狭窄的特点,这为在深井钻井过程中保持井眼系统的压力平衡提出了更高的要求。为此,针对深井钻井的特点,运用流变学、传热学和物质平衡的基本原理,建立钻井液循环和静止状况下的钻井液温度分布模式及高温高压密度模式和高温高压流变模式,应用这些模式和地层流体的PVT特性对一些实钻深井的溢流现象进行分析。结果表明,井眼水力系统流体热力学模型对深井、超深井的压力平衡控制至关重要。

The Study on Pressure Balance in Deep Wells

In deep wells, the safe window between pore pressure and fracture pressure is extremely narrow, and the pressure and temperature are very high at the bottom holes. The characteristics make it more difficult to control the pressure balance of hole in deep wells than in conventional wells. Aiming at the characteristics, a circulating and shut – in temperature distribution model, a HTHP density model and a HTHP rheologic model .This paper is presented based on the basic principles of Rheology ,Heat Transfer and Fluid Mechanics. With these models and the PVT properties of formation fluid, some kick phenomena in several deep wells are analyzed. The results show that the models presented by this paper are very important to control the pressure balance in deep wells.