地下水封洞库水幕孔注水试验渗流场及稳压时间分析

Analyses of Seepage Field Distribution and Pressure Stabilization Time for the Water Injection Test of Water Curtain Borehole in Underground Water-sealed Cavern

近年来我国建设的地下水封储油洞库均采用了水平水幕系统,水幕系统对于保证洞库水封性至关重要。水幕系统往往进行了大量的水力学试验,但如何拟定合理的试验方法和试验过程,如何有效利用试验数据并合理评价水封效果,还需结合工程实践进行深入研究。文章以某水封洞库为依托,基于单一水幕孔注水-回落试验,对试验的理论背景、试验过程的合理性及数据分析等进行了研究。首先,分析了单一水幕孔注水试验的试验过程和本质特征;然后,基于非稳定流分析原理推导了注水-回落试验的解析方程,并进一步分析了注水试验的水幕孔水压力、注水量与试验时间、岩体渗透参数的关系;最后,以某水封洞库为例,基于试验数据和理论分析,对注水试验的稳压时间进行了计算和分析,并建议了合理的试验过程和稳压时间控制要求。研究结果可为地下水封洞库水幕系统渗透性试验方法的建立提供理论参考依据。

In recent years,the horizontal water curtain system has been widely adopted in the construction of underground water-sealed oil reservoirs in China,and the water curtain system is essential to ensure the water sealing of the oil reservoirs.The water curtain system often carries out a large number of hydraulic tests and accumulates a large amount of data.However,how to reasonably formulate test processes,effectively use test data,and reasonably evaluate the water seal effect,are the key issues that need to be studied further by combining engineering practice.This paper studies the issues of the theoretical background of the test,the rationality of the test process,and the data analysis based on the water injection-drop test of a single water curtain borehole in a water-sealed cavern reservoir.Firstly,the processes and characteristics of the water injection-drop test are analyzed.Then,based on the theoretical principle of the unsteady flow,the analytical equations of the water injection-drop test are deduced and further,the relationships among the water pressure of the water curtain borehole,the water injection volume,the test time,and the permeability of the surrounding rock are analyzed.Finally,via the theoretical analysis of the experimental data,the pressure stabilizing time of the water injection test is calculated and analyzed,and reasonable procedures for the water injection-drop test and requirements for pressure stabilizing time control are suggested.The research results can provide a theoretical reference for the establishment of the permeability test method for the water curtain system in underground water-sealed oil storage caverns.