摘要
针对我国煤层气抽采率低的现状,首次提出在现有钻孔水压致裂的基础上,施以高压脉冲放电,以增加煤层水压致裂过程中裂隙的通透性;借助自主研发的高压脉冲水中放电实验装置,研究了脉冲放电水激波波前时间t及其斜率K随放电电压U及静水压力p0的变化规律,并结合相关的数据采集与分析系统进行了不同放电参数下的实验研究。通过建立水激波波前时间的理论计算模型,并对其进行求解,获得了t及K关于U和p0的二元函数关系式t=F(U,p0)及K=G(U,p0)。实验结果与理论计算均表明:当p0一定时,t随U的增大而减小,而K随U的增大而增大,即水压一定时,电压越高,水激波波前时间越短,峰值压力上升速度越快;当U一定时,t随p0的增大而增大,而K随p0的增大而减小,即放电电压一定时,水压越高,水激波波前时间越长,峰值压力上升速度越慢。该研究为煤层高压电脉冲水压致裂提供了理论依据。
In view of the present situation of low gas drainage and utilization ratio in China,a new method which combines hydraulic fracturing and pulsed high-voltage discharge was proposed to increase coal fracture.In order to explore how U(discharge voltage)and p0(hydrostatic pressure)affect t(front time)and K(slope)of water shock-wave caused by hydro-electric effect,an experimental research of different discharge parameters under the help of test device of high voltage pulse and data acquisition &analysis system was implemented.Meanwhile,binary functions t=F(U,p0)and K=G(U,p0)were established through the construction and solving of theoretical water shock-wave model.The conclusions of both experiment and theoretical calculation reveal that,when p0 is constant,with the increases of U,t decreases while Kincreases,i.e.a higher discharge voltage leads to a shorter water shock-wave front time and a higher rising velocity of peak pressure.When Uis constant,with the increases of p0,t increases while Kdecreases,i.e.a higher hydrostatic pressure leads to a longer water shock-wave front time and a lower rising velocity of peak pressure.Therefore,this research provides theoretical basis for high electric field pulse hydraulic fracturing in coal seam.
出处
《太原理工大学学报》
北大核心
2015年第6期680-684 690,共6页
Journal of Taiyuan University of Technology
基金
山西省煤层气联合基金资助项目:基于高压电脉冲的煤层瓦斯赋存环境及物态转换机理研究(2012012012)
关键词
煤层致裂
高压脉冲放电
等离子通道
水激波
波前时间
fracturing coal seams
pulsed high-voltage discharge
plasma channel
water shock-wave
front time
