关键词: 瓦斯压力, 球向钻孔, 径向钻孔, 平衡时间

Abstract: In this paper, the balance time and accuracy of passive method in gas pressure measurement was studied, the research shows that as long as there exits gas exchange face in the measurement process of passive method, the gas pressure can be measured. Meanwhile, through the calculation of established model, it is found that the pressure-relief diameter of spherical drilling hole is much smaller than that of the radial drilling hole in the formation process of drilling hole, thus, the gas loss is less. According to the limit equilibrium theory, the theoretical balance time is short, and the measured pressure value is slightly higher, that is, the accuracy is high. The calculation validity was verified by numerical simulation. The simulation results also show that as the free emission time increases, the spherical drilling hole takes a smaller percentage of the balance time of radial drilling hole, and the advantage of the balance time is more obvious. The field practice proves that the spherical drilling hole has obvious advantage in the balance time and accuracy during the gas pressure measurement process by passive method.