煤层瓦斯压力及压力梯度影响因素的分析

Analysis of Influencing Factors for Coal Seam Gas Pressure and Gas Pressure Gradient

由于煤层瓦斯压力的影响因素多且复杂,通过建立理论模型,得出了煤层瓦斯压力与煤层埋深、煤岩弹性模量、泊松比、温度梯度和地应力梯度等影响因素的关系式,并结合数值分析,对煤层瓦斯压力与其相关影响因素的关系进行了分析。通过分析得出,煤层瓦斯压力随着煤层埋深的增加而变大,在同一煤层埋藏深度,煤层瓦斯压力随弹性模量、泊松比、温度梯度的增加而降低,随地应力梯度的增加而增大。同时,煤层瓦斯压力梯度随煤岩弹性模量和泊松比的增大而增大,当煤岩弹性模量和泊松比较小时,煤层瓦斯压力梯度的变化率较小,当煤岩弹性模量和泊松比较大时,煤层瓦斯压力梯度的变化速率迅速增加。煤层瓦斯压力梯度随温度梯度和地应力梯度的增大而增大,基本呈线性变化。

As there are many complex influencing factors of gas pressure, this paper obtained the relation of gas pressure and burial depth, coal modulus of elasticity, poisson ratio, temperature gradient and in - situ stress gradient, through establishing theoretical mod- el. The relationship of gas pressure and the relevant influencing factors are analyzed by combining with numerical analysis. Analysis shows that the gas pressure increases with the increase of coal seam burial depth and in the same coal seam. the gas pressure decreases with the increase of coal modulus, poisson ratio, temperature gradient, and increases with the increase of in - situ stress gradient. What g more, gas pressure gradient increases with the increase of coal modulus and poisson ratio, the change rate of gas pressure gradi- ent is relatively smaller when the coal modulus and poisson ratio is smaller, the change rate of gas pressure gradient increases rapidly when the coal modulus and poisson ratio is large. The gas pressure gradient increases with the increase of temperature gradient and in - situ stress gradient and varies almost linearly.