气体释放速率对浅层气藏中气水运移的影响

为了论证在防治浅层气地质工程灾害中预先采取的有控制性排气措施的合理性和必要性,借助非饱和水气两相渗流原理,研究浅层气藏在气体释放路径下的气水运移规律.采用数值方法描述排气井不同释放速率对地下浅层气藏中气水运移的影响.结果表明:气体释放速率对气藏中的气水运移和分布形态有显著影响,释放速率越快,"水锥"效应越明显;实际工程中需结合详勘数据,选取适宜的排气速率,实施控制性放气措施,避免过早发生淹井,导致气井快速失效;在气藏中的浅层气体释放完毕后,砂土中会残留部分以气泡形式存在的气体,施工过程中需引起重视.

Effects of gas release rate on gas water migration in shallow gas reservoir

Laws for gas water migration in shallow gas reservoirs were analyzed in path of gas release with the theory of two phase seepage in unsaturated soil in order to verify the rationality and necessity of the controlling measure for pre exhausting gas in the process of preventing shallow gas geological engineering disasters. The effects of different release rates of exhaust shafts on the gas water migration in shallow gas reservoirs were described by using numerical methods. Results show that the gas release rate significantly affects the gas water migration and distribution in shallow gas reservoirs. The faster the gas release rate, the more significant water coning effects are. According to the detailed geological investigation data, the appropriate gas release rate should be selected to implement the controlling measure for gas release in practical engineering in order to avoid premature flooded shaft and rapid failure of the exhaust shaft. There are still some residual gas bubbles in sandy soil after the gas release,  which should be regarded in process of construction.