大牛地致密低渗透气藏启动压力梯度及应用

在相同含水饱和度条件下,大牛地致密低渗气藏的启动压力梯度随有效渗透率增加而减小;随含水饱和度的增加,气藏的启动压力梯度也增加。根据气体的不稳定渗流理论,推导出气井稳产期泄气半径的计算公式,并得出:在考虑启动压力梯度的条件下,产量相同时,有效渗透率增加,气井稳产期泄气半径增加;有效渗透率相同时,气井产量增加,气井稳产期泄气半径减小的关系。根据气井稳产期的泄气半径可以计算出一定配产条件下的最小井距,只有当气井的实际井距大于最小井距时,才不会因为井间干扰缩短气井的稳产时间。

Start-up pressure gradient of tight gas reservoirs in Daniudi gas field and its application method

Start-up pressure gradient of the tight gas reservoirs in Daniudi gas field decreases with increasing effective permeability under constant water saturation, and increases with increasing water saturation . The calculation formula for the drainage radius of gas well at production plateau is deducted from unstable percolation theory. If start-up pressure is taken into consideration and gas well production is identical, the drainage radius of gas well at production plateau increases with effective permeability. If effective permeability is identical, the drainage radius of gas wells at production plateau decreases with increasing gas well production. The minimum well spacing at a certain proration condition can be calculated by the drainage radius of gas well at production plateau. The production plateau of gas well will not be shortened by well interference only when the real well spacing is larger than minimum well spacing.