页岩气藏可采储量计算新方法

摘要

In the several previous calculating methods of the recoverable reserves of the shale gas,the pressure drop method doesn't consider the particularity of the shale gas reservoirs,the method of the production decline curve is only adopted to the wells that the production decline has occurred,the method is also not applicable to the shale gas reservoirs with low porosity and permeability although the controllable reserves are obtained by the static formation pressure and recoverable reserves are acquired as well.The method seeding the production indicative curve was proposed by means of the production data acquiring the controllable reserves of the shale gas reservoir,and furthermore taking advantage of the consideration of the adsorbed-gas material balance equation,the recoverable reserves under the abandonment pressure were calculated.The study achievements show that for every 1 MPa reduction of the abandonment pressure,the recovery is about enhanced by 3.4％.This method can not only be applied to the producing wells which production begins to decline,but also be adopted to the steady production wells that the gas flow has reached pseudo-steady state.The method possesses a certain application value.%前人计算页岩气可采储量诸多方法中,压降法未考虑页岩气藏的特殊性,产量递减曲线方法仅适用于已经发生产量递减的井,利用地层静压来获取控制储量然后进一步得到可采储量的方法也不适用于低孔低渗的页岩气藏.提出了利用生产数据求取控制储量来获取页岩气藏生产指示曲线的方法,再利用考虑吸附气的物质平衡方程计算废弃压力下的可采储量.研究表明废弃压力每降低1MPa,采收率大约会提高3.4％.新方法既可以应用于产量开始递减的生产井,也可以应用于气体流动达到拟稳态期的定产生产井,具有一定的应用价值.