束缚水饱和度对水力压裂非达西气井产能的影响

Effect of irreducible water saturation on deliverability of hydraulic fractured gas well taking into account non-Darcy flow

中高渗透气藏水力压裂气井,不仅在裂缝内存在非达西渗流,在储层孔隙内也可能存在非达西渗流。而对于储层内的非达西渗流,束缚水饱和度的影响不能忽略。在考虑储层和裂缝内气体非达西渗流的基础上,研究了储层内只存在束缚水时束缚水饱和度对非达西系数及水力压裂非达西气井产能的影响。结果表明,非达西渗流系数随束缚水饱和度的增加而增加,且渗透率越小,增加的幅度越大。对于中高渗透的气井,气体的非达西效应比较明显,储层渗透率越大,束缚水饱和度的影响越明显,对气井的产量影响也越大。

Non-Darcy flow is one of important characters of gas flow.Non-Darcy flow exists not only in hydraulic fractures but also in porous media in hydraulic fractured gas well in medium and high permeability reservoir.The effects of immobile water saturation on non-Darcy flow in porous media must be taken into account.Taking into account non-Darcy flow in fracture and reservoir,this paper studied the effects of immobile water on non-Darcy flow coefficient and the deliverability of fractured gas well with non-Darcy flow when only immobile water exist.The results show that the non-Darcy flow coefficient increases when the immobile water saturation increases and the added amplitude is more when the permeability is less.The non-Darcy effect is more obvious in the gas well with medium and high permeability,and the effect of irreducible water saturation is more obvious when the permeability in reservoir is higher,and the effects that on the deliverability of gas is more apparent.