水相滞留对低渗气层渗透率的损害分析

DAMAGE OF RESIDUAL WATER ON PERMEA-BILITY OF TIGHT GAS RESERVOIR

水相滞留是低渗气层最主要的损害因素之一。文章以克拉区块低渗气层为例,分析了自由水、束缚水、吸附水等不同方式滞留的水对低渗气层的渗透率损害。结果表明:束缚水对克拉区块低渗气层渗透率损害最严重,渗透率越低,其损害越严重;束缚水和吸附水对气层渗透率的损害难以恢复。降低低渗气层水相滞留损害的最好方法是减少水相的侵入,或使用经济匹配的非水基流体,如甲醇、CO2、N2等。一但水相侵入后,对低渗气层而言,再解除水相损害问题还没有非常有效的方法。

Residual water is one of the most damages to the permeability of tight gas reservoirs. Taking the tight gas reservoir in Kela block as example, the damage of different residual water, such as free water,bound water,adsorbed water etc. ,on the permeability of tight gas reservoirs is investigated. The results show the damage of bound water on the permeability of tight gas reservoirs in Kela block is the most severe. The lower the permeability is, the severer the damage is. It is difficult for the damage of bound water and adsorbed water on the permeability of tight gas reservoirs to be eliminated. The best way to decrease the damage of residual water on the permeability of tight gas reservoirs is reducing water invasion,or using economic fitting non-water fluid such as methanol,CO2, N2 etc. So far, there are few effective methods to eliminate the damage of residual water on tight gas reservoirs if water invades them.