Movable water recognition method research of low permeability gas reservoir

In order to identify whether there is movable water in reservoirs,the comparison between irreducible water saturation and original water saturation should be conducted.While the experimental methods to obtain the irreducible water saturation are various and it is hard to examine and approve the value.After comparing different experimental results of irreducible water saturation from block-A,the values from relative permeability curve method and centrifugal capillary force curve method are similar.By adopting these experimental results,the correlation equation between the permeability and irreducible water saturation has been regressed.Due to pressure sensitivity problem in the reservoir,overburden pressure correction should be conducted in the reservoirs with permeability lower than 1 x 10~(-3) μm~2.By applying the regressed irreducible water saturation calculation formula,combined with the overburden pressure correction permeability,the movable water situation of 12 wells in the block can be accurately determined.