Mechanism of Forming Low Resistivity in Shale Reservoirs

Figure 17

Anisotropic resistivity and water saturation of sample No. 10 from H6 well. The trend that the rock resistivity at different directions varies along with the water saturation is the same, whereas the variation degree is different. In pace with the decrease of water saturation, the resistivity perpendicular to the lamination may increase at a greater pace than that in other directions, especially for that parallel to the lamination where the increase is limited, which demonstrates that there are not enough conductive substances to create the connected network when the water saturation drops perpendicular to the lamination. As the saturation drops to 70%, the resistivity perpendicular to the lamination increases by five times as compared to that parallel to the lamination. For some samples with 100% water saturation, the resistivity in different directions is all below 10 Ω·m, indicating that this conductive network contains good conductors in all directions.