5.1.1. Lithological characterization of well
Data has collected during the activities of drilling from logging of geophysical interpretation on the two test wells (Table 1 and Fig. 2) and the drilling has suspended after 235m (Well No. 2) and 244m (Well No. 4) from the static water level. The lithological results from well logging in layer by layer have shown in Table 1. The correlation between the two log’s interpretations has also shown in Fig. 2(a). The description of litho-log and well design has described on (Fig. 2(a) and Fig. 2 (b)). From Table 1 the Well No. 2 has found 16 layers on 235m depth whereas the Well No. 4 has been found on 10 layers on 244 m depth. The resistivity log value is higher in the clay layers. Again, this log value is also higher on the sand layers but not higher the clay layers. These processes also the same in the self-potential log (sand value < clay value). From the Well No. 2, it has identified that 3rd, 5th, 7th, 9th, and 13th layers are mainly found as clay zone. These layers work as the seal of the sandstone. 1st, 4th, 14th, and 18th are the zone of fine to medium sand layers and 16th, 12th and 4th are the medium to massive sandstone layers. The 10th and 15th are called the layers of fine sand. The (14th-16th) layers are found as the water-bearing zone of the layers (170-235) m of the Well No. 2 and these layers are found as high permeable fine and medium sand. Moreover, the lithology of the Well No. 4 (Table 1) and (Fig. 2(a) and Fig. 2(b)), there is found 10 layers. The 5th, 7th, and 9th are the clay zone which is low permeable and but higher resistivity and SP log values. It has interpreted that 1st and 3rd layers fine with very fine sand, 2nd is found fine to medium sand. In addition, the layers 4th, 6th and 8th are found medium to fine sand. The high layers of fine to medium sand are the 10 layers where the water-bearing zone is located (Fig. 2(a) and Fig. 2(c)). The main aquifer zone has been found from the lithologic layers 10th (Well No. 4) and (14th-16th) (Well No. 2) and the zone of permeable fine to medium sandstone zone. Depth of the aquifer zone of two lithologic correlation layers (Well No. 4) (187m-244m) and (Well No. 2) (170m-135m) (Fig. 3(b) and Fig. 3(c)).