The ground layer consists of a reclamation layer with fine sand up to 1.5 m below the surface; from 1.5 to 38 m, it is composed of a marine sedimentary layer with silty clay, containing small amounts of fine gravel and shells in the lower part. The 38–42 m section is a soft rock...
The reservoirs are mainly composed of shale (SH), sandstone (SS), silt (SI), limestone (LS), and marl (MA), with fine- to medium grain size. The rocks in the JDB reservoirs can be described as dirty rocks rich in different types of clays. The clay content of the reservoirs is ...