TY JOUR TI HYDROCHEMICAL FEATURES OF GROUNDWATERS OF DEEPLY SET OIL AND GAS COMPLEXES IN THE NORTH-WEST CASPIAN AREA KW subsurface waters KW Northwest Caspian Sea area KW Astrakhan Anticline KW Paleozoic KW Kungarian stage KW water-bearing complexes KW ground hydrogeological deck KW salinity KW inversion hydrochemical zonality KW geological closeness JO Vestnik of Astrakhan State Technical University AU Degtyareva, N.. PY 2015 IS 2015 PB Astrakhan State Technical University