HYDROGEOLOGY OF THE HAWAII SCIENTIFIC DRILLING PROJECT BOREHOLE KP-1 .1. HYDRAULIC CONDITIONS ADJACENT TO THE WELL BORE

Temperature and formation resistivity logs obtained in borehole KP-1 o f the Hawaii Scientific Drilling Project indicate that the adjacent fo rmation is characterized by several zones of distinctly different aver age temperature and water salinity. A series of hydraulic analyses and water sampling programs were conducted to rule out the possibility of local hydraulic effects associated with the presence of the borehole in the generation of these apparent groundwater zones. Hydraulic tests and sampling with the borehole cased to a depth of 710 m and open bel ow that depth indicate that the deep aquifer contains seawater at a te mperature nearly identical to that of the open ocean at the same depth . Various analyses give estimates of aquifer transmissivity of about 1 0(-3) m(2)/s in the vicinity of the borehole, Isolation of this deeper aquifer from the overlying groundwater zones was investigated by perf orating the casing at six locations and then measuring the changes in water level in the bort hole, in the salinity of the fluid column, in the temperature profile of the fluid column, and in the rate of how in the fluid column induced by the perforations. These results positivel y confirm that the zones of distinctly different formation properties indicated on the temperature and resistivity logs are not caused by Bo w in or around casing. Flow and fluid column salinity induced by the p erforations also confirm significant differences between the hydraulic heads and geochemistry of the different groundwater zones inferred fr om the well logs.