WRRCTR No. 45 Density Logs from Underground Gravity Surveys in Hawaii

Abstract

The gravity method has been applied in three wells in Hawaii to estimate density and porosity logs. The wells are the Schofield shaft on the island of Oahu, the Kihei #3 shaft on the island of Maui and the Pahala shaft on the island of Hawaii. The method determines the "averaged" density and porosity values for Hawaiian rocks. On Oahu, the density at depth is 2.4 gm/cc and the corresponding porosity is 18 percent. For Maui, the density averages about 2.4 gm/cc and porosity at 17 percent. The Hawaii shaft shows a lower density of 2.0 gm/cc with a correspondingly higher porosity of 27 percent. All these values are based on a grain density of 2.9 gm/cc.