Heat flow near Orlando,Florida and Uvalde,Texas determined from well cuttings

Heat flow has been determined in a borehole near Orlando. Florida and another near Uvalde, Texas. Thermal conductivities in both boreholes were obtained by divided-bar measurements on rock discs and by needle-probe measurements on rock chips. For the needle-probe method, the rock chips were pulverized into powder, saturated with water, and the conductivity of the solid rock was obtained from the conductivity of the mixture by an empirical relationship. Divided-bar measurements for the Florida borehole indicate a heat flow of 0.92 = .03 H.F.U., while needle-probe measurements on rock chips show a heat flow of 1.24 = .06 H.F.U. The discrepancy is attributed to anisotropy of the sedimentary rocks penetrated by the borehole. Heat flow obtained from these two different methods of determining conductivity show good agreement in the Texas borehole. Divided-bar measurements indicate a heat flow of 1.08 = .03 H.F.U. while the chip technique gives a value of 1.13 = .03 H.F.U.