It is generally believed that for commercial geothermal wells, flow rates are sufficiently high so that the formation around the well comes to thermal equilibrium in a matter of days or weeks. After thermal equilibrium is established, very little temperature drop takes place in such wells as hot water (single phase) rises from the bottom to the top of the well. A two phase geothermal fluid is thought to undergo temperature decline in a commercial well bore as flowing pressure declines according to the water-steam vapor pressure curve. The common belief is that for commercial wells, one can ignore heat conduction from the welll to the formation for all practical purposes. Hence, one publication presented a geothermal well simulation approach without consideration of heat conduction. Gould, however, had pointed out the in precence of heat conduction in the performance of geothermal wells. Experience shows that for commercial wells needed for electrical power generation where the flow rates involved are tens of thousands of pounds per hour, it is often acceptable to ignore heat conduction. Whether such simplification is reasonable for wells for non-electrical geothermal projects has not been studied. Such wells are produced at a much smaller rate than wells for electrical power generation. It is quite likely that heat conduction and gravity head will have much more influence than the frictional pressure drop and drop acceleration effect on such low yield wells. The authors simulated behavior of flow in such a well using a numerical well bore simulator, an older version of which had been described before. The well studied was Bostic 1-A at Mountain Home, Idaho.This well had study of a direct geothermal use program. The well is 9,678 feet deep and 8 3/4 inches in diameter with a maxumum temperature of 372 F at 8,898 ft. A drill stem test was inconclusive and the well had not flowed before. It was decided to forecast the condition of the well effluent for various assumed flow rates so that, if the well could be made to flow, optimum production condition could be specified and the adequacey of the well for proposed project assessed.

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