Temperature and Pressure Model for the Námafjall Geothermal System in NE-Iceland and Development of a 3-D Numerical Model in 2011

Abstract

The Námafjall high-temperature geothermal area has a long history of geothermal research going back to the initial geothermal exploration study of the 1960´s. For decades the geothermal production in the area remained on a small scale but in the first years of the 21st century Landsvirkjun (National Power Company of Iceland) set up extensive plans for geothermal electricity production in the Námafjall area and therefore a 3-D geothermal reservoir model for the Námafjall area was developed in 2005 to estimate the response of the system to exploitation. Wells B-13, B-14 and B-15 drilled in 2006 and 2008, after the development of the model, show that the pressure draw down is restricted to the small area of utilization. The conceptual model of the area was revised between 2009-2011 based on new data from wells B-13, B-14 and B-15, and the numerical model rebuilt. Formation temperature and initial pressure of the wells reveal that previous production has had limited effect on reservoir temperatures and pressures. Results of the numerical simulation and volumetric method are consistent for the lower limit of the estimated production capacity, but there are more uncertainties in the upper limit.