News

MSc presentation by Mesay Fekadu Biru

19 May 2020

Mesay Fekadu Biru from Ethiopia, MSc Fellow in Reservoir Engineering at University of Iceland will give a presentation on his MSc project on Friday 22 May, 2020 at 11:00 at University of Iceland.  Due to the COVID precautions this will be a closed presentation.

The title of the project is:

Well Testing and Power Plant Scenario Analysis for Hverahlid Geothermal Field

Mesay's supervisors:

Benedikt Steingrímsson at ISOR, Halldór Pálsson, and Magnús Þór Jónsson at UI

The external examiner will be Guðni Axelsson, director of GRÓ GTP. 

The presentation will be streamed live.

Abstract

In this thesis, different methods for analyzing well test data to estimate capacity of a geothermal field are evaluated for Hverahlid. The thesis involves analysis of data from step-rate injection tests, temperature and pressure analysis, discharge test analysis and different power plant scenario analysis using Hverahlid geothermal field in the Hengill geothermal system, SW-Iceland as a case study. Power plant scenario analysis were conducted to determine the optimum electric power output and choose the most efficient energy conversion technology.

The computer numerical software called WellTester is used for the analysis of step-rate injection tests and the results are compared with results from other high temperature geothermal fields. Temperature and pressure profiles are analysed for each well to estimate the formation temperature and initial reservoir pressure. Total mass flow rate (kg/s), enthalpy (kJ/kg) and flow characteristics are calculated using the lip pressure method. The Engineering Equation Solver (EES) was used for modelling.

The estimated values of transmissivity (T) ranges from 4.21*10-8 -7.2 *10-7 m3/Pa*s from the injection test, whereas the storativity values (S) ranges from 23*10-8 to 4.26*10-7 m/Pa. The estimated value for the skin factor is negative indicating that the wells are well stimulated and in good connection with the surrounding reservoir.

The evaluation of temperature for wells HE-36, HE-53 and HE-61 suggests that reservoir temperature is in the range of 270-320°C and reservoir pressure in the range of 85-135 bar. The evaluated fluid enthalpy for wells HE-21, HE-36 and HE-53 is in the range of 1352 to 1683 kJ/kg, with the steam flow ranging from 6-29 kg/s with an assumed separation pressure of 17 bar.

Power generation is estimated for each scenario. Scenario 1 is a single flash power plant. The power output of the five wells is 49.0 MW. Scenario 2 is a double flash power plant, which generates about 53.5 MW. Scenario 3 is single flash with bottoming binary plant. The binary working fluid is isopentane. The power generation for scenario 3 is about 57.0 MW.