| Abstract |
There are more than 8000 deep hydrocarbon wells in Hungary; however, the majority of them are out of utilization. The Hungarian State owns 3000 wells, none of which is in operation. The State intends to sell them to geothermal project developers for utilization. The geothermal potential is fairly high in the Pannonian Basin and a lot of geothermal project developers tend to save financial resources through the recompletion of abandoned hydrocarbon wells. This case study deals with an investigation process, when the State recommended 18 wells to utilize in Eastern Hungary. Five municipalities were included, and they showed interest in developing geothermal projects. Geothermal Express Ltd. was asked to carry out a professional evaluation of the utilization of the 18 wells. The methodology of the evaluation included • Technical review of the well design and history by analyzing the well file • Regional geological review • Hydrogeological analysis of the well sites as well as the area of the related municipalities • Energy audit in the related five municipalities • Setting up geothermal concept including all technical and also financial issues A complex Team was set up by Geothermal Express Ltd. to implement a professional evaluation. The GeoEx Team focused on five professional directions: geothermal technology, deep drilling, hydrocarbon geology, hydrogeology and energetics. The Team collected the well files, visited the wells and investigated the well sites. The Team also prepared energy audits in the related municipalities and reviewed the expected industrial or agricultural development. In the results of their evaluation the Team distinguished three different cases of the 18 wells. • The well is technologically inappropriate for any kind of utilization • The recompletion of the well is very expensive • The location is far from the optimum site; the well does not serve profitable geothermal purposes None of the wells were appropriate to utilize for profitable geothermal purposes. The Team recommended an optimal geothermal utilization for every municipality, but the abandoned hydrocarbon wells were excluded. The result was rather frustrating. The Team reviewed the methodology of this evaluation in order to define if • the methodology of evaluation is inappropriate, • only the concerned area and these wells were inappropriate or • the concept of geothermal utilization of abandoned hydrocarbon wells is generally inadequate. The complex approach and the professional methodology were appropriate, but a few lessons are to be drawn. • No illusions concerning the well conditions and recompletion costs • A complete well file is essential • At least minor maintenance of the abandoned wells is needed • The site of the well should be saved. As a general conclusion, the Team recommended the continuation of the hydrocarbon well evaluation process, but without illusions and by taking into consideration the experience from former evaluation processes. |