Pressure Build-Up in Geothermal Reinjection Wells

Abstract

This paper presents a case study of pressure build-up in some geothermal re-injection wells in Sweden. The geothermal heat plant, in which the re-injection wells are used, has been in operation since the beginning of 1985. Each day since the start of the geothermal plant registration of the injection pressure has been done. The paper describes how a stimulation of the gravel pack outside the well screen can improve the hydraulic performance of the well. The stimulation is done by reversing the flow direction in the well. It is also shown how important it is to have a good well completion in order to receive a positive effect of well stimulation. The paper give example of recordings from two different re-injection wells. The recordings from one of the re-injection wells show that there are serious problems in the well, while the other one shows "normal" hydraulic behavior.