| Abstract |
Las Pailas Geothermal Field is located on the northwest part of Costa Rica and is the second field developed by the Costa Rican Electricity Institute (ICE). Las Pailas is located on the southwest flank of the Rincón de la Vieja volcano, has a liquid-dominated two-phase reservoir, with temperatures of 230-260 ºC. First unit of Pailas has been producing electricity since 2011, nowadays it is producing 35 MW in a binary cycle unit. Drilling for development of the second unit started in 2012 and ended in 2018, it is projected that the 55 MW power plant of single flash, will start operating during the second semester of 2019. This report includes an analysis of data related to reservoir engineering studies, obtained in transient pressure tests carried out in 3 deviated wells. Data were obtained in injectivity tests during completion and include determination of the reservoir parameters using the computer software Well Tester (V2.1.1, Marteinsson, K.) developed by Iceland GeoSurvey (ÃSOR). Estimated well parameters for the analyzed wells show a wide variation indicating different conditions in the reservoir, in detail it was observed that transmissivity varies between 2,8 E-07 and 9,7 E-09 [m3 /(Pa*s)], storativity varies between 1,8 E-07 and 3,3 E-08 [m/Pa] and injectivity indices varies between 14,2 and 1,5 [l/s/bar]. Considering that the geological environment of the study area is quite uniform and that the wells do not show skin effects, it is interpreted that structural conditions represent the most important factor for the behaviour of the wells parameters. Use of the Well Tester software will allow to obtain new information about the parameters of the reservoir, which will later be included in the numerical model of the different geothermal fields that are developed in Costa Rica. |