| Abstract |
Las Tres Vírgenes geothermal field is located on the peninsula of Baja California Sur, Mexico, 32 km to the NW of the city of Santa Rosalía, within the Las Tres Vírgenes volcanic complex, at an elevation of 720 meters above sea level. The site is located in the granodiorite (intrusive body that constitutes the regional base) and the reservoir is in the subcooled liquid region. The exploration of the field began in October 1986 with the drilling of the LV-2. Power generation began in the year of 2001. At present the installed capacity is 10 MW with two back-pressure of 5 MW generation units each. The produced fluid is a mixture water-steam with quality around 30 %. Produced brine has a high content of minerals, especially calcium and silica. During the production, in some wells flashing (phase change) occurs inside the well and others into the fractures. This phenomena, coupled with the high content of salts, causes the formation of scaling, mainly calcium carbonate (calcite CaCO3) whose solubility decreases with the increase of the temperature of the solution. Consequently, the production of wells is drastically reduced in short periods of time, as well as the generation of electric power. A system of scaling inhibitors has been implemented in some wells in order to reduce this phenomenon and sustain the electrical generation. Also, cleaning of wells and formation with acid treatment using flexible tubing, is routinely used with successful results. Monitoring of the evolution of the mechanical condition of each well and the physicochemical characteristics of the produced fluids are carried out continuously, in order to schedule workover, and ensure the generation of electrical energy. In this paper is discussed the behavior of the production characteristics of the wells of the geothermal field Las Tres Vírgenes, BCS, México, during the last 12 years of commercial exploitation. |