| Title | Geology of the Denizli Saraykoy (Gerali) Geothermal Field, Western Anatolia, Turkey |
|---|---|
| Authors | İsmail Hakkı Karamanderesi and Kadri ÷lÁenoğlu |
| Year | 2005 |
| Conference | World Geothermal Congress |
| Keywords | Geothermal geology, geophysics, electricity, drilling, alteration, production, scaling. |
| Abstract | The Denizli-Saraykˆy (Gerali) geothermal field is located in the eastern part of the B¸y¸k Menderes Graben, and is characterized by normal fault structures (Figure 1). The stratigraphic sequence of the Denizli-Saraykˆy (Gerali) geothermal field consists of metamorphic rocks of the Menderes Massif and sedimentary rocks deposited during the rifting period of the Menderes Massif in the Miocene and Pliocene. This is the first geothermal field studied and drilled by private enterprise for energy production in Turkey. In the field following geological studies, 24 geophysical resistivity measurements had been taken and the location of well number MDO-1 was given (Figure 2., 3). The well has been drilled down to 2120 meters in depth and than completed at this depth. Later the well was deepened down to 2401 due to the request of the owner (Figure 4). During drilling at every 2 meters cuttings were taken and properly labelled. The well was cased as follows: 0.00 - 100 m 20" casing, 0.00 - 488.50 m 13 3/8" casing, buttress thread, 0.00 - 1452 m 9 5/8" casing, buttress thread, 1452 - 2119 m. Slotted casing. Geological stratification of Gerali geothermal field from the bottom to top is as follows; at the bottom biotite-chlorite-calc-quartzschist. Above them marble and metamorphic basement of Menderes massif take place. Then Miocene and Pliocene sediments of 1950 meters thickness are found. Geological section is divided into two different hydrothermal alteration zones (Figure 4). At the well log too many fault zones have been seen. Faults cutting sedimentary limestone and marble are the main production zones. During the drilling, after 600 meters alteration has begun. Loss of mud circulation started after 900 meters. At the 1607-1619 meters, total of 300 m3 loss of mud circulation has occurred. After this level, the drilling has been continued; partial loss and alteration have been inspected continuously. After the well completion tests, 1250C bottom hole temperature was measured by Amerada temp gauge (Figure 5). Production of the well was determined at 50 lt/sec. At productions test deposition of CaCO3 scaling was seen from the surface down to 120 meters in depth. |