| Authors |
Kaya, Tevfik; Ulgun, Fahri; Bitlis, Harun; Daskin, Celal; Korkmaz, Umut; Satkan, Comert; Ersoy, Altan; Hosbas, Murat; Oglu, Ismail; Simsek, Ferhat |
| Abstract |
The oil and gas industry’s currently used drilling technology has been optimized over the past century for soft sedimentary rocks where petroleum deposits are found. Geothermal wells have also been drilled for over one century for geothermal utilization in power production and direct use application. Formation and reservoir conditions that characterize geothermal systems (typically higher enthalpy) require the adoption of drilling practices that differ from those utilized in conventional oil, gas, and geothermal well drilling operations. Temperature, Geology, and Geochemistry are the principal areas of difference which are all experienced by TPIC as the oil & gas expert company. Geothermal exploration in Turkey started in the early 1960s. In Turkey, the first geothermal well, which has a depth of 540 meters and a temperature of 198 °C, was drilled on high enthalpy fields for potential power production in 1968. Turkey issued a geothermal energy resources law finally in June/2007, and the law was enacted a year later in June/2008. Besides the current geothermal law, new amendments on the renewable energy law have already helped the geothermal projects development with the 10.5 cent/kwh buying warranty. Based on these recent developments in geothermal industry in Turkey, it is clear that geothermal energy will contribute significantly to Turkey’s future energy supply. Turkish Petroleum International Company (TPIC) was established in 1988 as a subsidiary of Turkish Petroleum Corporation (TPAO) to operate in all branches of oil industry comprising mainly exploration, drilling, field development, production, transportation, refining, crude oil and oil products trading and distribution. Besides the oil well drilling services, TPIC has conducted geothermal drilling activities and is very active in geothermal services (workover, cementing, well testing, wireline services, directional drilling etc.). In Turkey, almost 65,000 meters well drilling has been completed successfully by the end of April 2011. In order to develop geothermal projects, TPIC informs the investors providing new applications and methods by his own specialized staff and service providers. TPIC successfully applies project based solutions with horizontal drilling applications, Azimuth and inclination measurement for old and new wells (Gyro Survey), heat and pressure tests, deep casing mud services, well treatment / workover operations and drilling services. In this paper, in addition to the geothermal drilling experiences which are already gained by TPIC with oil experiences, difficulties and solutions typical to geothermal drilling conditions, and the drilling practices that have been developed to optimize will be shared. Cost of the geothermal well drillings including all related services will be detailed and compared with the oil wells in Turkey. |