Класс Месторождения: Среднее
Тип Месторождения: Нефтегазовое
Местоположение:
Местность:
Стадия разработки: В консервации
Год открытия: 1965
Источник информации:
Метод открытия:
Площадь: 8.23 км²
Dodan gas field
The Dodan gas field was discovered in 1965 by TPAO (Turkish Petroleum Company). The field is located in South-East Turkey, near to Dilektepe village which is locating at north-east of Batman province at a distance of 100 km to Batman province as shown in Fig. 1.
Fig. 1. The locations of Dodan Gas field and its wells.
The structure of the Dodan field is an NW-SE trending anticline with a length of 8 km and a wide of 1.5 km. There are three main gas producing formations in the field: Upper Sinan Formation, Garzan Formation, and formations member of Mardin Group: Karababa C, Karababa B, and Derdere Formation in Fig. 2. All of these formations are consist of Cretaceous carbonate reservoir rocks, which are shown in Fig. 3.
Fig. 2. The location and geological map of Dodan Gas field in Southeastern of Turkey
The average depth of Upper Sinan formation, Garzan formation, and Mardin Groups are approximately 850 m, 1800 m, and 2050 m, respectively. CO2 constitutes almost 90% of the producing gas.
Fig. 3. The generalized stratigraphy of Dodan Gas field
Reservoir temperature ranges from 430C to 780C and the temperature profile of a well is given in Fig. 4.
Fig. 4. The temperature measured (circles) and calculated (solid line) during logging
operations
Water saturation changes between 23% and 43% and permeability values are in the range of 10 md to 20 md which is a typical value for fractured carbonate reservoirs. The average composition of the produced gas is given in Table 1.
Table 1. Average gas composition of Dodan Gas field
There is also a reasonable amount of sulfur content in the field. The field has been producing since 1986 for the Enhanced Oil Recovery project of the Batı Raman heavy oil field which is at a distance of 80 km from the Dodan field. It was reported by (TPAO, 2014) that 2.9 MMscf gas produced from the Dodan field in 2014 and the total gas production from the field was 274.7 MMscf at the end of 2014. As 2.5 MMscf gas production per year is assumed, the total gas production is around 287.2 MMMscf. reported the recoverable gas in place as 388 MMMscf.
This means that 70% percent of the recoverable gas of the Dodan field has already produced. Thus, this field can be considered as a depleted gas reservoir very shortly. It is a common practice that water influx occurs in most of the gas wells due to the depletion of reservoir pressure. In most of the wells of Dodan Field, gas production stopped because strong water drive systems exist in all production zones. The locations of 21 wells in the Dodan field were identified in this study by using Google Earth as seen in Fig. 1. These wells are concentrated within a 7.5 km2 area. Thus, the water cut of these wells is considered to increase substantially. In such cases, production wells are usually abandoned due to high water production and a decline in gas production rate. The abandoned gas wells as in the Dodan gas field can be re-profited by producing for geothermal energy extraction. The distances between the grouped wells change between 250 m and 500 m. There are also some deviated wells drilled from the same well-pad. Permeability of the reservoir rock (as listed in Table 2) in the Dodan gas field is also good enough for using this area for geothermal production. The reservoir temperature (ranging from 430C to 780C) in the Dodan gas field is below 1500C which is suitable for direct-use applications (i.e. heat buildings, grow plants in greenhouses, etc.) rather than power generation. This is because, in the world, most direct-use applications use geothermal fluids in the low-to-moderate temperature range between 500C and 1500C.
Table 2. Reservoir properties of producing formations in Dodan field (revised from
Data source:Potential of geothermal energy production from depleted gas fields: A case study of Dodan Field, Turkey. Hakki Aydin, Sukru Merey. Renewable Energy 164 (2021)
Следующее Месторождение: Al Barde 2