Changes

During Aptian time, a new transgression flooded the erosional surface carbonate deposition which prevailed. Two sequences beginning with a transgression and ending with a shallowing upward character deposited. These two sequences, one in the Cenomanian, and the other in the Coniacian to Early Maestrichtian, have source rock potential.

During Aptian time, a new transgression flooded the erosional surface carbonate deposition which prevailed. Two sequences beginning with a transgression and ending with a shallowing upward character deposited. These two sequences, one in the Cenomanian, and the other in the Coniacian to Early Maestrichtian, have source rock potential.

The first sequence is divided into four facies types and numbered D1 through D4. All levels contain rich organic matter except D1. Main kerogen type is mainly Type II, but Type III is also present. Maturation varies from mature to a little overmature. The southern part of the region is mature, but northern areas are pre-overmature. This unit has TOC values 0.09–2.28.<ref name=Soylu_1991>Soylu, C., 1991, Oil source rocks in the Adiyaman area, southeast Turkey: Journal of Southeast Asian Earth Science, v. 5, no. 1-4, p. 429–434.</ref> <ref name=Sengunduzandsoylu_1990>

The first sequence is divided into four facies types and numbered D1 through D4. All levels contain rich organic matter except D1. Main kerogen type is mainly Type II, but Type III is also present. [[Maturation]] varies from mature to a little overmature. The southern part of the region is mature, but northern areas are pre-overmature. This unit has TOC values 0.09–2.28.<ref name=Soylu_1991>Soylu, C., 1991, Oil source rocks in the Adiyaman area, southeast Turkey: Journal of Southeast Asian Earth Science, v. 5, no. 1-4, p. 429–434.</ref> <ref name=Sengunduzandsoylu_1990>

Şengündüz, N. and C. Soylu, 1990, (Turkish with English abstract) Sedimentology and organic chemistry of sphaeroidal-rich horizon of the Derdere Formation, in Proceeding of 8th petroleum congress of Turkey, Ankara: Geology, p. 50–61.</ref> <ref name=Coruhetal_1997>Çoruh, T., Yakar, H., and Ediger, V. Ş., 1997, Güneydoǧu Anadolu Bölgesi Otokton İstifinin Biyostratigrafisi. Türkiye Petrolleri A. O. Araştirma Merkezi Grubu Başkanliǧi Eǧitim Yayinlari 30, 401 p.</ref> Distribution of rich TOC values may reflect paleotopographic irregularities. Maturation is tied to thickness of the sediment due to tectonic loading under the thrust.<ref name=Sengunduzandsoylu_1990 /> It has Type II kerogen and Tmax values are >435°C especially in the middle of the region (between Adiyaman and Şanliurfa trending NE-SW direction). According to Şengündüz and Soylu,<ref name=Sengunduzandsoylu_1990 /> oil generation started in Early Miocene. Oil has migrated toward the Pre-Miocene structures.

Şengündüz, N. and C. Soylu, 1990, (Turkish with English abstract) Sedimentology and organic chemistry of sphaeroidal-rich horizon of the Derdere Formation, in Proceeding of 8th petroleum congress of Turkey, Ankara: Geology, p. 50–61.</ref> <ref name=Coruhetal_1997>Çoruh, T., Yakar, H., and Ediger, V. Ş., 1997, Güneydoǧu Anadolu Bölgesi Otokton İstifinin Biyostratigrafisi. Türkiye Petrolleri A. O. Araştirma Merkezi Grubu Başkanliǧi Eǧitim Yayinlari 30, 401 p.</ref> Distribution of rich TOC values may reflect paleotopographic irregularities. Maturation is tied to thickness of the sediment due to tectonic loading under the thrust.<ref name=Sengunduzandsoylu_1990 /> It has Type II kerogen and Tmax values are >435°C especially in the middle of the region (between Adiyaman and Şanliurfa trending NE-SW direction). According to Şengündüz and Soylu,<ref name=Sengunduzandsoylu_1990 /> oil generation started in Early Miocene. Oil has migrated toward the Pre-Miocene structures.

Oil production comes from one field since the 1960s, and there are a number of gas shows in the wells drilled in the basin. Oil and gas shows are present in some wells in the İskenderun Basin. Some gas shows are also present in Adana Basin from shallow depths.

Oil production comes from one field since the 1960s, and there are a number of gas shows in the wells drilled in the basin. Oil and gas shows are present in some wells in the İskenderun Basin. Some gas shows are also present in Adana Basin from shallow depths.

There have not been many organic geochemical studies in the Adana Basin. Yalçin<ref name=Yalcin_1987>Yalçin, M.N., 1987, Adana Havzasi petrol ve doǧal gazin kökeni (Origin of hydrocarbons in the Adana Basin, south Turkey). Proceedings of 7th Petroleum Congress of Turkey, Ankara, 427-441. Turkish with english abstract).</ref> analyzed some samples from the Adana Basin sediments and some samples from the pre-Miocene sediments. Analyses indicate that Miocene sediments are poor in organic matter. Maturation values from vitrinite reflection are low. All are below 0.6%, indicating immature organic matter. The 0.6% value is reached at about 4000 m (13,123 ft) depth, meaning that only sediments buried under 4000 m (13,123 ft) have potential for generating oil. Oil analysis indicate that Bulgurdaǧ oil is derived from an organic matter whose vitrinite reflectance is 1.03%. Since Bulgurdaǧ field is producing shallower than 2000 m (6561 ft), the oil cannot be derived from Adana Basin sediments, or at least not the sediments surrounding the field.<ref name=Yalcin_1987 /> Samples (shales) from one of the wells yield 1.24–2.47% TOC. They contain a mixture of Type II and Type III kerogen. Therefore hydrocarbon generating potential of Paleozoic shales are greater than that of Miocene. It may be possible for the Paleozoic shales to be the source for the Bulgurdaǧ oil, however uncertainty exists.

There have not been many organic geochemical studies in the Adana Basin. Yalçin<ref name=Yalcin_1987>Yalçin, M.N., 1987, Adana Havzasi petrol ve doǧal gazin kökeni (Origin of hydrocarbons in the Adana Basin, south Turkey). Proceedings of 7th Petroleum Congress of Turkey, Ankara, 427-441. Turkish with english abstract).</ref> analyzed some samples from the Adana Basin sediments and some samples from the pre-Miocene sediments. Analyses indicate that Miocene sediments are poor in organic matter. [[Maturation]] values from vitrinite reflection are low. All are below 0.6%, indicating immature organic matter. The 0.6% value is reached at about 4000 m (13,123 ft) depth, meaning that only sediments buried under 4000 m (13,123 ft) have potential for generating oil. Oil analysis indicate that Bulgurdaǧ oil is derived from an organic matter whose vitrinite reflectance is 1.03%. Since Bulgurdaǧ field is producing shallower than 2000 m (6561 ft), the oil cannot be derived from Adana Basin sediments, or at least not the sediments surrounding the field.<ref name=Yalcin_1987 /> Samples (shales) from one of the wells yield 1.24–2.47% TOC. They contain a mixture of Type II and Type III kerogen. Therefore hydrocarbon generating potential of Paleozoic shales are greater than that of Miocene. It may be possible for the Paleozoic shales to be the source for the Bulgurdaǧ oil, however uncertainty exists.

===Reservoir Rocks===

===Reservoir Rocks===