Investigations on influences of faults and related stress fields on naturally fractured reservoirs in Adıyaman area, eastern Turkey

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Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Bilimleri Enstitüsü, Fen Bilimleri Enstitüsü, Türkiye

Tezin Onay Tarihi: 2019

Tezin Dili: İngilizce

Öğrenci: GÖKTÜRK MEHMET DİLCİ

Danışman: Erdin Bozkurt

Özet:

Northern Margin of the Arabian Plate is a novel area to study the effects of faults on fracture corridors since the region has heavily been subjected to reverse and strike- slip faulting regimes beginning with Eocene and Miocene, respectively. In Adıyaman province especially, verified discovery of a naturally fractured reservoir (NFR), Şambayat oilfield, necessitates more comprehensive explanations concerning to association of the fractured reservoir with the nearby Samsat Fault. Isolated effects of the fractures on reservoir qualities could be adequately measured within non-porous rocks. Therefore, this study has focused on initially non-porous NFR host rock of the Şambayat oilfield, the Campanian argillaceous limestone of Sayındere Formation. In the extent of this study, fractures within the Sayındere Formation were also investigated at outcrops close to Bozova Fault, which has analogous tectonic settings with the Samsat Fault. Main goals of this research are to explore the role of faults and stress fields on the formation of NFR's and to determine best directional drilling trajectories to produce oil from as much fracture porosity as possible. To achieve these goals, I suggested a new methodology comprising combination of surface and subsurface data as well as rock deformation experiments, in-situ stress measurements and slip-tendency analyses. In conclusion, (i) the Sayındere Formation was proven to have the lowest strength for brittle deformation among brittle rocks exposed in the basin. Therefore, it preferentially gets fractured first. (ii) Volumetric dilatational strain that forms on the fault bending domains can be distributed among shear and tension fractures and provides up to %10 fracture porosity as measured at outcrops (iii) Local stress intensification related to fault activity seems necessary and sufficient to fracture intact the Sayındere Formation. Therefore slip tendency of the existing faults must be studied to predict the localization of fault-related NFR's.