Тип бассейна: Платформ
Подтип бассейна: Внутриплатформенный (интракратонный)
Класс бассейна: Синеклизный
Возраст бассейна: Древний - Палеозойский
Тип полезных ископаемых:
Геологический возраст начало:
Геологический возраст конец:
Площадь: 117387.28 км²
Reggane basin
Geologic Setting
The Reggane Basin, located in the Sahara Desert portion of central Algeria, is separated from the Timimoun Basin by the Ougarta Ridge. The basin is an asymmetric syncline, bounded on the north by a series of reserve faults and on the south by shallowing outcrops, Figure 1. This basin may contain over 800 m of Silurian section, although well control in the deep northern portion of the basin is limited. The basin also contains the Upper Devonian Frasnian Formation which is reported to reach a maximum thickness of 400 m.
Figure 1. Reggane Basin Silurian Tannezuft Shale, Outline and Thermal Maturity
We have mapped prospective areas of 34,750 mi2 for the Silurian Tannezuft Shale and 4,680 mi2 for the Upper Devonian Frasnian Shale in the eastern portions of the Reggane Basin, Figures 2 and 3.
Figure 2. Reggane Basin Upper Devonian Frasnian Shale, Outline and Thermal Maturity
Reservoir Properties (Prospective Areas)
Silurian Tannezuft Formation. The depth of the prospective area for the Silurian Tannezuft Shale ranges from 16,000 ft on the north to 5,000 ft on the south, averaging 10,000 ft. The wet gas/condensate prospective area is slightly shallower than this average, while the dry gas prospective area is deeper. The gross thickness of the organic-rich section in the prospective area ranges from about 130 to 230 ft, with a high net to gross ratio. TOC is favorable, ranging from 3% to 5%. The thermal maturity places the prospective area of the Tannezuft Shale into the wet gas and condensate window (Ro of 1.0 to 1.3%) in the shallower south and into the dry gas window (Ro > 1.3%) in the deeper north, as illustrated by the north to south cross-section on Figure 3.
Upper Devonian Frasnian Formation. The depth of the shallower Upper Devonian Frasnian Shale in the Reggane Basin ranges from 5,500 ft to 16,000 ft, averaging about 10,500 ft in the prospective area, with the wet gas/condensate area shallower and the dry gas area somewhat deeper. The thickness of the organic-rich portion of the shale ranges from 260 to 330 ft, with a high net to gross ratio. The TOC of the shale ranges from 2% to 4%.10 The thermal maturity places the prospective area of the Frasnian Shale in the wet/condensate and dry gas windows (Ro > 1%). The Frasnian Shale is judged to have good porosity of about 6% with low water saturation, based on petrophysical evaluations of the Frasnian Shale in the adjoining Ahnet Basin.
Figure 3. Schematic Cross Section of the Reggane Basin, Algeria
Resource Assessment
Silurian Tannezuft Shale. Within its 24,600-mi2 dry gas prospective area, the Tannezuft Shale in the Reggane Basin has a resource concentration of 94 Bcf/mi2. Within its 10,150-mi2 wet gas and condensate prospective area, the shale has resource concentrations of 38 Bcf/mi2 of wet gas and 4 million barrels/mi2 of oil/condensate.
The risked resource in-place for the overall 34,750-mi2 Silurian Tannezuft Shale prospective area in the Reggane Basin is 542 Tcf of wet/dry shale gas plus 8 billion barrels of shale oil/condensate. Of this, 105 Tcf of wet/dry shale gas plus 0.3 billion barrels of shale oil/condensate are estimated as the risked, technically recoverable resource.
Devonian Frasnian Shale. Within its 2,110-mi2 dry gas prospective area, the Frasnian Shale in the Reggane Basin has a resource concentration of 97 Bcf/mi2. Within its 2,570-mi2 wet gas and condensate prospective area, the shale has resource concentrations of 104 Bcf/mi2 of wet gas and 11 million barrels/mi2 of oil and condensate.
The risked resource in-place for the overall 4,680-mi2 Devonian Frasnian Shale prospective area in the Reggane Basin is estimated at 94 Tcf of wet/dry shale gas plus 6 billion barrels of shale oil/condensate. Of this, 16 Tcf of wet/dry shale gas plus 0.2 billion barrels of shale oil/condensate are estimated as the risked, technically recoverable resource.
Data source: Technically Recoverable Shale Oil and Shale Gas Resources: Algeria.
U.S. Energy Information Administration (EIA). 2015
Следующий Бассейн: Rovuma