Table 2 Summary of zonation units from the biostratigraphic and sedimentological study within the Lower Bahariya member.

A

60–70 ft.

Carbonate-dominated cycle that marks the end of the Lower Bahariya member deposition at Shahd and Shahd SE structures. It developed under a shallow marine open system setting

B

10–40 ft.

Glauconitic sandstone facies representing a shallow shelf environment. This cycle is absent in the central crestal area due to erosion during the deposition of Cycle D

C

25–50 ft.

Developed at well Shahd SE-1 in the south eastern part of Shahd SE field, this cycle is characterized by shoreface to offshore facies

D

30–70 ft.

Sandstone-dominated cycle representing the peak development of the barrier system. It extends across much of the central area, with the bar crest flanked by marine facies

E

40–100 ft.

Dominated by sandy barrier bar facies, this cycle forms two main clusters around Shahd SE-5 and Shahd SE-2 wells (bar crest facies). These are laterally surrounded by bar margin facies that grade southeastward into lower shoreface to offshore deposits

F

5–20 ft.

Comprises two localized depositional lobes identified at Shahd-2ST, Shahd-3, Shahd SE-5, and Shahd SE-8. These bodies truncate the crestal facies of the main barrier bar complex (BBC)

G

5–15 ft.

A locally identified sandstone/shale cycle with lower shoreface to offshore facies. It is only observed incised into the BBC at Shahd-2ST and not recognized in other wells

BBC

30–70 ft.

NW-SE trending shallow marine barrier bar system