Kial Fm

R.A. Kamal named the Kial Formation after Kial Village adjacent to the Midyan field (Figure 1a) where the section is well-developed. The name was first published by Hughes and Filatoff (1995). The Kial Formation is defined in Saudi Aramco exploration well Midyan S-1 (MDYN-1) between 6,561–6,876 ft (315 ft, 96 m thick), onshore coastal Saudi Arabian Red Sea. Column: Red Sea Saudi Arabia. The Kial Formation consists in the subsurface of five formal members (from bottom to top): (1) Rayaman; (2) Yuba; (3) Nakhlah; (4) Sidr; and (5) Sabya. Uppermost formation in Maqna Gr

Synonym:

Claystone and anhydrite. The Kial Formation can be considered as representing a continuation of the depositional environments of the Jabal Kibrit Fm as it consists primarily of interbedded siliciclastic and evaporite members with localized carbonate equivalents. Two hypersaline events alternate with normal salinity events. At a locality south the road to Maqna, resistant anhydrite forms the tops of at least four well-defined benches, whereas the underlying soft, friable calcareous mudstone eds are recessive.

The Sabya Member of locally developed of bioclastic carbonates, interbedded with conglomeratic sands and conglomerates, and thin calcareous shales, that completely or partly replaces the Sidr siliciclastics within the region. It was deposited under normal salinity conditions within areas where siliciclastic sedimentation was minimal. The Sabya Member is named after Sabiyah Village, north of the Jizan-1 well locality, where this Member is well developed, and is defined in Saudi Aramco exploration well Jizan North-1 (JZNR-1) between 8,640–8,800 ft (160 ft, 48.8 m thick), onshore coastal Saudi Arabian Red Sea. The Sabya Member has been seen only in the subsurface with deposition limited to the Yanbu and Jizan basins The depositional environment of the Sabya Member is considered to have been shallow-marine, based on the absence of planktonic foraminifera..

The Sidr Member of siliciclastics and minor anhydrite carbonates, sandstone and calcareous mudstones. It represents a further return to normal salinity conditions prior to the establishment of a longer period of hypersalinity that produced the overlying Mansiyah evaporites. It is named after the Saudi Aramco exploration well Sidr-1, drilled onshore in the Midyan area, where it is well developed; and the term was first used by Saudi Aramco (R.S. Johnson, D. Rodgers and G.R. Savage, 1995, Saudi Aramco Report). The Sidr Member is defined in Saudi Aramco exploration well Midyan S-1 (MDYN-1) between 6,561–6,645 ft (84 ft, 25.6 m), onshore coastal Saudi Arabian Red Sea. depositional environment of the Sidr Member is moderately deep marine, based on the presence of a predominantly plantonic foraminiferal assemblage.

The Nakhlah Member represents a post-Yuba return to hypersalinity and the precipitation of regionally extensive deposits of anhydrite with minor halite. The Nakhlah Member is named after the Saudi Aramco exploration well Nakhlah-1 (NKLH-1), drilled onshore in the Midyan area, where the Member is well developed. The term was first used by Saudi Aramco (R.S. Johnson, D. Rodgers and G.R. Savage, 1995, Saudi Aramco Report). It is defined in Saudi Aramco exploration well Midyan S-1 (MDYN-1) between 6,645–6,779 ft (134 ft, 40.8 m thick), onshore coastal Saudi Arabian Red Sea. The Nakhlah Member to be generally widely developed along the margins of the Red Sea with average thicknesses varying from 20 to 50 m. It is not present in the subsurface of either the Jiddah or Ghawwas basins.. The depositional environment is moderately deep marine and hypersaline, based on its stratigraphic position above and below moderately deep-marine, planktonic foraminiferal-bearing sediments of the Yanbu and Sidr Members, respectively.

The Yuba Member consists of calcareous mudstones with minor carbonate and sandstone, that were deposited during a return to normal salinity conditions following the Rayaman hypersaline event. It is named after the Auxerap/Tenneco exploration well, Yuba-1, drilled offshore in the Midyan area, where the Member is well developed. The term was first used by Saudi Aramco (R.S. Johnson, D. Rodgers and G.R. Savage, 1995, Saudi Aramco Report). The Yuba Member is widely distributed throughout the Red Sea as a thin veneer (generally 6 to 21 m; maximum of 139 m) in the subsurface. The depositional environment is moderately deep marine, based on the presence of planktonic foraminifera.

The Rayaman Member is the basal evaporitic (anhydrite with local halite) member of the Kial Fm and is well-developed across the region and within the Red Sea generally. It is named after the Tenneco exploration well Rayaman-1, drilled offshore in the Midyan area, where it is well developed. The term was first used by Saudi Aramco (R.S. Johnson, D. Rodgers and G.R. Savage, 1995, Saudi Aramco Report). It is defined in Saudi Aramco exploration well Midyan S-1 (MDYN-1) between 6,802–6876 ft (74 ft, 22.6 m thick), onshore coastal Saudi Arabian Red Sea, and is distributed in the subsurface of the northern Red Sea with ten wells, drilling thicknesses ranging from 37 ft (Nakhlah-1) to 214 ft (Midyan-2). The Rayaman Member represents a hypersaline phase that succeeded the normal salinity conditions of the upper Jabal Kibrit Fm.

"The Kial Formation is early middle Miocene (Langhian) in age based on planktonic foraminifera and calcareous nannofossils in calcareous mudstones in the subsurface. Orbulina suturalis, Praeorbulina glomerosa circularis and P. glomerosa glomerosa (Hughes and Filatoff, 1995) belong to Planktonic Foraminifera Zone N9, and the calcareous nannofossil Sphenolithus heteromorphus (but without Helicosphaera ampliaperta) is indicative of Zone NN5. These marker species are also well known in the Belayim Formation, where further evidence is provided by the presence of Borelis melo curdica." (Hughes and Johnson, 2005)

The depositional environment of the Kial Formation is moderately deep marine, with shallow carbonate platform facies locally developed. The interbedded relationship of evaporites with planktonic foraminifera-bearing mudstones in the subsurface suggests deposition in a deep, episodically hypersaline, submarine environment. (Hughes and Johnson, 2005)