The Miqrat Formation is a tight gas reservoir in the interior Oman Salt Basin, situated in the Huqf area of central Oman. The formation was initially thought to be deposits of aeolian dunes, wet and dry sabkha, and playa lakes. However, recent reevaluation of the formation reveals new geological insights. This research utilizes outcrop-based facies analysis to interpret the paleodepositional environment. Based on the lithology, sedimentary structures, textures, and trace fossils, the formation can be classified into three informal members. The lower member is composed of reddish-brown mudstones and sandy siltstones with coarsening upward cycles. The fine-grained sandstone exhibits wavy ripples and low-angle cross-laminations, and large-scale desiccation cracks. The upper member is poorly exposed, showing lithological similarity to the lower member. The middle member is Pinkish–brown, fine to medium-grained planar and trough cross-bedded sandstones and wavy ripples. At the top of this member, the planar cross bedded sandstone exhibits Thalassinoides trace fossils. The sedimentary facies and trace fossils suggest the formation was deposited in a marginal marine environment, with tidally influenced (supratidal to intertidal) conditions in the lower and upper members and a subtidal setting in the middle member.

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Sedimentary Facies Analysis of Tight Gas Reservoir: An Example from the Miqrat Formation, Central Oman

  • Sohag Ali,
  • Numair Ahmed Siddiqui,
  • A. K. M. Eahsanul Haque,
  • Mohamed A. K. EL-Ghali,
  • Md Yeasin Arafath,
  • Nisar Ahmed,
  • Alidu Rashid

摘要

The Miqrat Formation is a tight gas reservoir in the interior Oman Salt Basin, situated in the Huqf area of central Oman. The formation was initially thought to be deposits of aeolian dunes, wet and dry sabkha, and playa lakes. However, recent reevaluation of the formation reveals new geological insights. This research utilizes outcrop-based facies analysis to interpret the paleodepositional environment. Based on the lithology, sedimentary structures, textures, and trace fossils, the formation can be classified into three informal members. The lower member is composed of reddish-brown mudstones and sandy siltstones with coarsening upward cycles. The fine-grained sandstone exhibits wavy ripples and low-angle cross-laminations, and large-scale desiccation cracks. The upper member is poorly exposed, showing lithological similarity to the lower member. The middle member is Pinkish–brown, fine to medium-grained planar and trough cross-bedded sandstones and wavy ripples. At the top of this member, the planar cross bedded sandstone exhibits Thalassinoides trace fossils. The sedimentary facies and trace fossils suggest the formation was deposited in a marginal marine environment, with tidally influenced (supratidal to intertidal) conditions in the lower and upper members and a subtidal setting in the middle member.