The Middle East is one of the world’s richest regions in terms of hydrocarbon reserves. According to the 2013 OPEC report, five Middle Eastern countries (Saudi Arabia, Iran, Iraq, the UAE, and Kuwait) rank among the top 10 globally for proven oil reserves. Additionally, Iran and Qatar hold the second and third largest proven natural gas reserves, respectively. Much of these reserves are found in carbonate reservoirs developed on vast epeiric platforms, making this region an ideal location for a field course focused on carbonate reservoirs.

Oman, while having smaller oil and gas reserves compared to its neighbors, offers a unique geological setting with world-class outcrops. The Oman Mountains and surrounding regions contain carbonate outcrops that serve as excellent analogues to subsurface reservoirs, providing invaluable insights into depositional environments, diagenesis, and sequence stratigraphy.

This field course aims to familiarize participants with the key characteristics of Middle Eastern carbonate reservoirs, bridging the gap between modern analogues and ancient outcrop examples. The course offers hands-on experience with carbonate depositional systems ranging from the Precambrian to the Lower Cretaceous, providing a comprehensive understanding of reservoir-seal pairs.

Learning Objectives

The overarching goals of this field course are to:

• Enhance participants’ observational skills, with a focus on describing carbonate rock textures using the Dunham classification.
• Understand the stacking patterns of carbonate rocks at outcrops and their depositional controls.
• Review the regional geological context of key stratigraphic intervals containing reservoir-seal pairs.
• Grasp fundamental concepts of carbonate deposition, including sequence stratigraphy, biological productivity, and diagenesis.
• Explore the tectono-stratigraphic context of Oman and the broader Middle East.

By visiting modern carbonate systems at Barr Al Hikman and various outcrops in the Oman Mountains, participants will gain a holistic view of carbonate reservoirs across geological time.nalysis, all of which are essential for careers in geoscience.

Itinerary and Key Outcrops

Day 1: Barr Al Hikman

We leave from the airport in Muscat, Oman, to visit Barr Al Hikman. This modern carbonate depositional system serves as a valuable analogue for ancient shallow marine environments. The group will camp overnight at Barr Al Hikman, allowing for early morning fieldwork.

Day 2: Barr Al Hikman and Sinaw

The morning is spent exploring various stops at Barr Al Hikman, with a focus on modern carbonate textures and sedimentary structures.

Day 3: Wadi Myadin

A full day is dedicated to exploring Wadi Myadin, where participants will observe ancient carbonate sequences from the Permian to Cretaceous period. Key outcomes include recognition of depositional facies and their stacking patterns, and understanding diagenetic processes and their impact on reservoir quality.

Day 4: Jebel Madmar

Jebel Madmar offers outcrops of Mesozoic carbonates, providing an excellent opportunity to study the Lower Cretaceous Natih reservoir and source rocks pair. We also focus on the unique sequence stratigraphy history of these carbonates.

Day 5: Jebel Madar

Participants spend the day at Jebel Madar, a salt dome with a carbonate carpace. We focus on the Lower Cretaceous Shuaiba to Natih Formations, highlighting some of the sequence stratigraphic implications of the succession. We also look at the Nahr Umr Formation, a regional shale deposit that forms the top of the Shuaiba reservoir. Finally, we explore the spectacular mineralization within fractures of the salt dome.

Day 6: Snake Gorge and Wadi Bani Karus

The final day in the field includes a visit to Snake Gorge and Wadi Bani Karus, where participants will observe the effects of tectonics on carbonate sequences. This includes fracture-related dolomitization of Neoproterozoic carbonates, and a large-scale regional uncomformity with spectacular outcrops. This sheds light on the regional tectonic controls on the deposition of carbonates on the Arabian plate.

Key Geological Concepts Explored

• Carbonate Reservoirs: Formation, evolution, and heterogeneity of carbonate rocks across different geological periods.
• Seal Integrity: Characteristics of caprocks and their role in hydrocarbon entrapment.
• Modern vs. Ancient Depositional Systems: Bridging modern carbonate systems with ancient outcrop observations.
• Sequence Stratigraphy: Identifying key stratigraphic surfaces and depositional sequences in carbonate successions.
• Diagenesis: Understanding post-depositional processes that impact reservoir quality.

Why Oman?

Oman provides exceptional geological exposures that are highly relevant to the energy industry in the Middle East. The diverse outcrops in the Oman Mountains showcase carbonate platforms, ramps, and basins from a wide range of ages and depositional environments. These outcrops serve as valuable analogues for subsurface reservoirs, enhancing participants’ ability to predict and model reservoir behavior.

The Oman Field Course combines modern analogue studies with ancient outcrop observations, offering a holistic approach to understanding Middle Eastern carbonate reservoirs and seals.