Abstract:

Coral Reefs form a primary basis for reconstructing sea level fluctuations over Earth’s

history and have been used to establish that, since the Last Glacial Maximum, sea level did not

always rise gradually, but was instead characterized by three periods of rapid inundation occurring

over several centuries. Recognizing the nature of past sea level rises (i.e., gradual or stepwise)

during deglaciation is critical for informing models that predict future vertical behavior of global

oceans, and thus this science benefits society’s welfare. Further, the change from hydrocarbons to

renewable energy will not be a quick transition. Hence, based on the current energy needs, better

secondary and tertiary recovery will be required. Future production, therefore, will require better

reservoir models to improve sweep and recovery from complex and heterogeneous carbonate

reservoirs (approx. 50% of all reservoirs) while keeping development costs at bay. Hence, modern

and ancient carbonate outcrop analogues are interrogated to create comprehensive data sets on

morphological evolution and depositional heterogeneities of carbonates.

Modern reefs are studied from south Texas shelf, Maldives, and Red Sea to understand the

sea-level fluctuations in the recent past, and Late Cambrian microbial reefs, central Texas, and

Late Jurassic Arabian carbonates in Saudi Arabia to characterize and understand depositional

heterogeneities. Datasets including multibeam bathymetric mapping, CHIRP sub-bottomprofiling, 3D drone surveys, GPR, and seismic are collected. These high-end techniques are

paired with tried and tested standard geological techniques of measuring (several) stratigraphic

sections anchored by outcrop spectral gamma ray logs, analysis of sediment samples (texture, grain

size, mineralogy) and fracture/fault surveys all integrated with full cores drilled in the outcrops.

Utilizing these datasets sea-level fluctuations in the recent past reveals that there were

episodes of catastrophic sea-level rise leading to a few m of sea level rise within few decades.

Additionally, during Holocene, Arabian Peninsula had a contemporaneous sea-level highstand

where sea-level was a few m higher than today, followed by a sea-level regression until recent

renewed rise. The ancient outcrops are statistically analyzed and reveal scaling relationships and

preferential growth directions owing to paleogeography, paleoclimatology, and paleoceanography,

which usually are never mapped or identified. The rules identified from these datasets can be used

as input for static analogue models and dynamic simulations to test sensitivities and determine

optimum development scenarios for improving ultimate recovery.