Introduction

Structural and stratigraphic traps in the Partitioned/Divided Zone (PZ) between the Kingdom of Saudi Arabia and Kuwait suggest minimal tectonics during carbonate build-ups within the Late Jurassic to Early Cretaceous (Figure 1). Today, these same reservoirs are structurally compartmentalized as determined from pressure data, wells and the incorporation of an array of 2-D/3-D seismic data (Figure 2).

The application and knowledge of regional tectonics indicates that left-lateral, strike-slip faulting produced many transpressional structures within the Arabian Peninsula. The transpressional faults form the traps and can be mapped using 2-D and 3-D seismic data. They are sub-vertical and trend NS to NNW with en-echelon faults trending NW-SE to SW-NE. In addition minor transtensional faults further provide a pathway for the migration of hydrocarbon. This structural framework was affected by single to multiphase inversion with a late stage en-echelon “collapse graben” faults that compartmentalize the Late Jurassic to Early Cretaceous hydrocarbon reservoirs (Figure 3).

Exploring and appraising Late Jurassic to Early Cretaceous reservoirs require combining our knowledge about the original depositional models where “optimum reservoir facies” reside and an awareness of structural/stratigraphic traps. Is the trap further compartmentalized? In the Partitioned/Divided Zone area we are applying the model from the Triassic Marrat to Eocene and through drilling to confirm additional traps (Figure 4).

Example

A recently drilled example is illustrated in the shallow Partitioned/Divided Zone reservoirs through the application of structural principles to predict structural traps where faults are linked to Jurassic and Cretaceous reservoirs (Figure 4). Similar structural mix-mode deformation is confirmed within Oman by Filbrandt et al. (2006, Figure 5). In this study both mixed-mode transpressional and transtensional traps are illustrated using Partitioned/Divided Zone examples. For the Ratawi reservoirs in the Partitioned/Divided Zone the compartmentalization is seen by NE-trending strike-slip faults. The compartmentalization was confirmed through variation of pressure data (Figure 6).

Our study emphasizes linking sequence-stratigraphic and tectonic concepts to illustrate optimal locations for future exploration and appraisal drilling leading to additional development area for more production within the Partitioned/Divided Zone of the Kingdom of Saudi Arabia and Kuwait.

Conclusion

During deposition of the Jurassic and Cretaceous reservoirs, such reservoirs realized minimal amount of structural tectonic deformation. Today, these same reservoirs under current tectonic regimes are compartmentalized and detailed fault interpretation provides the understanding for the conduit (migration) and trapping of hydrocarbons.

The application and knowledge of regional tectonics is critical to the awareness of the structural complexities. Technical application such as wrench tectonics is important in finding and drilling for additional hydrocarbons and such structures are realized within the Partitioned/Divided Zone of the Kingdom of Saudi Arabia/Kuwait.

Acknowledgements

We thank the Ministry of Petroleum of Saudi Arabia, the Ministry of Oil of Kuwait, Saudi Arabia Chevron (SAC), Kuwait Gulf Oil Company (KGOC) and Chevron for permission to present this study, and Tom Heidrick who influenced and supported transtentional/transpressional tectonics (Retired, Chevron).