Successful Application of Geomechanical Fracture Models in the Jurassic Section of Onshore Kuwait

Al-Ajmi, Mohammed D., Sunil Singh, Nikhil Banik, Neama Al-Ajmi, Heyam Al-Ammar, Haiqing Wu, Andrew Corley, Kuwait Oil Company, Ahmadi, Kuwait

The emerging fracture porosity exploration play within the Jurassic Najmah – Sargelu carbonates may hold considerable exploration upside for the country of Kuwait. A thorough understanding of the relationship between a complex Jurassic fault network and the varying lithologies observed in these intervals to that of fractures densities and orientations is essential to the successful execution of this high potential exploration play.

Several major tectonic episodes have influenced the present day structural morphology of onshore Kuwait. The structural fabric observed in the Jurassic section is one of left-later-al, deep-seated, vertical to sub vertical faults that are associated with very tightly folded and elongate ‘pop up’ anticlines. This structural fabric is one that is consistent with a transpres­sional structural regime.

The Middle to late Jurassic Najmah – Sargelu interval represents the deposition within three second-order cycles in a mid to outer ramp and basinal setting. The lithologies observed vary greatly within these two intervals and have been described, from core, as wackstones, mud rich to mud poor packstones and grainstones. These lithologies are great­ly dependent upon the development fracture porosity for commercial viability.

Geomechanical fracture models have been introduced into the Jurassic exploration pro­gram, in Kuwait, largely because of their ability to incorporate and integrate a complex struc­tural fabric with that of the many different rock properties that are present in the Najmah – Sargelu interval of onshore Kuwait. These models have been tested extensively, through exploration drilling, and have demonstrated the ability to reduce the risk in predicting frac­ture densities and orientations. The proven ability of these models to reduce risk in the pre­diction of fracture densities and orientations has made them an integral part of the Jurassic exploration program in onshore Kuwait.