A Diagenetic Trap in Southwest Onshore Abu Dhabi

Abstract

The diagenetic trapping scenario, which assumes up-dip sealing by cementation is much riskier than the structural trapping scenario, but has large up-side potential. Oil accumulations in diagenetic traps represent an equilibrium state between buoyancy forces trying to move oil through rocks and capillary pressures in the low permeable layer that resists this movement. The only requirement to develop a diagenetic trap is that the displacement (capillary) pressure is greater than the migration (buoyancy) force. Smaller pore throat sizes will greatly enhance the seal capacity, especially for the larger oil molecules expulsed during early oil migration, resulting in longer oil columns. The Mishrif stratigraphic trap in the southwest onshore Abu Dhabi is highly prospective since it is located adjacent to the mature Shilaif kitchen located in the Ghurab Syncline (Rub’ al Khali Basin). The Mishrif play prospectivity evaluation, including the detailed and integrated geological model and 3D seismic interpretation will guide future appraisal drilling. In addition, the knowledge gained from this study can serve as a basis for further exploration activities related to unconventional trapping styles in the Mishrif Formation.