Yamama Reservoir Compartmentalization in Majnoon: A Preliminary Perspective

The Yamama carbonate is the deepest drilled reservoir in Majnoon field with the second largest oil volume. The Yamama reservoir is about 300 m thick and subdivided by thin discontinuous mudstone units into Yamama A, B1 and B2 major reservoir units. Laterally, the Yamama A, B1 and B2 reservoirs are compartmentalised into at least two separate fault compartments based on the following evidence: 1. Seismic interpreted fault: A west dipping normal fault was interpreted on three 2D seismic lines on the crest of the field. The fault offset is subtle (less than one seismic loop) and 2D seismic quality is low therefore the lateral extent of this fault beyond the three interpreted seismic lines is highly uncertain. This suggests that the Yamama is compartmentalised with a western and eastern fault block. 2. Pressure data: MJ-12 (western flank well) shows pressures elevated by about 70 psi compared to MJ-08 and MJ-09 (crestal wells) at the datum depth of 3900 mTVDSS. 3. Fluid contacts: OWC in the western flank wells (MJ-03, MJ-12 and MJ-15) is about 120 m deeper than in the rest of the field.