Faults play an important role in creating hydrocarbon traps. Sealing along fault planes arises when reservoir/non-reservoir rocks of different petrophysical characters are juxtaposed against each other. This work throw light over the fault seal analysis of some selected mixed clastic reservoirs in the Nile Delta and Western Desert. The potential sealing parameters were checked in three different fields (West Abu Qir, Abu Sennan and Abu Madi-El Qar'a) with different hydrocarbon potentialities (gas and oil) as an attempt to model the sealing attributes in these areas. Different qualitative and quantitative techniques (including seismic and well logging attributes) were used in assessing and evaluating the properties of the fault rock seal types along the faulted reservoirs.
Number of juxtaposition and 3-D property diagrams (permeability, sealing capacity and relative areas of fault rocks) were constructed along the proposed sealing planes. Moreover, shale gouge ratio (SGR) and smear factor parameters (clay smear potential, CSP and shale smear factor, SSF) were estimated. Pressure data were analyzed on either side of the faults which cut through the potential reservoirs to calibrate the reservoir zones of known petrophysical and sealing parameters. In Abu Sennan and West Abu Qir areas, the structural control of faults is the main sealing factor. In terms of sealing efficiencies, the analyzed reservoirs show two different pressure regimes on either side of the studied faults associated with good sealing parameters (SGR 15-20% and SSF<7). While in Abu Madi-El Qar'a area, sealing is controlled by the combined effect of the deposition of the reservoir (stratigraphic control) and bounding faults (structural control)