The calibration of shaly-sand reservoir is challenging since the nature of geological complexity of the reservoir. This complex structure involves multiple scales that should be acknowledged during geologic and reservoir modeling activities. This paper is intended to show multi-scale response of shaly-sand reservoir, by integrating well, sector, and reservoir data. Reservvoir modeling is used as a tool to understand the concept and behaviour of shaly sand reservoir under multiple scenarios of shale geological setting and shale configuration.
The research is based on day-to-day findings in PHE ONWJ working area where drilling activities often encounter zones with very low water saturation or high pressure, even though the infill drilling is performed nearby depleted zones. This work demonstrates the needs of multiscale integration to analyze shaly-sand reservoir response. The geology of shaly-sand reservoir indicates "compartment" behavior. The interbedded shale layers disconnect the continuity of several layers. The global scale data, e.g. average reservoir pressure, cannot accurately capture the local responses and discontinuities. Therefore, huge amount of oil reserves becomes undetected and undeveloped.
Reservoir characterization based on Field X in PHE ONWJ area is used as a benchmark in modeling a generic reservoir model. The model utilizes several shale configuration and shale characteristics in order to mimic shaly sand reservoir behavior during a single primary production cycle. Whilst general production resultsis not the main concern of the current publication, The main goal of the publication is to observe pressure behaviour after several years of primary production.
The research provides a new insight on how field development plan should be prepared accordingly should there be a conviction of shaly sand reservoir from test data. Developing shaly sand reservoir should require multiple plans for higher number of infill well as well as its placement and economic aspects.