Extraction of Near Wellbore 3-Dimensional Reservoir Architecture: A New Generation Dip Modeling Software Application Using Image Logs

Understanding near wellbore intricate sub-surface structural and sedimentological framework is extremely difficult from coarse resolution seismic datasets alone. Therefore, planning and placing a new well in a complex geological setting always faces a number of ambiguities existing with a typical static reservoir model that is devoid of sub-seismic structural variations. Different petroliferous basins in India are no exception in terms of such geological intricacy.

This workflow aims at establishing the high resolution, near well-bore geological architecture based on the structural and sedimentary dip data derived from multiwell image logs outputs and high-resolution correlation in eXpandBG* software within Petrel* reservoir modeling platform. This dip and image log based application can resolve the fine scale geological complexities and it considerably reduces structural uncertainties in an existing 3D reservoir model.

In the current study, detailed multiwell image facies analysis and dip interpretation, which act as the primary input of this 3D dip modeling workflow, was carried out. Subsequently, logical filtering of the dip data was performed for extracting different local structural components by dip sequence analysis process .TST at borehole level was computed followed by stratigraphic correlation using TST indexed images/logs and well tops.

This TST data along with the structural dip projection was further used to create accurate isopach maps. Different geological surfaces were modeled honoring actual structural dip data from high resolution images. Finally, a 3D structural model was generated using key surfaces incorporating the sub-seismic complexities and their bearing on reservoir distribution. Cross sections along strike and dip directions of the 3D model clearly reveals the spatial variations in reservoir architecture. Therefore, it can play a pivotal role in updating the existing static reservoir model and thus can help in preparing a better well placement and effective development strategy based on well-level geological inputs.

AAPG Search and Discovery Article #90142 © 2012 AAPG Annual Convention and Exhibition, April 22-25, 2012, Long Beach, California