Application of Structural Modeling from Borehole Image and Dipmeter Data in Understanding Sub Seismic Structural Complexity of Reservoirs

Dipanka B. Roy, Chandramani Shrivastva, and Sutapa Bhadra
DCS, Schlumberger Asia Services Ltd., Mumbai, India

Structural delineation of a reservoir is a key factor in the successful exploitation of a field. Seismic data interpretation has been the basis of understanding the underlying structure that controls reservoir limits. Seismic surveys provide valuable information in low and constant dipping formations, though the quality and resolution of these data could leave lot to guesswork. Dipmeter data are useful in highly variable, steeply dipping zones and has the ability to resolve finer scale structural features. This study aims at describing a methodology of incorporating dipmeter data to reveal the structural complexities by modeling the dips picked on high resolution image logs. Such structural models provide a detailed understanding of the subsurface when upscaled to seismic.

The methodology involves structural dip analysis based on which filtering and regrouping of dips according to the structural axes is performed. This exercise is followed by automatic generation of cross-section based on basic structural rules for each defined structure with user defined structural model provided as an input, which includes Fault, Fold, Megagreen and Rollover models. The structural dip model hence generated has been validated by calibrating it with the existing seismic data. The calibrated structural model can then be utilized in numerous ways, which includes visualization of structural complexity at a finer scale, well to well log correlation, and input to the geological model for accurate well placements and better well controls. Examples from structurally complex basins illustrate the incorporation of these results in structural modeling of reservoirs.

The structural dip modeling enables geoscientist to zoom in through the seismic to have a better look into the sub seismic features and understand their existence and characteristic, to build accurate and reliable geological model.

Presentation GEO India Expo XXI, Noida, New Delhi, India 2008©AAPG Search and Discovery