Recovery from Heterogeneous Clastic Reservoirs Using
Borehole Image Sedimentology: Morrow Formation (Lower
Zarian, P.1, R.D. Blumstein1,
The Morrow Formation gas reservoirs on the northwestern shelf of
Our multi-well integrated analysis demonstrates borehole image sedimentology as an approach to create geological models based on specific observational criteria from resistivity borehole images. The wireline log responses of the Morrow sands lack distinctive characteristics for confident discrimination between different sand-body types. However, the high-resolution detail afforded by borehole imaging technology allows recognition of sedimentary features (e.g. bioturbation, scours, cross bedding, style of sand-on-sand contacts) and vertical stacking which can be used as criteria for facies-based differentiation of distinct depositional sub-systems (e.g. fluvial channel-fill, splay, marine bar, shoreface). In this way, the significance and potential continuity of sandstones encountered can be assessed deterministically, enabling prediction of fairways of productive sand facies.
The case-studies reservoirs discussed here were investigated in great detail using borehole image analysis to predict systematic down-dip facies distributions, paleotransport directions and sediment body geometries, which ultimately reduces geological uncertainty and thus facilitates decision-making for drilling and completion of future wells.