Stochastic Modeling and Risk Assessment of Variations in Preserved Sandstone Abundance Along an Upper Morrowan Incised Valley Filling Sequence in the Southwestern Kansas Kinsler Field Area

Richard L. Chambers, Van L. Leighton, and Patty F. Barron

The southwestern Kansas Kinsler Field complex has produced 23 MMBOE from an uppermost Morrowan incised valley filling interval. Interpretation of 212 well logs and core data from 12 wells along a 33 mile segment has led to the recognition of fluvial, floodplain and estuarine sediments within the valley. Fluvial deposition occurred in two distinct sequences, beginning with incision of a meandering river system which cut the original valley morphology. Subsequently, a braided river sequence incised a narrower valley within the pre-existing one.

Sandstone abundance in the earlier meandering sequence varies along the 33 mile valley length, with better preservation in the lower reaches. Geostatistical methods were used to estimate sand thickness (kriging) and to assess the uncertainty (stochastic modeling) of the prediction. Risk and probability maps created from 50 conditional simulations identify potential areas for additional development wells and provide an assessment of the associated drilling risk. Further, the technique hilights the riskiness of predicting sandstone abundance along long reaches of sparsely-drilled valleys.

AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California