Integrated 3-D Quality Control of Geological Interpretation Through the Use of Simple Methods and Programs

Jean-Yves Chatellier, Gustavo Flores, Quintero Magaly, and Cecilia Gonzales

Intergrating different petroleum geology disciplines gives insight and help in analyzing data and in checking the quality of different interpretations. Simple approaches and affordable programs allow rapid visualization of data in 3-D. Displaying geological data from stratigraphy, diagenesis, and stuctural geology together, allows identification of anomalies (i.e. development targets) and often gives clues of the controlling processes. Four case studies from world class fields are used to illustrate the vital need to integrate quality control of interpretation across disciplines.

Distribution of diagenetic alterations is revealed by visualising diagenetic and petrographic data against faults in a 3-D statistical program. Faults are transferred from 3-D seismic into such a program and then analysed against other data. Fault intersections wrongly correlated are also easily picked. Other powerful tools include a modified use of the Bischke Plots that allow the identification of missing sections previously identified as fault cut-outs.

The quality of interpretation has sometimes been assessed from the presence of stacked anomalies of various expression. ln other cases repeated unexpected isopach trends revealed subtle faults such as riedels sealing and compartmentising the reservoirs. Occasionally the timing of fault reactivation was assessed precisely whereas all other techniques failed even to identify these hidden features. Unrecognized porosity-depth trends were identified after filtering data for stratigraphy or sedimentology and studying it in its geographical and tectonic context. Three dimensional visualization was needed in cases of quartz overgrowth where grain size, depth, stratigraphy and location with respect to faults were all important.

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