Print this page3D Geologic Modeling to Improve Remedial Design
GAITHER, BRUCE E., TONY V. and CARVALHO
A case study is presented which demonstrates how existing, oil and gas production technology can successfully be transferred and applied to enhance environmental remedial design activities. Landmark Graphics' Stratamodel{TM} programs, designed for use by petroleum geologists and engineers, were used by environmental geologists to develop a three-dimensional (3D) geologic model of potentially contaminated sediments. If remediation were required at the site, air sparging would likely be a component of the remedial design.
A robust, interactive 3D geologic model was developed using data from approximately 50 electric cone penetrometer tests (ECPTs) which had been performed at the site. The ECPT lithology data consisted of digitally recorded tip and sleeve resistance, and were presented as traces on a log similar to a conventional e-log.
After experimentation with various interpolation algorithms, the potentially impacted sediments were modeled as transitional facies, Twelve separate lithofacies zones were discretized and modeled within three distinct "sequences". Lithofacies were interpolated onto a 3D stratigraphic framework (grid) developed from the conceptual geologic model formulated by the project's geologists.
The framework was constructed using 10 ft grid spacing in the horizontal, and 39 layers averaging 0.5-10.0 ft in thickness. Control grids for the layers and sequence boundaries were derived from geologic tops picked from the ECPT logs. The resulting model provided valuable information regarding the nature of geologic heterogeneities that would determine air and water flow paths during air sparging.