Predicting reservoir-scale faults with area balance: Application to growth stratigraphy

Abstract

A reservoir that appears to lack faults at one scale of resolution or at one sampling density may nevertheless contain faults that are below the resolution of the observations. The area-depth relationship from a balanced cross-section is shown to contain the necessary information for predicting the sub-resolution fault heave. Existing area-depth theory is extended to include growth units, allowing structural length and thickness changes to be separated from the depositional changes. The technique is validated with a numerical model of a growth full graben and a sand-box model of a half graben; then field tested in the Gilbertown graben, a growth structure within the regional peripheral fault trend along the northern margin of the Gulf of Mexico. A cross-section developed from wells alone is used to infer the abundance of sub-resolution faults by the area-balance technique. A small but significant amount of sub-resolution extension is predicted and then confirmed with a high-resolution seismic line. ?? 2003 Elsevier Science Ltd. All rights reserved.