Ibrahim M Al-Goba¹, Rami A Kamal¹

(1) Saudi Aramco, Dhahran, Saudi Arabia

ABSTRACT: Applying Curvature Analysis to the Modelling and Prediction of Water Flooding Patterns across the Arab D in Ghawar Field, Saudi Arabia

Curvature Analysis is the study of the curvature in deformed rock strata in order to predict the presence of fracture lineaments that were created as a result of the deformation. The benefits of successful curvature analysis studies in the subsurface are immeasurable, especially where seismically-unmappable fracture networks are an important player in reservoir fluid movement. Curvature analysis can also be used to define small-scale faults or highly fractured areas. In recent years various software has surfaced, which computerizes the process.

Folding is sometimes related to the development of faults and their relevant geometry. Small-scale faults can be detected from small flexures. Fractures are related to spatial variation of strain. Several workers have noted a relationship between areas of high curvature and fracture density.

The aim of this study was to predictively map areas or axes of intense reservoir curvature using the top Arab-D reservoir (Jurassic shelf carbonates) surface as mapped from 3D seismic, in order to define fractured zones. Productivity data was then used to validate the participation of the mapped fracture zones in fluid flow and production, by revealing areas of abnormal flow and matching them to these zones.

Predictive subseismic resolution fracture distributions, were compared against water arrival maps, faults mapped from 3D seismic data, dolomite distribution maps, and super permeability risk assessment maps (RAMs). The results clearly illustrate that curvature analysis is a valid ingredient in a basket of tools for meaningful fracture characterization and modelling of the Arab D reservoir.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado