Application of the Fused Fault Block Technique to Fault Network Modeling

Abstract

TX 75083-3836 U.S.A., fax 01-972-952-9435. AbstractFault network modeling of complexly faulted structuresthose containing hundreds or thousands of faults -can be an extremely difficult and time-consuming process. A variety of methods exist to create the appropriate relationships between the faults, due to truncations, crossing, or offsets due to younger episodes of faulting, but each has limitations. Pillar or node-based techniques are often based on the concept that faults only exist where there are interpreted data; extensions of faults to intersections with other faults and/or truncation of erroneously crossing faults is a manual process, requiring the addition of nodes or pillars to the truncating surface. The location of the intersections can be dictated by the orientation of the pillars of the two faults, and so may not reflect the correct structure. An automatically generated binary tree, or hierarchy, can generate a reproducible fault network, where fault relationships can be stored. However, a binary tree cannot correctly handle all types of fault relationships and has particular difficulty in easily representing crossing faults.Our technique uses a new concept of "fused" fault blocks. It begins with an approach somewhat similar to a binary tree, where each fault defines a hanging wall and foot wall side. However, our technique does not require faults that have an implicit relationship (that is, faults which do not intersect) to be explicitly defined in a tree. Fault intersections are determined from the active areas of the faults. Unlike a strict binary tree, fault relationships here can be modified at any time, as interpretation or data changes.Truncations can be stored and re-used, making the fault network repeatable. The accuracy of the fault network, the flexibility of modeling, and the use of this network to create reservoir grids allows an entire asset team to work with a highquality earth model.