Brian Link

Fracture Delineation Case History From Russia And Implications For Plays In North America

This paper describes examples of mapping fracture zones in carbonate reservoirs using duplex wave migration (DWM). This method is used following conventional pre-stack depth migration with a new and very different type of pre-stack depth migration called DWM plus interpretation. The theoretical basis of the DWM process enables its ability to provide accurate and detailed detection of the position and properties of vertical boundaries and of the fracture zones confined by them. Fracture zones revealed using the DWM process are compared with available well information that verifies the existence or absence of anomalous permeability, its direction, and most importantly, information about the intensity of open fracturing in productive wells. The locations of open fracturing are verified by the productivity factors and interconnection of these wells. Also, the DWM results are compared with the results of standard methods for seismic data interpretation, which are widely used for mapping of small-scale faults and fracture zones. Hydrothermal dolomite (HTD) plays in North America also involve the need to identify lateral inhomogeneities in carbonates. The applicability of DWM to HTD plays will also be illustrated.

The effect of stretch free stacking on a clastic exploration play in Alberta, Canada

A 3-D seismic survey was shot over a set of spatially complex channel leads that were thought to be charged with both gas and water. The prospects being investigated suffered from spatial and temporal reservoir resolution problems as well as fluid risks. In the attempt to address these challenges, the seismic data was processed using a new algorithm that promised to handle the long offset information advantageously. This algorithm is a new process that is meant to eliminate NMO stretch effects in the stack. Since fluid estimation was of such concern in this dataset, the algorithm was also used to create NMO stretch free gathers for AVO analysis. The results of this work seemed to be excellent. Numerous new prospects were identified on the 3-D survey, one of which could not have been identified without the stretch free stack process, or SFS (for brevity), and AVO analysis. As is sometimes the case, the most difficult and interesting task became that of understanding what the SFS process actually did to the data and why.