Evaluation of the Delta-K Method for delineation of reservoir structure - a feasability study

Conventional seismic imaging relies on recovering a broad bandwidth impulse from the target reflectors. The Delta-K approach, as pioneered in both radar and sonar imaging by Triad AS, offers the promise of improved imaging performance for both conventiona l and time-lapse surveys. A scattering volume defined by the geometry of the receiving and transmitting arrays is illuminated by a set of single "continuous" frequencies. Signals from this scattering volume can be integrated coherently over a long period. The features within the scattering volume are characterized by linear combination of these frequencies and non-linear processing resulting in Delta-K frequency pairs. The principle problem to be addressed is the signal/noise ratio obtained from a CWMF source with the Delta-K method from a target reflector several kilometres deep. If this shows improvement over the conventional seismic method then the Delta-K approach could lead to a significant improvement in reservoir imaging. The proposed fea sability study includes the following steps:- a) Identify a suitable known oil or gas reservoir with existing 3D seismic data as a target for this study. b) Define the geological model for the overburden and the target sands for this target. c) Use the observed Q-factor (attenuation) to model both the anticipated conventional (broadband) and CWMF source frequency responses. d) Use the output from c) to define the parameters for conducting a CWMF test over the reservoir, including the necessary p ower output. e) Model the expected performance of the CWMF/Delta-K approach to determine the optimum parameters for a physical test of the method. f) Outline the experiment to be conducted.