Time‐lapse multi‐component seismic modeling of CO 2 fluid replacement in Redwater Leduc Reef, Alberta

Abstract

Summary Common shot multi-component ray tracing modeling was undertaken to evaluate variations in the seismic response of the Redwater reef along the 2D line across the southern margin of the reef as well as with CO2 saturation in the Upper Leduc interval zone. The input geological model was based on well data and depth-converted seismic data from the interpretation of 2D seismic lines in the area. Pwave and P-S wave Ray tracing synthetic seismic sections demonstrate similar seismic attributes for the Mannville, Nisku, Ireton, Cooking Lake, and Beaverhill Lake Formations. The Cooking Lake and Beaverhill Lake formations display positive structure below the reef in time sections due to the lateral velocity change from on-reef to off-reef, but corrected in the depth sections. Terminations and the lateral position of the Upper Leduc and Middle Leduc events are obvious on the pre-stack time-migrated section and a modest improved on the depthmigrated section. Higher amplitudes at the base of UpperLeduc member are evident near the reef margin due to the higher porosity of the foreslope facies in the reef rim compared to the tidal flat lagoonal facies within the center of the reef. Time-lapse seismology proved showed amplitude and traveltime differences for the seismic data before and after CO2 saturation. A fairly good contrast reflection occurring at the top of upper-Leduc, top of the rim, and base of upper-Leduc near the reef edge was strong evidence to observe and monitor CO2 saturation with seismic data.