Pre- and Post-injection Vertical Seismic Profiling over the Southwest Regional Partnership's Phase II Fruitland Coal CO2 Pilot

In this study we report on the results of pre and post injection vertical seismic profiles collected at the Southwest Regional Partnership (SWP) on Carbon Sequestration’s San Juan Basin Fruitland Coal pilot test. The project is funded by the U.S. Department of Energy and is managed by the National Energy Technology Laboratory. The pilot test was undertaken in collaboration with ConocoPhillips as a joint enhanced coalbed methane recovery test and demonstration of CO2 sequestration in deep, unmineable coal seams. The SWP conducted the pilot in the Upper Cretaceous High Rate Fruitland production fairway southwest of the northwest trending basin hinge. CO2 injection began July 30th of 2008 and continued through August 14th of 2009. During the 12 month injection period approximately 319 MMCF, equivalent to nearly 18,407 short tons of CO2 were injected into the Fruitland coals. The pre-injection vertical seismic profiles were completed on June 2nd and 3rd of 2008. The post injection surveys were acquired on September 17th, 2009: a month after CO2 injection was completed. The monitor VSPs were not run until the reservoir was pressured down. Both preand post-injection surveys included a zero offset VSP and three offset VSPs. The zero offset source was located 114 feet from the injection well. Long offset sources were located 1498 feet from the injection well along a 216o azimuth, 1693 feet along a 34o azimuth, and 1942 feet along an azimuth of 349o. Elemental analysis through the lower Fruitland reveals thick coal seams in the intervals 2950’ to 2970’ subsurface, 2975’ to 2986’, 3048’ to 3060’ and 3111’ to 3336’. Compression and shear wave velocities were measured using the Sonic Scanner from 285 feet to 3132 feet subsurface. Density is also available from the Platform Express log suite. Synthetic seismograms are used to tie subsurface geology to surface 3D seismic in the area and the VSP responses. Results from time lapse processing are preliminary. The WVU funded processing effort through Schlumberger continues.