A Case Study of Monitoring Steam Flood Projects in Thin Vertically Stacked Reservoirs Using 3DVSP Technology

Kuwait Oil Company (KOC) is undertaking an EOR project on a heavy oil field. This 3DVSP project was designed to monitor a 30-day steam injection into two reservoir sands which are separated by thin shale and top sealed by a thicker shale.

The goals of this project include creating a repeatable baseline survey for future 4DVSP purposes, acquiring high resolution data so individual thin reservoirs can be imaged, reservoir characterization analysis, and estimation of the steam chamber size after a 30-day CSS injection. Obtaining the highest possible frequencies was identified as a critical success factor for achieving these goals.

Extensive modelling and innovative customization of the acquisition design resulted in high resolution 3D seismic which provided surveillance and steam monitoring of thin vertically stacked reservoirs. The results demonstrated the steam flow direction was complex rather than a simple radial pattern. Reservoir characterization helped explain some of the complexity of the Cyclic Steam Stimulation program. Understanding the reservoirs, barriers, and effectiveness the steam floods will help determine where infill producer or injection wells need to be drilled to optimize production.