Application of sensitivity analysis in DC resistivity monitoring of SAGD steam chambers

摘要

Steam Assisted Gravity Drainage (SAGD) is a proven technology to extract heavy oil from the Athabasca oil sands in Alberta, Canada. Research and pilot programs have shown the growth in steam chambers can be detected and monitored using electrical methods, indicating a decrease in electrical resistivity due to steaming process. We analyze surveys currently in practice using the sensitivity of the data to model perturbations. We show that certain surveys have greater sensitivity to important regions of the reservoir, and that inversions of data collected using these surveys provide better recovery of the chambers. The sensitivity analysis provides a computationally fast and inexpensive approximation of what a full inversion can recover, making it ideal in survey design studies. Our aim is to use analysis of the sensitivity matrix to design improved surveys as well as extend the surveys to multi-frequency electromagnetic methods.