On the Accuracy of Surface Movement Measurement over a SAGD Operation in Northern Alberta through Effective Survey Design

Abstract

Abstract Surface movement over a Steam Assisted Gravity Drainage (SAGD) operation can be related to production and injection. The amount and location of surface change can indicate the location of thermal dilation within the reservoir and may provide an indication of conformance. While the deformation expected in a SAGD operation is related to the depth of the reservoir and the stratigraphy, the typical ground movement is approximately 2-5 cm/year. This represents a relatively slow inflationary process over the ground. The movement may be confused with changes that are related to seasonal ground changes including water level changes in muskeg, for instance. This work provides a description of the accuracy of Interferometric Synthetic Aperture Radar (InSAR) measurement techniques including corner reflectors and advanced point and neighbourhood algorithms designed for the measurement of ground movement in Northern Alberta. The paper will describe the application of these methods to measuring surface movement above a SAGD operation. Specifically, this article describes methods for the determination of the accuracy of ground movement estimates as derived from InSAR. An effective survey design is critical to the monitoring of ground movement. The location and availability of measurement points is crucial to the use of high resolution Synthetic Aperture Radar (SAR) satellites for monitoring. The design and implementation of a survey includes an understanding of the relationship between available infrastructure and the ground signal to be expected. However, a critical aspect of monitoring is a verification of the accuracy of the measurement provided. By using repeated observations and even a combination of satellites, we show how the measurement of accuracy can be provided on an operational basis. This work provides a novel description of the calculation of accuracy of ground movement using emerging techniques in multiple-track / multiple-satellite observation of enhanced oil recovery operations.