Reservoir surveillance is a key component of SAGD operations. There are several widely used surveillance techniques which vary in spatial and temporal coverage, resolution, and cost. The most common of which include pressure and temperature observation wells and 4D seismic. This study aims to demonstrate the value of InSAR as a decision-making tool over operating SAGD pads when used in a coordinated surveillance program alongside existing techniques.
Results acquired from conventional surveillance techniques such as 4D seismic are often compared to those from InSAR at the scale of one of the data sets. A frequent challenge when making these comparisons is different acquisition frequency and coverage. This study compares the relative results from each data set to determine if the same conclusions could be drawn from InSAR as from seismic at varying scales. To do this, SAGD wells are divided into segments at various scales (half, third and quarter well). Results from InSAR and 4D seismic are extracted for each segment and statistics analyzed to determine if InSAR and 4D seismic lead to the same relative outcome and thus might lead to the same operational decisions.
Results will focus on the ability of InSAR to provide decision making information to SAGD operators like that of other surveillance techniques, but at higher temporal frequency. In particular, the scale at which InSAR provides comparable results to 4D seismic will be investigated and how using InSAR in coordination with seismic may result in more frequent well production optimization.
Previous attempts to correlate InSAR to existing SAGD surveillance techniques have shown mixed, though often promising results. Difficulties have arisen from attempts to directly compare discrete InSAR values to those of other techniques, often resulting in poor regression coefficients and a lack of confidence. Qualitative comparisons of gridded surfaces provide little insight on how to utilize the InSAR data. This study will demonstrate the scale at which InSAR can provide information to make operational SAGD decisions.