Time-lapse rock physics inversion of thermal heavy oil production

Date
2018-07-12
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Abstract
Time-lapse (4D) seismic monitoring of thermal heavy oil production represents a simple, robust and cost-effective method of characterizing changes in reservoir conditions. Conventional 4D seismic monitoring techniques track changes in a reservoir by comparing differences in seismic amplitudes and traveltimes over calendar time. These amplitude differences offer insight into the spatial extent of production and injection effects, but the physical cause of the observed amplitude differences is ambiguous. In order to properly distinguish between the effects of heated oil, steam, pressure, and temperature more information must be extracted from the seismic data. In this study, I combine AVO analysis and rock physics modeling in a rock physics inversion to quantify petrophysical changes in the reservoir thereby offering a more complete description of subsurface conditions during SAGD operations. With the resulting estimates for change in steam and heated oil saturations, the differentiation between varied fluid responses is possible. The heterogeneity of the SAGD operation is clearly observed. Areas surrounding the western well pairs with little to no steam or heated oil present contrast significantly with the large changes observed along the well pairs to the east. This leads to opportunities for improved production efficiency through the identification of zones with significant steam baffles and barriers, which significantly increase steam and energy requirement and prioritizing production of more efficient zones. Heated oil maps can also aid in identifying the most efficient zones and help track the mobilized bitumen to ensure it is not escaping or situated beyond the reach of the production wells. Together, results of this kind give operators valuable feedback that helps reduce both costs and environmental footprint for SAGD operations.
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Citation
Mutual, E. P. (2018). Time-lapse rock physics inversion of thermal heavy oil production (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/32407