A seismic acquisition system employing permanent buried sources and receivers has been used to continuously monitor production and steam injection at the Peace River heavy oil field since May 2014. Initial results show exceptionally high data quality and sensitivity. Observed 4D effects diagnose the extent of areal steam injection conformance. Frequent monitoring of the calendar-time evolution of these effects significantly improves understanding of reservoir dynamics, enabling pro-active reservoir management decisions and evaluation of their impact.
Although clear value has been demonstrated in offshore assets, several technical challenges have impeded development of time-lapse seismic as a monitoring tool for onshore fields. Changes in the reservoir between the baseline and monitor surveys are often masked by significantly greater changes in the near surface weathering layer or effects resulting from acquisition hardware differences between surveys [Hornman et al., 2012]. The SeisMovie® system, developed by CGG, is the most ambitious approach to overcome these technical challenges, exploiting the unmatched repeatability of permanent, buried receivers and exceptionally stable permanent, buried sources. Learnings from initial trials at Peace River in 2009 were incorporated into the first successful continuous timelapse monitoring trial conducted at Schoonebeek in the Netherlands in 2010-2012. The Schoonebeek trial demonstrated the capability to continuously monitor and characterize the spatial distribution of heat from injected steam, for the limited coverage area of the survey (0.1 km2) [Cotton et al. 2012, Zwartjes et al. 2015]. The largest field trial of this technology is being carried out in Peace River, Alberta, Canada to demonstrate feasibility of optimizing thermal EOR using daily time-lapse seismic information [Lopez et al., 2015].
Monitoring Thermal EOR at Peace River
The current trial extends learnings from the successful Schoonebeek trial to a full-pad 3D survey for monitoring the thermal EOR development at Pad 31 in Peace River. Pad 31 was first developed in 2001 with a series of horizontal wells, Figure 1 (red wells). The reservoir was originally stimulated using cyclic steam stimulation (CSS). After several cycles of CSS, the wells were converted to a horizontal steam drive configuration. These processes led to limited recovery of the bitumen originally in place due to insufficient stimulation of the reservoir volume.