Abstract
The application of NCG co-injection into matured SAGD development has been well documented. At several commercial development projects1–3, it has become the standard operating practice to improve the SOR of the patterns and total project.
At the Hangingstone Demonstration Project, JACOS had implemented the first NCG co-injection pilot in 2007 at Phase 1 wells (A-B wells), which was reported by Wang4. Since November 2010, continuous co-injection started at Phases 1 & 2 wells (A-E wells), but was temporarily shut-in in September 2011 due to several interruptions of the gas supply. We used this opportunity to re-establish a base case steam injection scenario only; stable steam injection and reservoir withdrawal took effect for the next 8 months. Co-injection restarted in June 2012 to again improve the thermal efficiency of the Phases 1 & 2 development. As a consequence, two distinctive NCG co-injection periods could be observed. The second and third periods took place between November 2010–September 2011, and between June-December 2012; respectively for the A-E well pairs (Phases 1 & 2).
Our NCG co-injection experience to-date revealed that: 1) Bitumen production is not compromised, 2) The steam oil ratio (SOR) can be reduced, 3) When NCG co-injection ceased, the gas previously in the chamber – observed via temperature observation well – could no longer be detected, 4) Lower emission intensity of CO2 gas from steam generation can be achieved, 5) The steam injected (CWE) was balanced against the water produced, and 6) Allocation of steam to new well(s) or non-thermally matured wells can maximize overall field production.
These positive results led to propose expanding the desired NCG co-injection into Phases 3 & 4 wells (H-Q well pairs), where some of the well pairs had been operating since November 2001 and at different stage of thermal maturity. The design of this NCG co-injection expansion along with field issues associated with implementation will also be discussed.
