Oil and gas explorer and producer Canadian Overseas Petroleum [LON:COPL] has said some of its high-pressure fields have come back online following the granting of a permit while an internal evaluation showed that the Shannon Barron Flats unit had higher volumes of oil than previously estimated.
The company’s production and development operations are based in Wyoming, US.
Several of COPL’s high-pressure flowing oil wells at the Barron Flats Shannon unit have been incrementally brought back online since early October after the company was granted a permit by the Wyoming Oil and Gas Conservation Commission to flare gas. This reduced production restrictions at certain high-pressure flowing oil wells which have been able to restart work in parallel with the commissioning of well site facilities to recover the vapours from the produced oil.The process has been designed for safety and efficiency because these wells have been restricted for several months. Oil production from these wells is not yet stable as the process is continuing, but is expected to increase once complete. The volumes of flared gas are currently around 900 Mcf/d, markedly below the permitted 3,500 Mcf/d.
In order to move the miscible bank in the eastern area enriched gas injection has restarted on the western injection patterns with lean gas injection continuing on the eastern injection patterns.
Purchases of butane have also restarted at 300,000 gallons per month, but remain significantly below the volumes of 1,800,000 gallons per month seen in 2021.
Reservoir volume has been underestimated
After an internal re-evaluation of the performance of the Shannon miscible flood and its gas injection strategy, Canadian Overseas Petroleum came to the conclusion that the reservoir volume has been underestimated. This year around 30% more of the enriched gas has been injected into the reservoir to achieve the production response than assumed in the original simulations. Consequently, the eastern injection patterns are full to design and the movement of the miscible bank is being observed.
Unexpected high pressures in five production wells appear to be caused by previously unrecognised trends in the reservoir, which only became apparent after the increase in reservoir pressure was studied. The delayed production response from the original reservoir simulations is likely due to the observed increase in reservoir volume and unrecognised production trends, which is affecting the movement of the miscible bank in these areas.
Specialist reservoir engineering firm International Reservoir Technologies (IRT) tested the internal evaluation in late September which was followed by a field-wide re-simulation of the miscible flood in early October. Once the testing is completed, likely this month, the company will be able to refine its injection strategy and better predict the high-pressure trends.
Deep oil discovery
Canadian Overseas Petroleum continues to refine its interpretation of its deep oil discovery, a combined structural-stratigraphic trap in the Dakota, Frontier 2 and Frontier 1 formations. They extend from the Cole Creek anticline at COPL’s Cole Creek unit to the Barron Flats Federal deep unit.
At Cold Creek, COPL has substantially booked proved and probable undeveloped reserves in the Dakota and Frontier 2 for future development with horizontal wells, and contingent resources in both formations at the Barrons Flat Federal dep unit. To date, no completion attempts have been undertaken in the Frontier 1 at Cole Creek despite excellent oil shows documented during drilling operations. Six well-bores have currently been identified as low-risk re-completion candidates as they are showing very good production casing and cement integrity.
