The Quantum Downhole Systems successfully cleans sand to stage #10
After a conventional wellbore clean out failed to restore acceptable production, Quantum Downhole System used its JetVak process to clean the wellbore of sand and significantly exceed production targets.
Well location: Kaybob field, Fox Creek, Alta., Canada in the Montney Oil zone.
The subject well was a relatively prolific producer in the earlier stages of its life and has fair to good cumulative oil production volume.Recently the operator struggled with maintaining an acceptable level of productivity 1.0m3 oil/day, with step changes in the decline analysis.
A conventional fluid/nitrogen circulation mill-out/clean-out to PBTD 3592m was attempted in August 2014. The true vertical depth 1830m, the depletion of the reservoir in this part of the pool and the extremely low bottom hole pressure of 3000kPa had a direct impact on the success level of the conventional mill-out/clean-out.
This caused loss of circulation, severe fluid losses and indications of sticky pipe which caused the operation to be halted.
The maximum depth of the mill was 2987m; 12 of the 22 stages were milled to 98mm. Conventional millout/cleanout techniques are heavily reliant on a very specific program, and this program must be adhered to very diligently. There are also many other factors that are out of the operator’s control such as reservoir depletion, bottom hole pressure, permeability and the location of natural fractures.
The client wanted to clean the well free of sand to stage #10 to improve and maintain consistent oil productivity. The client felt that a very important aspect of this operation was to create a localized drawdown at and near the frac port; this would ensure the fractures to be free of any loose sand that may cause future blockages in the liner.
A specific JetVak cleanout program was designed to optimize the jetting fluid volume and the fluid recovery volume to ensure an under balanced condition was maintained throughout the operation.
A second benefit the design achieved was to allow the system to clean the liner at a faster rate, ultimately speeding up the operation, which had a direct positive impact on the economics of the operation.
The Quantum JetVak operation was initiated on October 14, 2014. In-field produced water blended with H2S scavenger was used as the JetVak jetting fluid and power fluid.
- Surface pump rate was 80 litres per minute (66 lpm to operate the venturi and 14 lpm channelled through the jets)
- Gross return rate varied from 105 lpm to 115 lpm, depending upon the gas volume entering the pump from the formation. This resulted in an under-balanced environment of 25 to 35 lpm (36m3/day to 50.4m3/day).
- Highest gross return sand cut was 4.0% at an uncorrected depth of 2440mmd. The average gross sand cut for this run was ~0.5%.
- Specific areas of the liner where the oil cuts increased from 0.05% to 5.0 and 5.5% of gross returns. When calculating the net oil cut by removing the venturi and jet fluid volume, this results in a 22% net oil cut. Correlating and depth correcting these oil cuts with the frac intervals was very useful to the client in regards to reservoir characterization. This knowledge can be used to optimize development and return on investment in a given field.
- Another very encouraging piece of data was that during RIH #1 when the system was removing 36m3/day to 50.4m3/day, the bottom hole pressure remained steady at ~3.0mPa. This is optimistic in regards to potential productivity.
- Although this part of the reservoir is quite depleted, the over-all or cumulative deliverability volume of the multiple fractures is quite high. Sand cuts of .005% confirmed that the liner was clean to the RIH #1 maximum depth (2570m) which allowed for the ports to be cleaned a second time. When entering the un-cleaned section of the liner, the sand and oil cuts increased.
- The total volume of sand removed during this job was 1.25m3 or 1875 kg which equated to 16% of liner volume, assuming no inflow of sand from formation.
The subject well was put back on production immediately after the cleanout and is running smoothly at 4.0m3 oil/day. Quantum will do a 12 month review of the well to compare decline rate to similar wells in this pool or field.
The post Case study: Multi-stage horizontal well production increased 400% appeared first on Beacon Energy News.