Ryan Hieronymus, Oxy
Scott Wilson, Nations Consulting
David Green, Well Master Corp
Objective/Scope:
Presentation will review design, installation, and results of recent novel artificial lift pilot in the DJ Basin.
GALLOP (Gas Assisted Liquid Lift Oscillating Pressure) is a new variant of gas-lift, designed to unload
horizontal wells from the lateral. Unloading from the lateral can add years to a well’s life by preventing
heel loading when reservoir pressure drops too low to keep a well unloaded between the lateral and the
end of tubing.
Methods/Procedures/Process:
GALLOP system pilot was meticulously planned over multiple years prior to execution, in close collaboration with Scott Wilson (patent holder), Well Master / VaultPC (manufacturers), PETEX, and internal Oxy teams. Detailed system modelling was performed prior to install to ensure success (GAP
Transient, CFD modelling of downhole valve assembly, etc). Custom wellhead and downhole equipment were designed and manufactured to meet project scope. Candidate well was identified (low reservoirpressure well with existing gas lift infrastructure). GALLOP was successfully installed (workover / surface construction) following extensive planning with the Well Intervention and Surface Construction teams.
Results/Observations/Conclusions:
GALLOP pilot has successfully extended the life of the candidate well, which otherwise would have beena P&A candidate. Initial production with GALLOP proved that the system is capable of moving the target outflow – 20 BLPD flowrate for the pilot well, and modeling indicates the system is capable of producing rates up to ~40 BLPD if inflow will permit. Pilot well rates have fallen off faster than expected due to productivity being below expectation (well-quality inflow issue as opposed to artificial lift outflow issue). Even with inflow-related drop in production, GALLOP system has proven that it can stably produce rates as low as ~3 BLPD from the lateral, and potentially lower. Due to low rate nature of late life production,
GALLOP system will be most economically attractive on wells with existing gas lift infrastructure, and is potentially broadly applicable across US Onshore assets.
Novel/Additive Information:
GALLOP is a new type of gas lift that utilizes concentric tubing to produce from the lateral. Fluid enters into the tubing system through a downhole check valve during the ‘fill’ phase. Injection is intermittently applied down the annulus between the concentric tubing strings, which closes the check valve and lifts fluid that has entered the tubing system to surface. The Oxy pilot in the DJ Basin was installed and kicked off in early 2022, and is the first and only pilot of this system in industry to date. A review of the system with the wider SPE audience could unlock late life production from wells that would otherwise be candidates only for P&A.