Operating principle of the jet (ejector) pump
It is designed to create stable and adjustable underbalance at the bottomhole to induce flow. It has the ability to cut off the tubing-to-pipe message without resetting and removing special inserts.
A distinctive feature is that the jet cartridge (nozzle + mixer) is mounted in the jet pump insert, which can be backwashed or removed on a cable with collet catcher.
The high pressure working fluid is pumped through the nozzle, creating a high velocity and at the point where the fluid exits the nozzle there is a pressure drop, resulting in suction of the fluid from the sub-packer zone. The fluids are then mixed in a mixer and brought to the wellhead.
The use of jet pumps is currently the only way to instantly create, continuously maintain, smoothly control depression and induce inflow.
Tasks to be solved:
- Hydrodynamic and geophysical studies at controlled underbalances (with a preset underbalance value, e.g., not to exceed the gas saturation pressure of the oil).
- Chemical treatment with injection into the formation with timely flushing and extraction of reaction products (from 30 minutes), including the use of 2-3 packer arrangements;
- Physical treatment by cyclic depressions, acoustic, implosion, vibro-wave action on depressions;
- Extraction of fracture fluid after hydraulic fracturing with a jet pump in a single downhole operation, with the possibility of chemical treatment and bottomhole normalization;
- Cleaning of the bottomhole cavity from penetration products of drilling and cement muds;
- Development with installation in liners Ø from 102 mm, to create deeper underbalance in the formation without affecting the liner suspension (PCCZ);
- Cumulative underbalanced perforation, hydromechanical perforation followed by chemical treatment and well development;
- Oil production (no moving wear parts, easy maintenance), including pipe-in-pipe system.
Conditions of applicability of EneGro jet pumps
The applicability of the jet pump is limited by the ability to generate maximum pressure upstream of the pump. For example, when working with a static level of 2200 meters, it is necessary to create a pressure of 220-240 atm to compensate for the static level, the pressure above 220-240 atm will be spent on the jet pump. The maximum depression value is determined by the distance of the jet pump installation from the static level. Therefore, there is a requirement for tubing and fittings to be able to withstand the maximum injection pressure. For fountain fittings it is possible to use a fountain fitting protection device (FFPD) and create a discharge pressure of 350-400 atm.
A more detailed calculation to evaluate jet pump utilization as a function of static well level is given below.
Pump unit pressure required for jet pump operation: Pna(CH) = Pna – Pna(Nst) – Ptren
Pump unit pressure required for jet pump operation: Pna(CH) = Pna – Pna(Nst) – Ptren
Pna(Hst)** – pressure of the pump unit spent on lifting the liquid (compensation of static level);
Ptren is the pump unit pressure loss due to friction on the tubing.
All The calculations can be reduced to variable components: static level at the the moment of works and U – ejection coefficient = current well flow rate divided by the working fluid flow rate (nozzle flow).
Advantages of jet pumps over other types of development
Hydrodynamic studies during well development with jet pumps
Purpose of the study: Determination of reservoir parameters, bottomhole zone contamination (skin factor), assessment of reservoir homogeneity (presence of boundaries), within the study radius, energy state of the deposit in the area.
Well testing with a jet pump significantly reduced development time.
All works were completed within 3 days, including lowering and lifting of equipment. During this time the well was developed and operated in three modes of stationary filtration with constant flow rates, and two pressure recovery curves were recorded, which allowed to accurately assess the filtration parameters of the formation and bottomhole zone. The total fluid withdrawal volume was 61.62 m³.
Comparison of time costs for bottom-hole treatment (bottomhole zone treatment)
Jet pumps of LLC “EneGro” MJP series
MJP jet (ejector) pumps are own development of LLC “EneGro”. In the process of evolutionary development, essentially one basic model of MJP-1 has emerged. Based on this model, models have been developed for liner applications and for use in hydraulic fracturing. It is also supplemented with the possibility of using the insert (with check valves) for field geophysical research and use in wells with abnormally high formation pressures (insert for registering the pressure recovery curve and the mechanism of holding the ejector insert in the casing at overpressure in the sub-packer zone).
Complete set of jet (ejector) pumps of MJP series
