Bespoke Downhole Pumps for High-Viscosity Oil NVMK-50; NVMK-70; NVMK-86
This bespoke downhole pump (see Fig.) is designed for well operations complicated by sand-related problems and associated gas influence. It allows producing oil with viscosity of 5x10-4 m2/s (500 CentiStokes - cSt), containing up to 3% mechanical admixtures and maximum of 100 m3/m3 of gas factor. It can be operated at high temperature conditions up to 150 оС.
This pump consists of a short cylinder housing two sets of guide seals for an elongated hollow plunger. A suction non-return valve with increased flow area is fitted to the intake end (bottom) and a pressure non-return valve is fitted to the output (top) end inside the bore of the plunger.
The hydraulic resistance of the pump intake is reduced due to enlarged flow area of the suction valve. The valve is made of a hard alloy.
The pump is designed for the speedy extraction of the formation fluids with a wide range of viscosity characteristics with sand content. With high-viscosity oil, weighted (heavier) rods are used to ensure the plunger rods are heavy enough to push the plunger down smoothly and speedily.
The design of the pump also allows environmentally friendly well maintenance without oil spill.
Water content of deposit
|Temperature||within 393 оК (120 оС)|
|Mechanical admixtures||within 5 g/l|
|Dynamic viscosity||within 5 pa/s (5000 сПз)|
|Water mineralisation||within 60 g/l|
|Free gas||10% by volume|
|Hydrogen sulfide||within 50 mg/l|
|Discharge pressure (pump running depth plus tubing head pressure - Max)||1200 m|