FLAPUMP SUBMERGED HYDRAULIC WELL PUMP -
CAPACITIES AND DIMENSIONS
General Description
A typical FlaPump installation comprises four reciprocating pump cylinders operating in parallel shown in Fig. 1. Two and two pumps are combined in dual units shown in Fig. 2. The motor was developed specifically to be a robust and simple drive for high-pressure pumps. It is worth noting that the prize-winning motor represents a better technology. The shuttle controlling reciprocation is turned by the hydraulic fluid and makes no mechanical end contact. There are no springs or other no rigid mechanical parts. The hydraulic linear motor has a small diameter, it is slow moving and it is ideal for well pumping. There are only two moving parts. The motor works in a closed loop with oil or one can use filtered produced oil an let the returning oil follow the production oil stream. The service life of the motor is therefore superior. This is a drastic improvement compared with existing well pumps where the drive mechanism represents a weak point. The FlaPump piston pump can draw on the vast experience gained with sucker rod pumps. The service life of slow moving piston pumps is superior to the high-speed ESP centrifugal pumps. A standard hydraulic power unit moves FlaPump with standard coiled tubing for supply and if necessary return lines. A FlaPump installation is very simple and it is easy to operate and service.
Performance and Dimensions
The table in Fig. 4 provides typical characteristics of a FlaPump installation for 9-5/8” casing. Pump characteristics are shown in Fig. 5.a. and typical pressure drop in hydraulic tubing is shown in Fig 5.b. It is worth noting that the surface power requirement is considerably smaller than for conventional rod pumps.
FIG. 1: PARALLEL OPERATION OF PUMPS

Four pump cylinders arranged for parallel flow. Four pump cylinders in parallel are generally the optimum when considering pump diameter, assembly lengths, operating characteristics and diameters of hydraulic tubing. Six or more pumps in parallel can be used.
FIG. 2: DUAL FLAPUMP PUMP ASSEMBLY

Dual pump cylinder assembly with tandem hydraulic motor cylinders at each end of a common pump rod. One motor piston is pulling and one pushing at the same time so that the load on the rod is minimised. Pump valves and hydraulics not shown. A normal FlaPump installation comprising two identical dual pump assemblies.
FIG. 3: FLAPUMP INSTALLATION WITH MOTORS IN PARALLEL

This is the same installation shown in Fig. 1. All four hydraulic motor cylinders operate in parallel.
FIG. 4: TYPICAL FLAPUMP INSTALLATION FOR 9.5/8” CASING
Note 1) 400 bar hydraulic pressure is standard for modern hydraulic machinery for construction and mining machinery and numerous other industries.
Parameter |
Fig. 3 Operation |
Hydraulic motor hook-up |
Four in parallel |
Displacement |
1590 cum/day (10,000 bpd) |
Pump head |
0-100 bar (0-1450 psi ) |
Hydraulic supply pressure 1) |
0-400 bar |
Logging by pass tube |
114.30 mm (4”) |
Hydraulic power to pump assembly |
0-205 kW (0-280 hp) |
Pump/motor assembly efficiency |
90 % |
Overall length of assembly |
12 metres |
Pump OD |
106 mm |
Hydraulic pipes |
73.00 mm (2.1/2”) |
Hydraulic oil flow |
0-276 l/min |
Pump stroke length |
1000 mm |
Piston speed |
0-1 metre/sec |
Pump stroke speed |
0-30 double stroke/min |
Pump cylinder ID x WT |
90 mm x 5 mm |
Production tube diameter |
141.30 mm (5”) |
Motor cylinder ID x WT |
50 mm x 10 mm |
Average piston rod force |
0-48 kN |
