Application

Oil production, monitoring of equipment and well parameters in horizontal, vertical, and inclined wells with 0.5—30 m³/day production rate and up to 3 000 m depth.

Operation principle

The reciprocating rotor (hereinafter “slider”) of the submersible pump is driven by a linear permanent magnet motor installed below the pump.

The linear motor comprises a fixed round stator and rod with permanent magnets. The stator consists of three-phase winding cylindrical coils that are connected in series and powered by a variable frequency drive. The stator coils generate a travelling magnetic field that induces an electromotive force to move the magnetic slider which pushes the plunger pump rod.

SPLM advantages

• no failures caused by rod twisting, breakout, corrosion, and wear of rods and tubing
• suitable for operation in severe environment with low permeability, and in marginal wells
• easy onsite assembling
• lower maintenance costs
• smooth adjustment of length and number of strokes per minute
• average efficiency is 60—90 % higher comparing to other pumping systems
• energy consumption is 30—80 % lower comparing to other pumping systems
• suitable for high pressure wells — up to 30—60 MPa
• high withstanding voltage — tested at 3 000 V, 50 Hz, 200 °C within 1 minute
• high insulation resistance — 100 MOhm at 2 500 V
• remote control option
• run life — up to 10 years

Criteria for selecting SPLM systems

• flow rate from 4 to 30 m3/day, marginal wells
• pump installation depth down to 3 000 m
• directional and inclined wells and wells with periodic injection programs, requiring flow rate adjustment from time to time
• limited electric power

SPLM system includes:

• VFD
• power cable
• reciprocating (plunger) pump
• linear motor
• downhole sensor

Universal digital downhole sensor installed below the motor allows for real-time reading such oil production parameters as follows:

• pump intake pressure
• pump intake temperature
• motor temperature
• motor vibrations
• motor and power cable insulation resistance

The system is equipped with a variable frequency drive which along with the digital downhole sensor helps to increase oil production and protects the motor due to:

• smart control modes
• building of power and force charts
• evaluation of production and flow rates
• continuous analysis of forces to determine optimal SPM
• monitoring of environment (asphalt, resin and paraffin deposits, gas, viscosity, etc.) and prompt response to emergency situations

The variable frequency drive ensures easy and convenient change and adjustment of well operating parameters, as well as remote monitoring and control of oil production process.

The combination of a motor, pump and VFD is selected according to the installation depth, production rate, viscosity, and other parameters of the well.

Technical characteristics

Parameter	Value
Overall dimensions (system)	Ø 117 * 9 600 mm
Overall dimensions (stator)	Ø 117 * 6 240 mm
Slider stroke	1 260 mm
Power	35 kW
Voltage	900 V
Maximum output current	30—80 A
Traction force	2.4 ton
Pump flowrate range	0.5—30
Operating temperature	0…+150 °С
Well static pressure	0—30 m3/day

Comparative characteristics of SPLM, ESP, and SRP systems

SPLM system is cost effective, power efficient, and environmental friendly version of sucker-rod pump system. Moreover, SPLM is able to effectively replace ESP systems at marginal wells without infrastructure conversion.

Parameter	SRP	ESP	SPLM
Production, m3/day	<30	>15	<30
Running depth, m	<2 000	<3 000	<3 000
Operating mode	constant	periodic	constant
Unit power consumption, kW/t	20	10	8
Wellhead setup	required	no	no

Catalogues and documents

Submersible reciprocating pump unit with linear permanent magnet motor (SPLM)