Wax and wax-hydrated accumulations prevention in oil wells and pipelines
While developing oilfields with high viscosity and waxy oils, the following issues come to the front:
1. Formation oil flow
2. Tubing flow capacity decrease due to wax accumulation
3. Pipeline flow capacity decrease due to wax accumulation
Asphaltene accumulation, wax crystallization and gas-hydrate internal pipeline and tubing surface are the most sore problems of oilfields both as at an oil production and transportation.
A plenty of various methods (mechanical, chemical, thermal), are being used for struggling against accumulation of wax in the tubing of oil-producing wells, allowing to support an average level of an oil production successfully enough. But in the majority cases being periodic, such methods do not achieve the primary goal – the prevention of wax and gas-hydrate.
The exact given problem is solved by means of stationary Wells Electric Unit Heater, actually an electro cable heating unit and its modifications intended, first of all, for prevention wax and gas-hydrate accumulation by such a method which allows to warm up the internal space of the tubing and to maintain fluid temperature above of wax and hydrate drop point.(Operating principle is to heat tubing inside space with a purpose heating cable located in the area of intensive wax accumulation.)
Company executes design, sale and after sales cervices of the Wells Electrical Unit Heater (WEUH)
WEUH is wore effective remedy for wax and wax-hydrated accumulations in oil wells and pipelines.
How it works
WEUH’s are designed to prevent wax and wax-hydrated accumulations in oil wells, to reduce heavy oil emulsion viscosity, to heat water wells and injectors, to heat pipelines for wax accumulations prevention and oils viscosity reduction for high-viscosity oils transportation.
Operating principle is to heat tubing inside volume with a purpose heating cable located inside/outside of tubing and inside of rods. The cable is located within the interval of wax crystallization and heats fluid to the temperature exceeding the wax crystallization point.
When a cable operates the oil is heated to temperature exceeding wax crystallization point. The WEUH principle of work consists in heating inner space of oil-well tube by means of the special isolated heating cable placed inside tubing or placed on outside surface of tubing or placed in a column of hollow rods of a sucker rod pump (WEUH with the length equal to the interval of maximum wax crystallization).
During work the cable is heats up the liquid flowing through tubing, to the temperature, exceeding the wax crystallization temperature, what provides:
Round Cable Units for ESP-equiped oil wells
Operating principle is to heat tubing inside volume with a purpose heating cable located in the area of intensive wax accumulation.
Flat Cable Units for Flowing oil wells and Injectors
The Unit is designed to prevent wax and wax-hydrated accumulations in oil wells, to reduce heavy oil emulsion viscosity, to heat water wells and injectors. Accepted for all well types.
Operating principle is to heat pipeline inside volume with a heating cable located inside the pipeline. When a cable operates the oil is heated to temperature exceeding wax crystallization point.
Installation method depends on a pipeline design (buried, surface), length, diameter and angle of expansion joints.
WEUH has successfully been used on the oilfields of LUKOIL, ROSNEFT, GAZPROM, TNK-BP, SurgutNeftegas, Kazmunaineftegaz, Kirgizneftegaz and other oil produsers and, having got good reputation, is successfully applied by the above mentioned companies for prevention of wax accumulation. Units are maintained in all climatic zones, from the South up to the far North, solving the problem of long-term trouble-free work of wells, having shown the high economic efficiency.
At all wells equipped by electrical cable Units WEUH there has been identified well production rate increase by 10-30 %. Moreover, the wells equipped with ESP, the equipment lifetime continuity increased up to 700 and more days which appeared to be twice longer that it had been before – and due to nonstop work of the pump, and due to decrease in loading due to thinning down oil in the tubing.
Practical application of WEUH in oil production has shown, that a full recoupment period of units (for wells with production rate 25-35 cubic m /150-220 bbl/ daily and at continuous nonstop operation of a cable 50 KW) does not exceed 60 days, for more productive wells this period was two times shorter that allowed to lower expenses on production and reduce the cost price of extracted oil.
| STANDARD SET OF EQUIPMENT |
ADDITIONAL SET OF EQUIPMENT
Constructional cable features mean, first of all, its features of operation: its fastening on a well mouth and its working in the suspended position, at the raised temperature of heating strands, in aggressive gas-liquid environment. Therefore the cable except for wire-lines of load-bearing shield has the armored polymeric skin, and while using building cable lengths - from above 2000 meters (6500ft) - central load-bearing wire-line. For increase of cable reliability the heating conductors connected to various poles of a feed supply, are divided into groups through isolating wire bundles.
CONTROL DESK FOR CABLE HEATING
Heating Control Desk is designed for well heating control and heat tracing cable overload protection. The station is a metal weather-proof cabinet divided into three compartments: high-voltage, low-voltage and control compartments, frame support stand to be connected to the mounting platform flooring, and a termination cabinet (terminal box), 500х500х250 mm in dimension, which is to be installed directly in front of a well, for connecting heat tracing cable to the power feeder cable.
The Heating Control Desk accommodates:
The Control Desk is fully automatic and runs the following:
The Control Desk allows for data transmission to a dispatch control room or personal computer. In this regard it is possible to remotely monitor heating parameters on-line, correct input data, receive information from the station controller’ data backup archives without going out to the field. Data can be transmitted through one of the following communication channels: