General description

Two dispensable basic conditions are needed for the recovery of heavy oil reservoir : 1)heavy oil can flow continuously into the wellbore from the formation . 2)heavy oil in the wellbore can be artificially lifted successively upto the surface.The most commonly used method to keep the heavy oil flowing in the formation and flowing to the surface from the wellbore is the electric heating.Intermediate frequency electric heating is the patent technology developed & manufactured by our corp.The appurtenances of the technology were rated by 5 ministris and commissions including the ministry of science & Technology as the “national key product”.

This technology so far has been widely used on site since early 1990 s .Heating location expands from above the pump to underneath the pump and power supply provided from working frequency develops into intermediate frequency.It's application has been extended from it's original heavy oil recovery to the light oil recovery because of the use of new pressurized running process.

Constructure and heating principle

• construction

smart intermediate electric heating system consists of 4 major parts:program controlled smart intermediate power supply,hollow sucker rod , special heating cable and hollow circulating pump.

• hearing principle

When single phase AC passes through the heating cable and hollow sucker rod , It generates a skin effect on the inner wall of the hollow sucker rod. Electric current concentrately passes within the inner wall of the hollow sucker rod whereas the outer wall of the hollow sucker rod has no electricity,forming a very good insulator itself,therefore a skin effect heater has been constituted in a series loop formed between hollow sucker rod and heating cable.

The skin effect has two advantages,firstly,it has reduced the cross section of the steel pipe,through which the current passes,and has increased AC impedance,thus large heating power can be gained with lower heating current;secondly,only drain voltage and drain current exist on the surface of hollow sucker rod , which make heating system very safe.

Technical features and main parameters

• technical features

Smart electric heating oil recovery technology is researched and developed on the basis of working frequency electric heating oil recovery technology ,beside its simple structure , easy operation and flexible modulation , it also has a wide application of : heating both over the pump and underneath the pump ; it has no interference to the grid and save energy ; it posses strong anti-interference ability , reliable operation and long service life ; mechanical mandatoty open & close mechanism . for both traveling valve and standing valves of the sucker rod pump ; automatic control of wellhead tempreture and electric heating current of the system ; high automatic instrumentation.

• main parameters

The heating power oil well needed can be calculated by the program. Normally heating power used for heavy oil well is from 50~60w/m , special-heavy oil well is from 60-80w/m and super heary oil well is from 80-100w/m. When heating for the high pour point crude oil wells , heating power is 40-50w/m for the high pour point below 50 ℃ , 50-60w/m for the high pour point above 50 ℃ .The electric frequency used for those oil wells , is normally between 300-500Hz.

Application

The smart electric heating oil recovery technology can be widely used for various kinds of oil wells incuding light oil well , heavy oil well and high pour point well etc with the depth ≤ 2000 mters. So far more than one thousand sets of smart electric heating equipments have been used in liaohe oil field,shengli oil field and xinjiang oil field.