Logging Heating cables (LHC) serve the purpose of electrical-heating horizontal wells and wells equipped with electric submersible pump (ESP), by being brought down directly to production tube into the fluent of recovered fluid in order to prevent the appearance of dry fraction screening of paraffin hydrate.
Heating cables are developed on the basis of TU 3585-002-24118545-2004, they are certificated and разрешены к применению by the Federal Service on ecological, technical and atomic supervision, and are covered by the patent of the Russian Federation #35823.
Reference Designation of the Heating Cables looks the following way:
*Letter index "T" is put only in case of presence of temperature gauge.
Examples of reference designation: KGnCEC-10x2,15-60-100-AJ - Logging Heating cable, with 10 copper enameled conductors with cross section 2,15mm? in isolation from polypropylene, nominal breaking strength 60kN, max working temperature 100?C in armored jacket.
The absence of letter designation concerning material and isolation of heating elements is possible. In this case copper is considered to be the material of conductor and polypropylene - the material of isolation.
Depending on modification of heating elements the following types of heating cables and their constructive peculiarities can be enumerated.
|
Cable type |
Constructive peculiarities |
Power supply |
|
KGhC-1K KGhA -1K |
Logging heating cable with central current-conducting strand, with one coaxial heating current-conducting strand |
Direct-current |
|
KGhCP-12/2 KGhAP-12/2 |
Logging heating cable with gauges with twelve isolated copper or aluminum current-conducting heating strands divided into two groups by isolating flexible tubing |
Direct-current |
|
KGhCP-12/4 KGhAP-12/4 |
Logging heating cable with twelve isolated copper or aluminum current-conducting heating strands divided into three groups by isolating flexible tubing |
Three-phase alternating current Direct-current |
Table S.5.1
Cable constructive peculiarities involve first of all, peculiarities of its exploitation: - mounting at well-spring and work in suspension, at the increased temperature of heating strands and aggressive gas-fluid environment. Therefore, besides the wires of logging armor the cable possesses armored polymer jacket, and at the applying of cable factory length more than 1000 meters - it has central logging wire bundle.
In order to increase cable's durability heating conductors, attached to different poles of power supply, are divided into groups through isolating flexible tubings.
Basic constructions of heating cables manufactured by Pskovgeocable Ltd
|
|
|
|
|
KGhC-1K16/8-50-90-AJ |
KGhCPT-12/2x2,0-55-100-AJ |
KGhAP-14/4x2,0-60-100-AJ |
Designation of construction elements.
- Current-conducting strand.
- Isolative jacket.
- First layer of armor of logging wire bundle.
- Second layer of armor of logging wire bundle.
- Control wires of temperature gauges.
- Isolative core jacket.
- Current-conducting strands of heating elements.
- Dividing isolative flexible tubings.
- Isolative jacket of heating element.
- First layer of armor of heating cable.
- Second layer of armor of heating cable.
- Jacket
Basic characteristics of heating cables are given in tables S.5.2, S.5.3.
Mechanical Properties of Heating Cables
|
Cable Type |
Breaking strenght no less |
Used length |
Max working temperature |
Outside diametr |
Weight |
Weight in fresh water |
|
kN |
m |
degr.С |
mm |
Kg/km |
Kg/km |
|
|
KGh C-1К16/8-55-90-AJ |
55 |
1100 |
90 |
25,8 |
1027 |
|
|
KGh CP-12/2x2,0-55-100-AJ |
55 |
1100-1300 |
100 |
25,4 |
1020 |
|
|
KGh CP-12/4x2,0-50-100-AJ |
50 |
1100-1300 |
100 |
26 |
1056 |
|
|
KGh CP-12/4x2,0-60-100-AJ |
60 |
1300-2000 |
100 |
26 |
1180 |
|
|
KGh AP-12/4x2,0-50-90-AJ |
50 |
900-1100 |
90 |
26 |
856 |
|
|
KGh AP-14/2x2,0-50-90-AJ |
50 |
1000-1200 |
90 |
26 |
865 |
|
Table 4.5.2
The technology of application of heating cables boils down to the following simple operations: the descent of cable in production tube, connection to the instrument board and the supply of the necessary electrical power for maintaining the temperature on the shaft of the well higher than the temperature of precipitation of paraffin and hydrates.
Electrical Properties of Heating Cables
|
Cable Type |
Number and section of conductor |
Number of group |
Resis- tanse (one conductor) |
Insolulation condactiv |
Max working current (D / A) |
Type of supply voltage |
||
|
n |
x |
mm2 |
|
Ohm/km |
Mom*km |
A |
|
|
|
KGh C-1К16/8-55-90-AJ |
1 1 |
x x |
16 8 |
1+1 |
1,1 + 2.4 |
20 000 |
115 / - |
D |
|
KGh CP-12/2x2,0-55-100-AJ |
12 |
x |
1,76 |
6+6 |
10,8 |
20 000 |
125 / - |
D |
|
KGh CP-12/4x2,0-50-100-AJ |
12 |
x |
1,76 |
4+2+2+4 |
10,8 |
20 000 |
130 / 88 |
D / A |
|
KGh CP-12/4x2,0-60-100-AJ |
12 |
x |
1,76 |
4+2+2+4 |
10,8 |
20 000 |
130 / 88 |
D / A |
|
KGh AP-12/4x2,0-50-90-AJ |
12 |
x |
2,0 |
4+2+2+4 |
15,8 |
20 000 |
110 / 73 |
D / A |
|
KGh AP-14/2x2,0-50-90-AJ |
12 |
x |
2,0 |
7+7 |
15,8 |
20 000 |
120 / - |
D |
Table 4.5.3
Descent of cable is carried out with the help of the geophysical winch (for example PKS -5, PKS -7). The process of the descent of cable corresponds to standard works with the geophysical instruments and is carried out analogously. Fastening of the cable on the mouth is produced through the stuffing box device by a special lock (it is included into delivery set).
To control the warming up and protection of the heating cable "Pskovgeocable'" produces heating-up control stations, that make it possible to monitor the work of all modifications of the heating cables manufactured by "Pskovgeocable". Heating-up control stations have the capability to check in the real regime of time with the record into the archive the working parameters of heating cable and condition of equipment of control cabinet (current, stress, the temperature of heating cable along the length, the presence of the leakage current, the temperature in the ejected conduit, temperature inside the cabinet of control, the state of equipment for control). Furthermore, there is a possibility to organize the transmission of current and archival data to the dispatching board, along the wire communication line or through the radio-modem.
To perform the heating of wells which are more than 1300m deep application of heating cable is carried out with increasing transformer of TMPN type.
The experience of users confirms that the application of technology of the electric-warming of the oil wells by heating cables make it possible:
Consumers' experience proves that application of technology of electrical-heating of oil wells with heating cables allows:
- To exclude the cleaning of production tube with mechanical scrapers.
- To increase the time between overhauls of work of underground well equipment.
- To decrease losses of oil resulted from fault time of well during round-trip scraping, processing by hot oil.
- To stabilize the work of electric submersible pump.
- To stabilize the work of reservoir, to decrease water contaminability of oil and to increase dynamic level.
- To exclude well capital repair.
The main advantages of paraffin removal technology are once-and-for-all expenses on purchasing installation, descent of heating cable and starting of control system in the work.
Accumulated since 2001 experience of exploitation of heating cables shows that today electrical-heating is the only universal and the most effective means of control over paraffin.
Since 2004 Pskovgeocable Ltd. carries out researches on heating of wells equipped with sucker-rod and deep-seated pumps, with the aid of the heating cable, installed into the space behind the tube. Heating cables have flat form and are mounted from outer side of production tube analogously with cable for the nourishment of oil submersible pump. Cable nutrition is carried out from the instrument board with control of basic parameters of work of installation. Tests carried out on land deposits of Volga region have showed high effectiveness of cable work even in periodic behavior, excluding completely processing of wells with hot oil.
