Many contemporary technologies of an increase in crude-oil yield of layers consist in the application of technological liquids with the high aggressiveness (acidic, alkaline workings). With the entry of cable into the well subjected acidic working, embrittlement of the wires of armour is occurs, cable goes out of order. Analogous problems appear also with the work in the wells with the high content of hydrogen sulfide, and such wells are encountered practically everywhere in the territory of Russia. Practice shows that the reliability of standard geophysical cable or rope with the work in the wells with the aggressive medium is insufficient. The problem of an increase in the durability of cable is possible to solve by the application of the corrosion-resistant noncorrosive wire; however, the cost of this cable into dozen of times higher than cost of usual cable or rope. Since 2004 our enterprise mastered the production of cables with the armoured jacket. The armoured cables are developed by "PskovGeoKabel" Ltd and protected by patent RF 35901. The distinctive special feature of this group of cables is the presence of the reinforcing steel-polymer jacket. Jacket is the layers of the wires superimposed with 20-50 % overlaps and flooded by polymeric material. Polymers, possessing splendid chemical stability to the action of aggressive substances, are outstanding external protection for the wires of armour. Filling with polymer is made under the large pressure with the preheating of intermediate shell and the complete adhesion of external and intermediate shells is achieved and the absence of voids in the inter layers space. The wire is steel framework for the polymeric material of shell.
 |
 |
|
Usual cable |
Armoured cable |
In comparison with the standard load-bearing cables the cables with the armoured shell have the following advantages:
1) Resistance to the action of aggressive media, for example media with the high content of hydrogen sulfide, carbon dioxide, acids. This is reached by the presence of the polymeric shell, steadfast to the chemical action. Use of cables of this type is possible with the operations in the wells subjected to acidic and alkaline workings, also in the wells with the content of hydrogen sulfide is more than 15%.
2) Corrosion and mechanical resistance of cable rises, what is especially important with the significant period between the lowering-raising operations. Polymeric belt has antifriction properties and it prevents the straight mechanical contact of the wire of cable with the walls of well and between themselves, therefore the mechanical abrasion of wire is absent and zinc coating remains in the initial state considerably longer fulfilling its shielding functions;
3) The increased axial hardness of cable makes it possible to effectively conduct studies in the uncased wells and in the intertube space of the wells of the acting fund. In this case the probability of appearance of loops and seizure of drilling instrument as result of pulling the loop around pump compressor tube repeatedly decreases;
4) Outer covering prevents such defects of armoured sheath as the breaks of wires in the layer and "lamps";
5) The completely round surface of cable makes it possible to effectively condense it on the mouth, preventing the ejections of liquid and environmental pollution, it decreases the wear of sleeves and sealing devices.
Technical specifications of cables with armoured shell
Electrical specification of load bearing cables with armoured shell
Especially significant results were obtained by OJSK "Permneftegeofizika". The majority of the layers of the Perm province is characterized by the high concentration of salts, in addition to this a number of wells contain hydrogen sulfide. Initially work on a study and the mastery by swabbing of the well №132 of the Kolninsky layer was carried out on the standard geophysical cable. In the operation consecutively after 2-3 lowering-raising operations 4 construction lengths of the cable of brand KG 3x0,75-60-150 were out of order. After conducting of additional studies it was explained that this well contains 7% of hydrogen sulfide. Then a decision was taken to further performing the work on the cable of brand KG 3x0,75-55-90 Oa given by "PskovGeoKabel" Ltd for the field testing. In the course of 4 days the necessary volume of geophysical works and mastery of the well by swabbing were made. As results of work the management of OJSC "Permneftegeofizika" accepted the further use of the cables with the armoured jacket.
