Electricity: conductors and insulators – Conduits – cables or conductors – Conductive armor or sheath
Patent
1992-12-23
1995-04-25
Nimmo, Morris H.
Electricity: conductors and insulators
Conduits, cables or conductors
Conductive armor or sheath
174102R, 174109, 174121A, 174122G, H01B 722
Patent
active
054101069
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a cable (hereinafter referred to as "electric feed cable") utilized to supply electric power to a pump (hereinafter referred to as "oil well pump") for pumping crude oil from an oil well. In particular, this invention relates to a cable which possesses excellent thermal resistant and oilproof properties, as well as superior mechanical strength, while at the same time is not damaged even when repeatedly exposed to large changes in pressure.
Prior Art
Both high temperatures and high pressures are present in the environment within an oil well excavated for the purpose of pumping crude oil to the earth's surface (i.e., 160.degree. C. at 100 kg/cm.sup.2). Additionally, this environment also contains a hostile atmosphere formed from a mixture of gaseous crude oil, water vapor and such corrosive gases as hydrogen sulfide. Accordingly, a cable which is to be used in this type of environment for supplying electric power to an oil well pump must by necessity possesses thermal resistant and oilproof properties, as well as have sufficient mechanical strength and electrical insulating properties. Heretofore, there has been well known a cable used for this purpose as shown in FIG. 2, having a multi-conductor structure in which a plurality (three in FIG. 2) of conductors, around the outer surface of which an insulating layer 2 is formed, are cabled together and fill a jacket 3, the surface of the jacket 3 being further covered with a metallic armor 4.
However, while it is true that the conventional cable as described above has good mechanical strength, after repeated insertion into and withdrawal from an oil well within the high temperature-high pressure environment, it becomes impossible to avoid the breakdown of the cable caused by pressure changes. In other words, the following problems are present in the use of conventional cable as described above. When a cable is inserted into an oil well, gaseous components of the crude oil penetrate to the inside of the cable under conditions where volumetric expansion of the gaseous components is restricted. Since, in this case, through provision of jacket 3 and metal armor 4, the cable is provided sufficient protection, no damage is incurred from the gaseous component of the crude oil which has penetrated into the cable. However, when the cable is removed from the high pressure environment within the oil well, the pressure impinging on the cable drops rapidly and, due to this pressure drop, the gaseous components of the crude oil which have penetrated into the cable give rise to volumetric expansion, causing small holes to form in the cable. When such holes are formed in the cable, the breakdown in the electrical insulation of the cable progresses and eventually the electrical insulation of the cables becomes no longer sufficient. Furthermore, when a cable in which such holes have formed is again inserted into an oil well, the gaseous components of the crude oil permeate in these holes. Furthermore, when the cable is again withdrawn, the holes become even further expanded, leading to degradation of the cable.
It is therefore an object of the present invention to provide an electric feed cable for an oil well pump which, by preventing the formation of holes due to decompression upon withdrawal of the cable from an oil well, does not incur any damage, even when repeatedly inserted into and withdrawn from an oil well.
SUMMARY OF THE INVENTION
The electric feed cable for an oil well pump of the present invention is a multi-conductor cable in which a plurality of conductors, around the surface of which an insulating layer is formed, are cabled together, filling jacket 3; this multi-conductor cable possessing a protective layer formed by wrapping thermal resistant tape around the surface of at least one of either the insulating layer or the jacket.
Because of the provision of a protective layer formed by wrapping thermal resistant tape as described above, it is possible to prevent the format
REFERENCES:
patent: 3265808 (1966-08-01), Binch
patent: 3299202 (1967-01-01), Brown
patent: 3413408 (1968-11-01), Robinson
patent: 3509269 (1970-04-01), Elliott
patent: 3566009 (1971-02-01), Lamond et al.
patent: 3742363 (1973-06-01), Carle
patent: 3832481 (1974-08-01), Boyd et al.
patent: 3900701 (1975-08-01), Bayles et al.
patent: 4284841 (1981-08-01), Tijunelis et al.
patent: 4453035 (1984-06-01), Neuroth
patent: 4515993 (1985-05-01), MacKenzie
patent: 4665281 (1987-05-01), Kamis
patent: 5086196 (1992-02-01), Brookbank et al.
Haruyama Katsuo
Nishino Hideharu
Oogawara Touru
Sunazuka Hideo
Tanida Mitsutaka
Fujikura Ltd.
Nimmo Morris H.
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