JPS58178908A - Oil collecting cable - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oil extraction cable used as a power supply line for a pump pumping crude oil.

In oil fields that do not have artesian gushing, pumps are used to pump up crude oil. Since the depth of an oil field is usually more than 1,000 meters, the oil extraction cable used as the power supply line for the pump is immersed in crude oil and water at a temperature of at least 100 degrees Celsius, which is heated by geothermal heat. They are placed in a special and harsh environment where they cannot be helped.

What determines the lifespan of oil extraction cables is the protective sheathing material, which blocks out oil and water and protects the insulation. Hitherto, lead or nitrile rubber has been used as this protective coating material. However, although lead has no problems with its properties, it is extremely heavy and has the disadvantage of being difficult to install due to its lack of flexibility.

On the other hand, unlike lead, nitrile rubber does not have the above-mentioned problems during installation, and it maintains excellent resistance to crude oil and water for a short period of time, but it has poor resistance to heat deterioration, so it cannot be used for long periods at high temperatures. There was a problem that it could not withstand continuous use for a period of time. That is, assuming a one year service life, the limit was at most 100°C.

The temperature in oil fields often exceeds 100 degrees Celsius, which is not sufficient for practical use.

The purpose of the present invention is to solve the above-mentioned drawbacks of the prior art, and to
The purpose of the present invention is to provide a new oil extraction cable that can be used for a long period of time in oil fields with temperatures above 00°C.

In order to find protective coating materials that can overcome the drawbacks of conventional materials, we focused on light and flexible polymeric materials.
A lot of research has been done.

As a result, fluororubber, silicone rubber, and 7-acrylic rubber have significantly better heat resistance than nitrile rubber, but conventional fluororubber, made of vinylidene fluoride and propylene hexafluoride, has poor water resistance. Silicone rubber was inferior in oil resistance and water resistance, and acrylic rubber was inferior in water resistance, and neither of them was suitable for the purpose.

On the other hand, fluororesin has good heat resistance and is excellent against crude oil and water, but it lacks flexibility and is problematic.

On the other hand, tetrafluoroethylene-propylene copolymer is a newly developed copolymer, and because it is highly flexible and contains fluorine, it has excellent heat resistance and crude oil resistance, as well as water resistance. It was also found to be very good.

The gist of the present invention is that as a protective coating material for oil extraction cables,
The point is that a crosslinked product of a composition mainly composed of a tetrafluoroethylene-propylene copolymer is used.

The tetrafluoroethylene-prohebilene copolymer used in the present invention includes, in addition to the main components tetrafluoroethylene and glopyrene, components that can be copolymerized with these, such as ethylene, isobutidine, acrylic acid and its alkyl esters, and methacrylic acid. and alkyl esters thereof, vinyl fluoride, vinylidene fluoride, hexafluorogopene, chloroethyl vinyl ether, chlorotrifluoroethylene, perfluoroalkyl vinyl ether, etc. may be appropriately contained therein.

In such a copolymer, the molar ratio of tetrafluoroethylene/propylene is 9515 to 30/70.
In particular, it is preferable to select from the range of 90,710 to 45,155 from the viewpoint of heat resistance, moldability, etc. Also, the content of components other than the main component, which may be added as appropriate, is usually 50 mol or less, particularly 60 mol or more. It is preferable to select from a range.

In the present invention, the protective coating material is formed from a crosslinked product of a composition mainly composed of the above-mentioned tetrafluoroethylene-propylene copolymer. Various additives such as fillers, pigments, lubricants, antioxidants, and stabilizers can be added. Such a composition has a Mooney viscosity of ML 1+ 4(1
00°C: 20 to 150, especially about 60 to 90, is preferable from the viewpoint of moldability during coating, surface condition of the coated product, etc., and the type of tetrafluoroethylene-propylene copolymer is selected so as to provide such Mooney viscosity. It is desirable to adjust the average molecular weight, composition, etc.

In the present invention, the formation of a crosslinked product can be carried out by the action of a chemical crosslinking agent or ionizing radiation, but from the viewpoint of preventing residual ionic impurities after crosslinking and simplifying the operation, a method using paloxide vulcanization is preferred. is preferable and can be adopted.

In this case, specific examples of the crosslinking agent include dibenzoyl peroxide, di'acyl peroxide, dicumyl peroxide, di-t-butyl peroxide, t-butyl peroxyacetate, t-butyl peroxy Monoperoxy compounds such as peroxy esters such as isogropyl carbonate, 1-butylperoxybenzoate, and 2,5-dimethyl-2,5-di(t-
butylperoxy)-hexane-6.2.5-cytatyl-2,5-di(butylperoxy)-hexane,
1,4-bis-(t-butylperoxyinglobil)ben/zene, 1,6-bi7-(t~butylperoxyinglobin-
Ingropil) benzene, 2゜5-dimethyl-2,5-
Z (penzoylpanioxy)-hexane, etc.
Examples include oxy compounds.

These may be used alone or in combination of two or more. The amount of such a crosslinking agent used is usually 0.1 parts per 100 parts of tetrafluoroethylene-propylene copolymer.
~10 parts by weight, preferably about 0.5 to 5 parts by weight is employed.

When forming the above-mentioned crosslinked product, crosslinking aids can be used in combination, such as allyl compounds, sulfur, organic amines,
Crosslinking aids such as maleimides, methacrylates, divinyl compounds, etc. may be employed.

Preferably, polyallylic compounds such as diallyl phthalate, triallyl phosphate, triallyl cyanurate, triallyl incyanurate, diallylmelamine, and para-benzoquinone dioxime, P.

Oxime compounds such as y-dibenzoquinonosioxime are used, and polyallylic compounds are particularly preferred.

The amount of the crosslinking aid added is 0.1 to 20 parts by weight per 100 parts by weight of the tetrafluoroethylene-propylene copolymer.
Parts by weight, preferably about 0.2 to 10 parts by weight, may be employed.

Next, the present invention will be explained in detail.

As shown in the figure, the structure of the cable consists of six insulating cores coated with ethylene propylene rubber as the insulating material 2 on the circumference of the conductor 1, which are twisted together, and the composition shown in Table 1 is placed on the periphery of the conductor 1 as the protective covering material 3. It uses objects.

The protective coating material was mixed using a rubber roll, then coated on stranded 6-core insulating cores using a 150 m/m extruder, and cross-linked by applying steam at 20 atmospheres for 5 minutes. I let it happen.

Table 1 also shows the deterioration characteristics of the cable. The deterioration characteristics were evaluated by checking whether or not cracks occurred when the cable was immersed in 100'c of crude oil and water and then wound around a rod with a diameter of 50 pieces. As can be seen from this result, the example of the present invention has 30
It is recognized that it is extremely stable, with no cranking even after a long period of time.

In contrast, conventional nitrile rubber (comparative example) has only about 6 months of strength.

As described above, according to the present invention, an oil extraction cable that can withstand high temperature and long-term use has been developed. The value of the present invention is considered to be extremely high at a time when the number of oil fields capable of producing artesian water is gradually decreasing.

Table 1 *Wrap around a rod with a diameter of 50m

[Brief explanation of the drawing]

The figure is a cross-sectional view showing an embodiment of the cable of the present invention.

Claims (1)

[Claims] 1. A cable used in a high temperature atmosphere in the presence of crude oil and water, characterized by using a crosslinked product of a composition mainly consisting of a tetrafluoroethylene-propylene copolymer as its protective coating material. cable.