Novel underground mineral insulation oil-submerged pump cable

Abstract

The utility model discloses a novel underground mineral insulated oil-submerged pump cable, which comprises an armored metal belt positioned on the outermost layer, an insulated cable group positioned on the inner side of the armored metal belt and a preset steel pipe, and is characterized in that the insulated cable group comprises a plurality of mineral insulated cables which are linearly arranged; the mineral insulated cable sequentially comprises a conductor, an insulating layer and a cable sheath from inside to outside, the insulating layer is a magnesium oxide porcelain column tube with the granularity smaller than or equal to 5 micrometers and the purity larger than or equal to 99.5%, the preset steel tube comprises one or more stainless steel tubes, and the preset steel tube and the insulated cable set are arranged in a straight line side by side. The underground wiring end of the cable is connected with the electric submersible pump through the special intermediate connector, electric energy input is provided, safe and stable work of the electric submersible pump is ensured, when current passes through a cable conductor, the whole cable uniformly emits heat, generated heat energy is rapidly transmitted to a shaft, the effect of continuous heating is achieved, and the service life of the electric submersible pump is prolonged. The preset steel pipe has the functions of agent injection and signal transmission.

Description

TECHNICAL FIELD

[0001] The utility model relates to cable technical field, especially a novel downhole mineral insulation submersible pump cable. BACKGROUND

[0002] Petroleum industry is one of main energy of our country, along with our country to domestic each big oilfield unceasingly exploitation, well contain oil content greatly reduce, lead to the self -priming ability weaken. In order to increase the oil production, adopt various oil production method, the most used one is pumping unit (also known as head -knocking machine), its pumping efficiency is lower. Another is electric submersible pump unit, its pumping efficiency is higher. Therefore, electric submersible pump oil production technology has been more and more widely used, oil production depth is also more and more deep, the temperature, pressure, corrosion condition of electric submersible pump's working environment is also more and more high, each oilfield production site to the electric pump matched submersible cable's each performance puts forward higher requirement, and the existing ordinary submersible pump cable in the working condition 100 DEG C downhole, generally needs to be replaced in one year or one year and a half, such as in the working condition 150 DEG C high temperature downhole, can only run 2-3 months, already can not satisfy the scene production requirement.

[0003] At present, submersible pump cable can be divided into four types according to the insulating layer material: (1) polypropylene insulation, (2) EPDM insulation, (3) polyimide / F46 composite film + EPDM combined insulation, (4) fluoroplastic insulation. The inner sheath material can be divided into lead inner sheath and nitrile rubber inner sheath. The shortcomings of the existing submersible pump cable mainly include the following points:

[0004] (1) The temperature of the oil layer is too high, which causes the failure of the organic insulating material. With the increasing depth of oil exploitation technology, the temperature of the oil layer is also rising, and the temperature of most oil layers is around 100 DEG C. Some wells even exceed 150 DEG C. Under the condition of higher than the rated temperature of the submersible cable, the organic insulating material accelerates aging and cracking, and the insulating capacity decreases, which further causes the cable breakdown.

[0005] (2) Mechanical damage. During transportation and construction, improper operation, collision, extrusion and bending can cause damage to the insulating layer, which is a major form of cable damage. For example, the cable collides with the wellhead, the sharp edges or burrs in the wellbore cause damage, the cable clamp is too tight in the wellbore, which causes the sheath to deform severely and affects the insulating layer, etc.

[0006] (3) High pressure and corrosion cause damage to the insulating layer and the sheath. The pressure of the liquid and gas in the well has a serious impact on the working performance of the cable. Under high pressure and high temperature conditions, the corrosion of the liquid and gas in the well will be intensified, which will accelerate the aging and even failure of the cable insulating layer. Even the insulating material with oil corrosion resistance will lose its oil resistance under high pressure, and the oil corrosion resistance of the insulating material will decrease continuously under high temperature in the well.

[0007] (4) Control system failure or overload current impact damage. Due to the protection of the control system failure or overload, short circuit, protection setting time is too long, the cable for a long time to withstand the impact of large current, overheating, causing organic insulation layer material accelerated aging or melting, until the breakdown. Invention content

[0008] The utility model provides a novel downhole mineral insulation submersible pump cable, solved the high temperature resistance, high pressure resistance, corrosion resistance, high mechanical strength, overload capacity technical problem of cable. Can power supply for electric pump, can also heat for wellbore.

[0009] The technical solution of the utility model is as follows: a novel downhole mineral insulation submersible pump cable, including the armored metal belt in the outermost, the insulated cable group in the armored metal belt inside and the preset steel pipe, the insulated cable group includes the mineral insulation cable of linear arrangement of multiple, the mineral insulation cable includes conductor, insulating layer and cable sheath from inside to outside, the insulating layer is the magnesia ceramic column pipe of granularity 5um, purity 99.5%, the preset steel pipe includes one or more stainless steel pipes, the preset steel pipe and insulated cable group are in parallel and form a character.

[0010] The magnesia ceramic column pipe is made by dry pressing method: first, the magnesium oxide powder is impurity-removed, and the selected magnesium oxide must be high-purity seawater magnesium oxide powder with purity of 99.5% or above, then the high-purity magnesium oxide is subjected to 3-5 times of magnetic separation by using a strong magnetic separator to remove the magnetic metal inclusions in the powder until there is no magnetic adsorption particle on the surface of the magnet of the magnetic separator (magnetic separator model: TCXP50, output 20-30t / h, magnetic induction intensity >2500GS). Then, the magnesium oxide particles with relatively large particle size are sieved out by using a 200-325 mesh sieve to obtain high-purity magnesium oxide powder. After drying, a special binder is added to make it into a paste. The additive ensures that the preformed magnesia ceramic column pipe blank is pressed and formed, and makes the pressed magnesia ceramic column pipe blank easy to demold. Commonly used binders include cellulose, paraffin and other materials. The treated powder is sent to a press for pressing and forming into a ceramic column. The pressed magnesia ceramic column is placed in a storage box or conveyed by a conveyor belt to an electric furnace for calcination (calcination temperature is about 1200°C). The calcined ceramic column is sent to an assembly table. In order to prevent the ceramic column from being contaminated during assembly, it is first assembled into the pipe blank and positioned by a special core rod, and then the core blank is inserted. In order to avoid moisture absorption during assembly, the magnesia ceramic column should be assembled hot with a temperature of not less than 100°C.

[0011] Preferably, the conductor is one of a copper conductor, a copper-based alloy conductor or a nickel-chromium alloy conductor, and the power supply cable is only a copper conductor.

[0012] As a preference, the insulating layer is a magnesium oxide ceramic column tube composed of magnesium oxide powder and a binder compacted together.

[0013] As a preference, the cable sheath is one of stainless steel 304 / 321 / 316L or 825 alloy sheaths.

[0014] As a preference, the armored metal strip is one of galvanized steel strips, stainless steel strips or Monel steel strips.

[0015] The underground mineral insulated submersible pump cable of the present application is composed of an insulating cable group, a preformed steel pipe and an armored metal strip.

[0016] The insulating cable group, the preformed steel pipe and the magnesium oxide ceramic column are assembled into one body, and after assembly, repeated drawing and annealing processes are performed until the finished product is produced. During drawing, the speed is controlled to effectively ensure uniform deformation of the cable and prevent breakage due to excessive speed. The general speed is maintained at about 0.5 m / min. The annealing process is to soften the cable and remove the metal stress generated during drawing. The annealing temperature is maintained at about 1020°C.

[0017] The underground mineral insulated submersible pump cable of the present application is composed of an insulating cable group, a preformed steel pipe and an armored metal strip.

[0018] The underground mineral insulated submersible pump cable of the present application is composed of an insulating cable group, a preformed steel pipe and an armored metal strip.

[0019] (1) High temperature and low temperature resistance: the metal sheath does not melt or burn at the rated use temperature, and does not break at low temperature;

[0020] (2) Stable performance: the constituent materials are all inorganic materials, and their physical and chemical properties are relatively stable at the rated use temperature;

[0021] (3) Excellent mechanical strength: the metal outer sheath and the armored layer structure are strong and have high strength, and can withstand mechanical extrusion and bending;

[0022] (4) Long service life: the metal material and high-purity magnesium oxide do not have thermal aging problems, greatly reducing the frequency of replacement operations;

[0023] (5) Strong corrosion resistance: the armored layer steel strip and the outer sheath stainless steel material have good high pressure and corrosion resistance to crude oil;

[0024] (6) Multiple functions: has multiple functions such as transmission of electric energy, heating, injection, signal transmission, etc.

[0025] The downhole terminal of the cable is connected with the electric submersible pump through a special intermediate connector to provide power input and ensure safe and stable operation of the electric submersible pump. The cable body is bundled from the wellhead along the wellbore to the downhole, and when current passes through the cable conductor, the whole cable uniformly generates heat, and the generated heat energy is rapidly transmitted to the wellbore to achieve the effect of continuous heating. The wellhead outlet is connected to a special explosion-proof junction box, and precise control is realized through a matching electrical control system; the preset steel pipe can be used for injection and signal transmission, and the structure of the preset steel pipe can inject water, hydraulic oil or chemical viscosity reducer and other media into the downhole, so that the fluid viscosity is reduced, the heavy oil development and transportation capacity are effectively improved, and various monitoring sensors can be put into the downhole to collect temperature, pressure, viscosity, liquid level and other signals in real time and feed back to the ground receiving system; different sheath materials are selected according to the temperature, pressure, corrosion and other conditions of each well, and the excellent properties of oil resistance, pressure resistance, high temperature resistance and corrosion resistance of the cable itself are very suitable for use in the harsh downhole environment, thereby ensuring the safety and smoothness of oil exploitation. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is a structural schematic view of the utility model.

[0027] In the figure: 1, armored metal belt; 2, cable sheath; 3, insulation layer; 4, conductor; 5, preset steel pipe. DETAILED DESCRIPTION

[0028] In combination with the drawings Figure 1 Further description is made on the novel downhole mineral insulated electric submersible pump cable of the utility model.

[0029] The novel downhole mineral insulated electric submersible pump cable of the utility model comprises an armored metal belt 1 located at the outermost layer, an insulated cable group 2 located at the inner side of the armored metal belt 1 and a preset steel pipe 5, the insulated cable group comprises a plurality of linearly arranged mineral insulated cables, the mineral insulated cable comprises a conductor 4, an insulation layer 3 and a cable sheath 2 from inside to outside in sequence, the insulation layer 3 is a magnesia ceramic column pipe with a particle size ≤5um and a purity ≥99.5%, and the preset steel pipe 5 comprises one or more stainless steel pipes.

[0030] Further, the conductor 4 is one of a copper conductor, a copper-based alloy conductor or a nickel-chromium alloy conductor, and the power cable is only a copper conductor.

[0031] Further, the insulation layer 3 is a magnesia ceramic column pipe composed of magnesia powder and a binder.

[0032] Further, the cable sheath 2 is one of a stainless steel 304 / 321 / 316L or 825 alloy sheath.

[0033] Further, the armored metal belt 1 is one of a galvanized steel belt, a stainless steel belt or a Monel steel belt.

[0034] The working principle of the utility model is: the downhole wiring end of the cable is connected with the submersible electric pump through a special intermediate connector to provide power input and ensure the safe and stable operation of the submersible electric pump. The cable body is bundled from the wellhead along the wellbore to the downhole. When there is current through the cable conductor, the whole cable uniformly heats up, rapidly transfers the generated heat energy to the wellbore and achieves the effect of continuous heating. The wellhead outlet end is connected to a special explosion-proof junction box and is precisely controlled through a matching electrical control system. The preset steel pipe can be used for injection and signal transmission. The structure of the preset steel pipe can inject water, hydraulic oil or chemical viscosity reducer and other media into the downhole, reduce the viscosity of the fluid and effectively improve the development and transportation capacity of thick oil. In addition, various monitoring sensors can be put into the preset steel pipe to collect temperature, pressure, viscosity and liquid level signals from the downhole in real time and feed back to the ground receiving system. Different sheath materials are selected according to the temperature, pressure and corrosion of each well condition. In particular, the excellent properties of the cable itself, such as oil resistance, pressure resistance, high temperature resistance and corrosion resistance, are very suitable for use in the harsh downhole environment, thereby ensuring the safety and smoothness of oil exploitation.

[0035] The utility model discloses a downhole mineral insulation submersible pump cable prepares and insulates cable group, oxygen

[0036] The magnesium porcelain column and the prefabricated steel pipe are assembled into an integrated whole, and after assembly, repeated drawing and annealing processes are carried out until the finished product is produced. During drawing, the speed is controlled to effectively ensure uniform deformation of the cable and prevent breakage due to excessive speed. The general speed is maintained at about 0.5 m / min. The annealing process is to soften the cable and remove the metal stress generated during drawing. The annealing temperature is maintained at about 1020 DEG C.

[0037] The magnesium oxide ceramic column tube is made by dry pressing method: firstly, the magnesium oxide powder is required to be impurity-removed, the selected magnesium oxide must be high-purity seawater magnesium oxide powder with purity ≥99.5%, then the high-purity magnesium oxide is selected to be magnetically separated for 3-5 times by a strong magnetic separator to remove the magnetic metal inclusions in the powder, until the surface of the magnet of the magnetic separator is not magnetically adsorbed particles, (magnetic separator model: TCXP50, yield 20-30t / h, magnetic induction intensity >2500GS). Then the magnesium oxide particles with large particle size distribution are sieved out by using a 200-325 mesh sieve to obtain high-purity magnesium oxide fine powder. After drying, a special binder is added to make it into a paste. The additive can ensure the preformed magnesium oxide ceramic column tube blank to be pressed and molded, and can also make the pressed magnesium oxide ceramic column tube blank easy to demold. Commonly used binders include cellulose, paraffin and the like. The treated powder is sent to the press for pressing and molding into a ceramic column. The pressed magnesium oxide ceramic column is put into a storage box or conveyed by a conveying belt to an electric furnace for calcination (calcination temperature is about 1200℃). The calcined ceramic column is sent to an assembly table. In order to prevent the ceramic column from being contaminated during assembly, the ceramic column is first assembled into the tube blank and positioned by a special core rod, and then the required core blank is inserted. In order to avoid the ceramic column from absorbing moisture during assembly, the magnesium oxide ceramic column should be assembled hot, and the temperature should be not less than 100℃.

[0038] The above only describes the preferred embodiments of the present application, and all other embodiments obtained by those skilled in the art without creative labor should belong to the protection scope of the present application.

Claims

1. A new type of downhole mineral insulated electric submersible pump cable, characterized in that: The cable comprises an outermost armored metal strip, an insulated cable group inside the armored metal strip, and a preset steel pipe, the insulated cable group comprises a plurality of linearly arranged mineral insulated cables, the mineral insulated cable comprises a conductor, an insulation layer, and a cable sheath from inside to outside, the insulation layer is a magnesia porcelain column tube, the preset steel pipe comprises one or more stainless steel pipes, and the preset steel pipe is arranged in parallel with the insulated cable group.

2. A novel downhole mineral insulated electrical submersible pump cable as claimed in claim 1, characterized in that: The conductor is one of a copper conductor, a copper-based alloy conductor, or a nickel-chromium alloy conductor, and the power supply cable is only a copper conductor.

3. A new type of downhole mineral insulated electrical submersible pump cable as claimed in claim 1, characterized in that: The cable sheath is one of a stainless steel 304 / 321 / 316L or 825 alloy sheath.

4. A new type of downhole mineral insulated electrical submersible pump cable as claimed in claim 1, characterized in that: The armored metal strip is one of a galvanized steel strip, a stainless steel strip, or a Monel steel strip.

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