RU2578291C2 - Method of producing bimetal string - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to a method for producing bimetallic tubing and can be used in production of pipe product or repair of tubing. Method includes cleaning of outer and inner surface of tubing from deposits and dirt made of carbon steel, low alloy steel or stainless steel thin-walled electric-welded pipes, drawing on its outer surface, adhesive sealant, introduction of tubing channel wall electrically welded pipes coated with glue . Method then includes performing combined deformation by distributing tubing and said electric-welded pipes, threading, quality control of resulting pipe and hydraulic pressure test. Thin-wall electric-welded tube is made of steel with content of sulphur and phosphorus impurities of more than 0.01 %. During combined deformation of tubing and electric-distribution pipe by providing an increase in diameter of electric welding pipes more than 18 % of original outside of its diameter.

EFFECT: technical result is to improve ductility and formability cold liner without breaking continuity of base metal and welded joints.

1 cl, 2 ex

Description

The invention relates to tubular products, namely to tubing made from structural materials (steels).

The closest technical solution to the claimed invention are the RF patent for the invention No. 2338053 "Method for repair of tubing" (1) and the RF patent for utility model No. 71755 "Tubing" (2).

About 170 thousand oil wells are in operation in the oil industry of the Russian Federation (see the journal “Oil and Gas Vertical” No. 15, 2014). The operational fund of tubing (tubing) is approximately 3.5 million tons. During the operation of the tubing, under the influence of mechanical stresses (from the dead weight of the pipes, the weight of the extracting product, the friction forces arising from the contact of the pump rods, making reciprocating motion inside the tubing channel with the inner surface of the pipes) and corrosion processes under the influence of aggressive components (hydrogen sulfide , carbon dioxide, etc.) contained in the produced fluid are worn out and must be replaced.

The number of annually replaced worn tubing is approximately 250 thousand tons for a total amount exceeding 10 billion rubles. The cost of replacing worn pipes can be reduced by increasing the operational life of the tubing.

When solving this problem - increasing the operational life of the tubing, it should be borne in mind that the pipes must have both high strength (up to 90 kgf / mm ² ) and sufficient corrosion resistance, and these properties, as is known from the technical literature, are opposite to each other - when increasing the strength characteristics of pipes, their corrosion properties will inevitably decrease. The two-fold task is to increase the strength characteristics of tubing and increase their corrosion resistance, which together provides a significant increase in the operational life of pipes and, on this basis, a decrease in material and financial resources in oil production, is solved by creating a bimetallic tubing.

A known method of manufacturing a bimetallic lined tubing (LNCT) is as follows:

- the previously used tubing is cleaned of asphalt-resin-paraffin deposits (ASPO), scale and other contaminants of the inner surface of the tubing using pipe roasting at a temperature of 400-450 ° C and subsequent cleaning of the inner surface by shot peening;

- make an electric-welded thin-walled pipe (liner);

- apply adhesive sealant to its outer surface;

- inject the liner into the channel of the cleaned tubing;

- jointly deform the liner and the tubing with the distribution so that a completely annular annular gap (between the inner surface of the tubing and the outer surface of the liner) is selected, and the joint deformation of the liner and the tubing (distribution) is 0.2-0.3% of the original outer tubing diameter;

- create conditions for the polymerization of adhesive sealant;

- The tubing and liner are securely glued to each other and work like a pipe with a monolithic wall.

The description of the patent for the invention (1) indicates that for the unhindered (free) introduction of the liner into the tubing channel, the outer diameter of the liner should be 5 mm less than the inner diameter of the tubing, and the manufacture of the liner is carried out according to special specifications. However, in these patents and other available technical literature, technical requirements for the quality of the liners are not given, but they are of great importance for the smooth conduct of the process of deformation of the liner by distribution, carried out in the cold state. Of particular importance is the level of plasticity of the liner and its ability to deform without destroying the base metal and the welded joint. The total deformation of the liner (distribution) consists of two terms: first, due to deformation, an annular gap is selected between the minimum inner diameter of the tubing and the outer diameter of the liner, which, according to (1), can be up to 5 mm, and then, due to subsequent deformation, the annular the gap between the maximum and minimum tubing diameters. The size of this annular gap is determined by the tolerances of the nominal dimensions of the diameter and wall thickness of the tubing in accordance with GOST R 52203-2004 (3).

Let us illustrate this with an example.

Example 1

Calculation of the possible difference between the minimum and maximum values of the inner diameter of the tubing is performed using pipes with a diameter of 73 × 5.5 mm as an example.

According to GOST 52203-2004 (3), the maximum permissible deviation of the outer diameter of seamless tubing is ± 0.8 mm. Limit - the minimum and maximum deviations of the tubing wall thickness, respectively: from -12.5% to + 6.0% of its nominal value (5.5 mm). Based on the foregoing, the maximum and minimum outer diameter of the tubing (at a nominal value of 73 mm) assumes the values: 73.8 mm and 72.2 mm. The maximum wall thickness (at a nominal value of 5.5 mm) will be:

Smax = 5.5 × 1.06 = 5.8 mm,

where 1.06 is a coefficient taking into account the maximum permissible thickening of the tubing wall (+ 6.0%).

The minimum value of the tubing wall thickness of 73 × 5.5 mm is

Smin = 5.5-5.5 × 0.125 = 4.8 mm,

where 0.125 is a coefficient taking into account the maximum thinning of the tubing wall thickness (-12.5%).

The maximum and minimum values of the inner diameter of the tubing 73 × 5.5 mm are determined by the formulas

where Dнар.max and Dнар.min - the maximum and minimum values of the outer diameter of the tubing;

Smin and Smax are the minimum and maximum values of the tubing wall thickness.

Substituting the corresponding values of the dimensions of the pipes and the tolerances in the formulas [1] and [2], we obtain:

- the maximum value of the inner diameter of the tubing 73 × 5.5 mm

dv.max = 73.8-2 × 4.8 = 64.2 mm,

- the minimum value of the inner diameter of the tubing 73 × 5.5 mm

dv.min = 72.2-2 × 45.9 = 60.4 mm

- the maximum difference between the maximum and minimum values of the inner diameter of the tubing 73 × 5.5 mm is:

Δ = 64.2-60.4 = 3.8 mm.

Based on the foregoing, a conclusion is drawn: in order to ensure a tight fit of the outer surface of the liner to the inner surface of the tubing and the bonding of these surfaces of the liner and tubing, the total maximum increase in the diameter of the liner when it is distributed during lining

- should be 5 mm to select the initial annular gap between the inner (minimum) value of the tubing diameter and the outer diameter of the liner and 3.8 mm to select the difference between the maximum and minimum values of the tubing inner diameter 73 × 5.5 mm.

Thus, the total required deformation by the distribution (increase in diameter) of the liner during the lining process is - 8.8 mm, which is 15% of the nominal outer diameter of the liner (57 mm).

Electric-welded thin-walled pipes are manufactured according to the standards GOST No. 10704, 10706, 10707, 11068 [4-7] from carbon, low alloy and stainless steels of grades: 10, 20, 10X12H10T, 10X17H13M2T, etc. As one of the main requirements for the quality of electric welded pipes the specified standards set a technical requirement - pipe distribution tests, ranging from 6% to 12%. Some standards for the manufacture of electric-welded pipes (for example, GOST 10706) do not establish distribution requirements at all.

Comparison of the maximum distribution rate of standardized electric-welded pipes, established by current standards [4-7] in the range from 6 to 12% and the necessary distribution of the liner - 15% when lining tubing, ensuring reliable fastening of the liners and tubing, leads to an unambiguous conclusion - electric-welded pipes made by current standards, may not be applicable as liners. The manufacture of liners should be carried out according to special specifications containing, as the main technical requirement for the quality of electric-welded pipes, their high plastic properties, confirmed by testing the distribution of the liners with the establishment of the distribution norm - an increase in the diameter of the liners by 18% of their nominal value.

The technical feasibility of manufacturing thin-walled electric-welded pipes with high plastic properties was confirmed experimentally.

Example 2

In the manufacture of coiled steel used for the production of thin-walled electric-welded pipes for lining tubing, they reduced the chemical content of sulfur from 0.040% according to GOST 1050-88 to 0.006% and phosphorus from 0.035% to 0.010%. Thin-walled electric-welded pipes (50 pieces) made of this coiled steel were subjected to heat treatment according to the regime of heating to 820-830 ° C, holding at this temperature for 10 minutes. And air cooling. 20 samples were made from pipes and tested by distribution. All samples passed the distribution test with an increase in their initial diameter by 18%.

50 lined tubing manufactured according to the proposed technology were found to be suitable for use in field oil production conditions. Destruction of the liners was not observed.

The technical result from the use of the claimed object lies in the possibility of an unhindered process of distributing electric-welded pipes during lining of tubing, which is achieved by increasing the ductility of the metal of the liner by selecting its chemical composition - harmful sulfur impurities of not more than 0.006% and phosphorus of not more than 0.010%.

The economic result is ensured by reducing the costs associated with tubing lining, compared with the costs in the manufacture of new tubing.

Claims (1)

A method of producing a bimetallic tubing, including cleaning the outer and inner surfaces of the tubing from deposits and contaminants, making thin-walled electric-welded pipes from carbon, low alloy or stainless steel, applying sealant glue to its outer surface, introducing the tubing into the channel thin-walled electrically welded pipes with adhesive, joint deformation by distributing tubing and said electric-welded pipes, threading, quality control obtained pipe and a hydraulic pressure test, characterized in that a thin-walled electric-welded pipe is made of steel with a sulfur and phosphorus impurity content of not more than 0.01%, and when combined, the tubing and the electric-welded pipe by distribution provide an increase in the diameter of the electric-welded pipe by more than 18% from its original outer diameter.