RU2338053C2 - Method of tubing repair - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: invention concerns technics and technology of restoration of worn steel tubing. Method includes radiation monitoring, cleaning of external and internal surfaces of tubes from sediments and contaminations visual and instrument quality control, screw cutting and its quality control, proof by hydraulic pressure, threading of sleeves and torque member, marking and packing of tubes into package. Feature of invention is that into internal chamber of tube intended for repair it is introduced thin-walled electric-welded pipe-liner with glue-sealant preliminary applied on its external surface, and then they are effected by joint dragging in mode of dispensing by means of mandrel drawing through internal camber of liner.

EFFECT: increasing of corrosion resistance and bearing capacity of repaired tubes.

2 ex, 1 tbl

Description

The invention relates to the field of repair of steel and alloy products that were in operation, namely, to the technique and technology for the restoration of worn steel tubing (tubing).

During operation, tubing are subject to corrosion and erosion wear, as well as mechanical abrasion. As a result of the impact of these factors on the tubing, various defects are formed on their outer and especially inner surfaces, including ulcerations, caverns, risks, seizures, etc., which lead to a loss in the bearing capacity of the pipes, therefore, their further use for its intended purpose without appropriate repair is not possible. In some cases, repair of tubing by existing methods does not give a positive result due to the large size of the defects.

The closest technical solution to the proposed invention is the method of repair of tubing developed by OAO Tatneft, as set forth, for example, in the "Regulation on the procedure for quality control, restoration and rejection of tubing".

This method has been widely used in all oil companies in Russia.

The known method of repairing tubing establishes a specific procedure for performing technological operations of restoration repair and technical requirements for the quality of tubing that were in use (tubing used) and to be repaired. Restoration repair is carried out in the following sequence: radiation control of pipes; cleaning their inner and outer surfaces of asphalt, salt, paraffin deposits (paraffin deposits), corrosion products and other contaminants; visual control; patterning; flaw detection by physical methods; thread cutting and quality control at pipe ends (if necessary); clutch winding; pipe length measurement; hydraulic pressure test; marking; packing and sending pipes to consumers. The main technical requirements for the quality of the pipes that were in operation, sent for repair, establish standards for the curvature of the pipes and restrictions on their general and local wear. Defects and defects of tubing tubing must be no more than those for which the minimum residual wall thickness of the pipes specified in table 1 is ensured.

Permissible minimum wall thicknesses to be reconditioned, mm. Nominal sizes of tubing in accordance with GOST 633-80 Minimum wall thickness of NTKBU, mm The maximum allowable wear of the tubing wall thickness BU, mm Nominal nominal diameter of tubing, mm Nominal tubing wall thickness, mm 60 5,0 3.2 1.8 73 5.5 3.6 1.9 89 6.5 4.4 2.1

If on the surface of individual sections of the pipe there are unacceptable defects with dimensions exceeding the allowable, then such sections of the pipe are cut out, but the length of the remaining part of the pipe should be at least 5.5 m.

The disadvantages of this method of repair of tubing are:

- a significant limitation of the volume of tubing used for reconditioning due to the presence of unacceptable defects;

- the need to cut part of the tubing with unacceptable defects (such pipes or pipe parts are disposed of in scrap metal);

- reduced operational resource of repaired tubing used in comparison with new tubing.

The objective of the proposed technical solution is to increase the corrosion resistance and bearing capacity of worn tubing due to lining, which will increase the volume of maintainable pipes and use them for their intended purpose instead of purchasing and using new tubing. At present, Russian oil companies annually send about 200 thousand tons of pipes to replace worn tubing.

The problem is solved in that the proposed method includes the manufacture of a liner (pipe) according to special specifications, applying a sealing material to the outer surface of the liner and the inner surface of the tubing tubing BU, introducing the liner into the tubing tubing, distributing it, creating conditions for the polymerization of the sealing material primarily on an epoxy basis .

As a liner, a welded or seamless pipe made of ferrous, non-ferrous metals or alloys with increased corrosion resistance is used. The outer diameter of the liner is determined by the formula D _ln = D _vn.nt -Δ, where D _ln is the outer diameter of the liner; D _int.nkt - the actual internal diameter of the tubing tubing BU taking into account their real wear; Δ is the annular gap between the inner diameter of the tubing tubing and the outer diameter of the liner. The gap is determined based on the practical experience of free introduction of the liner into the internal cavity of the tubing tubing BU, as a rule, it ranges from 2-5 mm. The liner wall thickness is determined from the technical feasibility of its manufacture with a minimum value and from the economic feasibility of its use.

Example 1. As indicated in the description of the prototype, to restore the tubing BU is repaired in the following sequence: radiation monitoring; pipe cleaning from paraffin, processing; visual and instrument quality control; machining of pipe ends with threading and screwing up couplings; hydraulic pressure test. Statistical analysis showed that in this way, repair can restore up to 70% of the tubing of the used unit, the remaining pipes are disposed of in scrap metal. Refurbished tubing tubing after repair showed that their operational life is 15–25% less than that of new tubing.

Example 2. Pipe tubing BU, not meeting the technical requirements regulated by the existing technology (prototype) and indicated in Table 1, were repaired in the following sequence: radiation monitoring; pipe cleaning from ASPO, including shot peening. Visual and instrumental control established the presence of caverns, scuffs and worn parts on the inner surface, taking the wall thickness of the tubing tubing beyond the maximum permissible deviation. On experimental tubing tubing BU in different places along the length through holes were made through holes with a diameter of 3 mm. Welded thin-walled pipes made of corrosion-resistant steel with an outer diameter of 48 mm and a wall thickness of 2.0 mm were used as a liner. A sealing material 2 mm thick was applied to the outer surface of the liner and the inner surface of the tubing. At the front and rear ends of the tubing tubing BU were made sockets by introducing into the tubing tubing cone mandrel of the appropriate size and shape. A socket was also made at one end of the liner so that the inner surface of the socket of the rear end of the tubing tubing fit tightly with the outer surface of the socket of the liner. The liner was introduced into the tubing string with a gap between its outer diameter and the inner diameter of the tubing string equal to about 2.0 mm. The tubing tubing with a liner inserted into it was installed in the lunettes of the receiving table of the drawing mill. Pulling the mandrel through the inner cavity of the liner carried out joint deformation (distribution) of the liner and tubing BU. The working cylindrical part of the mandrel was designed so that the outer diameter of the tubing tubing after lining increased by 0.3-0.5% of its actual diameter before lining. The mandrel was pulled through the combined liner and tubing control unit by means of a rod, at one end of which a mandrel was fixed, and the other end was installed in the grips of the pulling cart of the drawing mill. After the distribution of the liner and the tubing of the control unit, the sealing material was polymerized at the workshop temperature. All pipes of the experimental batch withstood the tests for internal pressure in accordance with GOST 633-80. Bench tests of tubing tubing after this repair showed an increase in operational life by 5.2 times compared to new tubing. Maintainability tubing BU increased compared with the prototype and amounted to 87.5%.

The technical result from the use of the proposed facility is to increase the corrosion resistance and load-bearing capacity of worn tubing used, to increase the recovery volume of tubing used by increasing their maintainability. The economic result is to reduce the cost of servicing oil wells through the use of tubing after repair for its intended purpose instead of acquiring expensive new tubing, increasing the reliability and durability of bimetallic tubing due to giving the pipes high corrosion resistance provided by the corrosion resistance of the liner material.

Preliminary studies of patent and scientific literature available on the fund of the Ural State Technical University, Yekaterinburg showed that the set of essential features of the proposed invention is new and has not been previously used in practice, which allows us to conclude that the technical solution meets the criteria of "novelty" and " inventive step ”, and we consider its industrial applicability to be expedient and technically feasible, which follows from its full description.

Claims (1)

A method of repairing used tubing pipes (tubing BU), including radiation monitoring, cleaning the outer and inner surfaces of pipes from deposits and contaminants, visual and instrumental quality control, cutting and quality control of the threads, hydraulic pressure testing, screwing of couplings and safety parts , marking and packaging of pipes in bags, characterized in that a thin-walled electric-welded pipe is introduced into the internal cavity of the pipe intended for repair - a liner with pre-applied th at its outer surface sealant adhesive, and then they are co-drawability in dispensing mode by pulling the mandrel through the interior of the liner.