RU2838883C1 - Polymer reinforced pipe with transparent reinforcing frame and its diagnostics method - Google Patents

Abstract

FIELD: pipelines.

SUBSTANCE: invention relates to oil and gas industry, in particular to multilayer polymer reinforced pipes that can be used for collection and transportation of oil, water, gas, chemical reagents. Reinforced polymer pipe contains successively applied on inner polymer thermoplastic shell outer surface reinforced layer and outer polymer thermoplastic shell, wherein said reinforcing layer is composed of unidirectional tapes consisting of materials sintered by polymer matrix.

EFFECT: pipeline design, which allows its diagnostics, due to which operation reliability is increased.

8 cl, 3 dwg

Description

AREA OF TECHNOLOGY

The invention relates to the oil and gas industry, in particular to multilayer polymer reinforced pipes that can be used to collect and transport oil, water, gas, and chemical reagents. The technical result of the claimed invention is a pipeline design that allows for its diagnostics, thereby increasing the reliability of operation. The polymer reinforced pipe contains a reinforced layer and an external polymer thermoplastic shell sequentially applied to the outer surface of the inner polymer thermoplastic shell, wherein the reinforcing layer is made of unidirectional tapes consisting of materials sintered together by a polymer matrix.

PRIOR ART

Composite thermoplastic pipes are described in API Specification 15S, "Spoolable Reinforced Plastic Line Pipe", 2nd edition, March 2016 and GOST R 59834-2021 "Field pipelines. Flexible polymer reinforced pipes and fittings to them. General specifications". Pipes manufactured in accordance with these requirements are an inner pipe consisting of a thermoplastic polymer, onto which a composite reinforcing layer is applied, having a cohesive connection with the inner layer and the outer thermoplastic polymer layer. In some cases, a polymer tape reinforced with unidirectional fibers is wound onto the inner pipe without forming a bond.

According to standards, the service life of a pipe is determined on the basis of long-term hydrostatic tests, the conditions of which do not cover all possible operating conditions of pipelines and, accordingly, cannot ensure the reliability of information on the actual service life of such pipes.

The most likely cause of failure of these pipelines is a decrease in the strength of the reinforcing layer during operation, caused by the processes of destruction of the reinforcing fibers due to the diffusion of the transport flow medium, which can manifest itself as a general decrease in the strength of the fiberglass, or in the form of destruction of individual fibers.

Due to the fact that the main stresses arising during operation are absorbed by the reinforcing frame of the pipe, the task of diagnosing the technical condition of the reinforcing frame is the most significant for assessing the condition of polymer reinforced pipes as a whole.

A design of a reinforced polymer oil field pipe is known according to patent WO1995007428, which consists of a core based on thermoplastic, to which a composite material consisting of reinforcing fibers and thermoplastic is seamlessly attached.

A design of a reinforced polymer oil field pipe is known according to patent RU 204558 U1, which consists of an inner pipe made of a thermoplastic polymer, a composite material surrounding it, consisting of a thermoplastic polymer of a composite material and unidirectional continuous reinforcing fibers, and an outer polymer shell, in which the inner pipe, the composite material and the outer shell are smoothly fused together by means of heating, characterized in that the composite material of the composite pipe contains at least one elastic interlayer made of a thermoplastic polymer material, the elastic modulus of which is 20...3600 MPa less than the elastic modulus of the thermoplastic polymer of the composite material, wherein the elastic interlayer is fused with the composite material by means of heating.

A design of a flexible pipeline for transporting various media and a pipe for its manufacture RU 7245550 is known, which is intended for transporting various media overland with laying on the land surface, in a trench, in an embankment, on an overpass or in a sleeve. The flexible polymer reinforced pipe contains an internal liner, a reinforcing layer, a separating layer, a lining shell. The reinforcing layer may contain such elements as metal tapes, metal wires, polymer tapes and polymer threads in any combination or consist of only one item. Additionally, a multilayer auxiliary shell may be located over the lining shell, containing at least one separating layer and a protective shell. The auxiliary shell may contain a conductor layer and a heat-insulating layer. The conductor layer may contain electrical signal, power, heating, optical conductors and a communication channel, as well as a long pipe damage monitoring sensor.

A design of a reinforced polymer oil field pipe according to patent RU 7245550 is known, which provides high-temperature fiber-reinforced polymer oil field pipes and a method for producing such pipes. The oil field pipes are formed from a composite material containing a high-strength fiber material and a high-temperature thermosetting resin. The method comprises stages in which the high-strength fiber material and the high-temperature thermosetting resin are combined to create a highly effective composite material, and such a composite material is wound around a core while supplying sufficient heat to this material at the winding location to maintain the temperature of the thermosetting resin above its melting point. Additionally, the design may use coating materials that are applied to the composite material in such a way that external and internal effects of the environment on the composite material are prevented. Sensors may be embedded between the coating material and the composite material, including wireless sensors, wires, optical fibers and other devices.

Known designs do not allow for reliable diagnostics of the pipe condition along its entire length. Optical fibers used in the pipeline design are located above the reinforcing cord and serve to transmit information between sensors.

The objective of this utility model is to develop a pipe design that will provide the ability to diagnose the reinforcing frame.

DISCLOSURE OF INVENTION

The objective of the invention is to develop a design for a polymer reinforced pipe that allows for timely diagnosis of the destruction of the reinforcing frame, as the most critical part of the structure.

The technical result of the claimed invention is a polymer reinforced pipe consisting of an internal and external polymer thermoplastic shells and a reinforcing frame located between the shells, consisting of reinforcing tapes fused together. The reinforcing frame is formed by a winding of reinforcing tapes around the internal shell. The reinforcing tapes consist of unidirectional fiber materials (fiberglass, carbon fiber, carbon, Kevlar, aramid, but not limited to) located in a thermoplastic matrix similar in composition to the internal and external shells, to ensure sintering. To ensure the possibility of diagnostics, optical translucent fibers (quartz, plastic, but not limited to) are included in the reinforcing tape, which provide light transmission along the entire section of the pipe. The result is a reinforcing frame in which optical fibers are uniformly integrated.

The inclusion of optical fibers in reinforcing tapes occurs during the manufacturing process by alternating reinforcing and optical fibers.

The strength and diameter of the reinforcing and optical fibers must be selected to match each other as closely as possible to ensure equivalent stresses experienced by the reinforcing and optical fibers during pipe operation.

Depending on the required level of reinforcement cord control, the number of integrated optical fibers in the prepreg can vary.

The angle of the winding of the reinforcing prepregs from 1 to 89° to the axis of the pipe (at least one winding of the reinforcing prepreg has a winding direction opposite to the axis of the pipe).

The number of layers of reinforcing tapes and the direction of the layers are selected based on the required characteristics of the pipe.

The inner and outer shells can be made of thermoplastic polymers (polyethylene (PE, HDPE, LDPE), polyethylene of high (increased) heat resistance PE-RT (Polyethylene of Raised Temperature resistance), cross-linked polyethylene (PE-X or XLPE, PE-C), polypropylene (PP, PP-R), polypropylene copolymers, polybutene (PB, PB-1), polybutene copolymers, polyvinyl chloride (PVC, HPVC), acrylonitrile butadiene styrene (ABS), polyamide (PA), polyphthalamide (PPA), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polybutylene naphthalate (PBT), fluoropolymer (PFA), fluoroethylene propylene (FEP), polyvinylidene fluoride (PVDF), as well as mixtures and compositions of the above polymers, but not limited to them), the chemical composition of which is selected based on the required temperature, mechanical and gas barrier properties. If it is necessary to combine mechanical, temperature and erosion properties, the shells can consist of several layers sintered together, the number of which can be from 1 to 7 and the thickness of each layer from 0.2 mm or more. The total thickness of both the inner and outer shells must be at least 1 mm.

Considering that the main element that ensures the strength of the pipeline is the reinforcing frame, its diagnostics will provide a high degree of assessment of the residual strength (durability) of the pipe.

The diagnostics of the reinforcing frame consists of assessing the reduction in the light transmittance of the reinforcing frame, which occurs due to the destruction of fibers or their rupture. The magnitude of the reduction in light transmittance is determined during qualification tests at the manufacturer.

IMPLEMENTATION OF THE INVENTION

The polymer reinforced pipe (Fig. 1) contains a reinforcing frame (3) and an external polymer thermoplastic shell (2) sequentially applied to the outer surface of the inner polymer thermoplastic shell (1), wherein the reinforcing frame is made of spirally wound reinforcing tapes, into which optical light-transmitting fibers (4) are built in. In this case, the shells and tapes of the reinforcing frame are sintered into a single structure.

The winding angle of the reinforcing tapes is from 1 to 89° and at least one winding of the reinforcing tapes has an opposite winding direction compared to the winding below. The reinforcing tapes (Fig. 2) consist of unidirectional reinforcing threads (5) and unidirectional optical fibers (4) sintered with a polymer thermoplastic matrix (6). After applying the reinforcing tapes, a thermal sintering process is carried out between the tapes, the inner and outer shells.

The inclusion of optical fibers allows measuring the change in the luminous flux of the pipe reinforcing frame, as a result of which diagnostics is ensured. To ensure measurements of light transmittance during pipe operation (Fig. 3), a light source and luminous flux measurement sensors are built into the connecting fittings (7, 9), which are installed at the beginning and end of the pipe (8) (fittings are necessary for connecting pipes to each other), respectively. The luminous flux passes from the fitting in which the light source (9) is located through the reinforcing frame of the pipe (8) and is received by the luminous flux measurement sensors located in the fitting pressed onto the opposite end of the pipe (7). For the convenience of transmitting signals to the light source and the luminous flux measurement sensors, the signal and power cables (10) are brought to the surface into control cabinets (11).

The light flux passing through the reinforcing frame, entering the light flux measurement sensors (usually photocells are used, but not limited to) converts it into an electrical signal, which is proportional to the intensity of the light flux and is more convenient for further data transmission and interpretation.

To determine the rejection values of the reduction in light transmittance of the reinforcing frame, after the pipe is released at the manufacturing plant, it is necessary to measure the light transmittance of the reinforcing frame in order to record it before the start of operation, and then determine the breaking pressure. To assess the possible reduction in the light transmittance of the reinforcing frame of the base pipe, it is necessary to conduct qualification tests, for which it is necessary to manufacture batches of pipelines with a reduction in the number of reinforcing layers (or their thickness, while it is necessary to maintain the basic ratio of the number of reinforcing and optical light-transmitting fibers in the reinforcing tape), as a result of which we will get products with reduced strength, relative to the base pipe. Next, it is necessary to determine the light transmittance and breaking pressures for pipes with a reduced number of reinforcing layers, and based on the data obtained, construct a dependence of the reduction in pipeline strength on light transmittance, which will allow interpreting the results of the reduction in light transmittance on the reduction in the breaking pressure of the pipe.

BRIEF DESCRIPTION OF DRAWINGS

The polymer reinforced pipe (Fig. 1) contains a reinforcing frame (3) and an internal polymer thermoplastic shell (2) sequentially applied to the outer surface of the internal polymer thermoplastic shell (1).

The reinforcing frame (Fig. 2) consists of reinforcing tapes, which in turn consist of unidirectional reinforcing threads (5) with optical fibers (4) in a polymer thermoplastic matrix (6).

To ensure diagnostics during operation of the pipe (Fig. 3), a light source and light flux measurement sensors are built into the connecting fittings (7, 9), which are installed at the beginning and end of the pipe (8) (fittings are necessary for connecting the pipes to each other), respectively. The light flux passes from the fitting in which the light source (9) is located through the reinforcing frame of the pipe (8) and is received by the light flux measurement sensors located in the fitting pressed onto the opposite end of the pipe (7). For the convenience of transmitting signals to the light source and the light flux measurement sensors, the signal and power cables (10) are brought to the surface into the control cabinets (11).

Claims (8)

1. A polymer reinforced pipe containing a reinforced frame and an outer polymer thermoplastic shell sequentially applied to the outer surface of an inner polymer thermoplastic shell, which are sintered together, wherein the reinforcing frame is made of reinforcing tapes sequentially spirally wound and sintered together and with the inner and outer shells, which, in turn, consist of unidirectional reinforcing fibers and light-transmitting optical fibers that provide light transmission over a distance of not less than the length of the pipe, wherein the reinforcing and optical fibers are included in the reinforcing frame by alternation and sintered with the polymer matrix. 2. A polymer reinforced pipe according to paragraph 1, characterized in that the inner and outer shells consist of layers, the number of which for each shell can be from 1 to 7 and the thickness of each layer can be from 0.5 mm or more. 3. A polymer reinforced pipe according to item 1, characterized in that the layers of the inner and outer polymer thermoplastic shells are connected to each other (sintered). 4. A polymer reinforced pipe according to item 1, characterized in that the winding angle of the reinforcing tapes of the reinforcing frame relative to the axis of the pipe has a value from 1° to 89°. 5. A polymer reinforced pipe according to item 1, characterized in that at least one winding of the reinforcing tapes has a winding direction opposite to the axis of the pipe. 6. A polymer reinforced pipe according to paragraph 1, characterized in that fittings are used to connect pipelines, into which a light source is built on one side and sensors for measuring the luminous flux on the other side at opposite ends of the pipe. 7. A polymer reinforced pipe according to item 1, characterized in that the thickness of the reinforcing tape is 0.1-4 mm, and the width is from 20 to 500 mm. 8. A method for diagnosing the reinforcing frame of a polymer reinforced pipe, characterized in that a light flux is passed through the reinforcing frame made of successively spirally wound and sintered together and with the inner and outer shells of reinforcing tapes consisting of unidirectional reinforcing fibers and light-transmitting optical fibers, from the initial end of the pipe to the final end of the pipe, and the reduction in the light transmittance of the reinforcing frame is assessed, from the initial value determined for a new pipe during manufacture, to the actual light transmittance measured during operation, which corresponds to the degree of destruction of the fibers or the number of breaks in the reinforcing fibers.