CN106247030A - A kind of novel Land petroleum delivery combined tube - Google Patents

Abstract

The invention provides a novel combination pipe for oil and gas transportation on land, which includes an inner steel pipe, a concrete pipe and a plastic pipe with carbon fiber cloth inside. An insulation layer is arranged on the inner layer of the inner steel pipe, and a flexible, corrosion-resistant and freely deformable plastic pipe is arranged inside the insulation layer to transport highly corrosive crude oil or refined oil containing sulfur or other acidic substances. The concrete pipes are cast from fiber-reinforced concrete with spiral stirrups and longitudinal reinforcement. Advantages of the present invention: the novel combination pipe for onshore oil and gas transportation described in the present invention has the characteristics of low cost, strong internal corrosion resistance, high compressive bearing capacity, and good thermal insulation performance, making it possible to increase the interval of pumping stations. Since the composite pipe for oil and gas transportation according to the present invention uses anisotropic carbon fiber cloth to resist the pressure inside the pipe, the composite pipe has excellent deformation resistance and shock resistance compared with traditional steel pipes with the same bearing capacity . In addition, due to the good deformation and anti-seepage capabilities of the inner plastic pipe that undertakes the oil transportation function, even if the outer pipe is damaged, it can also ensure that oil and gas will not seep out.

Description

A new type of combination pipe for onshore oil and gas transportation

technical field

The invention relates to the field of oil and gas transmission pipelines in petroleum engineering, and provides a new type of pipeline that can not only resist internal pressure and overall deformation, but also overcome the corrosion problems (including internal corrosion and external corrosion) that plague traditional oil and gas transmission pipelines, and has good thermal insulation performance. Combination pipes for onshore oil and gas transmission.

Background technique

The pipes of oil pipelines are generally steel pipes, and the oil and gas in oil pipelines are rich in sulfur and acidic substances and the soil environment in which they work, making steel oil pipelines extremely prone to corrosion, which in turn causes various oil and gas leakage accidents . In Canada, 56% of oil and gas pipeline ruptures were caused by corrosion, while in the United States, 31.97% of oil pipeline ruptures and 18.75% of gas pipeline ruptures were caused by corrosion. According to a report on the economic impact of metal corrosion in the United States, the annual economic loss due to corrosion is 300 billion US dollars, accounting for 1% of the output of this oil pipeline industry.

In addition to the direct impact on the economy, the rupture of oil pipelines will directly lead to the flow of oil into the outside environment, which will lead to explosions, fires, human and animal casualties, and environmental pollution. Taking the United States as an example, from 1994 to 2013, there have been 745 serious oil and gas leakage accidents, resulting in 363 deaths and 1,059 injuries. Moreover, our country has not been spared in this regard. Among them, the Qingdao oil pipeline explosion accident that occurred in 2013 had a particularly far-reaching impact. In this explosion, 62 people died, 136 people were injured, and the direct economic loss amounted to 751.72 million yuan.

At present, the newly-built oil and gas pipelines in China are limited by the strength of the steel pipes used, the transmission pressure is not high, the transmission efficiency is low, and there are many intermediate pressurized pumping stations, which require a large investment. The delivery pressure of the early pipelines was 3.9-4.6MPa, but in recent years most pipelines have only increased to 6.4MPa, and the distance between pumping stations is about 60km. In developed countries, the pressure of the transmission pipeline can reach 8-12MPa, the distance between pump stations is 80-100km, and the comprehensive economic benefit indicators such as transmission efficiency, steel consumption, and pump station investment are much better than those in China. Obviously, continuously improving the strength and delivery pressure of pipeline steel is the development trend of oil and gas delivery pipes. To adapt to this trend, X110 and X120 steels have been successfully developed. However, due to the mutually reinforcing relationship between the strength and toughness of steel and the requirements for high-pressure transportation on the fracture toughness of steel, the highest steel grade that is mass-produced and officially put into use in developed countries such as Japan, Europe, and North America is only X80 high-grade steel. Among them, the second line of my country's West-East Gas Pipeline Project is the world's largest X80. As for the steel above X80, because the fracture toughness has not yet met the relevant requirements, it has not been put into the application of specific oil pipes on a large scale.

Obviously, the strength and toughness requirements of oil and gas pipelines have exceeded the limit of modern metallurgical technology. In order to solve this problem, glass fiber reinforced polymer pipe (GFRP pipe) has been studied abroad. Compared with traditional steel pipes, this kind of pipe has the advantages of good corrosion resistance, low quality-to-strength ratio (small mass but high strength), good water conservancy conditions (smooth inner wall, strong conveying capacity), and maintenance costs. However, due to the characteristics of high tensile strength and low compressive strength of glass fiber, this kind of pipeline is prone to inward buckling under vacuum or negative pressure, and is further damaged under the action of upper soil pressure.

In addition, foreign countries have studied composite reinforced line pipes (Composite Reinforced Line Pipes, CRLP), that is, steel/glass fiber composite pipes, which not only utilize the strength of steel, but also take advantage of the advantages of glass fiber in crack arrest. Steel/glass fiber composite pipe can reduce the material cost, installation cost and welding cost of pipeline engineering, and can also replace traditional coating. Compared with the above-mentioned glass steel pipes, the problem of buckling under vacuum or negative pressure may have been solved; however, the corrosion problem that plagues traditional steel pipes still exists.

Contents of the invention

The purpose of the present invention is to provide a new type of combination pipe for onshore oil and gas transportation, which can resist the ultra-high internal pressure and overall deformation of the oil pipeline, and has extremely strong corrosion resistance and good heat insulation performance, making it possible to transport high-pressure hot oil .

For this reason, the technical scheme adopted in the present invention is:

A new onshore oil and gas transmission combined pipe is characterized by a pressure-bearing structure and a non-pressure-bearing structure. Among them, the pressure-bearing structure consists of an inner steel pipe, a plastic pipe with carbon fiber cloth glued on the inside, and a concrete pipe with spiral stirrups and longitudinal bars poured between the two pipes. The non-pressurized structure mainly consists of insulation and plastic pipes. The thermal insulation layer is mainly used to prevent the loss of heat during the transportation of crude oil in the hot oil transportation process. Plastic pipes are mainly used for the transportation of oil and gas. The plastic pipe is required to have extremely strong corrosion resistance to acidic substances such as hydrogen sulfide and carbon dioxide, and is also required to have a strong resistance to large deformation.

Compared with prior art, the beneficial effect of the present invention is:

The pipeline not only has good corrosion resistance to the transported oil and gas and the external soil, but also has excellent mechanical properties, that is, external pressure resistance and overall deformation resistance. In addition, it has good thermal insulation performance for the oil and gas being transported, which provides feasibility for the hot oil transport process. In addition, because the materials used in the composite pipe are common and cheap materials, the cost of the composite pipe will be far lower than the traditional oil pipeline with the same performance but using pipeline steel.

Description of drawings

Fig. 1 is a transverse cross-sectional design drawing of a novel onshore oil and gas transmission combined pipe according to the present invention;

Fig. 2 is a layout diagram of lateral reinforcement of a new type of combined pipe for onshore oil and gas transportation according to the present invention.

Explanation of reference numbers:

Figure 1: 1. Steel pipe 2. Concrete 3. Spiral stirrup 4. Longitudinal reinforcement 5. Insulation layer 6. Plastic pipe

Figure 2: 1. Steel pipe 2. Shear connector 3. Spiral stirrup 4. Longitudinal reinforcement

detailed description

The invention provides a new combination pipe for onshore oil and gas transportation, which consists of two parts: a pressure-bearing structure and a non-pressure-bearing structure. As shown in FIG. 1 , the pressure-bearing structure is mainly composed of a layer of small-diameter ordinary steel pipe 1 and large-diameter plastic pipe 6 . The middle of them is filled with high-strength fiber concrete 2 with spiral stirrup 3 and longitudinal steel bar 4 mixed with expansion agent. Wherein, as shown in FIG. 2 , the steel pipe and the spiral stirrup are connected together through a shear-resistant connector 2 , and the longitudinal reinforcement 4 is bound to the spiral stirrup 3 at the same time. The non-pressure-bearing structure mainly refers to the steel mesh skeleton plastic pipe 6 in the pipe shown in Figure 1, the heat insulation layer 5 close to the steel mesh skeleton plastic pipe, and the outermost plastic pipe 6 of the pipeline. When making the pipe, the non-pressure-bearing structure is completed first, and then the steel pipes, large-diameter plastic pipes and various steel bars in the pressure-bearing structure are arranged, and finally the concrete is poured into it.

The invention describes a combination pipe for onshore and seabed oil and gas transportation. The selected materials are all common materials on the market. The inner part includes steel pipes, plastic pipes, and heat insulation layers, which have strong corrosion resistance. It can ensure that the oil and gas in the pipe have sufficient temperature to flow smoothly, and will not produce wax and hydrate to block the pipe; the outer part includes spiral stirrups, which have strong tensile properties and can effectively resist the high pressure during the fluid transportation process in the pipe; mixed with The high-strength fiber concrete of the expansion agent has strong compressive performance, can effectively resist the high pressure of the ultra-deep seabed, and has a certain deformation capacity; at the same time, longitudinal steel bars are added to enhance the flexibility of the pipeline and have a greater deformation capacity. Even in the event of earthquakes, seabed subsidence and other accidents, certain deformations can occur through displacement control so that the pipeline will not be damaged, and the oil and gas in the pipeline will not leak out and oil leakage accidents will occur.

The novel onshore combined oil and gas transmission pipe of the present invention has simple structure, safety and reliability, low price, convenient construction and wide market prospect.

Claims (4)

1. a novel Land petroleum delivery combined tube, including interior steel pipe, pipe of concrete and the plastic tube of interior patch carbon cloth, The internal layer of inner layer steel pipe arranges heat-insulation layer, and heat-insulation layer inside placement of flexible corrosion resistance can the plastics of Free Transform Pipe, in order to carry crude oil or the product oil of the highly corrosive of sulfur-bearing or other acidic materials, outermost layer one layer of plastic tube of set, use Carrying out casting concrete tube portion, pipe of concrete is poured by the fiber concrete of band tie hoop and longitudinal reinforcement and forms.

One the most according to claim 1 novel Land petroleum delivery combined tube, it is characterised in that in inner layer steel pipe Layer arranges heat-insulation layer, and heat-insulation layer inside placement of flexible corrosion resistance can the plastic tube of Free Transform, in order to carry The crude oil of the highly corrosive of sulfur-bearing or other acidic materials or product oil.

One the most according to claim 1 novel Land petroleum delivery combined tube, it is characterised in that pipe of concrete is for by carrying The fiber concrete of tie hoop and longitudinal reinforcement pours and forms, and for improving the mechanical property that pipeline is overall, ensures pipeline Safety.

One the most according to claim 1 novel Land petroleum delivery combined tube, it is characterised in that plastic tube can be effective Prevent the soil environment corrosion to pipeline.