Carbon fiber is a fibrous carbon material. Its biggest feature is its light weight and high strength. Its density is less than 1/4 of that of steel, but its tensile strength is 7-9 times that of ordinary steel. It has excellent corrosion resistance and high temperature resistance, and also has similar electrical conductivity to copper. It is a new material that combines excellent electrical, thermal and mechanical properties. Carbon fibers are prepared by firing organic fibers (polyacrylonitrile, pitch, etc.) in an inert gas at a temperature of 1000 ° C or higher, and removing other elements than carbon in the fibers to obtain carbon fibers. Carbon fiber is generally not used alone, but as a reinforcing material, it is added to resin, metal, ceramic or concrete to form a composite material. Among them, the most widely used is carbon fiber reinforced resin. Carbon fiber has been widely used in aerospace, high-end engineering equipment, major infrastructure construction projects, pressure vessels, and sports and leisure products from its birth to the present.
Application in sucker rod
In the oil and gas extraction industry, sucker rods are the main components of an oil extraction system. Traditional steel sucker rods have deficiencies in terms of flexibility and corrosion resistance. They have a greater loss when mining "three high wells" or ultra-deep wells. Below, carbon fiber material sucker rods are being widely used in the oil and gas extraction industry due to their excellent mechanical properties and mechanical strength. At present, carbon fiber sucker rods have been widely used in many oilfields in China. Oilfields such as Dagang Oilfield of China National Petroleum Corporation and Shengli Oilfield of Sinopec Group have launched the promotion of carbon fiber sucker rod technology. In 2015, the carbon fiber continuous sucker rod operating machine developed by the Jianghan Machinery Research Institute of China Petroleum Corporation's Drilling Engineering Technology Research Institute completed its first downhole test in Xinjiang Oilfield. The test was carried out in the Ke503 well located in the 553 well area of the No. 2 oil production plant in Xinjiang Oilfield. The well is 2068 m deep. It is designed to use a carbon fiber continuous sucker rod of 1080m and a pumping depth of 1799.47m. Oil test. The success of the test is expected to solve the production problems of deep wells, ultra-deep wells and corroded wells, which is of great significance for reducing the energy consumption of pumping wells and improving the efficiency of pumping.
Application in ultra-high pressure continuous pipe
The carbon fiber composite continuous pipe is composed of a carbon fiber reinforced epoxy resin structural layer and a thermoplastic inner lining, and the outside is covered with a wear-resistant thermoplastic material. At present, the burst pressure of 2T conventional continuous pipe QT-1000 is only 140MPa, which cannot meet the needs of ultra-high pressure water jet drilling technology. The commercial application of carbon fiber composite pipe can reach the rupture pressure of 207MPa, which meets the requirements of ultra-high pressure water jet operation, as shown in Figure 1. Under the condition of internal pressure of 83MPa, 2inQT-1000 continuous pipe failed after 16 times of drilling. The fatigue life of Incoloy-625 continuous pipe of QUALITY TUBING company was 70 times, while the fatigue of carbon fiber composite continuous pipe of FIBERSPAR SPOOLABLE PRODUCTS Life span exceeds 2000 times.
There are abundant oil and gas resources in the ocean. Oil and gas exploration and development are moving from land to the ocean, and gradually extend from the shallow continental shelf to the deep ocean. However, the environment in the ocean is complex and changeable, and the complex seawater has a high salt content, which is extremely corrosive to equipment and facilities. Many of the equipment and facilities are mainly made of steel. This virtually increases the cost of mining. Increased operational risk. The low density, high performance and high strength of carbon fiber materials can effectively alleviate the weight and pressure load of steel materials in deep sea environments. The umbilical cable, anchoring cable and tubing (riser) connected to the platform of the oil wellhead used in deep sea oilfields can all be replaced by carbon fiber materials, which can effectively reduce the weight of the platform and the pressure it bears, and save costs. For a 1500 m deep-sea platform, the amount of steel cables used is about 6,500 tons. If carbon fiber cables are used instead, the weight can be reduced by 1/6. Compared with steel materials, the depth of use of carbon fiber materials can be doubled. The flexibility of carbon fiber materials also facilitates transportation and construction operations.
Carbon fiber and its composite materials have broad application prospects in the field of petroleum engineering.