What Is Involved in Cannula Insertion?
Oil casing is a steel pipe used to support the wall of oil and gas wells to ensure the normal operation of the entire oil well during the drilling process and after completion. Each well requires several layers of casing depending on different drilling depths and geological conditions. After the casing is run down, the cement shall be used to cement the well. It is different from the tubing and drill pipe and cannot be reused. It is a disposable consumable material. Therefore, the consumption of casing accounts for more than 70% of all oil well pipes.
Oil Casing
- Chinese name
- Oil Casing
- Foreign name
- Oil casing
- Function
- Steel pipe used to support oil and gas well walls.
- Features
- Ensure the normal operation of the entire well
- Oil casing is a steel pipe used to support the wall of oil and gas wells to ensure the normal operation of the entire oil well during the drilling process and after completion. Each well requires several layers of casing depending on different drilling depths and geological conditions. After the casing is run down, the cement shall be used to cement the well. It is different from the tubing and drill pipe and cannot be reused. It is a disposable consumable material. Therefore, the consumption of casing accounts for more than 70% of all oil well pipes.
- The casing can be divided into: conduit, surface casing, technical casing and oil casing.
- Petroleum special pipe is mainly used for drilling of oil and gas wells and transportation of oil and gas. It includes petroleum drilling pipe, petroleum casing, and sucker pipe. Oil drill pipe is mainly used to connect drill collar and drill bit and transmit drilling power. Oil casing is mainly used to support the borehole wall during and after drilling to ensure the drilling process and the normal operation of the entire oil well after completion. The sucker pipe mainly transports oil and gas from the bottom of the well to the surface.
- Oil casing is the lifeline to maintain oil well operation. Due to the different geological conditions and the complex state of the downhole force, the combined effects of tensile, compressive, bending, and torsional stresses act on the pipe body, which places higher requirements on the quality of the casing itself. Once the casing itself is damaged for some reason, it may lead to reduced production of the whole well or even scrap.
- According to the strength of the steel itself, the casing can be divided into different steel grades, namely J55, K55, N80, L80, C90, T95, P110, Q125, V150 and so on. Different well conditions and depths also use different steel grades. In a corrosive environment, the casing itself is also required to have corrosion resistance. Where geological conditions are complex, casing is also required to have anti-collapse performance.
- 27MnCrV is the grade of TP110T steel
- Oil casing is a large caliber
- Weight calculation
- [(Outer diameter-wall thickness) * wall thickness] * 0.02466 = kg / meter (weight per meter)
- chemical composition
- (1) According to SY / T6194-96. The sleeve and its coupling adopt the same
- Different types of casing used in oil extraction: Surface oil casing protects the well from being contaminated by shallow water and shallow gas layers, supports wellhead equipment and maintains the weight of other layers of casing. The technical oil casing separates the pressure at different levels so that the drilling fluid can flow properly and protect the production casing. In order to install anti-burst devices, leak-proof devices and tail pipes in the drilling. Reservoir casings direct oil and gas from reservoirs below the surface. It is used to protect drilling and to layer drilling mud. When producing oil casing, the outer diameter is usually 114.3 mm to 508 mm.
- Protect wells from contamination from shallow water and shallow gas layers, support wellhead equipment and maintain the weight of other layers of casing.
The technical oil casing separates the pressure at different levels so that the drilling fluid can flow properly and protect the production casing. In order to install anti-burst devices, leak-proof devices and tail pipes in the drilling.
Reservoir oil casing-Extracts oil and gas from reservoirs below the surface. It is used to protect drilling and to layer drilling mud. When producing oil casing, the outer diameter is usually 114.3 mm to 508 mm.
- The types and packaging of petroleum casings are divided into two types: short-threaded casing and their couplings and long-threaded casing and their couplings according to SY / T6194-96 "oil casing".
- After nearly 20 years of hard work, China s production of tubing from scratch, from low prices to high prices, from low steel grades to API series products to non-API products with special needs, has been close to quantity The level of foreign casing products. China's domestic market share of oil well pipes has exceeded 80%, and has been a net export product for many years.
- In 2011, China's crude oil output reached 204 million tons, an increase of 0.32% compared with the same period in 2010; natural gas output reached 102.531 billion cubic meters, a year-on-year increase of 6.9%, a record high. China is still in the rapid development stage of urbanization and industrialization. It is expected that the average annual demand for oil in the next few years will increase by about 4%. The increasing demand for oil has promoted the continuous increase in the demand for oil drilling equipment in China.
- From the perspective of China's domestic regional distribution, the demand for tubing casing is no longer concentrated in the eastern region. From the perspective of the development of domestic oil and gas fields, from the initial development of eastern oil fields such as Daqing, Liaohe, and Shengli, to the development of western oil fields such as Sichuan and Xinjiang, attention is paid to the trend of offshore oil fields. In addition, it will also develop from land to beaches, from shallow to deep seas, and The drilling depth is getting deeper and deeper, and the drilling conditions are becoming more and more complicated, and the requirements for oil casing are bound to be higher and higher.
- Anticorrosion countermeasures for oil casing
- 1. First of all, do a good job of meeting water quality standards, and strictly monitor and manage water quality. Carry out decontamination and injection, strengthen the cleaning of main water pipelines, achieve water quality standards in stations and bottoms, and reduce the introduction of corrosion sources into the annular space;
2. For water injection wells that have been newly put into production, adopt annulus protection fluid that is mainly dosing and sterilizing, and form a system to dosing regularly;
3. In view of the accelerated effect of mechanical abrasion on the corrosion of petroleum casing, it is recommended to add a rubber ring to the tubing coupling or a centralizer in the serious area of the well to avoid the tubing from scratching the casing during the operation and water injection process and One side contacts the sleeve;
4. In view of the serious corrosion of the bacteria under the scale and the slow growth and killing of SRB under high temperature, you can periodically inject high temperature water or steam of 100 degrees Celsius into the annulus to kill the under scale.
5. It is not recommended to use cathodic protection and coated casing until the corrosion in the casing of the injection well is not effectively controlled.
- According to the American Petroleum Institute standard APISPEC5CT first edition in 1988, casing steel grades H-40, J-55, K-55, N-80, C-75, L-80, C-90, C-95, P- There are 10 types of 110 and Q-125. The casing should be supplied with threads and couplings, or in the form of any of the following pipe ends: flat ends, round threads without couplings or with couplings, partial trapezoidal threads with couplings or without couplings, direct connection Thread, special end processing,
- (1) Domestic casing is in accordance with SY / T6194-96, and the length of the casing is variable.
- Oil Casing
- (2) The inner and outer surfaces of the casing must be free of folds, hairlines, delaminations, cracks, folds and scars. These defects shall be completely removed, and the removal depth shall not exceed 12.5% of the nominal wall thickness.
- (3) The outer surface of the coupling must be free from defects such as folds, hairline, delamination, cracks, folds, and scarring.
- (4) The surface of the casing and coupling threads should be smooth, without burrs, tears, and other defects sufficient to interrupt the threads and affect the strength and tight connection.
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