Views: 5 Author: Site Editor Publish Time: 2023-11-29 Origin: Site
The material commonly used for drilling casing is steel. Specifically, high-strength, corrosion-resistant steel alloys are often chosen for drilling casing to withstand the challenging conditions encountered during drilling operations, such as high pressures, corrosive fluids, and mechanical stresses. Some common steel grades used for drilling casing include API 5CT grades such as J55, K55, N80, L80, C90, T95, P110, and Q125. These grades offer different levels of strength, corrosion resistance, and suitability for specific drilling environments.
The role of steel casing
Oil casing is a special type of pipeline mainly used for transporting and storing oil products. It has the characteristics of corrosion resistance, high temperature resistance and high compressive strength. The main functions of petroleum casing include transporting crude oil, natural gas, petroleum products and chemical products; storing liquid chemical raw materials and finished products; transporting fluids and gases for oil and chemical products; transporting high-temperature liquids and gases.
Material of steel casing
1. Carbon steel casing
Carbon steel casing is the most commonly used material in the petroleum industry. It has the advantages of being cheap, easy to process, and corrosion-resistant. However, its strength and corrosion resistance are slightly insufficient in high temperature and high pressure environments.
2. Alloy steel casing
Alloy steel casing has the advantages of high strength, corrosion resistance, and good high temperature and high pressure performance, and is widely used in the production and development of oil and gas wells. Commonly used alloy steels include Cr-Mo alloy steel, Ni-Cr-Mo alloy steel, etc.
3. Stainless steel casing
Stainless steel casing has the advantages of corrosion resistance and high temperature resistance, and is widely used in marine development and other fields. Commonly used stainless steel materials include 304, 316, 321, etc.
The functions of stainless steel oil casing:
(1) Extract oil and gas: After the oil and gas well is drilled and cemented, oil pipes are placed in the oil layer casing to extract oil and gas to the surface.
(2) Water injection: When the downhole pressure is not enough, water is injected into the well through the tubing.
(3) Steam injection: During the thermal recovery process of heavy oil, insulated oil pipes must be used to input steam downhole.
(4) Acidification and fracturing: In order to increase the production of oil and gas wells in the later stages of well drilling, acidification and fracturing media or solids need to be input to the oil and gas layers. The media or solids are transported through oil pipes.
4. Titanium alloy casing
Titanium alloy casing has the characteristics of low density, high strength, good corrosion resistance and good high temperature performance, making it an ideal substitute. However, due to its high cost, its application range is limited.
How to choose a suitable steel casing?
1. Understand the material of the casing;
High-quality casing materials should have the characteristics of high strength, toughness, corrosion resistance and wear resistance.
2. Choose a regular casing manufacturer;
3. Pay attention to the size and matching of the casing.