Oil Casing, commonly referred to as casing, is a critical component of oil country tubular goods (OCTG). OCTG includes various types of pipes such as casing, tubing, drill pipe, drill collars, couplings, sucker rods, and pup joints. Today, we’ll explore the classification and functions of oil casing pipes, which play a vital role in ensuring safe and efficient drilling operations.
**Drilling Guide Bush:**
The drilling guide bush is primarily used in offshore and desert drilling environments. Its main purpose is to separate seawater and sand, allowing for smoother drilling processes. This casing is essential in preventing contamination and maintaining well integrity. The standard dimensions for this type of casing are usually ∮762mm (30in) × 25.4mm and ∮762mm (30in) × 19.06mm, making it suitable for large-diameter wells.
**Surface Casing:**
Surface casing is installed during the early stages of drilling to penetrate through soft ground layers and reach the bedrock. It prevents formation collapse and provides a sealed environment. Surface casing typically has sizes like 508mm (20in), 406.4mm (16in), 339.73mm (13-3/8in), 273.05mm (10-3/4in), and 244.48mm (9-5/9in). The depth can vary from 80 meters up to 1,500 meters, depending on the soft layer thickness. It is generally made from K55 or N80 steel grades due to its relatively low pressure requirements.
**Technical Casing:**
Technical casing is used when drilling through complex geological formations, such as unstable rock, oil, gas, water zones, or salt-gypsum layers. Proper sealing with technical casing is crucial to avoid drilling complications. In deep and challenging wells, multiple layers of technical casing may be required, demanding high mechanical strength and sealing performance. Common steel grades include N80 and P110, while deeper wells might use non-API grades like Q125 or V150. Typical specifications include 339.73mm (13-3/8in), 273.05mm (10-3/4in), 244.48mm (9-5/8in), and others.
**Oil Layer Casing:**
Once the target oil or gas zone is reached, oil layer casing is installed to isolate the hydrocarbon-bearing formation and the overlying strata. This casing is the deepest and requires the highest level of mechanical strength and sealing capability. It is commonly made from K55, N80, P110, Q125, and V150 steel grades. Standard sizes include 177.8mm (7in), 168.28mm (6-5/8in), 139.7mm (5-1/2in), 127mm (5in), and 114.3mm (4-1/2in).
Understanding the different types of casing and their specific roles is essential for successful well construction and long-term production. Each casing type is designed to meet the unique challenges of the formation it is placed in, ensuring safety, efficiency, and environmental protection.
Seamless Stainless Steel Tube,Stainless Steel Seamless Tube,Stainless Steel Pipe,Stainless Steel Decorative Tube
Suzhou Yuhaoxuan Electromechanical Co., Ltd , https://www.essiont-pipeline.com