A drilling pipe screen, also known as a sand screen or gravel pack screen, is a critical component used in oil and gas wells during drilling and completion processes. Its primary purpose is to prevent sand, debris, and other solid particles from entering the wellbore while allowing oil or gas to flow through.
Different types of screens vary in mesh sizes and designs, according to the specific well conditions of oil Wells, different sand layers and production requirements., the steel grades and screen pipes types used are different, usually there are slotted, perforated, wound wire, Rod-Style and other types, each designed to suit specific well conditions and sand control needs.
Perforated Type Drilling Pipe Screen
Perforated drilling pipe screens, known as a perforated liner or perforated casing, is a type of sand control screen used in oil and gas wells. It is designed with regularly spaced holes or perforations along its length, are a cost-effective and commonly used method for sand control in oil and gas wells.
A perforated type screen’s main function is to control sand and filtration. Sand and other solid particles are carried into the wellbore by the movement of hydrocarbons (oil or gas). Larger sand particles cannot enter the wellbore because of the perforations in the screen, which permit the flow of formation fluids and hydrocarbons. Sand is retained thanks to the size and layout of the perforations, otherwise the sand particles can harm downhole machinery and lower well productivity in the absence of sand management procedures. By limiting the collapse of the surrounding formation, perforated screens additionally assist in supporting the wellbore. This is particularly crucial in rocks that are loose or unconsolidated because the drilling weight of the drilling mud and the pressure differential can cause formation collapse.
Slot Type Drilling Pipe Screen
Slotted pipe screens or liners are pipe sections with narrow slots cut into them. These slots allow fluid and hydrocarbons to flow through while blocking sand and larger particles. According to application, slotted screens can be divided into oil-slotted pipes and water-slotted pipes, using various steel grades to meet API Spec 5CT and other requirements. Slotted type drilling screens are suitable for formations with medium-sized sand particles.
Mesh screens are made of consist of a perforated base pipe with a wire-wrapped screen layer with precise openings, is one of the most commonly used screens in oil and gas wells. The gap of the wire screen can be accurately wound on the base pipe (oil, casing), and the seam width can be controlled within 0.15-0.5 ±0.05㎜, which can meet the needs of downhole sand control. The screen is manufactured by winding steel wire and firmly welding it on a metal liner evenly distributed on the surrounding screen rod or with a hole, leaving a certain gap for the screen hole. They are effective in controlling fine sands and are often used in stand-alone screen completions or as an inner liner in pre-packed screens.
However, this kind of screen has some shortcomings, especially when the strong pressure passes through the bend section of the highly inclined well or horizontal well, it will inevitably collide, squeeze and friction with the well wall or casing, resulting in screen damage or gap deformation, which will reduce the sand control effect or fail.
Rod-Style Pipe Screens
Rod-Style Pipe Screens, also known as rod-based screens, or wire-wrapped screens, which consist of a perforated base pipe with a wire-wrapped screen layer. These screens are known for their strength and resistance to collapse. It consists of a perforated base pipe or casing with a filter layer around the base pipe in a spiral pattern. They are effective in controlling fine sand and are often used in gravel packing operations.
In some cases, rod-style screens can be used in conjunction with gravel packing, that helps stabilize the formation and provides additional filtration capacity. Because of their robust design and efficient sand control capabilities, rod-style pipe screens are frequently used in wells with unconsolidated or poorly consolidated formations where sand control is critical, particularly when dealing with medium to fine sand particles.
Composite Pipe Screens
The pipe screen is composed of base pipe, microporous filter material and stainless steel slotted screen. It is suitable for silty sand rock, especially for horizontal well, branch well and high inclination well. The base pipe has a slotted base pipe and a drilled base pipe. The filter sleeve of the punching seam (hole) cylinder screen pipe is supported by the base pipe (sleeve, tubing), and has enough overall strength to resist the extrusion deformation of the formation, even if it is deformed, the gap of the pressure part will not increase, which inhibits the shortcomings of the punching seam screen pipe when it is externally squeezed, the pressure part will reduce the gap or close the gap under the action of external force, and has high reliability.
In conclusion, the choice of the appropriate drilling pipe screen type depends on factors such as specific well conditions, formation characteristics, the size of the particles to be controlled, the completion method. and sand control requirements. It’s crucial for engineers and operators to analyze the well’s parameters and choose the most suitable screen type to ensure effective sand control and optimal well performance.