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Production casing is the final casing string set in a well and usually reaches from the surface to Target Depth (TD). The type of casing used depends upon the different conditions in the well. Commonly, production casing sizes range from 4 + 1 ⁄ 2 in (110 mm) to as large as 9 + 5 ⁄ 8 in (240 mm). It is the last string cemented in a well ...
A typical size of surface casing is 13 + 3 ⁄ 8 inches (340 mm). [5] Intermediate casing may be necessary on longer drilling intervals where necessary drilling mud weight to prevent blowouts may cause a hydrostatic pressure that can fracture shallower or deeper formations. Casing placement is selected so that the hydrostatic pressure of the ...
The inside casing is 9 + 5 ⁄ 8 in (240 mm) L80 47 lb⋅ft (64 N⋅m) −1. The collapse pressure of this casing is 4750 psi. Therefore, pressure at the shoe of the 'B' annulus cannot exceed this. Given a hydrostatic head of 2116 psi, the pressure at the wellhead must not exceed 2634 psi.
In a completed well, there may be many annuli. The 'A' annulus is the void between the production tubing and the smallest casing string. The 'A' annulus can serve a number of crucial tasks, including gas lift and well kills. A normal well will also have a 'B' and frequently a 'C' annulus, between the different casing strings.
Annular capacity (bbl/ft) = (ID hole 2 - OD pipe 2) / 1029.4. where ID hole 2 = Inside diameter of the casing or open hole in inches OD pipe 2 = Outside diameter of the pipe in inches. Similarly Annular volume (bbls) = Annular capacity (bbl/ft) × length (ft) and Feet occupied by volume of mud in annulus = Volume of mud (bbls) / Annular ...
Most casing heads allow for the pressure readings to be taken on the annulus and provide the means to pump out or into if necessary. The top of the casing string and annulus is usually sealed. The most common size of casing hanger is 13 + 3 ⁄ 8 in (340 mm) with over 155,000 such units installed worldwide in 2014 alone.
Thus, the outer diameter of a catheter in millimeters can be calculated by dividing the French size by 3. [2] For example, a catheter with a French size of 9 would have an outer diameter of approximately 3 mm. While the French scale aligns closely with the metric system, it introduces redundancy and the potential for rounding errors.
Annular velocity is the speed of the drilling fluid's movement in a column called an annulus in oil wells. [1] It is commonly measured in feet per minute (ft/min) or meters per minute (m/min). Annular velocity is often abbreviated as AV, though this is not exclusively so, as AV also refers to apparent viscosity which is calculated from ...