What is a casing design factor?
Many factors enter into the production casing design. These include the mud weights required to drill the well and balance the formation pressures, the fracture gradients, casing seat depths, casing sizes, the directional plan, the cement program and the temperature profiles.
What is a casing joint?
1. n. [Well Completions] A length of steel pipe, generally around 40-ft [13-m] long with a threaded connection at each end. Casing joints are assembled to form a casing string of the correct length and specification for the wellbore in which it is installed.
What is casing yield strength?
A system of identifying and categorizing the strength of casing materials. For example, the casing grade J-55 has minimum yield strength of 55,000 psi [379,211 KPa]. The casing grade P-110 designates a higher strength pipe with minimum yield strength of 110,000 psi [758,422 KPa].
Why do we use casing?
The casing forms a major structural component of the wellbore and serves several important functions: preventing the formation wall from caving into the wellbore. isolating the different formations to prevent the flow or crossflow of formation fluid.
What is casing and its types?
Casing is installed in layers, in sections of decreasing diameter that are joined together to form casing strings. The five types of casing string are conductor casing, surface casing, intermediate casing, casing liner, and production casing.
How do you calculate maximum allowable casing pressure?
The MAASP can be determined from the following equation: MAASP = Maximum Allowable pressure at the formation just below the shoe minus the Hydrostatic Pressure of mud at the formation just below the shoe.
What is drill pipe pressure?
Shut-in drill pipe pressure (SIDPP), which is recorded when a well is shut in on a kick, is a measure of the difference between the pressure at the bottom of the hole and the hydrostatic pressure (HSP) in the drillpipe.
What is point D on a 9 5 8 casing?
In such a manner, Point D is determined for setting the 9 5 / 8 -in. casing at 9,500 ft. The procedure is repeated for other casing strings, usually until a specified surface casing depth is reached. Top-Down Design.
What are the mechanical properties of casing and tubing?
More information The most important mechanical properties of casing and tubing are burst strength, collapse resistance and tensile strength. These properties are necessary to determine the strength of the pipe and to design a casing string.
What is the design case for internal yield pressure of casing?
There are two main design cases for internal yield pressure of production casing. One is modeled with a tubing leak near the surface with the shut-in tubing pressure added to the packer fluid weight as an internal load.
What is the formula for buttress thread casing joint strength?
The buttress thread casing joint strength is given as the lesser of the fracture strength of the pipe body (the pin) and the coupling (the box). Pipe thread strength is given by = π/4 ( W 2 – d 1 2 ). These equations are based on tension tests to failure on 151 buttress-thread test specimens.