Tubing leak is a burst load case, where the unknown is the internal pressure profile of the casing / tubing.
Note: In this documentation we denote any tubular as casing or tubing. All calculations however encompass any tubular, such as tubings, casings, liners, tie-backs etc.
Summary
This load case is used in connection with production- and injection- operations, and represents a surface pressure on top of a completion fluid due to a tubing leak.
Printable Version
Inputs
The following inputs define the tubing leak load case
The true vertical depth (TVD) along the wellbore as a function of measured depth. Alternatively, the wellbore described by a set of survey stations, with complete information about measured depth and inclination.
The true vertical depth / TVD of
The hanger of the tubing, TVDhanger.
The shoe of the tubing, TVDshoe.
The packer depth, TVDpacker.
The perforation depth, TVDperforation.
The pore pressure profile from hanger to influx depth.
The packer fluid density, ρpacker .
The temperature at the perforation depth, Tperforation .
The gas gravity, sggas .
Calculation
The internal pressure profile of the casing / tubing is calculated as follows
1. Calculate the pore pressure at perforation depth, pp, perforation.
2. Calculate the gas density at perforation depth from gas gravity, using Sutton correlations, ρgas, perforation .
4. The internal pressure of the tubing depends on where the packer- and perforation- depth are related to each other and the shoe of the tubing. Explicitly, parametrize the tubing by TVD
a) If TVDshoe≤TVDpacker≤TVDperforation , or if TVDshoe≤TVDperforation≤TVDpacker , then
pi=phanger+ρpackerg(TVD−TVDhanger)(2)
b. If TVDpacker≤TVDshoe≤TVDperforation , then from hanger to packer
