Bleed and Lubricate is a small app that calculates the psi to bleed off for a given amount of mud.

An excerpt from a well control manual:
Pump mud into the annulus and allow the mud time to fall through the gas, then bleed off pressure at the choke equal to the hydrostatic pressure of the mud pumped into the annulus. Repeat the lubrication until all the gas has been replaced with mud.

This app has been tested on several different android devices.