Paper: Regaining Circulation Freeing Stuck Pipe With Nitrogen

On many occasions lost circulation is associated with stuck pipe and once circulation is regained the pine may become free. With a good mud system sometimes it is not advisable to contaminate the mud with other fluids; however, with Nitrogen the mud may be circulated through a degasser or across the shale shaker to break the gas out leaving uncontaminated mud. Nitrogen technical manuals will show pressure gradients of commingled nitrogen and liquid densities up to 11 lbs/gal. All gas laws are incorporated into their design. At low concentration of nitrogen and high pressure the charts show near linear conditions. An equation for field use by engineers will show the pressure gradient and amount of nitrogen required to lower the hydrostatic pressure of any weight fluid.