Patent ID: 7886849

Claim:
A method of drilling a well within a well bore with an under-balanced hydrostatic head of pressure, said well bore having a casing string therein, the method comprising: a) running into the well bore with a flow apparatus, said flow apparatus comprising: a tubular concentrically placed within the casing string, said tubular having a first injection port; a compression member disposed about an outer portion of said tubular, said compression member having extending therefrom an internal sliding mandrel, and wherein said internal sliding mandrel contains a second injection port; an external sliding sleeve operatively associated with said internal sliding mandrel, wherein said external sliding sleeve contains a third injection port; wherein in a closed position said first port, second port and said third port are misaligned and in an open position said first port, said second port and said third port are aligned; a compressible seal disposed about said external sliding sleeve and in contact with said internal sliding mandrel, said compressible seal responsive to longitudinal setting of weight on said compression member; b) setting down weight on said tubular; c) transferring the weight to said external sliding sleeve; d) moving said compression member relative to said external sliding sleeve; e) aligning said first port, said second port and said third port so that a passage is formed from an outer portion of said flow apparatus to an inner portion of said tubular; f) expanding said compressible seal within a well bore annulus, said well bore annulus being formed between said well bore and said tubular; g) lowering a drill string within said inner portion of said tubular, said drill string having a bit attached at a distal end; h) forming a tubular annulus between said inner portion of said tubular and said drill string; i) pumping a gas down said well bore annulus; j) directing the gas through the passage and into said tubular annulus; k) pumping fluid down an inner portion of the drill string; l) mixing the fluid and the gas within the tubular annulus; m) drilling the well with the bit; n) lightening the hydrostatic head of pressure at the bit with the gas and the fluid mixture within the tubular annulus.