Abstract: In one embodiment, a method for drilling a wellbore includes injecting drilling fluid through a drill string disposed in the wellbore and rotating a drill bit disposed on a bottom of the drill string. The drilling fluid includes a liquid and a gas. The drilling fluid is injected at the surface. The drilling fluid exits the drill bit and carries cuttings from the drill bit. The drilling fluid and cuttings (returns) flow to the surface via an annulus formed between the drill string and the wellbore. The liquid is injected at a rate so that a liquid velocity of the returns in the annulus is sufficient to transport the cuttings. The method further includes drilling through at least a portion of a non-productive formation.

Abstract: A method and apparatus are provided for obtaining measurements from a wellbore during tripping operations. A drilling sub is attached to the drillstring adjacent to or as near as possible to the drillbit before commencing normal drilling operations. Prior to commencing tripping operations, a logging tool is engaged within the drilling sub. The engagement of the logging tool within the drilling sub opens a window mechanism that enables the sensors of the logging tool to obtain data from the wellbore. As tripping operations are conducted, the logging tool obtains data along the length of the wellbore.

Abstract: An emulsifying composition for preparing low solids drilling fluids containing a mixture of polyoxyethylene glycol 500 mono-tallate, nonyl phenol ethoxylate containing approximately 43% by weight of oxyethylene groups and nonyl phenol ethoxylate containing approximately 65% by weight of oxyethylene groups; a well servicing fluid comprising an aqueous medium, a liquid hydrocarbon coating agent and an emulsifying amount of the emulsifying compositions; and a method of servicing a well during drilling, fracturing and completing operations.