Abstract:
A foamable drilling fluid for use in well operations such as deep water offshore drilling where risers are not employed in returning the fluid to the surface mud pit, comprises a prehydrated clay such as bentonite; water; a surfactant selected from α-olefinsulfonates, alkylpolyglycosides, alcohol sulfates and salts of ethoxylated alcohol sulfates; and a stabilizing surfactant such as cocoamine betaine. The drilling fluid can also contain an hydraulic material selected from Portland cement, siliceous material like fumed silica, blast furnace slag and pozzolans such as fly ash.
Abstract:
A conductor is cemented in a well bore underwater by using a cement slurry made from Portland cement, a foaming surfactant, a quantity of fine particle size cementitious material and nitrogen or other gas to foam the slurry. The slurry is introduced down the conductor pipe and permitted to return up the annulus of the well bore.
Abstract:
A lightweight cement composition for performing a variety of well cementing operations, the cement comprises slag cement, water sufficient to form a a pumpable slurry, a gas sufficient to foam the slurry and a foaming agent.