Abstract: An improved method and apparatus used for offshore drilling operations is disclosed which is particularly useful in those operations where a floating vessel or drilling platform is situated at the surface of a body of water with a riser assembly extending between the platform and the well and a blowout preventer assembly is positioned therebetween near the lower end of the riser assembly. In the practice of this invention at least one fluid bypass conduit provides a path for high pressure fluid to flow from the wall at a point below at least one of the blowout preventers to the riser assembly at a point below the surface of the water and above the blowout preventer assembly. A means in each of said bypass conduits controls the flow of fluid through the conduit to regulate the fluid pressure in the well when the blowout preventers are in the closed position.