Abstract: A multiple well platform is described for producing hydrocarbons, preferably using a free-standing single riser caisson. Although the wells are connected up to the surface, the largest casings (and preferably most of the other casings) are terminated at about the mudline. The apparatus uses a guide located at a level about the ocean floor which can be oriented to direct well installing apparatus to any of several exit holes and enables multiple wells to be installed through a riser caisson only slightly larger than the diameter of the largest size well casing. The apparatus preferably has a single riser caisson to extend from about the marine bottom to above the water level with at least one buoyancy chamber attached to its upper portion, and an enlarged bottom section. The bottom section contains the guide means to direct apparatus such as drills and casing into appropriate exit holes.

Abstract: This invention concerns means for protecting a marine wellhead (including the Christmas tree) on an offshore hydrocarbon-producing platform from damage due to fire. Special means are provided to protect a wellhead placed a small depth, e.g., 25 to 50 feet, below the water surface under the deck of the offshore platform. These special means include a horizontal support frame supported by the platform. The wellhead is supported at about the same level as the support frame. A heavy shield comprising a heavy framework somewhat bell- shaped with an open bottom is lowered over the wellhead and comes to rest on the fixed frame or shelf. This shield is removable, but is ordinarily kept in position. In event of a fire on the production platform above the submerged wellhead, debris that may fall from the platform is diverted by the shield. Ocean water continually surrounds the marine wellhead, so that, in case of fire, it cannot be damaged by heat.