Image Number 9 for United States Patent #4068729.
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.