Abstract: Apparatus and method of filling voids in a ground stratum in the vicinity of a well bore are enclosed. The apparatus is a self-contained device and, for example, it can be placed in the well bore in the vicinity of the voids to be plugged by dropping the apparatus down a drill string. Once in place it will automatically respond to the well pressure to provide the required plugging. To accomplish this the apparatus includes precursors of polymers such as precursors of polyurethanes, epoxy type polymers, polyesters or other polymers which are released from the apparatus and flow into the voids.

Abstract: A buoyancy system is disclosed for use in controlling the descent and ascent of an object, such as a pipe line being laid offshore. The system includes a plurality of inflatable, collapsible, submersible buoys which may be remotely controlled by air or other inflating mediums. As each of the buoys, and thus the load connected thereto, is lowered or raised in a body of water the pressure inside the buoys is controlled by a valve which is responsive to the hydro-static pressure in the body of water or the volume of the buoy to maintain a relatively small pressure differential between the pressure inside the buoy and the hydro-static pressure at all depths of submersion whether the amount of buoyancy provided by the buoys is to be positive, negative, or neutral. Also disclosed are a plurality of systems utilizing the submersible buoys of this invention for laying pipe line and other objects on or near the sea bottom.