Abstract: A fluid loss device has a housing, a seal assembly, a running tool, and a plug. The housing of the fluid loss device is placed in a production string before a well bore is completed. The plug is attached to the running tool, and the running tool is attached to a wash pipe.The fluid loss device is activated by lifting the wash pipe and the running tool, thereby engaging the plug with the seal assembly, engaging the seal assembly with the housing, and severing the plug from the running tool. Activation of the fluid loss device inhibits fluid communication through the fluid loss device and reduces damage to the well structure behind the fluid loss device while completion operations are performed in other areas of the well bore.The fluid loss device is deactivated by forcing the plug through the fluid loss device with mechanical force or pressure, or by chemically eroding the diameter of the plug until the plug passes through the fluid loss device.

Abstract: A fluid loss device has a housing, a seal assembly, a running tool, and a plug. The housing of the fluid loss device is placed in a production string before a well bore is completed. The plug is attached to the running tool, and the running tool is attached to a wash pipe.The fluid loss device is activated by lifting the wash pipe and the running tool, thereby engaging the plug with the seal assembly, engaging the seal assembly with the housing, and severing the plug from the running tool. Activation of the fluid loss device inhibits fluid communication through the fluid loss device and reduces damage to the well structure behind the fluid loss device while completion operations are performed in other areas of the well bore.The fluid loss device is deactivated by forcing the plug through the fluid loss device with mechanical force or pressure, or by chemically eroding the diameter of the plug until the plug passes through the fluid loss device.

Abstract: A flapper valve assembly includes a frangible valve closure member which is supported by an elastomeric hinge. The frangible valve closure member is a tempered glass plate, and the hinge is a block of elastomer material which is secured to the glass plate by a molecular bond. In one embodiment, the hinge includes an integrally formed elastomeric jacket which partially encapsulates the glass sealing element and is bonded thereto. In one arrangement, a fluid seal is provided by a resilient, elastomeric seal which is received within a valve pocket, and which is engaged directly by the glass plate. In another arrangement, an annular valve seat is formed in a valve housing sub, with the fluid seal being provided by the elastomeric jacket which is fitted about the glass closure plate.