f Estimation of Shear Force for Blind Shear Ram Blowout Preventers

The explosion of the Deepwater Horizon oil rig in the Gulf of Mexico showed once again that during the oil/gas drilling operation any failures of blowout preventers (BOPs) may result in death, injury and massive oil spills that have huge impact on the environment. During drilling operations, all formations’ high pressure fluids and gases in the earth are controlled by borehole pressure, which consists of hydrostatic pressure of drilling mud, pump pressure, and friction pressure loss in the annulus. If for any reason the borehole pressure falls below the formation fluid/gas pressure, the formation fluids/gases would enter the hole and a pressure “kick” occurs. If a kick cannot be controlled properly, uncontrolled formation fluids/gases would reach to the surface where the drilling rig is located. Such a catastrophic event is known as blowout.