Engineers had spent days pumping heavy drilling fluid into the leaking well head on the ocean floor in a high-pressure bid to smother the gushing crude and ultimately seal the well with cement.

A new adjustable way was developed first time which use cluster well to decrease drilling cost and increase benefit in deep imbedded, low permeability, high pressure reservoir.

The preliminary practices show that underbalanced pressure drilling is completely fit to high pressure and low permeability as well as low pressure and leakage formations.