Abstract: A downhole blowout preventer has a blowout preventer tubing string containing a circulation unit, a packer unit and a pressure-building unit connected in sequence from top to bottom. The pressure-building unit is configured to be activated in response to a command, so as to build up pressure in a space inside the blowout preventer tubing string. The packer unit is configured to be activated when a pressure in said space reaches a first predetermined value, so as to seal an annulus between said blowout preventer tubing string and an external casing or borehole. The circulation unit is configured to be activated when the pressure in said space reaches a second predetermined value, thereby creating a circulation path between an interior and an exterior of the blowout preventer tubing string. The first predetermined value is less than the second predetermined value.

Abstract: A downhole blowout preventer has a blowout preventer tubing string containing a circulation unit, a packer unit and a pressure-building unit connected in sequence from top to bottom. The pressure-building unit is configured to be activated in response to a command, so as to build up pressure in a space inside the blowout preventer tubing string. The packer unit is configured to be activated when a pressure in said space reaches a first predetermined value, so as to seal an annulus between said blowout preventer tubing string and an external casing or borehole. The circulation unit is configured to be activated when the pressure in said space reaches a second predetermined value, thereby creating a circulation path between an interior and an exterior of the blowout preventer tubing string. The first predetermined value is less than the second predetermined value.

Abstract: The present invention provides a downhole auxiliary drilling apparatus, including an impact energy generator capable of converting the energy of the drilling fluid to the axial impact energy, and an impact energy distributor capable of redistributing the impact energy generated by the impact energy generator to convert the axial impact force into a combined impact force, which provides the drilling bit with a high-frequently changing combined impact force, thus greatly improving the rock breaking efficiency and the rate of penetration of the drilling tool. The downhole auxiliary drilling apparatus is further provided with a shock-absorbing and torque-stabilizing device arranged between the impact energy generator and the impact energy distributor, which can reduce the axial vibration of the drilling tool and the damage on the drilling bit, and greatly extend the lifetime of the drilling bit.

Abstract: The present invention provides a downhole auxiliary drilling apparatus, including an impact energy generator capable of converting the energy of the drilling fluid to the axial impact energy, and an impact energy distributor capable of redistributing the impact energy generated by the impact energy generator to convert the axial impact force into a combined impact force, which provides the drilling bit with a high-frequently changing combined impact force, thus greatly improving the rock breaking efficiency and the rate of penetration of the drilling tool. The downhole auxiliary drilling apparatus is further provided with a shock-absorbing and torque-stabilizing device arranged between the impact energy generator and the impact energy distributor, which can reduce the axial vibration of the drilling tool and the damage on the drilling bit, and greatly extend the lifetime of the drilling bit.