Rigless drilling and wellhead installation

A method for installation of a surface casing using a vessel, the method comprising:

• preparing a well casing assembly, a HPH running tool, a cement stinger, a high pressure housing (HPH) side entry sub and a high pressure housing (HPH) lifting sub into one unit onshore or on a vessel;
• connecting a hose from the vessel to the side entry sub of the surface casing assembly;
• dispatching the well casing assembly from the vessel;
• lowering the well casing assembly by means of a crane or winch on the vessel;
• stabbing the well casing assembly into the low pressure housing and running it into the borehole supported by the wire;
• latching and locking the high pressure housing of the well casing assembly into the low pressure housing;
• cementing the well casing in place by pumping cement from the vessel, through the hose, into the side entry sub, through the HPH running tool and down and out of the cement stinger;
• releasing the HPH running tool;
• and,
• pulling out of the borehole together with the lifting sub, the side entry sub and the cement stinger by using the hoisting means on the vessel.

A system for establishing a well foundation and drilling of a borehole using a vessel, the system comprising:

• a subsea node comprising a low pressure housing and configured to be preinstalled on a seabed;
• a bottom hole assembly comprising a drill bit, a drilling motor, a kelly bushing adapter, a non-rotating string, a side entry sub and a lifting sub and configured to be lifted from a vessel and lowered down into the sea by means of a hoisting means on the vessel;
• where the bottom hole assembly is configured to be set into the subsea node with the low pressure housing;
• a locking mechanism configured to lock and unlock the kelly bushing adapter to one from the group consisting of:
• the low pressure housing, a suction anchor and a high pressure housing;
• and,
• a pump being configured to pump a fluid through a hose into the side entry sub and down the non-rotating string in order to drive the drilling motor in order to drill a desired depth of the borehole.

A system for installation of a surface casing using a vessel, the system comprising:

• a surface casing assembly comprising a high pressure housing, a surface casing, a HPH running tool, a cement stinger, a HPH side entry sub and a HPH lifting sub, where the surface casing assembly is configured to be dispatched from a vessel and then lowered down on a wire of a crane on the vessel and is further configured to be stabbed into a subsea node with a low pressure housing and to be run into a borehole on the wire;
• and
• a hose from the vessel and connected to the side entry sub of the surface casing assembly;
• wherein the high pressure housing of the surface casing assembly is configured to be locked into the low pressure housing;
• wherein the cement stinger is configured to cement the surface casing in place in the borehole by means of a pump configured to pump cement from the vessel, through the hose, into the side entry sub and through the HPH running tool;
• and
• wherein the HPH running tool is configured to be released and pulled out of the borehole together with the lifting sub, the side entry sub and the cement stinger by using the wire of the crane on the vessel.