Method and apparatus for drilling and lining a wellbore

A drilling apparatus comprising:

• a drill string including a section of expandable tubing;
• a drill bit mounted on the string;
• and
• a tubing expander mounted on the string, wherein the expandable tubing is deformable by compressive plastic deformation of the tubing with a localised reduction in wall thickness, resulting in a subsequent increase in tubing diameter and wherein the drill bit may be retrieved through the expanded tubing,
• wherein the drill bit is a bi-centred bit.

A drilling apparatus comprising:

• a drill string including a section of expandable tubing;
• a drill bit mounted on the string;
• a tubing expander mounted on the string wherein the expandable tubing is deformable by compressive plastic deformation of the tubing with a localised reduction in wall thickness, resulting in a subsequent increase in tubing diameter and wherein the drill bit may be retrieved through the expanded tubing;
• and
• a drill assembly mounted to the lower end of the expandable tubing section.

A drilling apparatus comprising:

• a drill string including a section of expandable tubing;
• a drill bit mounted on the string;
• and
• a tubing expander mounted on the string, wherein the expandable tubing is deformable by compressive plastic deformation of the tubing with a localised reduction in wall thickness, resulting in a subsequent increase in tubing diameter and wherein the drill bit may be retrieved through the expanded tubing,
• wherein a lower portion of the expandable tubing carries an external seal arrangement for cooperating with the surrounding bore wall.

A drilling apparatus comprising:

• a drill string including a section of expandable tubing;
• a drill bit mounted on the string;
• and
• a tubing expander mounted on the string, wherein the expandable tubing is deformable by compressive plastic deformation of the tubing with a localised reduction in wall thickness, resulting in a subsequent increase in tubing diameter and wherein the drill bit may be retrieved through the expanded tubing,
• wherein the tubing expander comprises a body and at least one rolling expander member mounted on the body.

An apparatus for lining and drilling a wellbore, comprising;

• an expandable tubular;
• a drill assembly having a drill bit;
• and
• a tubing expander comprising one or more radially extendable members that are directly fluid pressure actuated.

A method for lining and drilling a wellbore, comprising:

• running a drill string into the wellbore, the drill string comprising:
• an expandable tubular;
• a drill assembly having a drill bit;
• and
• a tubing expander comprising one or more radially extendable members that are directly fluid pressure actuated;
• rotating the drill bit and advancing the drill string through the wellbore;
• plastically deforming at least a portion of the expandable tubular by rolling expansion;
• and
• retrieving the drill string from the bore.

An apparatus for lining and drilling a wellbore, comprising;

• an expandable tubular having a constant diameter;
• a drill assembly having a drill bit;
• and
• a tubing expander comprising one or more radially extendable members that are directly fluid pressure actuated;
• wherein the diameter of the expandable tubular is uniformly increased within the wellbore.