Two string drilling system using coil tubing

An apparatus for drilling a well bore in a hydrocarbon formation, comprising:

• a concentric coiled tubing drill string consisting essentially of an inner coiled tubing string, said inner coiled tubing string having an inside wall and an outside wall and situated within an outer coiled tubing string having an inside wall and an outside wall, said outside wall of said inner coiled tubing string and said inside wall of said outer coiled tubing string defining an annulus between the coiled tubing strings;
• a drilling means attached to the lower end of the concentric coiled tubing drill string;
• and
• a drilling medium delivery means for delivering chilling medium through one of said annulus or inner coiled tubing string for both operating the drilling means to form a borehole and for entraining and removing drill cuttings through said other of said annulus or inner coiled tubing string.

A method for drilling a well bore in a hydrocarbon formation, comprising:

• providing a concentric coiled tubing drill string having an inner coiled tubing string, said inner coiled tubing string having an inside wall and an outside wall and situated within an outer coiled tubing string having an inside wall and an outside wall, said outside wall of said inner coiled tubing string and said inside wall of said outer coiled tubing string defining an annulus between the coiled tubing strings;
• connecting a drilling means comprising a positive displacement motor and reverse circulating drill bit at the lower end of the concentric coiled tubing drill string;
• and
• delivering drilling medium selected from the group consisting of drilling mud, drilling fluid and a mixture of drilling fluid and gas through one of said annulus or inner coiled tubing string for operating the drilling means to form a borehole and removing exhaust drilling medium by extracting said exhaust drilling medium through said other of said annulus or inner coiled tubing string.

A method for drilling a well bore in a hydrocarbon formation, comprising:

• providing a concentric coiled tubing drill string having an inner coiled tubing string, said inner coiled tubing string having an inside wall and an outside wall and situated within an outer coiled tubing string having an inside wall and an outside wall, said outside wall of said inner coiled tubing string and said inside wall of said outer coiled tubing string defining an annulus between the coiled tubing strings;
• connecting a drilling means comprising a reverse circulating mud motor and a rotary drill bit at the lower end of the concentric coiled tubing drill string;
• and
• delivering drilling medium selected from the group consisting of drilling mud, drilling fluid and a mixture of drilling fluid and gas through one of said annulus or inner coiled tubing string for operating the drilling means to form a borehole and removing exhaust drilling medium by extracting said exhaust drilling medium through said other of said annulus or inner coiled tubing string.

A method for drilling a well bore in a hydrocarbon formation, comprising:

• providing a concentric coiled tubing drill string having an inner coiled tubing string, said inner coiled tubing string having an inside wall and an outside wall and situated within an outer coiled tubing string having an inside wall and an outside wall, said outside wall of said inner coiled tubing string and said inside wall of said outer coiled tubing string defining an annulus between the coiled tubing strings;
• connecting a drilling means comprising a positive displacement motor and a reverse circulating drill bit at the lower end of the concentric coiled tubing chill string;
• and
• delivering drilling medium through one of said annulus or inner coiled tubing string for operating the drilling means to form a borehole and removing exhaust drilling medium by extracting said exhaust drilling medium through said other of said annulus or inner coiled tubing string.

A method for drilling a well bore in a hydrocarbon formation, comprising:

• providing a concentric coiled tubing drill string having an inner coiled tubing string, said inner coiled tubing string having an inside wall and an outside wall and situated within an outer coiled tubing string having an inside wall and an outside wall, said outside wall of said inner coiled tubing string and said inside wall of said outer coiled tubing string defining an annulus between the coiled tubing strings;
• connecting a drilling means at the lower end of the concentric coiled tubing drill string;
• delivering drilling medium through one of said annulus or inner coiled tubing string for operating the drilling means to form a borehole and removing exhaust drilling medium by extracting said exhaust drilling medium through said other of said annulus or inner coiled tubing string;
• and
• providing a downhole flow control means positioned at or near the drilling means for preventing flow of hydrocarbons from the inner coiled tubing string or the annulus or both to the surface of the well bore.

A method for drilling a well bore in a hydrocarbon formation, comprising:

• providing a concentric coiled tubing drill string having an inner coiled tubing string, said inner coiled tubing string having an inside wall and an outside wall and situated within an outer coiled tubing string having an inside wall and an outside wall, said outside wall of said inner coiled tubing string and said inside wall of said outer coiled tubing string defining an annulus between the coiled tubing strings;
• connecting a drilling means at the lower end of the concentric coiled tubing drill string;
• delivering drilling medium through one of said annulus or inner coiled tubing string for operating the drilling means to form a borehole and removing exhaust drilling medium by extracting said exhaust drilling medium through said other of said annulus or inner coiled tubing string;
• and
• providing a surface flow control means positioned at or near the surface of the well bore for preventing flow of hydrocarbons from a space between the outside wall of the outer coiled tubing string and a wall of time borehole.

A method for drilling a well bore in a hydrocarbon formation;

• comprising the steps of:
• providing a concentric coiled tubing drill string having an inner coiled tubing string, said inner coiled tubing string having an inside wall and an outside wall and situated within an outer coiled tubing string having an inside wall and an outside wall, said outside wall of said inner coiled tubing string and said inside wall of said outer coiled tubing string defining an annulus between the coiled tubing strings, said concentric coiled tubing drill string further comprising a discharging means comprising a flare means for flaring hydrocarbons produced from the well bore positioned at or near the surface of the well bore;
• connecting a drilling means at the lower end of the concentric coiled tubing drill string;
• and
• delivering drilling medium through one of said annulus or inner coiled tubing string for operating the drilling means to form a borehole and removing exhaust drilling medium by extracting said exhaust drilling medium through said other of said annulus or inner coiled tubing string.

A method for drilling a well bore in a hydrocarbon formation, comprising the steps of:

• providing a concentric coiled tubing drill string having an inner coiled tubing string, said inner coiled tubing string having an inside wail and an outside wall and situated within an outer coiled tubing string having an inside wall and an outside wall, said outside wall of said inner coiled tubing string and said inside wall of said outer celled tubing string defining an annulus between the coiled tubing strings;
• connecting a drilling means at the lower end of the concentric coiled tubing drill string;
• and
• delivering drilling medium through one of said annulus or inner coiled tubing string for operating the drilling means to form a borehole and removing exhaust drilling medium by extracting said exhaust drilling medium through said other of said annulus or inner coiled tubing string;
• and
• providing a shroud means positioned between the outside wall of the outer coiled tubing string and a wall of the well bore for reducing the flow of exhaust drilling medium through a space between the outside wall of the outer coiled tubing string and a wall of the borehole.

An apparatus for drilling a well bore in a hydrocarbon formation, comprising;

• a concentric coiled tubing drill string having an inner coiled tubing string, said inner coiled tubing string having an inside wall and an outside wall and situated within an outer coiled tubing string having an inside wall and an outside wall, said outside wall of said inner coiled tubing string and said inside wall of said outer coiled tubing string defining an annulus between the coiled tubing strings;
• a drilling means attached to the lower end of the concentric coiled tubing drill string, said drilling means comprising a positive displacement motor and a reverse circulating drill bit;
• and
• a drilling medium delivery means for delivering drilling medium through one of said annulus or inner coiled tubing string for operating the drilling means to form a borehole and removing exhaust drilling medium by extracting said exhaust drilling medium through said other of said annulus or inner coiled tubing string.

An apparatus drilling a well bore in a hydrocarbon formation, comprising:

• a concentric coiled tubing drill string having an inner coiled tubing string, said inner coiled tubing string having an inside wall and an outside wall and situated within an outer coiled tubing string having an inside wall and an outside wall, said outside wall of said inner coiled tubing string and said inside wall of said outer coiled tubing string defining an annulus between the coiled tubing strings;
• a drilling means attached to the lower end of the concentric coiled tubing drill string, said drilling means comprising a reverse circulating mud motor and a rotary drill bit;
• and
• a drilling medium delivery means for delivering drilling medium through one of said annulus or inner coiled tubing string for operating the drilling means to form a borehole and removing exhaust drilling medium drill cuttings by extracting said exhaust drilling medium through said other of said annulus or inner coiled tubing string.

An apparatus drilling a well bore in a hydrocarbon formation, comprising:

• a concentric coiled tubing drill string having an inner coiled tubing string, said inner coiled tubing string having an inside wall and an outside wall and situated within an outer coiled tubing string having an inside wall and an outside wall, said outside wall of said inner coiled tubing string and said inside wall of said outer coiled tubing string defining an annulus between the coiled tubing strings;
• a drilling means attached to the lower end of the concentric coiled tubing drill string, said drilling means comprising a positive displacement motor and a reverse circulating drill bit;
• and
• a drilling medium delivery means for delivering drilling medium through one of said annulus or inner coiled tubing string for operating the drilling means to form a borehole and removing exhaust drilling medium by extracting said exhaust drilling medium through said other of said annulus or inner coiled tubing string.

An apparatus drilling a well bore in a hydrocarbon formation, comprising:

• a concentric coiled tubing drill string having an inner coiled tubing string, said inner coiled tubing string having an inside wall and an outside wall and situated within an outer coiled tubing string having an inside wall and an outside wall, said outside wall of said inner coiled tubing string and said inside wall of said outer coiled tubing string defining an annulus between the coiled tubing strings;
• a drilling means attached to the lower end of the concentric coiled tubing drill string;
• a drilling medium delivery means for delivering drilling medium through one of said annulus or inner coiled tubing string for operating the drilling means to form a borehole and removing exhaust drilling medium by extracting said exhaust drilling medium through said other of said annulus or inner coiled tubing string;
• and
• a downhole flow control means positioned at or near the drilling means for preventing flow of hydrocarbons from the inner coiled tubing string or the annulus or both to the surface of the well bore.

An apparatus drilling a well bore in a hydrocarbon formation, comprising:

• a concentric coiled tubing drill string having an inner coiled tubing string, said inner coiled tubing string having an inside wall and an outside wall and situated within an outer coiled tubing string having an inside wall and an outside wall, said outside wall of said inner coiled tubing string and said inside wall of said outer coiled tubing string defining an annulus between the coiled tubing strings;
• a drilling means attached to the lower end of the concentric coiled tubing drill string;
• a drilling medium delivery means for delivering drilling medium through one of said annulus or inner coiled tubing string for operating the drilling means to form a borehole and removing exhaust drilling medium by extracting said exhaust drilling medium through said other of said annulus or inner coiled tubing string;
• and
• a surface flow control means positioned at or near the surface of the well bore for reducing flow of hydrocarbons from a space between the outside wall of the outer coiled tubing string and a wall of the borehole.

An apparatus drilling a well bore in a hydrocarbon formation, comprising:

• a concentric coiled tubing drill stung having an inner coiled tubing string, said inner coiled tubing string having an inside wall and an outside wall and situated within an outer coiled tubing string having an inside wall and an outside wall, said outside wall of said inner coiled tubing siring and said inside wall of said outer coiled tubing string defining an annulus between the coiled tubing strings;
• a drilling means attached to the lower end of the concentric coiled tubing chill string;
• a drilling medium delivery means for delivering drilling medium through one of said annulus or inner coiled tubing string for operating the drilling means to form a borehole and removing exhaust drilling medium by extracting said exhaust drilling medium through said other of said annulus or inner coiled tubing string;
• and
• a discharging means having a flare means for flaring hydrocarbons produced from the well bore positioned near the top of said concentric coiled tubing drill string for discharging said exhaust drilling medium through said discharging means away from said well bore.

An apparatus drilling a well bore in a hydrocarbon formation, comprising:

• a concentric coiled tubing drill string having an inner coiled tubing string, said inner coiled tubing string having an inside wall and an outside wall and situated within an outer coiled tubing string having an inside wall and an outside wall, said outside wall of said inner coiled tubing string and said inside wall of said outer coiled tubing string defining an annulus between the coiled tubing strings;
• a drilling medium delivery means for delivering drilling medium through one of said annulus or inner coiled tubing string for operating the drilling means to form a borehole and removing exhaust drilling medium by extracting said exhaust drilling medium through said other of said annulus or inner coiled tubing string;
• and
• a shroud means positioned between the outside wall of the outer coiled tubing string and a wall of the well bore for reducing the flow of exhaust drilling medium through a space between the outside wall of the outer coiled tubing string and a wall of the borehole.