Annular Pressure Cap Drilling Method

A method for drilling an oil or gas well having a return flow pattern where no fluids return up an annulus between an inner tubing string and a production casing, wherein drilling fluid alternatively returns up an annulus between the production casing and an intermediate casing, comprising:

• installing a blowout preventer, the blowout preventer being in fluidic communication with the casing head;
• installing the intermediate casing to the casing head;
• installing a flow line from the casing head to a production separator;
• installing the production casing concentric with and inside the intermediate casing;
• installing the inner tubing string concentric and inside the production casing;
• wherein the production casing is ported above a lower extremity of the intermediate casing to enable the return flow of fluids from the annulus between the tubing and the production casing, into the annulus between the production casing and the intermediate casing, to the casing head, and to the separator;
• and
• installing an Annular Pressure Control Diverter between the blowout preventer and the casing head, the Annular Pressure Control Diverter configured to selectively block the annulus between the inner tubing string and the production casing to create a return flow pattern where no drilling fluid and produced fluids return up the annulus between the inner tubing string and the production casing and instead drilling fluid and produced fluids return up the annulus between the production casing and intermediate casing.

A method for drilling an oil or gas well wherein drilling fluid returns are flowed through a well head located below an all-inclusive blowout preventer stack to a drilling choke, comprising:

• installing an intermediate casing attached to a casing head;
• installing a production casing concentric with and inside the intermediate casing;
• installing a flow line from the production casing head to a separator;
• inserting an inner tubing string concentric with and inside the production casing;
• wherein the production casing is ported above a lower extremity of the intermediate casing to enable the return flow of fluids from an annulus between the tubing and the production casing into an annulus between the production casing and the intermediate casing, to the casing head, and to the drilling choke and
• installing an Annular Pressure Control Diverter below the blowout preventer stack, the Annular Pressure Control Diverter configured to selectively block the annulus between the inner tubing string and the production casing.