Cementing sub for annulus cementing

A wellbore tubular comprising:

• a tubular body including a first end, an opposite end and a wall defined between an inner bore extending from the first end to the opposite end and an outer surface;
• a port through the wall of the tubular body providing communication between the inner bore and the outer surface, the port including an openable closure;
• a conduit along the wall of the tubular extending from an inlet adjacent the first end and an outlet adjacent the opposite end, the inlet and outlet opening to the outer surface and being isolated from communication with the inner bore;
• a first annular packer encircling the tubular body and positioned between the port and the inlet;
• and a second annular packer encircling the tubular body and positioned between the port and the outlet.

A tubular installation in place in a borehole comprising:

• a tubing string in a borehole creating an annular space between the tubing string and a wall of the borehole, the tubing string including a tubular body including a first end, an opposite end and a wall defined between an inner bore extending from the first end to the opposite end and an outer surface;
• a port through the wall of the tubular body, which when open provides communication between the inner bore and the outer surface;
• a conduit along the wall of the tubular extending from an inlet adjacent the first end and an outlet adjacent the opposite end, the inlet and outlet opening to the outer surface but being isolated from communication with the inner bore;
• a first annular packer encircling the tubular body and expanded to seal against communication between the port and the inlet;
• and a second annular packer encircling the tubular body and expanded to seal against communication between the port and the outlet, the first packer and the second packer dividing the annular space into an upper annular space above the second packer, a middle annular space between the first packer and the second packer and a lower annular space below the first packer.