WELLBORE CHEMICAL INJECTION WITH TUBING SPOOL SIDE EXTENSION FLANGE

A wellbore chemical injection assembly includes an extension flange including two ends joined by a flange wall defining an inlet. The first end can fluidically couple to a tubing spool inlet of a wellhead installed at a wellbore surface. The second end can fluidically couple to a fluidic outlet of the wellhead. An extension member is attached to the flange wall at the inlet at a non-zero angle. An axial length of the extension member defines a through opening of increasing inner diameter from the inlet towards an end of the extension member. The end can be fluidically coupled to a chemical reservoir from which chemical is injected through the extension member and the extension flange into the tubing spool. Multiple valves are seated in the through opening of the extension member. The multiple valves are sized differently to seal the through opening of increasing diameter.