An injection quill design and methods of use for injecting a first fluid into a second fluid. The injection quill may comprise a hollow stem having a closed end and a sidewall, the stem having a curved cross-section defined by a major axis, and a minor axis, and at least one orifice for injecting the first fluid into the second fluid, wherein the major axis is greater than the minor axis and/or the orifice extends through the sidewall and/or the orifice has an internal chamfer with a chamfer angle ranging from less than 0° but greater than 90°.