Underwater blowouts from gas and oil operations often involve the simultaneous release of oil and gas. Presence of gas bubbles in jets/plumes could greatly influence oil droplet formation. With the aim of understanding and quantifying the droplet formation from Deepwater Horizon blowout (DWH) we developed a new formulation for gas-oil interaction with jets/plumes. We used the jet-droplet formation model VDROP-J with the new module and the updated model was validated against laboratory and field experimental data. Application to DWH revealed that, in the absence of dispersant, gas input resulted in a reduction of d /react-text 50 react-text: 182 by up to 1.5 /react-text react-text: 183 /react-text react-text: 184 mm, and maximum impact occurred at intermediate gas fractions (30–50%). In the presence of dispersant, reduction in d /react-text 50 react-text: 260 due to bubbles was small because of the promoted small sizes of both bubbles and droplets by /react-text surfactants react-text: 262 . The new development could largely enhance the prediction and response to oil and gas blowouts.