Patent ID: 7575073

Claim:
A system for handling drilling fluids including drilling cuttings returned from a wellbore during drilling, the fluids further comprising an intermittent and unpredictable flow of gaseous hydrocarbons entrained therein, wherein a wellhead comprises a flow diverter and a BOP for redirecting drilling fluids from the flow diverter to a choke manifold the system comprising: a vertical separator for receiving the drilling fluids from the flow diverter; the system further comprising: a liquid volume having a liquid level control, a stagnant zone of liquid for separating the entrained gaseous hydrocarbons from the drilling fluids, a solids outlet for gravity discharging substantially gas free drilling solids therefrom, a liquid outlet for discharging substantially gas free liquids therefrom, and a gas outlet for discharging evolved gaseous hydrocarbons at substantially atmospheric pressure therefrom; a shale shaker for receiving substantially gas free drilling solids and substantially gas free liquids discharged from the separator and for further separating the drilling solids from the liquids; a recirculation line for flowing substantially gas free separated liquids from the shale shaker to the separator wherein the substantially gas free drilling solids discharging from the solids outlet join the substantially gas free liquids for recirculation to the shale shaker; a secondary line connected between the choke manifold and the separator; an ignition source connected to the gas outlet for receiving and combusting evolved hydrocarbons from the wellbore; a source of addition fluid connected to the flow of combustible hydrocarbons between the choke manifold and the ignition source; and a venturi for accelerating the flow of combustible gas with the addition fluid for inducing flow of combustible gas to the ignition source, wherein the addition fluid is continuously provided to the flow of gaseous hydrocarbons in a velocity in excess of a minimal flame propagation velocity to prevent backflash from the ignition source to the separator.