Abstract: Methods and systems for removing drilling fluid from wet drill cuttings are described. According to some embodiments, the method comprises: at a pressure above atmospheric pressure: using an internal combustion engine, combusting an air-fuel mixture comprising air and a hydrocarbon-based fuel, thereby producing a combustion exhaust at a first temperature; providing the combustion exhaust to the wet drill cuttings to contact and directly heat the wet drill cuttings by convection so that at least some fluid is evaporated therefrom and at least some dry solid drill cuttings remain, the evaporated fluid comprising drilling fluid and water; condensing at least a portion of the evaporated fluid to produce condensed drilling fluid, water and non-condensable inert gas; and separately recovering the condensed drilling fluid, the water and the dry solid drill cuttings.

Abstract: Systems and methods for removing drilling fluid from wet drill cuttings are described. According to some embodiments, the method comprises, at a pressure above atmospheric pressure: combusting a rich air-fuel mixture at a rich combustion temperature, thereby producing a generally low oxygen, inert rich exhaust; providing said rich exhaust to the wet drill cuttings to contact and directly heat the wet drill cuttings by convection so that at least a portion of the drilling fluid is evaporated therefrom and at least some dry solid drill cuttings remain; condensing at least a portion of the evaporated drilling fluid to produce condensed drilling fluid; and separately recovering the condensed drilling fluid and the dry solid drill cuttings.

Abstract: Methods and systems for removing drilling fluid from wet drill cuttings are described. According to some embodiments, the method comprises: at a pressure above atmospheric pressure: using an internal combustion engine, combusting an air-fuel mixture comprising air and a hydrocarbon-based fuel, thereby producing a combustion exhaust at a first temperature; providing the combustion exhaust to the wet drill cuttings to contact and directly heat the wet drill cuttings by convection so that at least some fluid is evaporated therefrom and at least some dry solid drill cuttings remain, the evaporated fluid comprising drilling fluid and water; condensing at least a portion of the evaporated fluid to produce condensed drilling fluid, water and non-condensable inert gas; and separately recovering the condensed drilling fluid, the water and the dry solid drill cuttings.

Abstract: Methods and systems for removing drilling fluid from wet drill cuttings are described. The methods may comprise: at a pressure above atmospheric pressure: separating air into constituent nitrogen and oxygen gases; heating a first mixture comprising the constituent oxygen gas with a mixture of air and natural gas to a combustion temperature, to produce a first combustion exhaust; transferring heat from the first combustion exhaust to a second mixture comprising the constituent nitrogen gas and non-condensable inert gas, thereby heating the second mixture to a first temperature; providing the heated second mixture to the wet drill cuttings to contact and directly heat the wet drill cuttings by convection so that at least a portion of drilling fluid is evaporated therefrom and at least some dry solid drill cuttings remain; condensing the evaporated drilling fluid to produce condensed drilling fluid; and separately recovering condensed drilling fluid and dry solid drill cuttings.

Abstract: Drill cuttings associated with drilling fluid are thermally cleaned. The wet cuttings are fed into a vessel chamber having mechanical mixers, such as ribbon blenders, extending lengthwise of the chamber. Direct heating is applied to the chamber contents by introducing hot combustion gas from a heater. A combination of direct heating and mechanical back mixing of wet colder cuttings with drier hotter cuttings results in conditioning and conduction heating of the wet cuttings. The drilling fluid is evaporated and removed as gas. Dried cuttings are separately recovered. Caking and agglomeration of the solids is reduced.