Hydrocarbon recovery from drilling mud stored in salt cavity

Method of disposing of material heavier than brine that has been contaminated with hydrocarbons, comprising the steps of:

• selecting a salt formation that is located below the surface of the ground;
• forming a flow path for water to flow into the salt formation by extending a water flow pipe from the surface of the ground down to the salt formation;
• circulating water downhole into said salt formation to solubilize the salt and thereby form a cavity that is filled with brine;
• said cavity has an upper, middle and lower part;
• forming a flow path along which the contaminated material flows from the surface, down to the lower part of the cavity by extending an inlet feed pipe from the surface of the ground down into the cavity;
• displacing the brine from said cavity by injecting quantities of the contaminated material thereinto whereupon the relatively dense component of said contaminated material gravitates to the bottom of said cavity while the relatively light hydrocarbons separate from the contaminated material and rise toward the surface of the earth, leaving the residual material on the bottom of the cavity;
• displacing the brine from said cavity by forming a flow path for water to flow from the surface, into the middle part of the cavity forcing the brine to flow uphole to the surface of the ground;
• forming a tortious flow path within said cavity for the upwardly flowing hydrocarbons by interrupting the salt formation with a plurality of anhydride ledges that form spaced apart baffles within the cavity, and thereby coalescing the upwardly flowing hydrocarbons by contact with the ledges of anhydride as the separated hydrocarbons rise up through the brine and flow toward surface of the ground;
• whereby, material heavier than brine that has been contaminated with hydrocarbons can be deposited in the lower part of the cavity, while hydrocarbons separate from the material and flow uphole toward the top of the cavity, and brine can be produced from the cavity by flowing the brine to the surface of the ground.

In a subterranean salt cavity communicated with the surface of the ground by a cased borehole, a method of treating used drilling mud to separate and reclaim hydrocarbons therefrom while safely storing the residual separated mud downhole in said cavity, comprising the steps of:

• flowing water into a subterranean salt cavity to provide a saturated solution of brine within said cavity;
• flowing drilling mud into the bottom of said cavity;
• separating said drilling mud into hydrocarbon and residual mud, with the residual mud gravitating to the bottom of the cavity and the hydrocarbons gravitating to the top of the cavity to form a three phase system wherein there is a separated hydrocarbon layer at top of the cavity, a separated residual mud layer at the bottom of the cavity, and a solution of brine therebetween;
• displacing either of the brine and hydrocarbons from the cavity by pumping either of contaminated mud and water into the cavity;
• selecting the cavity in a geological formation that includes a plurality of baffle members in the form of anhydride ledges;
• and,
• using the ledges to form a circuitous flow path for the flow of hydrocarbons separated from the contaminated mud.

Method of disposing of material heavier than brine and admixed with hydrocarbons by reclaiming the hydrocarbons therefrom while the residual material is stored underground, comprising the steps of:

• selecting a downhole salt formation and forming a solution cavity therein by forming a flow path between the salt formation and the surface of the ground and solubilizing some of the salt formation by flowing water along said flow path into said solution cavity;
• flowing material heavier than brine and admixed with hydrocarbon from the surface into the cavity, whereupon the hydrocarbon separates from the material and the residual material flows to the bottom of the cavity;
• forming said cavity in a geological formation that includes a plurality of baffle members in the form of anhydride ledges, whereby the ledges form a tortious flow path respective to the upward flow of hydrocarbons separated from said residual material;
• displacing a volume of brine from the solution cavity with a volume of said material by flowing said material into the solution cavity;
• forming a layer of hydrocarbon within the upper part of the cavity by collecting the separated hydrocarbon that ascends the cavity,
• collecting a layer of residual material within the lower part of the cavity, and collecting a layer of brine therebetween;
• producing brine by flowing the brine along a flow path that extends from the layer of brine to the surface of the ground, and producing hydrocarbon by flowing the hydrocarbon along a flow path that extends from the layer of hydrocarbon to the surface of the ground.