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red-et-lyy7 rb~~r Utr1tKHL t_r+ei ~ i uaL 3,759,328 LATERALLY EXPANDING Olt. SHgLE PERM£ABILIZATION CROSS REFERENCES TO RELATED APPL1CA710N5 This application is a continuation-m-part o! copend- rag parent application Scr. No. 57,209 filed July 22, 1970, now abandoned. BACI:GROUND OF THE INVE1rT10N The present tnven[ion relates to production of hydro- carbons and/or water soluble and/or hear sensitive min- erali from underground oil shalt (otmations by con- rrolled circulation of a hot aqueous fluid throuq)t said oil shale formation to u [o venrcally and horirpntally expand a permeable sons of rubbles oil shale within said formation by leaehtng and recovering said miner als from a relatively deep location within the (reared area of the formation and thereafter injcctmg a pyro- lyzing (lord into the rubbles oil shalt to c(fcct pyrolysis and recovery of hydrocarbons therefrom. Venous methods have been proposed for imparting permeability to underground oil shale formations such as fracturing by hydraulic or explosive means and/or a[rdtzatson but they have proven to be intflective and- /or too expensive [o use. Thus, oil shalt formations which have been fracturr.A on subsequent pyrolysis with pyrohzing fluid to offset oil recovery, such frac- tures tend [o close unless high pyrolyzing Ruid circula- tion pressu res at least equal to the overburdrn pres- sure, are masntaincd and this is difficult to do Acrdtza. (ion of an ail shale formation is expensive and difficult to control. SUMMARY OF 7~HE 1htiENTIOti at The present invention is dirceicd to an improved method of recovering hydmearbons and water-soluble carbonates and/or heat sensitive ma[enals from undct- ground oil shale for-mstions tonuining substantial amounCt oC said carbonate and/or minerals by forming a cavern therein by leaching wish an aqueous Ruid said carbonates and/or minerals and imparting pcrmeabiliry while effecting rabbling of the oil shalt in said treated area 6y conucting and Rowing a hot aqueous Ruid downward from a re]atively'shallow depth alonga vcrd- cal interval of said treated oil shale to Cause horizonul expansion and recovering from a relatively deep depth an squeezes liquid tonuining dissolved therein water soluble carbonates and/or heat ecnsitive minerals and subsequently injeCUng a pyrolyzing Ruid or solvent to c Cfcu rccavery of hydrocarbons from the rubbles oil shale. DESCRIPTION OF 7 HE DRAWING FIG. 1 is a vertical section showing a eubtcrtanenn od shale end downhole equipment for practicing the pres- cntinvennon, t FIG. 2 is a schematic illustration of a flow path far [nculabng Rwd in accordanec with the present inven- tion. _ FIG ~ is a ver[ieal section showing en alternative ar- rangement of downholt cquiprntitt of the type shown in FIG. 1. DESCRIPTION OF THE IN VEN'TION [V'Jl ~r~ t~r~ r.lzit~ 2 nsficant amount o(heat sensitive minerals and/or water soluble carbonates a hot aqueous fluid can be reused to (law along a path that cause a horitonul expansion of [hr. cavern. !n a tavern within such art oil shale, the 5 rate aI which a ho[ aqueous fluid is aegregatcd into lay- ers having increasing densities, has been found to be related to the rdte at which heat tan be tranafertcd into the wink of the eavcm in a manner conducive t0 the u- ublishing and maintaining of the flow path described t0 above, and the resultant heating and leaching along subsisntially vtrvcal porvons of the want of such a eav- cm has been loons to cause a honzonral expansion of the cavern. The term "cavern" is used to refer to any ulativdy I S solids free opening, bush az a cave, void, tunnel, bore- hole, or interconnected fraemres, etc., in which the rate of gravrty segregation of fluids is not significantly impeded 6y a lack of permcabiliry. !n the present process, the fluid circulation and eav 20 ern expansion operations can be initiated by opening at !test a single well into an interval of oil shale that con- tains heat srntstrve minerals and/or water soluble car- bonate, inROwrng hot fluid into tOntact with an upper portion of the borehole wall, (lowing [he hot fluid down 25 slung the borchale wall, and removing liquid tonuin- ing dissolved minerals and/or water-soluble carbonates from a lower portion of Nt borehole glternatively, a plurality of wells can be used [o provide Row paths into a horuontally extensive cavern in or adjacent f0 Od J0 shale that canuitts heat sensitive minerals and/or wa- ter-soluble carbonates and the wells and the cavern can be utilized to cause a concurrent hnrizonul and verti- cal expansion of a permeable zone by inRowing hat aqueous Ruid into contact with a upper portion of such 35 oil shale, Rowing Ruid downward along a vertical intcr- val of such oil shale, Rowing Ruid horizontally along the roof of the cavern, and removing Irquid tonuining dis- solved minerals and/or water-soluble carbnnattf Crom within the eavcm. a0 As used herein, the [erin "beet sensitive and/or ws- ur-soluble carbonate" refers to materials that decom- pose relatively rapidly at d relatively low temperature, such az one between about 250' F to about 700' F, to yield ru bon dioztde and water. Examples of heat sensl- 45 rive Carbonate minerals include naheolit~dawsonite. trona, and the Itke minerals. w 'ch art usLr@ I in ~ve ~sa7sne ear bonate and/or bicarbanatc molecular struCmres ~ mortie"s"~~'-`-~-'' 50 In a preferred embodiment of the present invcn[ion, a borehole is drilled into a relatively low-lying portion of of shalt which Contains or is adjacent to a Isyer or region chat is rtla[irely rich in water soluble mineral. Such water soluble rninenls (generally saline minerals) ss arc frcquendy cncnuntaed in oi4 shale fnrma4ons m the United Stites, such as the Green River (ormation in Colorado, in the form of brdf, lenses, nodules, nodes, veins or the likes. Ezampio of such water soluble minerals seclude the alkali metal chloride salts rush as ~ halite minerals and/or water soluble heat sensitive car- bonatr minerals such as nahcnlitc, trans, of the like. The locations of portions of subterranean oil shales which contain specsfie mineral components, such az heat sensitive carbonate minerals and/or water soluble 65 minerals, can be determined by means of known geo- 12