简介：

简介：Shales,themostabundantofsedimentaryrocks,arevaluedasthesource-rocksandsealstoporouspetroleumreservoirs.Overthepast-twentyyears,organic-richshaleshavealsoemergedasvaluablepetroleumsystems(reservoir,seal,andsourcerockscontainedinthesameformation).Assuchtheyhavebecomeprimarytargetsforpetroleumexplorationandexploitation.ThisPart1ofathree-partreviewaddressesthebulkproperties,multi-scalegeometryandgasadsorptioncharacteristicsofthesediverseandcomplexrocks.Shalesdisplayextremelylowpermeability,andtheirporosityisalsolow,butmulti-scale.Characterizingthegeometryandinterconnectivityofthepore-structureframeworkswiththenatural-fracturenetworkswithinshalesisessentialforestablishingtheirpetroleumexploitationpotential.Organic-richshalestypicallycontaintwodistincttypesofporosity:matrixporosityandfractureporosity.Inadditiontointer-granularporosity,thematrixporosityincludestwotypesofmineral-hostedporosity:inorganic-mineral-hostedporosity(IP);and,organic-matter-hosted(withinthekerogen)porosity(OP).Whereas,thefractureporosityandpermeabilityiscrucialforpetroleumproductionfromshales,itiswithintheOPwhere,typically,muchofthein-situoilandgasresourcesresides,andfromwhereitneedstobemobilized.OPincreasessignificantlyasshalesbecomemorethermallymature(i.e.,withinthegasgenerationzones),andplaysakeyroleintheultimaterecoveryfromshale-gassystems.Shales'methanesorptioncapacities(MSC)tendstobepositivelycorrelatedwiththeirtotalorganiccarboncontent(TOC),thermalmaturation,andmicroporevolume.Claymineralsalsosignificantlyinfluencekeyphysicalpropertiesofshalerelatedtofluidflow(permeability)andresponsetostress(fracability)thatdeterminetheirprospectivityforpetroleumexploitation.Claymineralscanalsoadsorbgas,somemuchbetterthanothers.Thesurfaceareaoftheporestructureofshalescanbepositively