Compositional Analysis for Gas Condensate

Compositional analysis for Gas Condensate Reservo eservoir ir uids uids contai contain n hydro hydrocar carbon bon from from C1 to compou compounds nds with with carbon carbon numb number er grea greate terr than than 50 50.. Comp Compos osit itio ion n of Reser eservo voir ir uid uids s is gene genera rall lly y expressed in volume percent of nonhydrocarbon compounds !sour gases" and compounds hydrocarbon Cl through C#$orC10$.  %he main di&erence di&erence between various uids and produces crude oil is in their composition. the highest the amount of methane is found in the natural gas and the amount decreases in the gas condensate. 'n the other hand the amount of heavier compounds !i.e.( C7+) is C7+) is less in the natural gas and the gas condensate. Characteri)ation of reservoir uids and crude oils mainly involves characteri)ation of hydrocarbon plus fractions generally expressed expressed in terns of C#$ fractions. *sually the only information( available for the C#$ +cti +c tion on are are the the mole mole facti faction( on( mole molecu cula larr weight, and speci,c speci,c gravity. gravity. %he characteri)ation procedure involves how to present this mixture in terms of  arbitr arbitrary ary number number of subfra subfracti ctions ons !pseud !pseudoco ocompo mponen nents" ts" with with -nown -nown mole mole fraction( boiling point( boiling point( speci,c gravity( and molecular weight. %his approach is called pseudoi)ation. +ccu +c cura racy cy of char charac acte teri ri)a )ati tion on of reser eservo voir ir uid uids s lar largely gely depe depend nds s on the the dist distri ribu buti tion on mode modell used used to expr xpress ess comp compon onen entt dist distri ribu buti tion on as well well as characteri)ation methods of petroleum fractions. %he most accurate method to determine a property of a uid is through experimental measurement of  that that prope property rty. owev owever( er( as this this is not possib possible le for every every petro petroleu leum m uid( uid( meth method ods s of esti estima mati tion on of vari variou ous s prop proper erti ties es are are need needed ed by   processor operation engineers. %he most accurate method of estimating a property of a mixture is through -nowledge of the exact composition of all components existing in the mixture.  %he /uality and properties of a petroleum uid uid depend mainly on the mixture comp compos osit itio ion. n. +c +ccu cura rate te char charac acte teri ri)a )ati tion on of a reser eservo voir ir uid uid re/ui e/uirres a comple complete te analysi analysis s of the mixtur mixture e with with -nown -nown mole mole fracti fraction on and carbon carbon

number.

+s experimental

measurement

of the

composition

is time

consuming and costly the predictive methods play an important role in determining the /uality of a petroleum uid. +n accurate description of  pseudocomponent compositions or ingle Carbon umber !C" fractions is an integral part of the reservoir uids characteri)ation process. 2ery often the re/uired extended compositional analysis is not available and it is very hard to experimentally do this compositional analysis. 3t is needed to generate this analysis using mathematical relations that are called the splitting schemes.