Hydrocarbon fluid inclusions and source rock parameters:A comparison from two dry wells in the western offshore,India

Fluid inclusions represent the direct evidence of paleofluids and can provide valuable information on the evolution of sedimentary basins and oil-bearing strata.Hydrocarbon fluid inclusion(s)(HCFIs)are the vestiges of oil from the geological formations.The paper delineates the paleotemperature(Th)/oil win-dow,the oil quality of HCFIs and Raman peaks corresponding to hydrocarbon species of HCFIs using fluid inclusion techniques,and source rock potential of hydrocarbon generation,thermal maturity,the quan-tity of organic matter,and the kerogen types obtained through Rock-Eval pyrolysis data from two dry wells RV-1 well of Mumbai offshore and KKD-1A well of Kerala-Konkan Basin.The present study com-pares the fluid inclusion parameters as well as the source rock geochemical characteristics of these two dry wells to address the scientific problem of the wells going dry.Further,evaluated whether the results agree with an earlier finding from a case study of two wells named KK4C-Al(Kerala-Konkan basin)and RV-1 well where only a few parameters such as temperature of homogenization(Th)&API gravity were utilised,and the chances of getting oil in the nearby areas of these two wells were reported.In the present study,the fluid inclusion parameters such as the palaeotemperature(Th),API Gravity and Raman spectra were obtained from micron sized fluid inclusions at different depths for a quick assess-ment of nature of oil inclusions within the two dry wells.Along with fluid inclusion parameters,different source rock parameters obtained from Rock-Eval Pyrolysis analysis(secondary data)such as S1,S2,S3,Tmax,Hydrogen Index(HI),Oxygen Index(OI),Potential Yield(PY),Production Index(PI)and Total Organic Carbon Content(TOC)were also considered for a detailed source-rock evaluation of two wells(RV-1 and KKD-1A)and the results act as the supporting evidence to address the reason for the wells gone dry.Temperature of homogenisation(Th)of hydrocarbon Fluid Inclusion Assemblages(FIAs)from both the wells fall in the oil window(60-150℃)range indicating that there was a conducive thermal condition favourable for oil generation in these two basins.API gravity of oils in RV-1 well of Mumbai offshore(48-53)was lighter when compared to those in KKD-1A(18-22)of Kerala-Konkan basin.Raman spectra of HCFI samples could decipher important hydrocarbon species from RV-1 well samples.Raman spectra of KKD-1A well show less prominent peaks(broad)only.Pyrolysis data shows that Paleocene-Early Eocene s