Reservoir sedimentology and prediction of the Lower Cretaceous subtle hydrocarbon traps in the Honggang region,Songliao Basin

The study of reservoir sedimentology shows that the feldspar sandstone as a main type of sandstones developed in the central part of the Honggang region,Songliao Basin is characterized by low maturity,well to moderate sorting,moderate to poor roundness and low matrix contents.Sedimentary structures and penecontemporaneous deformation vary greatly.There occur from west to east the(fan) delta or shallow,semi-deep and deep lacustrine deposits which are assigned to three depositional systems.The favourable sedimentary facies consists of(fan) delta front deposits and turbidites.The sandstone reservoirs have moderate porosity,and moderate to low permeability due to weak diagenesis and well-developed secondary porosity.The results of research in reservoir sedimentology have been applied to the recognition and prediction of the Lower Cretaceous subtle hydrocarbon traps in the Honggang region,Songliao Basin.