Research On Petroleum Pathway System Of Mesozoic Yanchang Formation In Honghe Oilfield,Ordos Basin

Based on comprehensive analysis of geological,well logging and seismic interpretation,this paper makes a research on main pathway systems(including sand bodies,faults and cracks)of Yanchang Formation in Honghe Oilfield,interpreting characteristics of conduit framework and its important at the primary accumulation period.By the method of basin simulation,the reservoirs of Chang 8 Formation are situated in over-pressured system at the primary accumulation period,and overpressure becomes the main ancient dynamic for hydrocarbon migration.The quantitative analysis of migration characteristics and sealing characteristics of faults,based on the shale gouge ratio(SGR)and fault tightness index(IFT)methods,reflects the difference of faults` conduction properties.Adopting effective migration-space coefficient(Cm),sandstone migration coefficient(Ks),storage coefficient(CS)and transmissibility(VO),this paper makes a quantitative analysis on the migration characteristics of the main carrier bed.Based on relationship between coefficients and oil &gas shows,these make coefficients as a standard for judging conduction properties.Combining the QGF and QGF-E,prediction of hydrocarbon accumulation areas agree basically with the present distribution of reservoirs.Research suggests that,under the background of the low porosity and low permeability of reservoirs of Yanchang formation in Honghe oilfield,during critical accumulation period “fault-sand body-crack” passage system is the main channel for hydrocarbon migration and accumulation.