Weak structural belts in this paper refer to Wenan and Lixian slope zones of the oil-rich sags in Jizhong Depression，where the exploration maturity is low but resource potentials are large and exploration prospects are good.Based on the integrated analysis of geological elements and in combination with physical simulation experiments

the paper illustrates the main controlling factors of hydrocarbon accumulation

reveals hydrocarbon accumulation patterns and establishes hydrocarbon accumulation models

so as to provide theoretical guidance for further oil and gas exploration of the weak structural belt.The result shows that the main controlling factors of hydrocarbon accumulation in weak structural belt are source rock

carrier system and nose structure.Among them

the source rock controlled the distribution range and the enrichment degree of hydrocarbons

the carrier system controlled the horizons of hydrocarbon accumulation and the reservoir types

and the nose structure controlled the hydrocarbon migration direction.Two hydrocarbon accumulation models were established for the weak structural belt based on the configuration relationships between the source rock and the carrier system.One is distal stepwise accumulation model on wide-gentle slope zone

featuring in joint driving of overpressure and buo-yancy

stepwise migration dominated by lateral transportation through sandbody and adjusted vertically by faults

accumulation in multi-layers far from the source rocks.The other is proximal Z-style accumulation model on gentle slope belt

featuring in driving of buoyancy

Z-style migration through vertical adjustment of faults and lateral transportation of sandbo-dies

the accumulation in multiple layers near the source rocks.