Hydrocarbon generation history and accumulation period of the Kongdian formation in Weibei depression

To study the accumulation process and distribution of hydrocarbon, the IES-PetroMod and fluid inclusions were used to analyze the hydrocarbon generation history and the accumulation period of Weibei Depression. There are three sets of source rocks and two hydrocarbon generation centers. The north subdepression is the main source rock in Weibei Depression. The first hydrocarbon generation made the biggest contribution which occurred from the middle sedimentation of Es4 to Dongying tectonics movement, and the source rocks have entered mature hydrocarbon generating stage while the lower source rocks have entered the cracked gas generation period. For the denudation of the Dongying tectonics movement, the hydrocarbon generation almost ceased and secondary hydrocarbon generation only occurred in the northwest part where post-deposition thickness exceeded its eroded thickness. There are two hydrocarbon accumulation periods of the discovered reservoirs: the first hydrocarbon charge was from the middle of the sedimentation of Es4 to the Dongying tectonic movement, restricted by various geologic conditions. Most reservoirs were filled and distributed in Zaohu nasal belt where the sealing condition is better. The second hydrocarbon charge happened in the Guantao stage, and only supplied hydrocarbon for the traps nearby, which is a favorable region for deep natural gas.