Abstract: For large-scale magma intrusion area, magma intrusion effects on hydrocarbon generating and expulsing of source rocks have not been recognized distinctly. In Jizhong depression of Bohai Bay basin, where the W en 'an slope encountered with magma intrus ion that entered in-to the Carboniferous-Permian coal measure strata in Palaeogene, which has great effects on thermal evolution of the source rocks. As shown from the basin modeling,the magma intrusion could be regarded as additional geothermal source which can be put as an equivalent terrestrial heat flow value into the modeling in terms of the magma-intrusive depth and geothermal data,obtaining the hydrocarbon-generated and-expulsed re-sults of the source rocks. The estimation shows that the contribution rate of the magma intrusion to hydrocarbon generation in Carboniferous-Per-mian source rocks is up to 62.4%.

Key words: Jizhong depression, Wen an slope, magma, intrusion, hydrocarbon expulsion, modeling, simulation