PETROLEUM MIGRATION AND POOL-FORMING MODELS OF THE SOUTHWEST MARGIN OF JIANGHAN BASIN

The results of oil and source rock correlation and fluid potential in the southwest margin of Jianghan Basin show that,the oils in the north primarily come from the high maturity source rock in the Meiguiqiao-Niutougang Sag,and the oils in the south primarily come from the local low maturity source rock,and the oils in the medium are mixed.The distance of petroleum migration in this region is short.The distribution and accumulation of petroleum are controlled by some factors such as faults and the type of entrapment.The reservoir beds in uplifted wall being connected with the source beds in throw wall by fault was the key factor of forming the new-sourced and old-reservoired.The fault seals better in the upside than in the underlayer,fault-seal controlled the distribution of the better reservoirs.There are two important petroleum trap called fault-nose and fault-block,fault-nose locates in throw wall and fault-block locates in uplifted wall.According to the diversities of accumulation and reservoir,the petroleum pools are sorted out three different models which known as self-sourced and self-reservoired,new-sourced and old-reservoired and old-sourced and new-reservoired.