Analysis of tectonic-sedimentary setting and facies based on cores and well logging shows that Lower Devonian F4 unit is submarine fan that can be divided into two cycles by correlating a fan-wide marine mud datum named middle mud. The association of lithofacies forms five facies, including slump, braided channel complex and depositional channel, channel-distal lobe, turbidity-sheet sand, and hemipelagic deposits. Mapping intrafan units reveals an aggradational–retrogradational stacking pattern of the F4 unit, which is a multiple point source sand-rich fan who supplied from northwest, southeast, and south. This study provides not only correlation strategy, but also a reliable geological model for the further development of F4 unit. [ABSTRACT FROM AUTHOR]