More than 140 small lacustrine Meso-Cenozoic remnant petroliferous depressions and basins are distributed along deep fault zones in southeastern China. Some contain abundant oil and gas reserves in high-yield traps, although areal extent of this type of petroliferous basin is only 800-1000 km². Among the structural and lithologic characteristics of hydrocarbon accumulations in these depressions and basins are (1) distribution along deep fault zones, (2) widely distributed, thick source rocks, (3) well developed sand bodies, (4) high geothermal gradient, and (5) multiple-trap styles.

Meso-Cenozoic remnant depressions and basins in southeastern China contain thick, deep-water lacustrine shale, the primary source rocks for the region's hydrocarbon accumulations. These dark, organic-rich, fine-grained strata were deposited in the deeper parts of lake depressions and basins. Consequently, the principal source rocks have been well preserved over much of their original extent, although uplift and erosion following shale deposition have resulted in the destruction of depression and basin margins.

Most of these small remnant structures occur as half-grabens resulting from successive development of faults along one side of the basin; however, some also may appear as full grabens. Well developed remnant depressions and basins consist of three characteristic structural elements--(1) step-faulted belt on the steep flank, (2) central, low buried-hill belt, and (3) monoclinal slope belt on the gentle flank. Examples of these types of depressions and basins include the Damintun, Lanpu, and Sulu depressions, and the Baishe and Sanshui basins. Poorly developed remnant basins consist of (1) a step-faulted belt on the steep flank, (2) central trough, and (3) monoclinal slope belt on the gentle flank. Examples of these types include the Biyang, Changwei, Qianjiang, and Yuanjiang depression , and the Maoming basin.