Abstract: Petroleum Geology in Tarim Basin, China

Guojun Zhou

Tarim basin is a superimposed basin with two tectonic regimes and contains multisources, multireservoirs, and multiseals. Almost all major strata within the Paleozoic, Mesozoic, and Cenozoic exist in the basin, and they are grouped by six regional unconformities, which are related to hydrocarbon accumulation.

Source rocks are Cambrian marl; Lower Ordovician black carbonaceous shales; Middle Ordovician dark gray limestone; Upper Ordovician brownish black carbonaceous shales and oil shales; grayish black carbonaceous shales, dark gray and grayish brown bituminous marl, and reef limestone in the Carboniferous and Permian; and gray to dark gray shales in the Triassic-Jurassic oil-bearing strata. Reservoir rocks in the Cambrian-Ordovician oil-bearing strata and the Carboniferous-Permian oil-bearing strata are mainly fractured limestones and sandstones. The fracture distribution is related to unconformities. Vugs and casts also exist in most limestones; intergranular porosity exists in sandstones. The reservoirs in the Triassic-Jurassic are fluvial-deltaic sandstones, and above are Cretaceous gy sum and halite seals.

Ten types of traps are found in this basin: (1) fold-related anticline traps, (2) anticline-fault traps, (3) fault drag-related anticline traps, (4) traps underneath thrusting faults, (5) fault-block traps, (6) traps made from cross or arc-like fault and monocline, (7) salt dome traps, (8) traps created by intrusion, (9) lenticular or pinch-out traps, and (10) unconformity and overlap traps.

AAPG Search and Discovery Article #90984©1994 AAPG Annual Convention, East Lansing, Michigan, September 18-20, 1994