Petroleum Systems and Favorable Exploration Direction in the Donghe Area, Tarim Basin, NW China

Abstract

The hydrocarbon formation mechanism and potential targets in clastic strata from the Tabei Uplift, Tarim Basin, are documented using the fault-fracture mesh petroleum systems theory based on integrating seismic, well log, well core and geochemistry data. The reservoirs in the Donghe area are typical allochthonous and far source fault-fracture mesh petroleum systems. There are two sets of fault-fracture meshes in the study area, the Donghe sandstone, Permian and Triassic strata combination as well as the J_IV and J_III formation combination, in the Jurassic strata. The fault-fracture mesh petroleum play in the Jurassic is a secondary reservoir that originates from the Carboniferous Donghe sandstone reservoir adjustment based on source correlation. The fault-fracture mesh carrier systems are divided into four styles, which include the fully-connected, fault-unconformity-transient storage relay, fault-transient storage-unconformity relay and transient storage-fault relay styles, according to the architecture of the fault-fracture mesh. Based on the characteristics of the fault-fracture mesh petroleum systems, the reservoirs are divided into three categories, including an upper-transient storage, inner-transient storage, and margin-transient storage styles, and 15 styles of those reservoirs. Integrated analysis of the hydrocarbon generation and faulting time periods reveals that there were four periods of hydrocarbon charging, with the first three stages charging the reservoirs with oil and the last stage charging the reservoirs with gas. There are multiple stages of reservoir accumulation and adjustment in the fault-fracture mesh in the study area. These multiple stages of fault-fracture mesh accumulation and adjustment are the main reason that the reservoir distribution multiple vertical units have different hydrocarbon properties. Fault-block reservoirs and lithologic reservoirs related to the inner-transient storage and upper-transient storage styles are the main exploration targets in the clastic strata in the study area.

AAPG Datapages/Search and Discovery Article #90323 ©2018 AAPG Annual Convention and Exhibition, Salt Lake City, Utah, May 20-23, 2018