Hydrocarbon Accumulation Regularity of Donghe Sandstone in Tazhong Area, Tarim Basin, China

Abstract

Donghe sandstone in Tazhong area is important producing layers in Tarim Basi. Previous studies on hydrocarbon accumulation regularities of this region lack of systemic analysis of the hydrocarbon accumulation architecture in this region and the influence of unconformity complexes on hydrocarbon accumulation is ignored. Based on the knowledge of hydrocarbon accumulation controlled by unconformity complexes, this paper deals with the architecture and regularities of hydrocarbon migration and accumulation in Donghe sandstone. With faults which are connected with source rocks, high-quality reservoirs and reservoir's post adjustments well developed, Donghe sandstone strata in study area make up a typical meshwork-carpet oil and gas accumulation system. The system has two unconformity complexes and their corresponding hydrocarbon accumulation layers. A few conductive systems are identified, including faults, unconformities, connected sand bodies, volcanic rocks, et al. The reservoirs developed are also of varies types, such as structural reservoirs, stratigraphic reservoirs, lithological reservoirs and their composite variations while most of them distributed inside the unconformity complexes. Combined with the static geological model, the hydrocarbon accumulation process is numerically simulated and analyzed; the results show the control of unconformity complexes on hydrocarbon migration and accumulation. The results also show that inside the unconformity complexes there exist differences in hydrocarbon migrating routes, accumulation patterns, trap filling degrees, et al. For hydrocarbon accumulation, anticline trap is the most favorable, overlapping trap comes second, while fault block trap, fault block-lithological trap and unconformity barrier trap are relatively less favorable than the first two types.

AAPG Datapages/Search and Discovery Article #90217 © 2015 International Conference & Exhibition, Melbourne, Australia, September 13-16, 2015