The Ordovician carbonate reservoir is the most productive deep-earth reservoir in Tahe
Oilfield and other oilfields in Tarim Basin. Exploration and production successes in recent
years reveal a new reservoir type, namely faulted karst reservoirs, which is closely related to
regional strike-slip faults and very different from the well-recognized paleo-karst reservoir.
The paleo-karst reservoirs distribute mainly in weathering crust regions in the northern Tahe
Oilfield. Their primary reservoir spaces are meter-scale caves and the fluid conduits are
predominantly the unconformable surfaces. In production, paleo-karst reservoirs always
have sufficient energy, therefore high productivity. The faulted karst reservoirs mainly
develop in southern Tahe Oilfield, controlled by the different ordered strike slip faults and
related dissolutions. Their reservoir space is smaller than which of paleo-karst reservoirs.
The predominant fluid conduits in these reservoirs are the faults. In production, reservoirs
along major strike-slip faults have sufficient energy, high productivity and slow watercut
increase like paleo-karst reservoirs. While in areas with less strong energy, faulted karst
reservoir exhibits weak productivityand rapid watercut increase, implying a rule of “big
fault big reservoir, small fault small reservoir, no fault no reservoir. A comprehensive
understanding of the geophysical features, distribution characteristics, reservoir property,
and production behaviors of the two reservoir types will assist further exploration and
production in Tahe Oilfield and other basins containing such reservoirs.
Real Time Impact Factor:
Author Name: Xinbian Lu, Yan Wang, Debin Yang, Xiao Wang
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Keywords: Karst reservoir, faulted karst reservoir, carbonate, Tahe Oil?eld, Tarim Basin