The previously coined fault-karst reservoirs have become new exploration and exploitation targets and types of marine carbonate hydrocarbon reservoirs. However, these reservoirs are significantly different from conventional weathering-crust karst reservoirs and also show diverse reservoir types and structural characteristics themselves. By delving into the differences in the dissolution and tectonic fracturing of fault-karst reservoirs, we categorize these reservoirs into three types: the over-dissolved residual type, the fractured and highly dissolved type, and the highly fractured and weakly dissolved type. Investigations into these types of fault-karst reservoirs reveal that these reservoirs significantly differ in dissolution intensity, fracture and vug sizes, cumulative oil production, formation energy, and fracture-vug connectivity. Furthermore, the distribution of over-dissolved residual fault-karst reservoirs is influenced by both weathering crust unconformities and the longitudinal dissolution of fault zones. In contrast, the formation and distribution of the remaining two types, manifesting a minimal association with unconformities and tectonic locations, are primarily governed by the fracturing and dissolution intensity of dissolved fault zones. Specifically, large-scale caves occur in the cores of dissolved fault zones, gradually transitioning to fractured-vuggy and fractured reservoirs towards their both sides.

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 reservoirq. 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.