Sanmenxia Basin is a Mesozoic-Cenozoic fault basin located on the western Henan uplift in the southern margin of the North China block. No petroleum resources and effective source rocks were discovered during previous exploration activities. In recent years

non-profit oil and gas surveys have confirmed the presence of the Paleogene source rocks in the southern margin of the basin and have gained new insights into oil and gas accumul

ation. To verify the hydrocarbon potential of the basin

Well Yuxiadi 1 was drilled at Hanguguan structural belt. Drilling data of Paleogene Xiao’an Formation reveal that the porosity ranges from 13.43 % to 20.60 %

and the permeability varies from 35.1 mD to 215.5 mD. The drill stem test (DST) results of the lower oil layer of Xiaoan Formation demonstrate a wellhead oil production of 17.52 m

3

under 24-hour intermittent flow conditions (water-free). Through formation testing by layer

combined with mechanical pumping production

the upper

middle

and lower oil layers of Xiaoan Formation have achieved the stable daily oil production of 4.79 m

3

6.79 m

3

and 15.83 m

3

(water-free)

respectively. These results indicate that the Hanguguan structural belt develops the water-free wax-bearing light oil reservoirs characterized with medium-high temperature

medium porosity

medium permeability

medium-shallow depth

and normal pressure. A comprehensive research shows that the oil source of Well Yuxiadi 1 may be derived from the lower Member of Xiaoan Formation and the upper Member of Podi Formation

the mudstone in Liulinhe Formation and its overlying strata serve as regional cap rocks

and normal faults act as the primary hydrocarbon transportation system. Sanmenxia Basin develops four sets of potential source-reservoir-cap assemblages

and it is inferred that its hydrocarbons have the characteristics of "short-distance migration

multiple hydrocarbon accumulation types

and forming reservoir in late stage"

and the main accumulation stage is in the Himalayan period. The oil and gas breakthrough in Sanmenxia Basin signifies the emergence of a new petroliferous basin

which is expected to re-attract attention from the industry on medium- to small-sized basins

such as Southern North China Basin and Weihe Basin. This is of certain reference value and guiding significance to the exploration of oil and gas resources in these basins.