Huabei area suffered a sedimentary interruption of about 130 million years during Late Ordovicianto Devonian period. Therefore, whether the Early Palaeozoic carbonate rocks with a stable distribution and alarge thickness can secondarily generate hydrocarbon and form Primary oil and gas Pool is an important issueregarding the prospecting for Primary oil and gas Pools in the Lower Palaeozoic formations. Well Konggu 3,located in the northwestern Kongdian anticlinal structural belt, produced oil from the Primary Ordovician limestoneoil pool reserved in the Ordovician Fengfpog Formation. The crude oil Characteristics and oil-source correlationshow that oil source rock are Ordovician limestone. So it is a primary oil pool with source and reservoir rads inthe same formation. The studies on the secondsry hydrocarbon generation of source rocks and the primary oil ofWell Konggu 3 have a great significance to firmly prospect for Lower Palaeozoic primary oil and gas pools inHuabei area. Huabei area suffered a sedimentary interruption of about 130 million years during Late Ordovicianto Devonian period. Thus, either the Early Palaeozoic carbonate rocks with a stable distribution and a large thickness can secondarily generate hydrocarbon and form Primary oil and gas Pool is an important issueregarding the prospecting for Primary oil and gas Pools in the Lower Palaeozoic formations. Well Konggu 3, located in the northwestern Kongdian anticlinal structural belt, produced oil from the Primary Ordovician limestoneoil pool reserved in the Ordovician Fengfpog Formation. The crude oil Characteristics and oil-source correlationshow that oil Source rock are Ordovician limestone. So it is a primary oil pool with source and reservoir rads inthe same formation. The studies on the secondry hydrocarbon generation of source rocks and the primary oil of Well Konggu 3 have a great significance to substantive prospect for Lower Palaeozoic primary oil and gas pools in Huabei area.