New fields, new types and resource potentials of oil-gas exploration and development in Hailaer Basin

Hailar Basin is a Mesozoic-Cenozoic continental rift basin located on the northern border of China. After more than 60 years of continuous exploration, the main oil-bearing series has entered the mid-late stage of development. Shallow buried, large-scale, and easily-discovered structural reservoirs have been almost completely drilled and explored, it is more and more difficult to increase reserves in recent years. Through systematically reviewing the oil-gas exploration history in Hailar Basin, in combination with current exploration and development practices, it is pointed out that to exploit the less explored subsag areas and deep strata is essential to open a new situation for oil-gas exploration in Hailar Basin. The basin has great exploration potentials in four fields:shale oil in the condensed section of Nantun Formation, glutenite lithologic reservoir in Tongbomiao Formation, oil reservoir in Jurassic Tamulangou Formation, and interior reservoir in bedrocks of buried hills, of which the total oil resources are predicted to be 5.96×10⁸ t. The oil reservoirs in new fields and the discovered reservoirs have spatial complementarity, thus forming the petroleum system in complex rift basins that involves multiple types and multiple strata from middle-shallow to deep formations, from slope belts to subsag areas, and from conventional to unconventional fields, and displays ordered distribution and differential enrichment of oil reservoirs, and its exploration potentials can be further explored.