Pearl River Mouth Basin a resplendent pearl in the 21st century's oil and gas exploration in China

摘要

The Pearl River Mouth Basin, located in the northern shelf of the South China Sea, is a large Cenozoic rifted basin, which forms a huge petroliferous basin together with the underlying Mesozoic depressional basin. Since 1983 when oil exploration began, 33 oil fields and oil-bearing structures have been discovered with the total reserves of nearly 600 million tons. Since the first oil field was put into production in 1990, 12 oil fields have been put on stream. Cumulative production so far is over 80 million tons and yearly production over 10 million tons have been maintained for 6 consecutive years. It has already become one of the important oil production bases in China. The regularity for the enrichment of hydrocarbons in the Tertiary in the eastern part of the Pearl River Mouth Basin are summarized as the following five points: 1. rich oil generation sags control main hydrocarbon accumulations; 2. northwest trending faults control the distribution of main hydrocarbon accumulations and the latest tectonic movement controls the final accumulation of hydrocarbons; 3. oil/gas accumulations so far discovered are mainly within the transgressive systems tract and highstand systems tract of the large third order marine sequences in Tertiary; 4. accumulations are mainly sourced from the underlying formations and secondly,accumu-lations just formed the source rocks and 5. rollover and compressive anticlines, drape anticlines and large carbonate buildups are the main traps; while faulted anticlines, faulted blocks and small stratigraphic oil pools are the secondary. These rules will continue to guide the future exploration in the immature areas. The exploration in the Pearl River Mouth Basin is still immature. The 170,000 square kilometers area has huge potential, where there is less than one exploration well per 1000 square kilometers. The potential exhibits in four aspects: first of all, petroleum in Mesozoic is a totally new area waiting for exploring and breaking through; deep water lowstand fan will become the main field for petroleum exploration in this century in the basin; the old relatively mature area has the potential to expand and gas exploration will be an important break through in the basin. As the exploration and research in the basin going deeper, new exploration concepts in the relatively matured area are formed gradually, new realms and sequences are continuously discovered in the immature area, it is seen that the reserves in the Pearl River Mouth Basin will expand to a new scale in the near future. The basin will still be a resplendent pearl in oil and gas exploration in the 21st century in China.