1前言自30年代早期在越南西北面的安沛一些探井钻到油浸泥盆纪碳酸盐开始，人们就知道越南有油气（图1）。但只有当近海工业开始发展时近诲油气菌及其特征最近才使人知晓。在越南一些第三纪盆地现已发现了油气。过去25年来的钻井勘探已发现数个油气田（例如Hoa包等，1986，Tan 1 Introduction Since the early exploration of oil-bearing Devonian carbonate in the exploration wells in the northwest of Vietnam in the early 1930s, people have known that there is oil and gas in Vietnam (Figure 1). However, it has only recently become known when the coastal industry is beginning to develop and the characteristics and characteristics of these bacteria are known. Oil and gas have now been found in some Tertiary basins in Vietnam. Drilling exploration over the past 25 years has identified several fields (eg Hoa et al., 1986, Tan