我国天然气勘探现状及方向

EXPLORATION STATUS QUO AND DIRECTIONS OF GAS EXPLORATION IN CHINA

近年来,随着我国天然气勘探在一些重点领域、区带和层系取得突破,我国天然气储量和产量的增长很快,2005年我国天然气产量近500×108m3,截至2005年底全国共累计探明天然气地质储量49536×108m3,目前我国天然气勘探进入快速增长的阶段。2005年以来天然气勘探主要在以下领域取得了突破和进展:松辽盆地深层、塔里木盆地塔中I号坡折带、川中上三叠统、鄂尔多斯盆地古生界。从近年来的勘探进展看,天然气勘探区包括四种类型:①资源潜力清楚,含气面积迅速扩大;②资源潜力基本清楚,但勘探成果进展缓慢;③地质条件认识有待深入,但勘探效果较好;④地质条件复杂,勘探历程曲折。研究表明,天然气富集区主要受控于煤成气或裂解气两大气源、大面积分布的孔隙型储层、大型构造或岩性地层圈闭、优质区域性盖层等。由于我国天然气勘探程度仍然不高,天然气大场面的勘探前景并不完全明朗,不同地区差别较大。未来的中国天然气勘探要立足于大油气田,并根据勘探现状和地质认识分层次部署。

In recent years, breakthrough has been made in Chinese gas exploration upon many important areas, zones, layers, and strata. Both reserves and production of Chinese natural gas have increased in rapid speed these years. Gas production of China reached up to 50 billion m^3 in 2005; while the total geologic gas reserves all over China had been summed up to 4953.6 billion m^3 till by the end of 2005. Obviously Chinese present gas exploration has entered into the rapid-developing period. It is concluded that achievements for gas exploration in China has been made since 2005 in such areas, i.e. the deep Songliao Basin, TZ-1 break slope of the Tarim Basin, upper Triassic of the Middle Sichuan Basin, Paleozoic of the Ordos Basin. The gas exploration districts can be divided into four types: ①gas resources is clear and discovered gas-bearing area expand rapidly; ② gas resources is basically clear, but exploration progress is slow; ③geological setting is not clear, but great exploration achievement has been made; ④geological setting is complicated, exploration progress is tortuous. Geological research shows that natural gas accumulation is controlled by coal measure and over-matured marine source rocks, widely-distributed pore reservoir, big structural or lithostratigraphic traps, good regional seals. Because gas exploration rate in China is rather low at present, gas exploration prospect in the future is not optimistic, however, and there are great differences in different areas. Therefore, it is suggested that Chinese natural gas exploration should concentrated on large oil and gas fields to set out exploring plan at different levels based on the exploration current situation and with enough geological knowledge in mind.