不同生态区域油气田开发对土地覆盖变化的影响

利用RS-GIS技术,分析了四川合兴场气田周围1988年和2000年TM影像和新疆艾桑油气田周围1992年和2000年TM影像土地变化情况。分析结果表明:生态发达的四川合兴场气田周围在油田田开发前后主要为耕地,而建设用地在1988年占区域面积的12.6%,到2000年增加到17.8%。位于生态脆弱区的艾桑油气田,兴建前后主要土地利用类型均为戈壁荒漠、盐碱地,建设用地面积则明显增加,从1992年占总面积的0.02%增加到2000年的0.24%。由此可见,大面积分布式的油气田开发改变了油气田周围土地利用类型的分布。景观格局分析指数表明,四川合兴场周围多样性指数及均匀度指数均呈增加趋势,而艾桑油气田周围多样性指数及均匀度指数均呈现下降趋势。四川合兴场气田周围空间景观呈多样化发展,而新疆艾桑油气田周围空间景观多样性下降,荒漠土地呈扩大化发展趋势。

Land Cover Change Caused by Oil and Gas Field Development in Different Ecological Region

The RS and GIS technique and four TM images were used to analyze the land cover change in the surrounding region of Hexingchang gas field in Sichuan Province in 1988 and 2000 and Aisang oil fieldin Xinjiang area in 1992 and 2000. The Fragstats calculation method was used to work out the change value of land cover and indices for landscape spatial structure. The analysis results showed that land cover in the region surrounding gas filed was moderately influenced by the widely distributed oilfield. The built-up cover of Hexinchang gas field, where land is dominated by cropland, increased from 12.6% in 1988 to 17.8% in 2000. In comparison, the same land cover of Aisang oilfield, where main usage type of land is hungriness and serir, increased from 0.02% in 1992 to 0.24% in 2000. The indices for both diversity and evenness in Hexingchang gas field decreased and the landscape spatial pattern of the area surrounding the gas field tended to become fragmented and diversified. On the contrary, the same indices in Aisang oil field increased, and the diversity of landscape spatial pattern tended to be simplified, and the hungriness and serir tended to increase. Above events indicated that the development of oil-gas field have important effects on land pattern.