川西坳陷中段须家河组天然气勘探开发战略研讨

DISCUSSION ON NATURAL GAS EXPLORATION AND DEVELOPMENT STRATEGIES OF XUJIAHE FORMATION IN THE MIDDLE SECTION OF WEST SICHUAN DEPRESSION

川西坳陷天然气资源丰富。资源量结构表明,深层须家河组潜力大,目前探明率尚低,存在较大的勘探空间。此外,龙门山前缘彭灌飞来峰地区和川西坳陷东坡地区,都具备形成新勘探领域的地质条件,值得进一步研究。文章针对勘探中存在的“四超”难点,提出了相应的研究方法和技术,其中特别就影响勘探成功率最突出的“超晚期构造”问题,结合勘探事实的分析认为,区内基本上属于早期成藏的地质环境,主要圈闭均具非背斜性质,常规的背斜勘探模式已不适用,进而提出了古构造分析和高分辨层序地层学的重要性,深入圈闭研究,其中特别是沉积、成岩圈闭识别与评价的必要性。

The West Sichuan Depression is rich in natural gas resources. The resource statistical result indicates that the deep Xujiahe Formation has great potential and exploration prospects because of its low resource-proved rate at present. In addition, the klippe region of Longmen Mountain front and the east slope region of the West Sichuan Depression are provided with the geological conditions of forming a new exploration field and are worth further studying. In light of the 'Four-Ultra' difficulty in gas exploration, the relevant research methods and techniques are proposed in the paper. Through analyzing the 'ultra-late structure' problem affecting prominently exploration success ratio, in combination with the exploration reality, it was considsered that the conventional anticlinal exploration pattern has been unapplicable, because this region belongs to the geological environment of early reservoiring on the whole and the main traps are non-antichlinal; and the paleostructural analysis and high resolution sequence stratigraphy are very important'to the trap research, especially to the identification and evaluation of the sedimentary-diagenetic traps.