鄂尔多斯盆地上古生界致密砂岩储层金字塔结构

Pyramid Structure of Tight Sandstone Reservoirs in the Upper Paleozoic in Ordos Basin

致密砂岩气是大面积多藏分布、受浮力作用影响很小的天然气聚集,＂甜点＂是相对高产富集区。引入金字塔结构对致密砂岩储层与＂甜点＂分布的内在规律进行统计分析,指导勘探开发部署。基于国内外典型致密砂岩气盆地大量孔隙度和渗透率分布数据,结合鄂尔多斯盆地上古生界致密砂岩气勘探实践,认为致密砂岩储层孔渗分布是一种自组织形式,具有多层次金字塔结构。致密砂岩储层一般发育10%-20%由常规储层组成的相对高产＂甜点＂,而＂甜点＂应该成为致密砂岩气勘探开发的首选目标,应首先集中财力物力寻找这类＂甜点＂。致密砂岩储层和＂甜点＂储层开发中应采用不同的技术方式。致密砂岩储层用大型压裂改造储层,＂甜点＂储层可考虑采用水平井自然能量开发,减少储层伤害。

Tight sandstone gas is a kind of natural gas accumulation, which characterized by a large area of multi reservoir distribution and little affected by buoyancy. ＂Sweet spot＂ is a relatively high yield gas enrichment area. According to the a- nalysis of massive porosity and permeability data of typical tight sandstone gas basin at domestic and abroad, and the explo- ration practice of tight sandstone gas in the Upper Paleozoic of Ordos Basin, we believe that the porosity and permeability distribution of tight sandstone reservoir is a kind of self-organization form with a multi-level Pyramid structure. In general, 10% - 20% of the tight sandstone reservoir is composed of conventional reservoir, which formed the relatively high yield ＂sweet spot area ＂ . The ＂sweet spot＂ should be the first choice for exploration and development of tight sandstone gas, and it is the most effective way to reduce the cost and improve the economic efficiency. In addition, tight sandstone gas and ＂sweet spot ＂ gas should be used with different mining techniques and methods.