鄂尔多斯盆地上古生界煤层气与致密气联合优选区评价

鄂尔多斯盆地上古生界具有煤层气和致密砂岩气成藏的有利条件。上古生界煤层气与致密砂岩气具有相同的烃源岩，且煤层与致密储层垂向上相互叠置，为二者联合勘探开发奠定了地质基础。在综合考虑煤层气与致密砂岩气成藏地质条件的基础上，建立了鄂尔多斯盆地煤层气与致密砂岩气共同勘探选区的评价指标体系，包括煤层厚度、烃源岩热演化程度、生气强度以及致密储层厚度4个指标。依据建立的评价指标体系，对鄂尔多斯盆地内5个区块进行煤层气与致密砂岩气共同选区评价，评价结果为区块Ⅱ、Ⅲ和Ⅴ为勘探目标区，主要分布在盆地的东西缘，煤层厚度大、烃源岩生气强度大，勘探前景好；区块Ⅰ和Ⅳ为勘探有利区，呈条带状分布在盆地的东北部和西北部，煤层气与致密砂岩气协同勘探潜力较大。

Joint Optimization of Coal-Bed Methane and Tight Gas in the Upper Paleozoic of the Ordos Basin

Through a comprehensive analysis of accumulation conditions of coal-bed methane (CBM) and tight sandstone gas in the Upper Paleozoic of Ordos basin, it is conducted that the Upper Paleozoic is favorable to form coal-bed methane and tight sandstone gas resources. They have the same source rock, the tight sandstone reservoir and coal seam developed interbedded, which provide favorable conditions for the joint exploration and development of coal-bed methane and tight gas. Based on the accumulation conditions of both CBM and tight sandstone gas, this paper has established an evaluation parameter system, including coal thickness, R_o, gas generating intensity and tight gas reservoir thickness. Using the evaluation system, 5 blocks in Ordos basin were evaluated. The result shows that there are 3 target exploration areas and 2 favorable areas, which indicates a great exploration potential of CBM and tight sandstone gas resources in the Upper Paleozoic. The former areas are located in the east and west of Ordos basin, with thick coal layer, high intensity of gas generation, while the latter has a banding distribution in the northeast and northwest of the basin.