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榆林气田和子洲气田是位于鄂尔多斯盆地东部的2个地质储量均超过1 000×108 m3的上古生界大气田,二叠系山西组2段是榆林—子洲气田的主力产层。鄂尔多斯盆地榆林—子洲地区山2气藏烃源岩在区域上呈广覆式分布,成熟度高;储层致密,源储近邻,生储盖组合关系良好;存在众多小型岩性圈闭群,圈闭界限不明显,很难判断气藏的边界;全区大面积含气,区域上没有明显的气水倒置现象,砂体连通性差、非均质性强,不存在明显的边底水;气水分布复杂、分异不明显,现今构造对于气水分布及产出基本不起控制作用;气藏的成藏富集主要受烃源岩的生烃强度,储层物性及有效砂体厚度联合控制。通过研究气藏的成藏特征、天然气成藏富集规律,表明鄂尔多斯盆地榆林—子洲地区山2气藏符合准连续型气藏“储层致密,主要为源外成藏、近源储集,天然气呈准连续分布,圈闭介于有形与无形之间”的特征。
The Yulin gas field and the Zizhou gas field are two Upper Paleozoic gas fields in the eastern Ordos Basin each with a geological reserve of over 1 000 × 108 m3. The Permian Shanxi Section 2 is the main pay zone of the Yulin-Zizhou gas field. The source rocks of Shan 2 gas pool in Yulin-Zizhou area in the Ordos Basin are widely distributed and have high maturity; the reservoirs are dense, the source-reservoir neighbors and the reservoir-cap assemblages are good, and there are many small-scale lithologic trap groups , The trapping limit is not obvious, it is very difficult to judge the boundary of the gas reservoir. There is no gas-water inversion in the whole area with large-area gas, and the sand body has poor connectivity and strong heterogeneity. There is no apparent edge water ; The distribution of gas and water is complex and the difference is insignificant; the present structure basically can not control the gas and water distribution and output; the accumulation and enrichment of gas reservoirs are mainly affected by hydrocarbon generation intensity, reservoir physical properties and effective sand body Thickness joint control. By studying the hydrocarbon accumulation characteristics of gas reservoirs and the accumulation of natural gas, it shows that the Y2 gas reservoir in the Yulin-Zizhou area in the Ordos Basin conforms to the “quasi-continuous” gas reservoirs and is mainly composed of source-reservoir formation and near-source reservoir Set, the gas is quasi-continuous distribution, trap between the visible and invisible "features.