什股壕地区上古生界气藏类型再认识及其意义

鄂尔多斯盆地北部什股壕地区地质条件特殊，气藏类型及分布情况一直未明确，制约了该区天然气勘探开发工作的进展。为此，在分析该区油气成藏地质特征的基础上，结合最新测井、钻井、地震、试气等资料， 分层系、分区域对典型气藏进行了解剖，重新认识了该区上古生界气藏类型。结果认为：①该区构造区划可细分为斜坡带与隆起带，构造面貌差异性影响着下二叠统下石盒子组2+3段的气藏类型；②平面上，锦33井处是盒2+3段气藏类型的分界线，该井以东隆起带主要发育构造背景控制下的构造—岩性复合气藏，该井以西斜坡带发育的岩性气藏含气面积广、储量规模大，是下一步天然气勘探开发的有利目标和方向；③纵向上，受构造复杂及天然气侧向运聚成藏的影响，不同层位的气藏类型差异性明显，由下往上构造因素的控制作用减弱，下部下二叠统山西组1段、下石盒子组1段主要发育岩性—构造复合气藏，上部盒2+3段则以岩性气藏为主。

Recognition of Paleozoic gas reservoir types in the Shiguhao region of the northern Ordos Basin and its significance

The Shiguhao area in the northern Ordos Basin is unique in geological conditions and relatively complex geological structures. The types and distribution of gas reservoirs in this area are still poorly understood, which impedes gas exploration and production there. Based on the analysis of the geological characteristics of hydrocarbon accumulation and in combination with the available new logging, drilling, seismic and gas production test data, the Paleozoic gas reservoir types were recognized in different sequences and at different areas. The findings were achieved as follows. a. The structures in this area can be finely divided into a slope zone and an uplifted zone. The structural differences between them influence the gas reservoir types in the He 2+3 (the 2^nd and 3^rd members of the Lower Permian Shihezi Fm). b. Laterally, the Well Jin 33 is the demarcation line of gas reservoir types in the He 2+3. In the uplifted zone to its east, structural lithologic reservoirs are predominant. In contrast, in the slope zone to its west, lithologic reservoirs are predominant and are large in gas bearing areas and reserve potential, thus being favorable targets of future exploration. c. Vertically, the complex structures and lateral gas migration result in different gas reservoir types at different horizons. The control of tectonic structure on gas reservoir types is getting weak upwards. Lithologic structural gas reservoirs are dominant in the 1st member of the Lower Permian Shanxi Fm and the 1st member of the Lower Shihezi Fm, while lithologic gas reservoirs are predominant in the He 2+3.