【作者】 段杰；

【导师】 张哨楠；

【作者基本信息】 成都理工大学 ， 矿产普查与勘探， 2009， 硕士

【摘要】 鄂尔多斯盆地是我国第二大盆地,也是最大的含能源盆地之一,近年来,鄂尔多斯盆地勘探面临的对象越来越复杂,因此在加强理论攻关的同时,勘探将进一步注重针对新领域、新层系。新领域主要指盆地西部及南部一些勘探程度较低的地区,新层系主要针对下古生界奥陶系风化壳及以下的层系等。本次研究从基本地质条件出发,通过岩芯、铸体薄片、物性、沉积相、成岩作用、储层厚度、孔隙类型及结构特征、单井试气及产能等参数,结合研究区下古生界地层的实际情况,有步骤、分层次地开展《鄂尔多斯盆地南缘下古生界碳酸盐岩储层特征研究》研究。主要取得了如下研究成果:鄂尔多斯南缘下古生界寒武系可勘探潜力较低,仅在张夏组与三山子组具有一定的储层,且其价值尚未得到求证;奥陶系可勘探潜力明显好于寒武系,其中又以奥陶系风化壳以及生物礁最为主要。盆地南部奥陶系风化壳在不同的地区,溶蚀与充填差别较大,马五1若为开壳层位,溶蚀孔洞最为发育;奥陶系风化壳储层的形成、演化与古岩溶作用息息相关,古岩溶作用是该区储层发育的主控因素,另外,不同的岩溶期次对储层形成、分布特征也具有不同的控制作用;沉积相与风化壳储层之间具有一定匹配关系:如果大面积分布的含膏云坪与开壳层位一致,则有利于溶蚀作用发生与强化,因此最有利于储层的形成。奥陶纪生物礁层位上属于中奥陶的平凉组和上奥陶的背锅山组中,溶蚀-充填作用较发育,但溶洞孔没有全部保存下来,大多数被充填,只在部分地区见到有些大溶洞,这些溶洞的形成可能与加里东构造运动有关,除此以外,压溶作用形成的缝合线也是较常见的。如果这些生物礁位于加里东古风化壳上,溶蚀孔洞将可能非常发育。根据物性特征建立评价标准,表明研究区为低孔、低渗致密风化壳储层,并通过储层的沉积相特征、岩石学特征、古地貌单元储层特征、储层分布特征等特征对研究区下古生界进行综合评价,预测有利的勘探区域。更多还原

【Abstract】 Ordos Basin is the second largest basin and one of the largest resource bases in China. In the recent years, exploration in Ordos Basin is facing more and more complicated objects, therefore at the time to strengthen the theory research, exploration will further focus on the new areas and new stratum. The new areas in western and southern mainly refer to the basin with low level of exploration, whereas the new stratum aims at the weathering crust of Ordovician of the Lower Palaeozoic group and the one below, etc..Based on the basic geological conditions and the parameters, including the core, the cast, physical properties, sedimentary facies, diagenesis, reservoir thickness, pore types and structure characteristics, single-well gas testing and productivity, this study combines the actual situation of the Lower Palaeozoic group in the research region, and takes gradual steps by different levels to carry out the research of the characteristics of carbonate reservoir of the Lower Palaeozoic group in the southern margin of Ordos Basin. The main research results obtained are as follows:The exploration potential of Cambrian of the Lower Palaeozoic group in the southern margin of Ordos Basin is relatively low, and only Zhangxia and Snashan groups have certain reservoir, whereas its value has not been confirmed. Exploration potential of Ordovician is significantly better than that of Cambrian, the weathering crust of Ordovician and biogenic reef as major.Weathering crust of Ordovician in southern basin in the different areas, erosion and filling are quite different. If Mawu 1 is open shell, the solution cave is the best developed. Formation and evolution of weathering crust reservoir of Ordovician is closely related to the role of fassil karst, and the fassil karst is the major controlling factor of the reservoir. In addition, different karst periods have an important effect on formation and distribution characteristics of the reservoir. Sedimetary facies and weathering crust reservoir have certain matching relationship. If dolostone containing gypsum that is distributed in large scale is consistent with the open shell , it helps for dissolution occurred and strengthening, therefore best for formation of the reservoir.Biogenic reef of Ordovician belongs to the Pingliang group of middle Ordovician,and the Beiguoshan group of the upper Ordovician in horizon, erosion and filling role is developed relatively, then not all cave holes saved, most are filled in parts, only some large caves can be seen, and the formation of these caves may be related to Caledonian movement. Besides, the seam acted by the pressure solution is common. If these reefs are located Caledon ancient weathering crust, the solution caves are very developed.According to the characteristics of the property, establishing the evaluation standard and determining the research area is the low porosity and low permeability dense weathering crust reservoir, making a comprehensive evaluation on the Lower Palaeozoic group in research area through sedimentary facies of the reservoir, petrological characteristics, paleogeomorphology unit reservoir characteristics and reservoir distribution characteristics, and then predicting the favourable exploration areas.更多还原