摘要： 鲁西豫东地区奥陶系碳酸盐岩中赋存丰富的地热资源,但研究区内的热储特征及其主控因素仍不明确。综合露头、岩心、薄片、测录井等地质与地球物理资料,对奥陶系碳酸盐岩岩溶热储特征、演化过程及地热田的形成进行了深入研究。结果表明,研究区奥陶系主要储集岩性为颗粒灰岩、角砾灰岩、灰质白云岩、晶粒白云岩及硅质灰岩。凸起区残厚约500~1000 m,孔隙度均值为2.76%,凹陷区残厚约0~500 m,均值为2.22%,凸起区相较于凹陷区,残厚相对大,孔渗相对较大; 受兰聊断裂影响较为明显,“凹凸”呈环状分布; 岩溶热储经历了胶结、白云化、压实、压溶、溶蚀、充填、重结晶及构造破裂等成岩作用综合改造; 岩溶热储主要经历了早成岩期增孔(早—中奥陶世)、表生成岩期增孔(晚奥陶世—早石炭世)、中—晚埋藏期减孔(晚石炭世—早三叠世)、表生成岩期增孔(中新生代,主要发育于菏泽凸起区)4个阶段。岩性岩相、成岩作用以及构造应力控制着研究区奥陶系岩溶热储的形成演化,综合研究区地热的源—储—盖基础条件分析,明晰了研究区奥陶系岩溶热储流体循环特征,预测了地热资源量。

关键词: 鲁西豫东地区, 奥陶系, 岩溶热储, 地热田

Abstract: There are abundant geothermal resources in Ordovician carbonate rocks in the Western Shandong-Eastern Henan Area,but the characteristics and main controlling factors of thermal storage are still unclear. In this paper,geological and geophysical data from outcrops,cores,thin sections,and wells are integrated to investigate the characteristics of the karst thermal reservoirs,evolution processes,and formation of geothermal fields in Ordovician carbonate rocks. The results show that the main reservoir lithologies of the Ordovician in the study area are grainstone,carbonate breccia,calcareous dolostone,crystalline dolostone and siliceous limestone. The residual thickness of the uplifted area is about 500~1000 m,and the average porosity is 2.76%,whereas the residual thickness of the depression area is about 0~500 m,and the average porosity is 2.22%. Compared with the depression area,the residual thickness of the uplifted area is relatively large,and the pore penetration is relatively large;the influence of the Lanlao fracture is obvious,and the “uplift-depression”is distributed in a ring-like pattern. The karst thermal reservoirs experienced a comprehensive transformation by cementation,dolomitization,compaction,compressional solution,dissolution,filling,recrystallization,and tectonic rupture. The karst thermal reservoirs mainly underwent augmentation during the early orogenic period(early-middle Ordovician),during the epigenetic period(late Ordovician-early Carboniferous),during the middle-late burial period(late Carboniferous-early Triassic),and during the epigenetic period(middle Cenozoic,mainly developed in the Heze uplift). The lithology,diagenesis and tectonic stresses controlled the formation and evolution of the Ordovician karst thermal reservoirs in the study area. Analysis of the geothermal source-storage-cover base conditions has clarified the fluid circulation characteristics and geothermal resource prediction of the Ordovician karst thermal reservoirs in the study area.

Key words: west Shandong-eastern Henan area, Ordovician, karstic geothermal reservoir, geothermal field

中图分类号: 

• P588.24+5