【摘要】 山西太原地区奥陶系碳酸盐岩地热资源丰富,为了提高对该区碳酸盐岩热储特征、成因及控制因素的认识程度,指导该类型地热田的勘探,基于岩心、野外露头观察,结合薄片、扫描电镜等分析方法,研究了该区奥陶系热储的岩石特征、储集空间特征和成岩作用类型,揭示了岩溶孔隙的发育规律和主控因素。研究结果表明:①该区奥陶系热储主要包括石灰岩和白云岩两种类型,孔洞、裂缝和孔隙为其主要的储集空间;②储层受破坏性成岩作用和建设性成岩作用的叠加,其中建设性成岩作用中的岩溶作用、白云石化作用对次生孔隙的形成具有决定性的影响;③该区岩溶作用以表生岩溶和埋藏岩溶为主,前者对储层的贡献占主导作用,后者对储层的后期溶蚀改造作用显著并使得储层孔隙度增加;④奥陶系碳酸盐岩热储平面上整体处于储集性能较好的岩溶斜坡地带,含水层的岩性通常为成分不纯及结晶程度较高的石灰岩、白云岩;⑤岩溶发育分布主要受岩性及沉积相、构造、地下水动力条件等因素的控制,尤其是构造断裂控制了岩溶的发育方向,影响着岩溶发育的规模和岩溶裂隙水动力条件。结论认为,该区奥陶系地热资源的勘探有利区为晋源凹陷西北部和中东部、西温庄隆起中西部。更多还原

【Abstract】 The geothermal resources of Ordovician carbonate rocks are abundant in the Taiyuan area, Shanxi province. In order to achieve a better understanding of the characteristics, genesis and controlling factors there and guide the exploration of this type of geothermal fields, we studied the development characteristics of Ordovician thermal reservoir rocks, reservoir space types, and diagenesis types in this study area based on the data of core and outcrop observation, thin section and scanning electron microscopy, and revealed the main controlling factors of thermal reservoir characteristics and the most favorable targets. The following results were achieved.(1) The Ordovician thermal reservoirs in the Taiyuan area mainly consist of limestones and dolomites, with karst caves, fractures, and pores as the main reservoir space.(2) The reservoirs are subjected to both destructive and constructive diagenesis, and karstification and dolomitization have dominant influence on the formation of secondary pores.(3) Karstification results in mainly supergene karst and buried karst. The contribution of supergene karstification to reservoirs is dominant, and burial karstification plays a significant role in the later dissolution and transformation of reservoirs, which increases their porosity.(4) Ordovician carbonate reservoirs are generally located in the karst slope zones with a good storage performance on the thermal reservoir plane. The lithology of thermal reservoir aquifers presents usually limestones and dolomites with impure composition and high crystallinity.(5) The development and distribution of thermal reservoir karst pores mainly depend on lithology(including rock composition, texture, thickness, etc.), structure(fracture and unconformity), sedimentary facies, groundwater dynamic conditions, and other controlling factors, especially, tectonic faults control the direction, affecting karst development scale and karst fissure hydrodynamic conditions. It is concluded that the most favorable targets for Ordovician carbonate thermal reservoir karst development in the Taiyuan area are the northwestern and eastern parts of the Jinyuan sag and the central and western parts of the Xiwenzhuang uplift.更多还原