轮南地区奥陶系储层特征及其影响因素

奥陶系碳酸盐岩储层是轮南地区主要产层之一,油气藏类型为古潜山油藏.自早奥陶世(O1p)至晚奥陶世(O3S),奥陶系经历了半局限台地相→开阔海台地相→台地边缘相→台缘斜坡相→混积浅水陆棚相的沉积演化,沉积了多种岩石类型,储层岩石主要为亮晶颗粒灰岩.压实作用、胶结作用使得奥陶系储层基质孔隙度较低、孔喉结构差,为差或非储层.由于奥陶系后多次构造运动,使奥陶系裂缝、岩溶作用发育,形成有大量溶蚀孔、洞、缝的有效储层.岩溶、裂缝发育区,为储层的有利分布区.轮南地区西部、中部为风化壳岩溶发育区,东部为深部岩溶发育区.

Characteristics of the Ordovician carbonate reservoir in Lunnan area and their controlling factors

Ordovician carbonate reservoir is one of main production layers in Lunnan area,and the oil reservoir is burial hill reservoir.From early to late Ordovician period,the reservoir experiences the sedimentary evolution from semi-limited platform facies,open-sea platform facies,platform edge facies,platform edge slope facies,to mixed shallow shelf facies.There are multiple rock types in the reservoir,and bright grain limestone is main rock type.Compaction and cementation make the porosity and permeability of the Ordovician reservoir little and pore throat worse,so the reservoir becomes bad reservoir or non-reservoir.But because of many times tectonic movements after Ordovician and karstification,a lot of dissolved pores,holes and fractures are formed in the Ordovician reservior,which makes it become effective reservoir.The zones in which pore,hole and fracture are developed are favorable reservoir.Weathering crust karst is developed in the western and central parts of Lunnan area and deep karst is developed in the eastern part of Lunnan area.