川东七里峡—云安厂地区飞仙关组储层特征及主控因素研究

Reservoir Characteristics and Main Control Factors of the Feixianguan Formation in the Qilixia-Yunanchang Area,Eastern Sichuan Basin

四川盆地东部下三叠统飞仙关组海相碳酸盐岩油气勘探具有巨大的前景,目前已进入地层-岩性油气藏勘探阶段,因此加强对该区储层发育特征及分布预测的研究显得尤为重要。本文以精细岩心观察和薄片鉴定为基础,结合扫描电镜、物性和孔隙结构等资料分析,对该区储层发育特征及主控因素进行分析,预测了该区有利储层分布区域。研究区飞仙关组主要的储集岩类型是白云岩类,鲕粒灰岩次之;物性总体上呈现低孔、低渗的特征,且主要储集空间为粒内溶孔和晶间溶孔;储层类型主要是裂缝-孔隙型;储层发育程度受控于岩石类型、沉积相带分布、海平面升降、白云岩化作用等因素影响。其中鲕滩发育区为有利储集相带、相对海平面下降有利于储层孔隙的形成,埋藏成因的粉晶-细晶白云岩、鲕粒白云岩是飞仙关组储层中最普遍也最为重要的成岩作用类型,也是优质储层形成的关键。综合飞仙关组储层特征及主控因素分析,预测了有利储层发育区。

The exploration of marine carbonate oil and gas has great prospects in the Lower Triassic Feixianguan Formation, east ofSichuan basin. It has into entered the stratigraphic-lithologic gas pool exploration stage. Therefore, it is especially important tostrengthen the research on the reservoir characteristic and distribution prediction for the studing area. Based on core observation andthin section analysis, combined with the SEM, physical property and pore structure analysis, this paper analyses the reservoirdevelopment characteristic and main control factors and predicts the potential reservoir distribution area. The main reservoir rock typesof the Feixianguan Formation are dolomites and oolitic limestones. The porosity and permeability are low. The intragranular and intergranular bore hole are the main reservoir space. The type of reservoir is fracture-pore. The development of reservoir is controlled byrock types, sedimentary facies distribution, sea level, and dolomitization. Oolitic belt is the favorable reservoir facies. The relativeregression of the sea-level is good for forming pores in the reservoir. The buried quartz-fine-grained dolomite, oolitic dolomite reservoirare the most common diagenesis of the Feixianguan Formation, and it is the key to the formation of the high quality reservoir. Based onour data of reservoir characteristics and main controlling factors of the Feixianguan Formation, we have forecasted the favorablereservoir in the studied area.