关键词: 成岩作用, 桥口地区, 次生孔隙, 砂岩体, 储层特征, 溶蚀作用, 次生加大, 铁白云石, 碳酸盐胶结, 成熟阶段

Abstract: Members S₃^3-4 of Qiaokou area,Dongpu depression,have reached the mature stage B and over-mature stage of mesodiagenesis.On the basis of deposition,strong diagenesis has resulted low-porosity and low-permeability sandbodies in most of them which can be divided into two types:(1)quartzovergrowth-cemented;and(2)carbonate-cemented.The pore spaces in the reservoirs are charactorized by the predominance of micropore and microfracture,with well developed secondary pore spaces only few layers.During the burial,diagenesis of the sediments,two periods of solution have been undergone,and the resultant secondary porosity in each period was different in scale,quantity and effective preservation because of their different diagenetic environments.There are favorable for the development of secondary pore spaces and may provide good spaces for hydrocarbon accumulation.There are internal relations among diagenetic facies,depositional facies and development of secondary pore spaces.Turbidity-Channel and Stormchannel sandbodies are favorable for the development of secondary pore spaces and may provide good spaces for hydrocarbon accumulation.