高青地区中生界顶部不整合结构特征及输导作用

STRUCTURAL FEATURES AND TRANSPORTING ACTION OF THE UNCONFORMITY ON THE TOP OF MESOZOIC GROUP IN GAOQING AREA

为了剖析高青地区中生界顶部不整合在油气运聚过程中的作用,对地震、测井、岩心资料以及矿物、元素的微观特征等进行了综合分析。研究表明:自上而下不整合可分为不整合面之上岩石、风化黏土层和半风化岩石,为3层结构;风化黏土层岩石结构遭到严重破坏,石英和黏土矿物含量相对较高;后期地层压实作用致使风化黏土层物性变差,为非渗透层;半风化岩石中长石含量明显高于风化黏土层,矿物元素表现出富Al贫Ca、Na的特征;残余的方解石等不稳定矿物在风化淋滤作用下发生溶解,形成次生溶孔,溶孔、裂缝发育,物性较好,属于良好的渗透层;不整合输导作用主要有不整合侧向输导、不整合遮挡2种方式。

In order to further analyze the roles of the unconformity on the top of Mesozoic group in the process of the hydrocarbon migration and accumulation in Gaoqing area,the comprehensive analysis was conducted for the seismic,logging and core data and moreover the microscopic characteristics of the minerals and elements. The study shows that the three-layer structures can be classified for the unconformity from top to bottom： the rocks above the unconformity,weathered clay horizons and semi-weathered rocks; the structures of the weathered clay horizons are seriously damaged,the contents of the quartz and the clay mineral are relatively higher; the late stratigraphic compaction action results in the petrophysical properties deterioration of the weathered clay,the weathered clay are nonpermeable layers; the content of the feldspar in the semi-weathered rock is obviously higher than that of the weathered clay,the mineral elements show the characteristics of rich Al and poor Ca Na; the residual calcite and otherunstable minerals are dissolved under the actions of weathering and leaching,and furthermore form the secondary dissolved pores,the dissolved pore and fractures are well developed,the petrophysical properties are much better,the semi-weathered rocks are good permeable layers; two actions of the unconformity transportation are mainly presented： unconformity lateral transportation and unconformity barrier.