论文部分内容阅读
不整合是构造运动和海(湖)平面升降的产物,其风化粘土层可作为油藏的良好封盖层,半风化岩石孔缝系统可作为油气运移通道,也可为油气聚集提供良好储层.深入分析不整合结构在矿物含量变化、元素及其氧化物含量变化方面的微观特征是划分不整合结构的基础,对不整合油气藏的勘探实践具有重要意义.不整合结构可划分为风化粘土层-半风化岩石型、半风化岩石型和沉积间断型.通过济阳坳陷义和庄凸起前第三系风化粘土层-半风化岩石型不整合结构矿物与元素变化的实测数据,结合典型地区风化壳的矿物、元素分析结果,分析了风化粘土层-半风化岩石型不整合结构的矿物学、常量元素地球化学特征:其矿物学特征主要表现为长石、云母等原生矿物的蚀变和高岭石、伊利石及蒙脱石等次生粘土矿物的明显增多,粘土矿物在风化粘土层中部或风化粘土层下部-半风化岩石上部较为富集;其常量元素地球化学特征表现为Ca、Na元素含量迅速减少,在风化粘土层下部与半风化岩石上部通常具有Fe、Al元素的富集带,K、Mg元素的变化由于交代作用等因素而变得复杂.
Unconformity is a product of tectonic movements and sea-level (LAS) plane uplift. Its weathered clay layer can be used as a good capping layer for reservoirs. Semi-weathered rock pore-gully systems can act as hydrocarbon migration channels and also provide good reservoir for hydrocarbon accumulation In-depth analysis of the microscopic features of unconformity structure in mineral content changes, elemental and oxide content changes is the basis for the division of unconformity structure and is of great significance to the exploration practice of unconformity oil and gas reservoirs.The unconformity structure can be divided into weathering Semi-weathering rock type and sedimentary discontinuity.According to the measured data of the mineral and element changes of the pre-Tertiary weathering clay-semi-weathering rock-type unconformity structure in the Yihezhuang uplift of Jiyang Depression, Based on the mineral and elemental analysis results of the weathering crust in the typical area, the mineralogy and the elemental geochemical characteristics of the weathered clay-semi-weathered rock-like unconformity structure are analyzed. The mineralogical characteristics of the weathered crust-semi-weathered rock-type unconformity are mainly the feldspar and mica Alteration and the obvious increase of secondary clay minerals such as kaolinite, illite and montmorillonite, clay mineral in the middle part of weathered clay layer or the lower part of weathered clay layer - The upper part of weathered rocks is more enriched. The geochemical characteristics of their major elements are Ca and Na, the content of which decreases rapidly. Generally, there are Fe and Al enrichment belts in the lower parts of the weathered clay and the semi-weathered rocks. The changes of K and Mg Due to factors such as accountability and become complicated.