三塘湖盆地牛东地区石炭系卡拉岗组火山岩风化壳模式与识别

三塘湖盆地上石炭系卡拉岗组火山岩风化壳储层是吐哈油田近年来油气勘探的重要目标。根据该区钻井、测井和分析化验资料所揭示的火山岩风化壳剖面及其岩石学特征、物性特点,认为该风化壳在纵向上可划分为风化粘土层(沉积盖层）、强风化碎石层(风化壳上带）、弱风化块石层(风化壳下带）及未风化岩石层(致密火山岩带）；有效的储集空间发育在强风化碎石层和弱风化块石层。根据火山岩储集层的孔隙成因及火山岩与烃源岩、盖层的匹配关系,认为该区火山岩风化壳模式是：火山岩之下上石炭统哈尔加乌组为烃源岩,之上为非烃源岩,风化壳内的溶蚀孔隙与洞缝为储层并与上覆的碎屑岩盖层,构成了良好的生储盖组合。指出对该区块火山岩风化壳的识别方法对下一步在三塘湖盆地寻找火山岩风化壳储层具有重要意义。

Weathering Crust Model and Recognition of Carboniferou Kalagang Formation(C2 k)Volcanic Rocks in Niudong Block,Santanghu Basin

Weathering crust reservoir of C₂k  volcanic rock was the significant target of oil and gas exploration in recent years in the Santanghu Basin of Tuha Oilfield. According to its petrology and the natural characteristics revealed by drilling and logging data, this crust of weathering can be divided in vertical into weathered clay layer (sedimentary cover), highly weathered detritus, (the upper belt of weathering crust), weakly weathered block layer (the bottom belt of weathering crust) and non\|weathering rock (dense volcanic belt). Effective reservoir space is developed in highly weathered detritus and weakly weathered block layer. According to the pore origin of the volcanic rock reservoir and the relations of the hydrocarbon source rock and the volcanic rock, the pattern of the volcanic rock crust of weathering is that  the group hydrocarbon source rock for the volcanic rock is in C₂h, the upper of which is non\|hydrocarbon source rock, reservoirs are dissolved pores and fissures, and the upper part of the rocks is caprock, which constitute a good source\|reservoir\|cap association. The recognition of the volcanic rock crust of weathering is significant for seeking volcanic rock crust of weathering reservoir in the Santanghu Basin.