塔里木盆地库东-轮台地区苏维依组Ⅱ砂组沉积储层特征

摘要

Based on drilling, logging, seismic and testing data, combined with sandstone comparison and seis-mic attribution technique, it was studied in this paper the sedimentary facies and reservoir features of the updip pinch-out sandstones in the sandstone team Ⅱ of the Suweiyi Formation in Kudong-Luntai area. The target for-mation, mainly of beach-bar facies, is consisted of brown-grey medium-or fine-grained lithic arkose, and is featured by wave-cross bedding, wave-generated ripple and bioturbation. The reservoir space comprises intergranular porosity, emposieu and fractures. In general, the reservoir is of low/ultra-low porosity and low permeability, high displacement pressure, small pore throat radius, general sorting, mainly fine skewness and partially coarse skewness. The pore structures are generally poor, but the microfractures improve reservoir storage capability. Several updip pinch-out lithologic traps have been found in the study area, showing good exploration potentials in the Suweiyi Formation.%以钻井、测井、地震和分析测试资料为依据，利用砂体精细对比、地震属性综合分析等手段，对库东-轮台地区苏维依组（Ⅱ砂组）上倾尖灭型砂岩沉积相及储层特征进行了研究。目的层段为滨浅湖滩坝砂沉积，其岩性主要为棕褐色-褐灰色中-细粒岩屑长石砂岩，沉积构造以浪成交错层理、浪成波痕、生物扰动等为特征。储集空间类型以粒间孔为主，少量粒内溶孔、颗粒破裂缝，储层物性主要表现为低-特低孔-低渗型储层，排驱压力较高，孔喉半径较小，分选性一般，以细歪度为主，少量粗歪度，孔隙结构总体较差，但微裂缝对储层储集性能具有改造作用。研究区发育多个上倾尖灭性岩性圈闭，苏维依组岩性油气藏具有良好的油气勘探前景。