鹿乡断陷C区块双阳组测井岩性识别及储层有效厚度的确定

针对伊通盆地鹿乡断陷五星构造带油藏,提出一种适用于本区块的测井岩性识别模式及确定储层有效厚度的方法。利用包括自然伽马(吉林伽马)、普通电阻率、声波时差和自然电位曲线的综合分析,通过绘制各类曲线交会图,确定各类岩性的有效指标范围,确认出本区可识别的6种岩石类型即泥岩、粉砂岩、细砂岩、中砂岩、粗砂岩和砂砾岩。在测井解释近似的情况下,提出反推排除法,结合区域整体沉积相带分布规律和相邻井之间的测井曲线相互关系,区分细砂岩与含砾砂岩。在测井解释的基础上进行储层有效厚度研究,建立孔隙度、渗透率、含油饱和度模型,总结出岩性下限标准、物性下限标准、电性下限标准,利用建立的模型及解释图版,对本区块的39口井进行油水层校正,编制单砂层有效厚度图和单砂层岩性-微相图。

Identification of logging lithology and assessment of reservoir effective thickness in Shuangyang Formation of C-Block,Luxiang Fault Depression

According to the oil reservoir characteristics of Wuxing structural belt in Luxiang Fault Depression, Yitong Basin, this study proposed a model of identifying logging lithology and a method of defining reservoir effective thickness. Six types of rocks, including mudstone, siltstone, fine-grained sandstone, medium-grained sandstone, coarse-grained sandstone and sandy conglomerate, are recognized by comprehensive analysis of gamma ray (Jilin gamma), resistivity, interval transit time and spontaneous potential curve, and cross ploting of well logs for lithology determination. The backward-inference method is proposed under the circumstance of similar log curve characteristics. Integrating regional sedimentary facies distribution and log correlation with adjacent wells this method can distinguish fine-grained sandstone from pebbled sandstone. Moreover, the authors studied the reservoir effective thickness based on well log interpretation, built the models of porosities, permeabilities and oil saturation, summarized the lower limits of lithology, physical property and electrical property to calibrate the oil and water layers encountered in 39 wells in the study area and mapped the effective thickness and litho-facies of single sand layer.