应用粒度分析资料建立洪积扇沉积环境判别模式——以克拉玛依油田七中东区克拉玛依组为例

ESTABLISH THE MODE CHART OF ALLUVIAL FANS AND ALLUVIAL FACIES DEPOSITION SETTING BY GRAIN SIZE ANALYSIS——EXAMPLE AS 7TH BLOCK KARAMAY FORMATION

粒度分析资料是一个传统的划相指标,洪积扇储层的概率粒度曲线以其粗粒度、宽区间、低斜率为特征.洪积扇主槽样品的概率粒度曲线Ф值从-6^+6,而一般河道样品的概率粒度曲线Ф值一般都大于0,粒度曲线斜率相对陡.体现了洪积扇沉积物颗粒粗细混杂、粒级分选极差的特点.洪积扇样品概率粒度曲线的截点一般也多于河道样品的曲线Ф值截点.以克拉玛依油田西北缘七区储层的洪(冲)积扇沉积为例,以粒度平均值MZ、粒度标准偏差SI、偏度SKI和峰态KG等4项粒度参数为准,运用粒度资料建立了洪积扇的福里德曼模式和萨胡洪积扇沉积环境判别图,通过与河流、三角洲沉积的对比,认为洪积扇样品具有偏度与标准偏差都大的特点,在弗里德曼离散图上判别洪(冲)积扇沉积环境界限是明显的,该模式对克拉玛依组洪积扇相划分是可行的,对其他地区类似洪积扇的划相工作也有一定参考意义.

Abstract： Grain analysis is a traditional means of sedimentary facies decision. The probability curves of alluvial fan conglomerate reservoir have the characteristics of coarse-grained, wide-range and low-slope. The probability curves interval of alluvial groove is from -6 to 6. While most of the probability curves value of channel is positive, its slope angle is larger than alluvial groove＇s, which display that the characters of alluvial fan conglomerate reservoir appear to be grain miscellaneous and sorting bad. The probability curves of alluvial samples usually have more truncated-point than channel＇s. Based on plenty of grain size analysis of 7th block of north-west reservoir of Karamay oil-field, Exampled as 4 parameters mean grain size MZ, grain standard deviation SI, deviation value SKI and peak value KC~ The author created Friedman pattern of alluvial fan and gived Sahu alluvial facies depositional setting mode chart. It is feasible and distinguishable to compare these mode chart with delta and fiver deposits, . And also it is useful to distinguish alluvial facies from other analogous deposit zones.