泌阳凹陷南部陡坡带核桃园组岩相古地理及时空演化

核桃园组是泌阳凹陷南部陡坡带的主要含油气目的层。本文依据岩心资料,结合岩石学特征、测井相及其他相标志,将研究区核桃园组划分为扇三角洲、辫状河三角洲、曲流河三角洲和湖泊沉积体系。通过对碎屑重矿物资料、钻井和录井资料等相关地质资料的综合分析,编制各段砂砾岩粒度平均值等值线图等图件基础上,系统编制了核桃园组核三段—核一段岩相古地理图。其古地理展布特征是:南部发育扇三角洲,东北部发育辫状河三角洲,西北部发育曲流河三角洲,中部发育湖泊。在核三期到核一期的古地理演化过程中,扇三角洲和曲流河三角洲规模持续缩小,曲流河三角洲在核一期被滨浅湖所充填,湖泊面积逐渐增大。辫状河三角洲规模从核三期到核二期逐渐变大,到核一期开始减小。

Lithofacies paleogeography of Hetaoyuan Formation in the southern steep slope zone of Biyang depression

Hetaoyuan Formation in the southern steep slope zone of the Biyang depression is a major hydrocarbon-bearing target zone.Based on the multidisciplinary analysis of drilling core data,petrological characteristics and facies marks,this paper divides the Hetaoyuan Formation into four sedimentary systems: fan-delta deposits,braid river delta deposits,meandering river delta deposits and lacustrine deposits.Based on a comprehensive analysis of detrital heavy minerals,well-logs and well logging data,the authors systematically drew lithofacies-paleogeographical maps from 3rd Member to 1st Member of the Hetaoyuan Formation.The paleogeographic distribution characteristics are as follows: Fan delta is developed in the south,braid river delta occurs in the northeast,meandering river delta exists in the northwest and lacustrine sediments are developed at the center.In the paleogeographical evolution process from 3rd Member to 1st Member of the Hetaoyuan Formation,the fan delta and meandering river delta kept shrinking,and the meandering river delta was filled by the shallow lake in 1st Member of the Hetaoyuan Formation.The area of the lake expanded gradually and the braid river delta became bigger from 3rd Member to 2nd Member and began to decrease in area in 1st Member of the Hetaoyuan Formation.