多井无震资料背景下三角洲湖岸快速厘定方法——以鄂尔多斯盆地安塞地区晚三叠世三角洲为例  

A quich determination of lake-delta shoreline under more wells and no seismic datum background——A case study of Late Triassic delta in Ansai oilfield of the Ordos Basin

作　　者：张金良[1] 屈红军[2] 张志升[1] 高雨 孙晓晗 董文武 ZHANG Jinliang;QU Hongjun;ZHANG Zhisheng;GAO Yu;SUN Xiaohan;DONG Wenwu(Xingzichuan Oil Production Plant,Yanchang Oil field Corporation,Yan’an 717400,China;Department of Geology,Northwest University,Xi’an 710069,China)

机构地区：[1]延长油田股份有限公司杏子川采油厂,陕西延安717400 [2]西北大学地质学系,陕西西安710069

出　　处：《西安科技大学学报》2022年第6期1148-1154,共7页Journal of Xi’an University of Science and Technology

基　　金：国家自然科学基金项目(41390451)。

摘　　要：确定安塞地区长6三角洲湖岸线位置不仅可以为油气勘探提供更可靠的地质依据,同时可探索多井无震资料背景下三角洲湖岸的快速厘定方法。利用岩心相、沉积旋回分析,结合标志层间地层厚度陡坡突变带的确定,对鄂尔多斯盆地安塞油田长6油层组湖岸线进行精确厘定。结果表明:湖岸线以上的三角洲平原亚相岩心颜色不均一,发育泥砾、煤线以及大量碳化植物碎片,测井曲线发育正旋回沉积序列;湖岸线以下的三角洲前缘亚相岩心颜色较均一,常发育直立虫孔,测井曲线既发育正旋回沉积序列,也发育有逆旋回沉积序列;长6油层组中上部K3与K4标志层之间的长61+长62地层厚度从东北到西南逐渐增加,在厚度75~90 m时出现厚度突变带。根据岩心相与沉积旋回分析标定的典型井及厚度突变带的位置,确定长6三角洲湖岸位于安塞区坪桥镇张家塬村—坪桥镇寺湾村—建华镇寺沟村—建华镇郝家坪村一线。Being the earliest super-giant oilfield discovered in the Ordos Basin,the main oil layer of Ansai Oilfield is the Chang 6 reservoir of Upper Triassic Yanchang Formation,which developed delta front facies deposits with great exploration significance,therefore determining the lakeshore line location of Chang 6 delta in Ansai area can not only provide a more reliable geological basis for oil and gas exploration,but also can search ways to quick determine lake-delta shoreline under more wells and no seismic datum background.Based on the analysis of core facies and sedimentary cycles,and the determination of steep slope mutation zone of stratum thickness between marker beds,the lakeshore line of Chang 6 reservoir in Ansai oilfield is determined accurately.The results are as follows:The delta plain subfacies above the lake shoreline is characterized by diverse core colors,the mud gravel,coal lines and a large number of carbonized plant fragments,and normal positive sedimentary cycle sequence is basically developed in logging facies.The delta front subfacies below the lake shoreline are relatively uniform in core colors,and upright wormholes are often developed,with both positive cycle sedimentary sequence and reverse sedimentary cycle sequence produced.The stratum thickness of Chang 61+Chang 62 between K3 and K4 maker beds in the middle and upper parts of Chang 6 reservoir increases gradually from northeast to southwest,and the thickness mutant change zone appears between 75m and 90m.According to the location of the thickness mutation zone and the typical wells calibrated by core facies and logging facies,the lakeshore line of Chang 6 delta is located along Zhangjiayuan village,Pingqiao Town-Siwan village,Pingqiao town-Sigou village,Jianhua town-haojiaping village,Jianhua town,and Ansai district.

关 键 词：安塞油田 长6油层组 三角洲 湖岸线 

分 类 号：TE122.3[石油与天然气工程—油气勘探]