98 2017年12月
文章编号：10013873(2017)060678-08
新疆石油地质
XINJIANGPETROLEUMGEOLOGY DOI: 10.7657/XJPG20170608
Vol.38,No.6 Dec.2017
玛湖凹陷八道湾组辫状河三角洲沉积特征及模式
厚刚福"，吴爱成”，邹志文"，尤新才？，徐洋"，郭华军”
（1.中国石油杭州地质研究院，杭州310023；2.中国石油新疆油田分公司勘探开发研究院，新疆克拉玛依834000）摘要：早侏罗世八道湾期，准噶尔金地玛潮凹陷构造环境相对稳定，沟槽和坡折发育，物源供给充足，为状河三角洲发育提供了条件。辨状河三角洲沉积具有粒度、成熟度低、率引流沉积构造发育、垂向上多期水下分流河道切割叠置和呈正放国沉积序列等特征，可细分为辫状河三角洲平原和辨状河三角洲前缘2种亚相。在平面上，由于不同地区坡度不同，而导致群状河三角洲规模具有差异，陡坡带群状河三角洲规模较大，缓坡带彝状河三角洲规模相对较小。在垂向上，在湖平面上升的不同阶段，静状河三角洲发育不同的亚相组合和砂体构型，湖平面上升单期，发育群状河三角洲平原亚相；湖平面上升中期，群状河三角州前缘亚相占据主导地位；潮平面上升晚期，发育“泥包砂“型状河三角洲前缘沉积。
关键词：准噶尔盆地；玛湖凹陷；保罗系；八道湾组；群状河三角洲；沉积模式
中图分类号：TE122.221
文献标识码：A
Depositional Characteristicsand Models of Braided RiverDelta in BadaowanFormation of
MahuSag，JunggarBasin
HOUGangfu',WUAicheng,ZOUZhiwen',YOUXincai,XUYang,GUOHuajun
(1.Hangzhou Research Institute of Geology, Petrochina, Hangzhou, Zhejiang 310023, China; 2.Research Institute of Exploration and
Development, Xinjiang Oilfield Company,Petrochina, Karamay,Xinjiang 834000, China)
Abstract: The tectonic environment of Mahu sag in Junggar basin was relatively stable in Badaowan stage of Early Jurassic, during which grooves and slopes were developed and the sediment supply was sufficient, providing conditions for development of braided rive delta, The sediments of the braided river delta that are characterized by coarse grain, low maturity, developed tractive-current depositional structure, incision and superimposition of multi-stage underwater distributary echannel vertically and normal eyele of sedimentary sequence and so on, can be divided into 2 subfacies such as braided-river delta plain and braided-river delta front. On the plane, different slope gradients in dif-ferent areas result in the differences of sizes of braided river deltas whose sizes are relatively large in steep slopes and relative small in gen-tle slopes. Vertically, different subfacies associations and sanibody configuration were developed at different stages of lake level rising Braided-river delta plain was mainly found at the early stage of lake level rising; braided-river delta front was the dominant subfacies at the
middle stage of lake level rising; mud-coated sand type of braided-river delta front was developed at the late stage of lake level rising Keywords: Junggar basin; Mahu sag: Jurassic; Badaowan formation; braided river delta; depositional model
辩状河三角洲最早由McPherson提出"，是由辩状河体系前积到停滞水体中形成的、富含砂和砾石的三角洲沉积，其沉积特征介于正常三角洲和扇三角洲之间，比扇三角洲具有更好的储集性能和含油气性，因而受到油气地质学家的重视2-]。国内外地质学家，尤其是油气地质学家，从不同角度对辩状河三角洲进行了研究。文献[2]根据沉积物的输人、波浪能量和潮汐能量这3种作用，提出了包括扇三角洲、状河三角洲和曲流河三角洲在内的三角洲完整体系的分类，讨论了扇三角洲和辩状河三角洲的成因和沉积特征；文献[7]通过对岱海状河三角洲沉积特征考察，认为辩状河三角洲主要发育在湖盆的短轴方向或近
收稿日期：2017-08-19
修订日期：2017-09-18
基金项日：国家科技重大专项（2016ZX05001-05）
物源区的湖岸，是受间歇性洪水控制的沉积产物，沉积规模主要受湖岸坡度及河流注人量的影响；文献[8]根据岱海辩状河三角洲沉积特征，认为辩状河三角洲前缘没有水下分流河道，分流河道一人湖即消失；文献[9]通过对柴达木盆地马仙地区下干柴沟组上段辩状河三角洲沉积特征研究，认为分流河道和水下分流河道砂体厚度大且分布广泛，具有广阔的油气勘探前景。20世纪90年代以来，按照“跳出断裂带，走向斜坡区”的勘探思路，新疆油田在玛湖凹陷三叠系百口泉组部署的多口探井获得突破，表明玛湖凹陷斜坡区具备扇控大面积油气成藏的地质特征。2016 年，玛湖凹陷多口老井在下侏罗统八道湾组经复查，
作者简介：厚刚福（1982-），男，甘肃静宁人，T程师，层序地层和沉积销层，(Tel)0571-85224912(Email)hougf_hz@petrochina.com.cn 万方数据