龙门山地区中泥盆统观雾山组岩相古地理恢复

发布时间：2018-03-20 09:05

本文选题：龙门山　切入点：中泥盆统　出处：《石油学报》2017年12期 　论文类型：期刊论文

【摘要】：川西地区近期部分井的油气勘探发现显示,龙门山地区中泥盆统观雾山组发育展布良好的白云岩储层,但受龙门山断裂带推覆影响,观雾山组地层展布特征仍然认识不清、岩相古地理研究仍处于定性分析阶段。为厘清川西龙门山地区中泥盆统观雾山组岩相古地理特征:首先,基于平衡剖面技术定量恢复了龙门山断裂带北、中、南3段的剖面,建立起野外露头点现今位置与初始位置之间的函数关系,恢复了露头点的推覆距离,认为龙门山断裂带总体推覆距离约40 km,地层展布恢复后,观雾山组在彭灌古岛与都江堰之间存在一个沉降中心,观雾山组整体呈西厚东薄、南厚北薄的分布趋势;其次,以恢复后的观雾山组地层展布为基础,通过野外实测、岩心及测井资料综合分析,重建了龙门山地区观雾山组岩相古地理特征。研究发现,龙门山地区中泥盆统观雾山组岩石类型以白云岩(粉晶-细晶白云岩、砾屑-角砾白云岩、生屑白云岩和生物白云岩)为主,局部发育灰岩(泥晶灰岩、生屑灰岩和生物灰岩)及少量的碎屑岩与碳酸盐岩混合沉积;识别出台地边缘礁滩相、开阔台地相和局限台地相3种主要的沉积相类型;台地边缘礁滩相分布于桂溪—大木垭地区,开阔台地发育在K2井、擂鼓镇、龙王庙一带,局限台地位于彭灌古岛—宝兴古岛以东至上扬子古陆之间的地区;随着海平面上升,台地边缘礁滩相呈现出向东迁移的趋势。
[Abstract]:Recent oil and gas exploration in some wells in western Sichuan shows that well-distributed dolomite reservoirs are developed in the Guanwushan formation of the middle Devonian in the Longmenshan area, but the stratigraphic distribution characteristics of the Guanwushan formation are still unclear due to the influence of nappe of the Longmenshan fault zone. The study of lithofacies paleogeography is still in the qualitative analysis stage. In order to clarify the lithofacies and paleogeographic characteristics of the Middle Devonian Guanwushan formation in Longmen Mountain area, western Sichuan, the sections of the north, middle and south sections of the Longmenshan fault zone are quantitatively restored based on the balanced section technique. The functional relationship between the present position and initial position of outcrop point in the field is established, and the nappe distance of outcrop point is restored. It is considered that the overall nappe distance of Longmenshan fault zone is about 40 km, and the formation distribution is restored. There is a settlement center between Pengguanggu Island and Dujiangyan in Guanwushan formation. The Guanwushan formation has a distribution trend of thickness from west to east and thickness from south to north. Secondly, based on the stratigraphic distribution of recovered Guanwushan formation, it is measured in the field. The lithofacies and paleogeographic characteristics of Guanwushan formation in Longmen Mountain area were reconstructed by comprehensive analysis of core and logging data. It was found that the rock types of Guanwushan formation in the middle Devonian in Longmen Mountain area were dolomite (powdery fine-grained dolomite, conglomerate and breccia dolomite). The lithoclastic dolomite and biological dolomite are dominant, and the limestone (argillaceous limestone, bioclastic limestone and biolimestone) and a small amount of clastic rock are mixed with carbonate rock to identify the reef and beach facies on the edge of the ground. The open platform facies and the limited platform facies are three main sedimentary facies types, the reef and beach facies on the platform margin are distributed in Guxi-Damiya area, and the open platform is developed in K2 well, Laigu Zhen and Longwangmiao area. The limited platform is located between Pengguanggu Island and Baoxing ancient island between Yangtze and Yangtze land, and along with the rise of sea level, the reef beach facies of the platform edge shows a trend of eastward migration.
【作者单位】：中国石油勘探开发研究院;中国石油杭州地质研究院;中国石油天然气集团公司碳酸盐岩储层重点实验室;中国石油西南油气田公司勘探开发研究院;振华石油控股有限公司;
【基金】：国家重大科技专项(2016ZX05004-002) 中国石油天然气集团公司重大科技专项“深层油气勘探开发关键技术研究”(2014E-32-09)资助
【分类号】：P618.13

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