龙门山地区中泥盆统观雾山组岩相古地理恢复  

Lithofacies palaeogeography restoration of the Middle Devonian Guanwushan Formation in the Longmenshan area

作　　者：熊连桥[1,2] 姚根顺 倪超 熊绍云[2,3] 周刚 王键[5] 郝毅 

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]中国石油杭州地质研究院,浙江杭州310023 [3]中国石油天然气集团公司碳酸盐岩储层重点实验室,浙江杭州310023 [4]中国石油西南油气田公司勘探开发研究院,四川成都610041 [5]振华石油控股有限公司,北京100031

出　　处：《石油学报》2017年第12期1356-1370,共15页Acta Petrolei Sinica

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

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。Through the recent oil-gas exploration of some wells in the western Sichuan area,it is found that the dolomite reservoirs with favorable distribution are developed in the Middle Devonian Guanwushan Formation of Longmenshan area.But due to the nappe impact from Longmenshan Fault Belt,the distribution characteristics of Guanwushan Formation are still obscure,and the study on lithofacies paleo-geography is still in a stage of qualitative analysis.To clarify the lithofacies paleo-geographic characteristics of the Middle Devonian Guanwushan Formation in Longmenshan area of the western Sichcuan,the following two steps have been conducted：（1）The three profiles,i.e.,the north profile,the central profile and the south profile,of Longmenshan Fault Belt are quantitatively restored based on the balanced section technique,so as to create the function relationship between current location and initial location of field outcrop point and restore the nappe distance of outcrop point.It is considered that the total nappe distance of Longmenshan Fault belt is about 40 km,and after the restoration of stratigraphic distribution,there is a subsidence center between Pengguan Paleo-island and Dujiangyan of the Guanwushan Formation.On the whole,Guanwushan Formation tends to be thicker in the west while thinner in the east and thicker in the south while thinner in the north.（2）Based on the stratigraphic distribution of Guanwushan Formation after restoration,the lithofacies paleo-geographic characteristics of Guanwushan Formation in Longmenshan area are reconstructed by field measurement and comprehensive analysis on core and well-logging data.Meanwhile,the study shows that the rock types of the Middle Devonian Guanwushan Formation in Longmenshan area are dominated by dolomite（silty crystal-fine grain dolomite,gravel-brecciated dolomite,bioclastic dolomite and biogenic dolomite）;in local area are developed limestone（micrite,bioclastic limestone and biogenic limestone）and a small a-mount of mixed sediments consisting of cla

关 键 词：龙门山 中泥盆统 观雾山组 平衡剖面 地层展布 岩相古地理 

分 类 号：TE122[石油与天然气工程—油气勘探]