蜀南地区龙马溪组优质页岩段岩相分布及其特征研究

【作者】 李洁；

【导师】 蒋裕强；

【作者基本信息】 西南石油大学 ， 地质学， 2018， 硕士

【摘要】 页岩岩相的研究是页岩地质特征的基础和重要组成部分。目前对于页岩岩相的划分越来越精细,有利于识别有利岩相组合及分布,为页岩气勘探评价提供重要地质依据。基于测井、钻井、岩心资料、薄片鉴定及X-射线衍射全岩矿物分析,对蜀南地区龙马溪组优质页岩段的岩相进行了研究,将研究区目的层段龙一 1亚段自下而上细分为:1小层、2小层、3小层、4小层。以TOC含量、矿物组成为基础的“两步法”划分页岩岩相,共划分出19种岩相。本研究层位主要发育7种岩相:1.高碳硅质页岩相;2.高碳碳酸盐质-硅质页岩相;3.中碳硅质页岩相;4.中碳碳酸盐质-硅质页岩相;5.中碳硅质-碳酸盐质页岩相;6.中碳黏土质页岩相;7.低碳黏土质页岩相。通过对页岩岩相空间展布特征分析:(1)纵向上,从下向上,页岩岩相从高碳硅质页岩相向低碳黏土质页岩相逐渐过渡。(2)平面上,岩相类型变化较大,由北西至南东向,岩相类型逐渐向高碳硅质页岩相逐渐过渡。(3)从有机碳含量、矿物组分、物性特征、储集空间特征、含气性五方面对这7种岩相进行岩相综合评价,划分出3类有利页岩岩相:高碳硅质页岩相、高碳碳酸盐质-硅质页岩相为Ⅰ类有利岩相,中碳硅质页岩相、中碳碳酸盐质-硅质页岩相为Ⅱ1类有利岩相,中碳硅质-碳酸盐质页岩相、中碳黏土质页岩相为Ⅱ2类有利岩相,低碳黏土质页岩相为Ⅲ类有利岩相。Ⅰ类有利岩相主要分布在1小层是佳勘探层段。更多还原

【Abstract】 The study of shale facies is the foundation and an important part of the shale geology research.At present,the division of shale facies is more and more fine,which is advantageous to identify favorable lithofacies combination and distribution,and provides important geological basis for shale gas evaluation and exploration.Based on logging,drilling,core data,thin sections and X-ray diffraction analysis,this paper studies the lithofacies of the high quality shale section of the Longmaxi Formation in the south Sichuan,and divides the 11 sub sections of the target segment of the research area into four layers from bottom to top:1 small layer,2 small layer,3 small layer,4 small layer.The paper divides the shale facies by two steps,which is based on TOC content and mineral composition,and divides 19 lithofacies.In this study,7 lithofacies were identified in the study area:1.High-carbon siliceous shale facies;2.High carbon carbonate-silica shale facies;3.Medium Carbon Silica shale facies,4 medium carbon carbonate-silica shale facies,5 medium carbon siliceous-carbonate shale facies,6 medium carbon clay shale facies,7.Low carbon clay shale facies..Through the analysis of the characteristics of the shale facies and their distribution,we found that:(1)vertically,from the bottom to the top,the shale facies transit from the high carbon shale facies to the low carbon shale facies.(2)regionally,the lithofacies types change greatly,from north West to south East,and the lithofacies type gradually transit to the high carbon siliceous shale.from north west to south east(3)based on organic carbon content,mineral composition,physical property characteristics,reservoir space characteristics,the 7 lithofaciesare synthetically evaluated,and 3 kinds of favorable shale facies are identified:and high carbon siliceous shale,high carbon carbonate-silica shale facies are favorable lithofacies of I class.Medium-carbon siliceous shale facies,medium carbon carbonate-silica shale facies,and favorable lithofacies of Ⅱ 1 class.Medium carbon siliceous-carbonate shale facies,and middle carbon clay shale facies are favorable lithofacies of Ⅱ2 class.Low carbon clay shale facies are advantageous lithofacies of Ⅲ class.The I-type favorable lithofacies are mainly distributed in 1 small layers and are good exploration strata.更多还原