雪峰地区牛蹄塘组海相页岩脆性特征及影响因素——以湘张地1井为例  

Brittleness characteristics and influencing factors of marine shale of Niutitang Formation in Xuefeng region:A case study of Well XZD-1

作　　者：苗凤彬 彭中勤[2] 汪宗欣[2] 张保民 王传尚[2] 巩磊[3] MIAO Fengbin;PENG Zhongqin;WANG Zongxin;ZHANG Baomin;WANG Chuanshang;GONG Lei(Hubei Key Laboratory of Paleontology and Geological Environment Evolution,Wuhan 430205,Hubei,China;Wuhan Center of China Geological Survey,Wuhan 430205,Hubei,China;College of Geosciences,Northeast Petroleum University,Daqing 163318,Heilongjiang,China)

机构地区：[1]古生物与地质环境演化湖北省重点实验室,湖北武汉430205 [2]中国地质调查局武汉地质调查中心,湖北武汉430205 [3]东北石油大学地球科学学院,黑龙江大庆163318

出　　处：《中国地质》2024年第3期743-761,共19页Geology in China

基　　金：中国地质调查局项目(DD20230323);古生物与地质环境演化湖北省重点实验室基金项目(PEL-202307);国家科技重大专项“中扬子高演化页岩气赋存机理与富集规律研究”(2016ZX05034001-002)联合资助。

摘　　要：【研究目的】开展页岩储层脆性评价对页岩气勘探开发中的有利层段优选具有重要意义。【研究方法】基于矿物组成、地球物理测井、岩石力学实验与裂缝发育程度等基础资料,采用矿物组分法与基于地球物理测井的岩石力学参数法对雪峰地区牛蹄塘组海相页岩的脆性特征进行分析与评价,并以此探讨页岩脆性的影响因素。【研究结果】基于石英、长石、黄铁矿和碳酸盐含量的脆性矿物组分法对该区牛蹄塘组页岩脆性的评价最为适用,以区内湘张地1井为例,页岩脆性指数为59.2%~93.8%,平均值74.4%,受沉积环境、成岩演化、埋深、构造作用等因素共同影响。【结论】稳定的深水陆棚-盆地相沉积环境与晚成岩演化阶段决定牛蹄塘组页岩脆性整体较高,该环境下生物成因的硅质、黄铁矿等脆性矿物较为富集,并受沉积时水体深度变化影响自下而上呈现先升高后降低、整体逐渐降低的含量变化趋势,导致页岩脆性及天然裂缝发育程度具有相似的纵向变化规律,三者之间相辅相成;同时,此类脆性矿物与有机质含量具有良好的正相关关系,其对页岩脆性的贡献远大于有机质本身对塑性的加成。此外,岩石力学参数与脆性指数之间的相关性表明,杨氏模量在该区牛蹄塘组页岩脆性评价中的权重高于泊松比。This paper is the result of oil and gas exploration engineering.[Objective]The brittleness evaluation of shale reservoir is of great significance for determining the favorable stratigraphic zone in shale gas exploration and development.[Methods]Based on the basic data of mineral composition,geophysical logging,rock mechanics experiment and fracture development characteristics of Lower Cambrian Niutitang Formation in Xuefeng region,the brittleness characteristics of Niutitang Formation shale are comprehensively analyzed and evaluated by mineral composition and rock mechanics parameter based on geophysical logging,and the influencing factors of shale brittleness are discussed.[Results]The results indicate that the brittle mineral composition based on the contents of quartz,feldspar,pyrite and carbonate is the most suitable method to evaluate the brittleness of Niutitang Formation shale in this region.Taking Well XZD-1 in this area as an example,the brittleness index of Niutitang Formation shale is 59.2%-93.8%,with an average value of 74.4%,which is influenced by sedimentary environment,diagenetic evolution,burial depth,tectonism and other factors.[Conclusion]The stable deep-water shelf basin facies sedimentary environment and late diagenetic evolution stage determine that the overall brittleness of Niutitang Formation shale in Xuefeng region is relatively high.In this sedimentary environment,biogenic brittle minerals such as siliceous and pyrite are more abundant.The content of brittle minerals is affected by the change in water depth during sedimentation,showing a trend of increasing first and then decreasing from bottom to top,gradually decreasing overall.This leads to a similar vertical variation law in shale brittleness and the development of natural fractures,and the three complement each other.Meanwhile,such brittle minerals have a good positive correlation with organic matter content,and their contribution to shale brittleness is much greater than that of organic matter to shale plasticity.In addition,the co

关 键 词：脆性特征 影响因素 牛蹄塘组 页岩气 湘张地1井 雪峰地区 油气勘查工程 

分 类 号：P618.13[天文地球—矿床学]