黄铁矿对页岩油气富集成藏影响研究  

Study on the effect of pyrite on the accumulation of shale oil and gas

作　　者：曹涛涛 邓模[2] 宋之光[3] 刘光祥[2] 黄俨然 Andrew Stefan Hursthouse Cao Tao-tao1 , Deng Mo2 , Song Zhi-guang3 , Liu Guang-xiang2 , Huang Yan-ran1 ,Andrew Stefan Hursthouse1(1.Hunan Provincial Key Laboratory of Shale Gas Resource Utilization, Hunan University of Science and Technology ,Xiangtan 411201 ,China ; 2.Wuxi Research Institute of Petroleum Geology, SINOPEC ,Wuxi 214126 ,China ; 3.Guangzhou Institute of Geochemistry ,Chinese Academy of Sciences ,Guangzhou 510640 ,China)

机构地区：[1]湖南科技大学页岩气资源利用与开发湖南省重点实验室,湖南湘潭411201 [2]中国石化石油勘探开发研究院无锡石油地质研究所,江苏无锡214126 [3]中国科学院广州地球化学研究所,广东广州510640

出　　处：《天然气地球科学》2018年第3期404-414,共11页Natural Gas Geoscience

基　　金：国家科技重大专项(编号:2016ZX05061);国家自然科学基金项目(编号:41503033;41603046);国家重点基础研究发展计划"973"项目(编号:2012CB214704)联合资助

摘　　要：黄铁矿在富有机质泥页岩中广泛分布,是泥页岩形成的沉积环境和成岩环境的指示矿物,但其对页岩油气形成与富集成藏影响的研究相对较少。对扬子地区及茂名盆地富有机质泥页岩中黄铁矿的发育形态研究,发现静水缺氧的深水陆棚相和盆地相页岩中草莓体黄铁矿集合体数量多、粒径小;含氧的半深湖—深湖相页岩中发育了大量粒径较大的草莓体黄铁矿集合体;滨岸沼泽和浅水陆棚相页岩中黄铁矿很少存在。黄铁矿含量与TOC、液态烃(S1)含量之间具有较好的正相关性,反映了黄铁矿的形成和含量与有机质含量之间存在密切关系,并能对有机质热解和裂解起促进作用。有机/黄铁矿复合体内发育了丰富的有机孔,能够增加页岩的比表面积,进一步促进甲烷吸附容量的增加。草莓体黄铁矿内较多的晶间孔及其表面、以及黄铁矿被溶蚀脱落后形成的铸模孔能为液态烃、游离气提供较多的储集空间。因而页岩储层中黄铁矿尤其是草莓体黄铁矿是促进有机质生烃演化和页岩油气富集成藏的重要因素,根据黄铁矿在纵横向上的富集程度在一定程度上能够预测页岩油气成藏的有利区。Pyrite is widely distributed in organic matter rich mudstones,which is regarded as an indicator mineral of sedimentary and diagenetic environment. However, the study on the effect of pyrite on shale oil and gas accumulation is relatively poor.The study on the morphologies of pyrite in organic-rich shales from Yangtze region and Maoming Basin reveals that （1）pyrite framboid in shales formed in hydrostatic deep- water shelf and basin facies is plentiful and has a small size, （2）the shale formed in oxygenic semi-deep to deep facies has a large number of large-sized framboid pyrites, and （3）there is few or no pyrite in shale formed in shoreland-swamp and shallow shelf environments.Pyrite has positive correlations with TOC and liquid hydrocarbon （S1）contents,reflecting that the formation and content of pyrite is closely related to or ganic matter and pyrite could promote the pyrolysis and cracking of organic matter.Abundant organic pores are developed in the organic/pyrite assemblages,which could significantly increase the specific surface area and then increase methane sorption capacity of shale.A large amount of intergranular pores in pyrite fram boids and their surface areas and the moldic pores related to the dissolution of the pyrites are able to pro vide large space for liquid hydrocarbon and free gas. Therefore, the pyrite, especially framboid pyrite, is an important factor of the evolution of organic matter and hydrocarbon accumulation in shale reservoir, and the favorable area of shale gas could be predicted according to the distribution of pyrite in vertical and hori zontal directions.

关 键 词：草莓体黄铁矿 沉积环境 生烃演化 有机孔 晶间孔 页岩油气富集 

分 类 号：TE122.3[石油与天然气工程—油气勘探]