石油与天然气地质 ›› 2010, Vol. 31 ›› Issue (4): 449-454.doi: 10.11743/ogg20100408

• 石油与天然气地质 • 上一篇    下一篇

层序界面成岩反应规律及其对储层储集物性的影响

  

  1. 长江大学油气资源与勘探技术教育部重点实验室,湖北荆州434023
  • 出版日期:2010-08-28 发布日期:2010-10-20
  • 作者简介:韩登林(1979—),男,博士,储层成岩作用。
  • 基金资助:

    国家自然科学基金项目(40602013,40572078)联合资助。

Diagenetic reaction pattern of the sequence boundary and its impacts on reservoir quality

  • Online:2010-08-28 Published:2010-10-20

摘要:

在三角洲沉积体系层序界面附近进行密集取样并对样品进行详细的岩石学和矿物成分分析后,总结得出层序界面附近的成岩反应规律。层序界面对于成岩反应的制约因素体现在以下三方面:首先,层序界面代表着相对湖平面下降,由此引发大气淡水对储层的充注和淋滤,使得硅酸盐颗粒(主要是不稳定的长石颗粒)普遍高岭石化,在全岩成分上表现为层序界面之下储层中高岭石含量增加;其次,层序界面代表相对较长的沉积驻留时间,这使得在层序界面之下储层内碳酸盐胶结物含量增加;最后,层序界面伴随着可容空间的下降,使得大量细粒沉积物被上覆粗粒沉积物冲刷侵蚀,并通过充填渗滤进入界面之下的地层,而随着埋深的不断增加,这些充填物质在压实作用下成为假杂基,从而表现为层序界面之下泥质杂基含量增大。以上成岩改造对储层储集物性的影响较为明显,其中自生高岭石胶结物对储层储集空间起着建设性作用,而泥质杂基和碳酸盐胶结物对储集物性却有着相对的破坏性作用。

关键词: 假杂基, 高岭石, 碳酸盐胶结物, 储集物性, 层序界面, 成岩作用, 惠民凹陷, 济阳坳陷

Abstract:

Cluster sampling was performed in the vicinity of the sequence boundary within deltaic sedimentary system and a detailed analysis of lithological and mineral composition was carried out on the samples gathered. The results reveal the diagenetic reaction patterns near the boundary. The constraints of the sequence boundary over diagenetic reaction are reflected in the following aspects.First,sequence boundary indicates a relative fall in lacustrine level,which led to flush and leach of meteoric waters and facilitate the kaolinitization of siliciclastic grains(mainly unstable feldspar),thus causing a higher kaolinite content in the bulk composition of the under-lying formation of the boundary. Secondly,the boundary means a relative longer residence time of the sediments,which increasing the content of carbonate cement in reservoirs under the boundary. Finally,the boundary is usually accompanied by a decrease in accommodation space,causing a large amount of fineˉgrained sediments being flushed and eroded by overlaying coarseˉgrained sediments and then leached into the underlying formation. With the increase of burial depth,these filling materials become pseudo matrix under compaction and reflected as a signal of higher content of claymatrix under the boundary. These diagenetic alterations have an obvious impact on reservoir quality. The kaolinite cement,for instance,has a positive effect upon the porosity of reservoirs; while clay matrix and carbonate cement,on the contrary,exert a negative effect upon reservoir porosity.

Key words: pseudo matrix, kaolinite, carbonate cement, physical property of reservoirs, sequence boundary, diagenesis, Huim in Sag, Jiyang Depression

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