石油与天然气地质 ›› 1985, Vol. 6 ›› Issue (1): 91-95.doi: 10.11743/ogg19850115

• 论文 • 上一篇    下一篇

具二氧化碳气顶储层的成岩作用研究

杜韫华   

  1. 胜利油田地质科学研究院
  • 收稿日期:1983-12-10 出版日期:1985-03-25 发布日期:2012-01-16

STUDY OF DIAGENESIS OF RESERVOIR WITH A CO2 GAS CAP

Du Yunhua   

  1. Geological Research Institute of Shengli Oilfield
  • Received:1983-12-10 Online:1985-03-25 Published:2012-01-16

摘要:

通常认为,烃类在储集层中聚集以后,成岩作用便告结束,本文提供了一个烃类聚集以后成岩作用仍在继续进行的实例。

Abstract:

It is usually considered that diagenesis will end by and large as soon as hydrocarbon accumulates in reservoirs.In this paper,a case is presented in which diagenesis still continues after hydrocarbon accumulation.The reservoirs studied are sandstone with a CO2 gas cap located in the western part of Dongying depression.Diagenesis mainly consists of cementation,replace-ment and solution before oil and gas are accumulated.The cement mineral contains mainly dolomite and calcite,and the latter is a soluble mineral.Cementation of the above dolomite and calcite stops while a large amount of dawsonite associated with kaolinite and primary quartz are produced.Poorly permeable sandstone reservoirs are generated because of the decrease of permea-bility caused by diminished porosity in sandstone filled by dawsonite.The generation of dawsonite is closely related to carbon dioxide.In gas-bearingformation,there is more CO2,then the amount of dawsonite is large too,asmuch as 35%;in oil-bearing formation,less amount of CO2 could be found,dawsonite is of less amount too,about 6-8%;in aqueous formation,the amount of CO2 is the least,the amount of dawsonite is the least too.The poor physic 1 properties of the reservoir caused by diagenesis after the accumulation of oil and gas will not be favourable for the high yielding of oil and gas.However,the effect can be eliminated by acidization and hydraulic fracturing,and production can be increased because dawsonite is the aqueous carbonate.