辽东湾地区孔隙演化的机理

孔隙演化机理对研究中深层储层控制因素、预测中深层有利储层及中深层隐蔽油气藏勘探具有重大意义.通过辽东湾地区的辽中凹陷、辽西凸起及辽西凹陷孔隙演化分析表明,辽东湾地区凹陷和凸起的孔隙演化阶段是一致的,即在总体降低的背景中存在4个次生孔隙发育带,所不同的是凹陷的次生孔隙发育带相对凸起深,次生孔隙发育带与成岩演化、有机质的演化、粘土矿物的转化、超压、油气的早期充注密切相关.探讨了孔隙演化过程中孔隙度降低和次生孔隙发育的机理,认为辽东湾地区4个次生孔隙发育带的形成主要源于有机酸对碳酸盐胶结物、长石、岩屑的溶蚀以及超压和早期油气充注对孔隙的保护.

Mechanism of the Pore Evolution in Liaodong Bay Area

The mechanism of pore evolution is significant to the research of deeper reservoir controlling factors,predicting the favorable reservoir and subtle reservoirs exploration in middle-deep strata.The pore evolution analysis of Liaozhong sag,Liaoxi uplift and Liaoxi sag in Liaodong Bay area were analyzed,which indicates that there are four similar secondary pore zones during the whole porosity reduction current background in different sags and uplifts.The only difference is that the depth of secondary pore development in sag is deeper than that in the uplift,and the secondary pore zone is related to the diagenesis,organic evolution,clay mineral evolution,overpressure and early oil and gas injection.This paper discusses the mechanism of the porosity loss and the secondary pores development,and the emphasis is placed on the analysis of the relation among the pore evolution,diagenesis,organic evolution,clay mineral evolution,early oil and gas injection and overpressure.On the basis of the discussion,it is pointed out that the formation of the four sencondary pore development zones is due to the dissolution of the carbonate cement,feldspar and the clastic debris by the organic acid,and the protection from the overpressure and the early oil and gas injection.