Response of The Typical Fresh Formation Water Chemical Fields in Opening Lacustrine Faulted-Basin： A Case Study of Paleogene System in Zhanhua Sag

详细信息   

• 责任者：Chen Zhonghong (College of Earth Science and Technology ; China University of Petroleum ; Qingdao ; Shandong 266580 ; China) ; Zha Ming
• 刊名：Chinese Journal of Geology
• 出版年：2012
• 卷期：47(2)
• 关键词：油田水 ; oil field water ; 水化学 ; hydrochemistry ; 水岩作用 ; water-rock interaction ; 渤海湾盆地 ; Bohaiwan Basin
• 页码：p.387-405
• 图表：illus., 1 table, 26 refs.
• 分类号：1003
• issnNo：ISSN0563-5020
• isbnNo：CN11-1937/P

摘要

On the basis of calculation and analysis of 1 160 testing datum including salinity, formation water types, content of each ion such as Cl^-, Na⁺ , Ca²⁺ , Mg²⁺ , HCO₃^-, SO₄^2- , and physical property of crude oil such as density, viscosity, freezing point, paraffin content the formation water chemical field of the Paleogene system of Zhanhua sag was investigated. The results showed the obvious differences to the characteristics of the sealing and stagnating formation water chemical field of the Paleogene system of Dongying sag,the formation water chemical field of the Paleogene system of Zhanhua sag had typical characteristics of opening lacustrine faultedbasin：the content of total salinity and ions were low （total salinity averaged 10 g/L）, the characteristics of cyclic section were obvious, and the characteristics of circle in plane and zonality in section were not obvious; mainly developed the type of NaHCO3 formation water （proportion attained 80% ）, and the value of rNa⁺/rCl^- and [ rHCO₃^-＋rCO₃^2- ]/rCl^- were high （the average values respectively higher than 1.0 and 50）, which displayed the stronger metamorphic process and alternation of the formation water; the low value of rCl^-/r（HCO₃^-） of most samples of the type of NaHCO₃ formation water demonstrated the noticeable dissolution and corrosion,and the negative correlation between the contents of Ca2 and Mg²⁺  from some samples manifested the dolomitization was mainly occurred in the type of CaCl2 formation water; the deficiency of Na⁺ and excess of Ca were not remarkable, and the relation of them presented Ca = 0. 997 4 （ Nadeficit ） ＋29. 355 （ R² = 0. 859 6） ; the physical property of crude oil had marked response, and most secondary high viscosity oil samples were from the formation water with low salinity, which indicated the viscosity of crude oil in the history of hydrocarbon migration and accumulation in the opening environment. The macroscopic typical characteristics of formation water chemical fields in opening lacustrine faulted-basin not ruled out some sealing and stagnating formation water chemical fields in some areas such as Bonan subsag.